Why no 700HP in the FF Roadster

[KolonelKraig]

I have often read on this forum that putting 700HP motor into the FF Roaster is ridiculous and will not work on the street.

Can anyone explain this to me? I own a Yamaha V-Max. This bike makes life worth living! LOL I was looking to the Roadster to do the same. My V-Max has 197HP in a 684lbs bike. That is roughly 3.5 pounds per HP. Putting a 700HP motor into a 2,200 pound FF Roadster is 3.1 pounds per HP. What am I missing?


THX Guys!

[Pylons]

account for your weight and re-do the numbers

the way I look at it is my LS3 C6 vette with 430-ish hp was pretty much as much as I could ever want or use on the street...the "measley" 360hp I'm putting in my car will make better power-to-weight than that car

I'd agree that 700hp is ridiculous for the street...I have no idea when you'd be able to use it.

[Gordon Levy]

I've done it and it's a lot of fun but there is a ton of additional parts and set up for it to work well. You need to think along the lines of a new rider on a 200hp bike. It just doesn't end well. Same thing about hi hp on these cars. Approached with proper diligence it really isn't a problem.

[skullandbones]

I guess you can handle the 200 hp bike. That's a given since you are still posting. The real problem with a monster hp roadster is two fold. The short wheelbase in combination with the hp and the driver's experience. I have limited experience as I had a 500+hp BBC in a "roadster" of different variety. The saving grace for this hot rod was it had a 1967 Corvette chassis under it with a 98 inch wheelbase. So it was heavier and longer wheelbase than the FFR roadster. It also had 14 inch wide tires. It was a little like driving on ice but still manageable. If you take that FFR formula with 90 inch wheelbase, lighter, and add 200 hp, that's really pushing the envelope. I think that's why some C***** replicas have extended wheelbases. That extra few inches of wheelbase can make the car much more forgiving. At least for me, driving a short wheelbase car is more challenging than anything I've driven in the muscle car class because the added hp makes for unpredictable results. WEK.

[tirod]

While YOU may have the experience and habits to handle that hp to wt ratio, the average builder does not. In fact, postings and video uploads generally reflect a complete lack of knowledge by the average builder.

There is a very pointed commentary when you compare the early origins of Shelby Cobra - as race track driving instruction - and the vendors on the forum today. None. Nada. Not one driving course sponsor. They are out there, they literally have their roots based on Shelby starting his course, but the builder's here never discuss it.

Get on some AR forums and the subject of taking a weekend Carbine course, learning tactics, and actually shooting over 1,000 rounds in three days is common. Many who do say it was highly informative and barely scratched the surface.

Nobody talks about taking your car to the track much here unless they are actually competing. It's as if the human male is in complete denial. You CANNOT expect a car built in the garage to be properly set up and handle correctly on the street, much less at speeds up to 140mph on a track, without actually taking it there and learning what it will do. It's not going to be 100%, and neither is the driver.

That is why we see Cobras fishtailing out of control all over the country, banging curbs, crashing thru garage doors, and sliding sideways into trees with catastrophic results. It doesn't help with all the over the top descriptions of them being nearly lethal and uncontrollable machines only a real man can drive. It attracts the well heeled older man who has constantly had to put off actually owning or driving one until he could afford it. Unfortunately, he's past his prime and it's pretty late in life to learn it all - that requires setting aside their ego and realizing they are just another newbie like any twentysomething.

Most of these cars are just weekend cruisers, the responsible owners realize that and keep it toned down. But, some can't, and that is exactly why the insurance rates are what they are - superbike or supercar. Too many elevate the risk pool because they have no clue what they are doing behind the wheel.

Nope, "nobody" needs 700hp when the 450hp cars are already careering about smacking into fixed obstacles.

[KolonelKraig]

I appreciate the incite guys!

[OCCPete]

Here's an 800hp CSX4000 Shelby:

http://pictures.topspeed.com/IMG/crop/201406/800-hp-shelby-cobra-_600x0w.jpg

[KolonelKraig]

MAN ~ ya just made me cry!

[Plebeian]

If you're talking 700 fwhp there are quite a few roadsters running that and doing just fine WHEN properly set-up. If your talking rwhp, most of those I know of that are running over 700 are turbocharged and then it becomes a question of what speed you can hook up. At a little over 800 rwhp Steve Berg's street driven Cobra does 0-125 mph in 5.5 seconds (1/8th mile). Bear in mind to truly compare a bike to a car you need to factor in weight with driver for both to get a fair comparison. Cheers.

[KolonelKraig]

If you're talking 700 fwhp there are quite a few roadsters running that and doing just fine WHEN properly set-up. If your talking rwhp, most of those I know of that are running over 700 are turbocharged and then it becomes a question of what speed you can hook up. At a little over 800 rwhp Steve Berg's street driven Cobra does 0-125 mph in 5.5 seconds (1/8th mile). Bear in mind to truly compare a bike to a car you need to factor in weight with driver for both to get a fair comparison. Cheers.

The power plant I was looking at was the Edelbrock Supercharged 5.0L Coyote Crate Engine (700 HP & 606 TQ).

Thoughts guys?

I know I am going to have to modify the hood for clearance of the low profile charger. I was looking at a Super Snake like hood like the one pictured here:
30636

[carbon fiber]

Don't forget the Racelogic traction control. I'm going to use it in my GTM build.

[KolonelKraig]

I was wanting to use the 6 speed to get "decent" gas millage on the interstate. From what I have been reading I will have to use the IRS in order to fit the 6 speed. Some have said that the IRS will not handle the 700HP. Is that true? Is there a special pack/kit I can purchase for the IRS to beef it up?

[David Hodgkins]

I was wanting to use the 6 speed to get "decent" gas millage on the interstate. From what I have been reading I will have to use the IRS in order to fit the 6 speed. Some have said that the IRS will not handle the 700HP. Is that true? Is there a special pack/kit I can purchase for the IRS to beef it up?

Kraig, what is you timeline for purchase of the kit?

:)

[skullandbones]

Don't forget the Racelogic traction control. I'm going to use it in my GTM build.

I find it sort of curious that I've almost never heard of a roadster set up with traction control. I think I did talk with a fellow at HB and he said he had a line lock but the system he had also had traction control capabilities. However, I don't think he had it hooked up. It just seems like a good idea.

WEK.

[KolonelKraig]

I am looking to purchase everything at one time in about 6 months when I am done with DC and return to the Southwest Border.

[KolonelKraig]

I find it sort of curious that I've almost never heard of a roadster set up with traction control. I think I did talk with a fellow at HB and he said he had a line lock but the system he had also had traction control capabilities. However, I don't think he had it hooked up. It just seems like a good idea.

WEK.

I know I for one kind-a want a purest feel to the car... no power anything/no computer assist.

[Blue MK3]

Kraig, it sounds like your mind is made up and set on 700hp. If so, why come here and ask for support for your decision? You read what the others say. Hope we don't read about you in the morning news.

[David Hodgkins]

Kraig, it sounds like your mind is made up and set on 700hp. If so, why come here and ask for support for your decision? You read what the others say. Hope we don't read about you in the morning news.


I think it's a good thing he is asking and it sounds to me like he asked a legit question, which was NOT "should I run 700HP", but rather "why don't you guys run 700HP".

Knowledge gain is a huge reason why this forum exists and I'd NEVER want to discourage someone from asking questions, whether they be basic or something highly nuanced and technical.

:)

[billjr212]

Kraig - it's your car and your money, so definitely do what you want. I will throw in my 2 cents though since you put it out there.

(1) A history of cars like that (700 hp) combined with inexperienced "pilots" are the reason a lot of insurance companies won't touch these things;
(2) Might be worth it to drop your butt in the passenger seat of one with 400 hp at the 'drag races' at next year's London Cobra Show to see just how far even that amount of power will get you (or any other way you can find to get a first hand impression);
(3) As a few people mentioned, add rider/driver weight to get true pounds per HP figure - assuming 200 pound driver, you would get to the same ratio with "just" 535 flywheel horsepower;
(4) the way a motorcycle and a car put down power and the medium that they use to do so (tires) and are wildly different, so comparing them as you've suggested above won't get you anywhere.

Best of luck with your planning and build!

[edwardb]

While YOU may have the experience and habits to handle that hp to wt ratio, the average builder does not. In fact, postings and video uploads generally reflect a complete lack of knowledge by the average builder.

There is a very pointed commentary when you compare the early origins of Shelby Cobra - as race track driving instruction - and the vendors on the forum today. None. Nada. Not one driving course sponsor. They are out there, they literally have their roots based on Shelby starting his course, but the builder's here never discuss it.

Get on some AR forums and the subject of taking a weekend Carbine course, learning tactics, and actually shooting over 1,000 rounds in three days is common. Many who do say it was highly informative and barely scratched the surface.

Nobody talks about taking your car to the track much here unless they are actually competing. It's as if the human male is in complete denial. You CANNOT expect a car built in the garage to be properly set up and handle correctly on the street, much less at speeds up to 140mph on a track, without actually taking it there and learning what it will do. It's not going to be 100%, and neither is the driver.

That is why we see Cobras fishtailing out of control all over the country, banging curbs, crashing thru garage doors, and sliding sideways into trees with catastrophic results. It doesn't help with all the over the top descriptions of them being nearly lethal and uncontrollable machines only a real man can drive. It attracts the well heeled older man who has constantly had to put off actually owning or driving one until he could afford it. Unfortunately, he's past his prime and it's pretty late in life to learn it all - that requires setting aside their ego and realizing they are just another newbie like any twentysomething.

Most of these cars are just weekend cruisers, the responsible owners realize that and keep it toned down. But, some can't, and that is exactly why the insurance rates are what they are - superbike or supercar. Too many elevate the risk pool because they have no clue what they are doing behind the wheel.

Nope, "nobody" needs 700hp when the 450hp cars are already careering about smacking into fixed obstacles.

Seriously? No choice but to respond. At the very least, the OP (a relatively new forum member with a low post count) should get a little more balanced input. I submit:

- Many times on this forum and the other one, guys recommend track time and/or instruction to learn the limits of their cars. Even if they don't plan to complete. "Nobody talks about taking your car to the track unless they are actually competing..." is just plain wrong. Period.

- I just attended the London Cobra Show. (Have you ever attended an actual event BTW?) There were 150+ cars. Every kind of car from low power to high power. Every kind of driver young to old. I was there the whole four days. With all the events, cruises, etc. literally thousands of miles driven. Didn't observe a single instance of "fishtailing out of control all over the country, banging curbs, crashing thru garage doors, and sliding sideways into trees with catastrophic results." Does it happen? Of course. Just like any high powered performance car. Any more than any others or all the time? No. Get a grip.

- Also related to the London Cobra Show, part of the event was an auto cross event on Sunday, and a 2-day instruction and driving course at Mid-Ohio the following week. This was widely discussed, encouraged, and many attended. Some race regularly, but many do not. I talked to a bunch of guys that were attending or have attended in the past. And they're not race drivers. Just regular guys with real jobs that want to learn how to drive better. Again, "Nobody talks about taking your car to the track"? I don't think so. Actual evidence suggests otherwise.

- I've got 4,000+ miles of seat time in my Mk3 Roadster. Not a ton (many have much more) but enough to have real world experience about driving one of these cars. I've done several 1/8 miles runs with it, but the rest just street and highway cruising. It's plenty fast and very quick. But it's not the highest HP out there by any means. Around 375HP. While I respect it greatly, and am very careful that I don't get over my head, I'm pleasantly surprised how easy it is to drive and how solid it is on the road. I've only let me two sons drive it, but I've taken many people for rides. All say the same thing.

- "It attracts the well heeled older man who has constantly had to put off actually owning or driving one until he could afford it. Unfortunately, he's past his prime and it's pretty late in life to learn it all - that requires setting aside their ego and realizing they are just another newbie like any twentysomething." You do realize this is insulting to nearly anyone who would read it? All I can think to say is why are you even posting a statement like this?

To the OP, I would respond as follows: If you want to get into a HP bragging contest, go for it. As Gordon already stated, properly set up might be OK. But everyone I've spoken with (and my actual experience) suggests the following: These cars don't need 700HP to be fun. And I agree with several of the other comments that your margin for error at that HP is very low. At 300-400-500HP they will take your breath away. Plus the ultra high horsepower typically makes less than a friendly streetable drive. These cars are an absolute blast to drive, but if driving is a chore (heavy clutch, poor idle, high RPM torque curve, etc.) you may be missing out on a lot of the fun. Plus high HP drives up the cost in every area. My personal recommendation is to dial it back.

[KolonelKraig]

First off, I admire you guys! You have done what I have always dreamed of doing for almost 40 years. You are the proud owner of a Roadster (Co_ _ _)!!! I reached out to you – not to start fight amongst lifelong friends and enthusiast for our chosen steed, but instead with my hat in my hand for your life experiences with this car.

I value every input on this thread and take them all to heart. I just wanted to see if there was something like, “over 500 lbs. of torque will twist/bend the frame” or “there is no rear end that will fit this chassis to handle that much power”.

Ya see gentlemen, I am a simple Border Patrol Agent by trade and a reserve sergeant in the Air Force that has now reached his retirement. I have been savings for years and am seeking your advice because this is a one shot thing. I will never have the funds to build another car.

With that being said – I am of the mindset, if you are going to be a bear, be a panda!!! Pandas chew bamboo into slivers and live off of swallowing bamboo slivers! Take that grizzly!... I want to build the highest performing machine I can for the funds I have saved up.

Once again gentlemen, my hat goes off to all of you, and from the bottom of my heart – thanks for ALL your input.

[edwardb]

First and most importantly, thank you for your service. I have close personal knowledge (I'll leave it at that) of the BP, including the training, what it's like especially the last months, and the hard work you guys do. Congrats to all our hard working BP for just celebrating 90 years protecting our borders.

For this thread, there are some good comments here from people with real experience. I would only say don't equate "highest performance" with "highest horsepower." There's much more to it than that. It's the entire package that matters. I would really encourage you to reach out to people in your area that you can see in person, take a ride, etc. Most (certainly including me) are happy to do that whenever asked. That more than anything else IMO will help you to make some of the necessary decisions.

Good luck with your retirement and whatever you choose to do.

[bansheekev]

I'll make this simple - my MKIV / Coyote Aluminator (normally aspirated) will light up the tires pretty much at will in 1st, 2nd, and 3rd with 355's in the rear. I know guys with 871 blown big block Camaros that get in this thing and say "oh sh**".

Just raw information, do with it what you please. Taking a ride in one is probably your next step to quantify your expectations. What does xxx horsepower/torque feel like in this kind of car? I've had plenty of high horsepower Mustangs over the years and from the very first drive it was obvious that this car is in another league after shedding 1500-1700lbs off of the Mustangs I was used to.

Kevin


First off, I admire you guys! You have done what I have always dreamed of doing for almost 40 years. You are the proud owner of a Roadster (Co_ _ _)!!! I reached out to you – not to start fight amongst lifelong friends and enthusiast for our chosen steed, but instead with my hat in my hand for your life experiences with this car.

I value every input on this thread and take them all to heart. I just wanted to see if there was something like, “over 500 lbs. of torque will twist/bend the frame” or “there is no rear end that will fit this chassis to handle that much power”.

Ya see gentlemen, I am a simple Border Patrol Agent by trade and a reserve sergeant in the Air Force that has now reached his retirement. I have been savings for years and am seeking your advice because this is a one shot thing. I will never have the funds to build another car.

With that being said – I am of the mindset, if you are going to be a bear, be a panda!!! Pandas chew bamboo into slivers and live off of swallowing bamboo slivers! Take that grizzly!... I want to build the highest performing machine I can for the funds I have saved up.

Once again gentlemen, my hat goes off to all of you, and from the bottom of my heart – thanks for ALL your input.

[Jeff Kleiner]

Tirod,
Where do you come up with this stuff?

Jeff

[Scud67]

Yes, believe me... take a ride in one. I do a "ride along" every year at the Woodward Dream Cruise in Detroit in August. I got a ride in a 535 rwhp (other manufacturers replica) MK3.... white knuckle ride. Quickest car I have ever been in and I've been in some serious cars. 500 hp is more than enough.

[Plebeian]

I was wanting to use the 6 speed to get "decent" gas millage on the interstate. From what I have been reading I will have to use the IRS in order to fit the 6 speed. Some have said that the IRS will not handle the 700HP. Is that true? Is there a special pack/kit I can purchase for the IRS to beef it up?

79PACECAR on the other forum runs over 850 rwhp thru the IRS on his FF Roadster. He boxed the front IRS mount, has a steel housing with billet caps using studs, Control Freaks cover, Auburn E-locker, DSS level 5 axles, poly bushings in tripod arms, and aluminum front housing bushings. Probably way overkill for your situation though.

[j.miller]

700 HP is $20,000 ...350HP is $7,000.......Spend the diff of $13,000 dollars on performance driving school and you'll have you're wish of beating 98% of anything on the road and surviving......Start with 700HP and the best you can hope for is a wrecked car....gets worse from there.

[jimgood]

Dude, build your dream car, for Pete's sake! You want 700hp? Do it. You will enjoy the challenge of learning to drive the crap out of it!

Yes, these cars are fun with even "low" hp numbers. But that's what people say about Miatas. That gets old for some people. Some people want a car that can push through the aerodynamic brick wall at 140 mph.

[carbon fiber]

I find it sort of curious that I've almost never heard of a roadster set up with traction control. I think I did talk with a fellow at HB and he said he had a line lock but the system he had also had traction control capabilities. However, I don't think he had it hooked up. It just seems like a good idea.

WEK.
It may be both the expense and the fact that some consider t/c a "nanny" and "real men" don't need 'em. If you've got a light/high hp car, (plus short wheelbase on the roadster) it takes it from something that's a white knuckle experience to something that's enjoyable to drive. (Plus you're going faster when the tires aren't spinning) It won't hurt when you get caught in the rain either. The Racelogic t/c is adjustable as well. It can be turned off completely as well, for burnouts, doughnuts and such.

[Plebeian]

Start with 700HP and the best you can hope for is a wrecked car....gets worse from there.

Jeff, perhaps for you that statement is true, but that's a pretty broad brush your painting, lol. Like our thread starter, I was used to riding fast motorcycles before transitioning to a Cobra. I wanted something with a little more protection and be able to take passengers along. I've been running more than 700 fwhp for over 7 yrs now and it cont to be a joy for me. Furthermore, all the turbocharged roadster guys I know (we're about a 1/2 dozen) have managed driving their cars just fine. I bet that supercharged Coyote would have good driving manners, and you have this thing called a gas pedal (and common sense) to control it. The car does have to be setup properly. Cheers.

[Pylons]

I want to build the highest performing machine I can for the funds I have saved up.
Then my advice would be to take the $$$ that it takes to go from 450hp to 700 hp and spend it on something that will actually make a difference on the street.

I'm coming at this less from a "danger" standpoint (although I think that's a legitimate argument...even for skilled drivers...I've got a decade of pretty serious autocross experience, but my Corvette put me in a couple "code brown" situations on the street) and more from a "diminishing returns" angle. For the street, adding on those last 200-250hp is just hardly ever going to make a material difference.

[Plebeian]

KolonelKraig, this video is from about 4 yrs ago on a track that is nonprepped and dusty. I'm guessing around 750 fwhp. As you can see, my car is very controllable, 1st pass I'm leaving off idle. It's all in the set-up and driver due dilligence. http://www.youtube.com/watch?v=AQtmrxaRVTg

[skullandbones]

KolonelKraig, this video is from about 4 yrs ago on a track that is nonprepped and dusty. I'm guessing around 750 fwhp. As you can see, my car is very controllable, 1st pass I'm leaving off idle. It's all in the set-up and driver due dilligence. http://www.youtube.com/watch?v=AQtmrxaRVTg

It's too bad we don't have a dedicated "sub forum" for performance based info on the roadsters. The more experienced drivers could save some people with less seat time and racing experience a lot of anxiety instead of having to learn how these cars handle thru the "school of hard knocks"! I know many of the build ideas I've gotten over the years have saved me hours of frustration so this could be accomplished in a similar manner. WEK.

[rich grsc]

Seriously? No choice but to respond. At the very least, the OP (a relatively new forum member with a low post count) should get a little more balanced input. I submit:

- Many times on this forum and the other one, guys recommend track time and/or instruction to learn the limits of their cars. Even if they don't plan to complete. "Nobody talks about taking your car to the track unless they are actually competing..." is just plain wrong. Period.

- I just attended the London Cobra Show. (Have you ever attended an actual event BTW?) There were 150+ cars. Every kind of car from low power to high power. Every kind of driver young to old. I was there the whole four days. With all the events, cruises, etc. literally thousands of miles driven. Didn't observe a single instance of "fishtailing out of control all over the country, banging curbs, crashing thru garage doors, and sliding sideways into trees with catastrophic results." Does it happen? Of course. Just like any high powered performance car. Any more than any others or all the time? No. Get a grip.

- Also related to the London Cobra Show, part of the event was an auto cross event on Sunday, and a 2-day instruction and driving course at Mid-Ohio the following week. This was widely discussed, encouraged, and many attended. Some race regularly, but many do not. I talked to a bunch of guys that were attending or have attended in the past. And they're not race drivers. Just regular guys with real jobs that want to learn how to drive better. Again, "Nobody talks about taking your car to the track"? I don't think so. Actual evidence suggests otherwise.

- I've got 4,000+ miles of seat time in my Mk3 Roadster. Not a ton (many have much more) but enough to have real world experience about driving one of these cars. I've done several 1/8 miles runs with it, but the rest just street and highway cruising. It's plenty fast and very quick. But it's not the highest HP out there by any means. Around 375HP. While I respect it greatly, and am very careful that I don't get over my head, I'm pleasantly surprised how easy it is to drive and how solid it is on the road. I've only let me two sons drive it, but I've taken many people for rides. All say the same thing.

- "It attracts the well heeled older man who has constantly had to put off actually owning or driving one until he could afford it. Unfortunately, he's past his prime and it's pretty late in life to learn it all - that requires setting aside their ego and realizing they are just another newbie like any twentysomething." You do realize this is insulting to nearly anyone who would read it? All I can think to say is why are you even posting a statement like this?

To the OP, I would respond as follows: If you want to get into a HP bragging contest, go for it. As Gordon already stated, properly set up might be OK. But everyone I've spoken with (and my actual experience) suggests the following: These cars don't need 700HP to be fun. And I agree with several of the other comments that your margin for error at that HP is very low. At 300-400-500HP they will take your breath away. Plus the ultra high horsepower typically makes less than a friendly streetable drive. These cars are an absolute blast to drive, but if driving is a chore (heavy clutch, poor idle, high RPM torque curve, etc.) you may be missing out on a lot of the fun. Plus high HP drives up the cost in every area. My personally recommendation is to dial it back.

Thanks, well said. That was more polite that my response would have been. Mr i know everything has had foot in mouth more than once

[j.miller]

Plebeian, You are correct. That was a quick broad stroke and unfair. I have not driven a roadster with 700 but I have driven several in the 500's and one an honest 650. On the track, no problem. On the street it is just no fun (for me) to much work . It's the unexpected that is the problem with big power. On the track everyone is on the same page and direction. On the street you have things happening from all directions......actually, Kolonel asked a question(I've been in this game a long time and have seen it.) I gave my opinion and I'm good with that...da Bat

[Plebeian]

J.Miller, I partially agree with you in the sense that if you make that hp with a wild cammed snarling beast type build then street driveability can be a lot of work and not a lot of fun. No doubt you've seen more of these cars then most of us. Cheers.

[Carlos C]

I have often read on this forum that putting 700HP motor into the FF Roaster is ridiculous and will not work on the street.

I'm building a Coupe using my race/street donor car. The engine makes 603 RWHP. The Mustang was comfortable while driving on the street. The only thing I had to do differently was to never use 1st gear on my T-56, unless I was racing it (the street tires would always break loose at every stop light/sign, no matter how well I try to feather it). I drove this car from VA to FFR's Open House in 2006 and back, with no issues.

My point here is that depending on your power train set-up (i.e. camshaft, fuel delivery, rear end gears, converter stall speed if using an automatic tranny, etc.), 700 HP can be street-able. If you're not planning to race the car, it'd basically be a waste of money, not to mention that you'd be a regular at every gas station in your area. I'm using my engine on the Coupe, simply because I already had it. If I were to buy or build an engine, I wouldn't build it with that much power; it's not necessary on a car that weighs half a ton less than a Mustang.

Regardless of how much/little horsepower the engine makes, you will have tons of fun driving it. If you decide to use the 700 HP engine, keep the pedal off the floor, be prudent, and you'll be fine.

Carlos

[CraigS]

I don't see any problem w/ 700hp. You have the motorcycle experience so I will assume you have some idea about approaching the limits w/ some care. The main issue w/ an FFR is traction. Personally, I don't want so much hp that I can't floor it in 2nd gear. So I would have some discussions w/ Gordon Levy (posted above)and Wayne Presley (of Very Cool Parts because he has also built a few high HP cars) about how to set the car up tire (probably drag radials) and suspension wise. There will be two parts to the suspension discussion. One will be how to tune it as in spring, shock and swaybar rates. The other, probably more important, will be how to make it last which will heavily influence which type suspension you choose. Lastly search here and the other forum for Eric Treves who built a high HP super(turbo?)charged car he called the Green Lantern. Reading his build thread I think will be quite helpful. Welcome and good luck.

[Lynnhowlyn]

For what it's worth, Dave Smith made a comment at the Huntington Beach show a few weeks ago about putting too much horsepower in one of these cars ... that it can be like "cutting butter with a chain saw".

HTH

Lynn

[Plebeian]

Lynn, he also says that 350 hp is perfect in these cars and then runs 500 hp in his, lol.

[skullandbones]

It's interesting that most of the very high HP roadsters I've seen in person and on video are single purpose more or less. That is, they are dedicated to drag racing or AX or track (even if they are driven on the street some). I don't know how many there are out there but I would guess, not that many. So if you build a 700+ HP car and don't have a goal in mind, that would be strange. A lot of resources spent for "what" purpose? Maybe bragging rights and occasional high risk moments on the street would justify it for some people. The one I've ridden in that was 630+ HP (NA) was automatic with drag slicks. It will go very fast in a straight line and 10 sec + in the quarter. That was OK but sure wouldn't want it for myself. If you have one of those, it takes a special person to handle it and know when to let it go. I'm glad there are serious limitations to the extreme HP goal such as money. If there wasn't, it would be hard to say how many videos you would see of crashed C*****s out there. I've seen more than my share as it is. WEK.

[schu7076]

I was at the London cobra show with the red cobra and twin turbos , 700 HP is easy to handle in these cars IF YOU KNOW HOW TO SET IT UP, (straight line can't comment in curves ).... Its not for everyone . How much are you willing to spend ? Horsepower costs and with such a light car your going to have to run good engine management and turn it down when the car can't handle it . When you start entering this level with a car like this you have to be on guard at all times and things happen fast. Self control is important .

[Pylons]

I was at the London cobra show with the red cobra and twin turbos , 700 HP is easy to handle in these cars IF YOU KNOW HOW TO SET IT UP, (straight line can't comment in curves ).... Its not for everyone . How much are you willing to spend ? Horsepower costs and with such a light car your going to have to run good engine management and turn it down when the car can't handle it . When you start entering this level with a car like this you have to be on guard at all times and things happen fast. Self control is important .
well, driving on the street involves some turning...

and if it were "easy to handle" you wouldn't "have to be on guard at all times"

[KolonelKraig]

Again guys, from the bottom of my heart ~ THX!

The "spirited" discussion here makes me all the more want to get stated on this beast!

I will keep ya'll posted on the progress and I am sure reaching out to the gurus here for your learned advice.

Wish me luck!

[schu7076]

Driving on the street does involve turning so slow down in the turns ....I was referring to straight line acceleration

[tirod]

I would only say don't equate "highest performance" with "highest horsepower." There's much more to it than that. It's the entire package that matters.

As much as we may agree to disagree, this is something that EdwardB is right about. Unfortunately, many don't build balanced cars.

It was asked where do I come up with this stuff? Reading posts here and on TOS. You collectively tell me what is wrong with the cars, on a daily basis. In large part, it's because the effort to build one isn't well sorted out, and thus, the reports of owners who are injured, and the numerous associated videos of people driving kits into curbs, parked cars, into garages, and trees.

I don't have to make anything up. I just keep my mind open and recognize that a car with 3.5 pounds to hp ratio is NOT for the average driver. And who replies that they don't have issues also say they took the time to sort them out, and have extensive experience with them.

That is not average. That is a hard earned skill and you don't get it by wishing. With the number of professionals who daily post their career stories about things becoming a disaster at work, would you then say that just anybody who walked in off the street could do your job?

Of course not. And no one off the street instantly qualifies just because they can afford the entry fee. We read a large number of questions from builders who are having difficulty getting the basics right with cooling systems, alternators, starters, etc. And it's been discussed more than once that building a kit straight off donor parts will not result in something that can or should be driven hard on the track. The brakes alone are all wrong for the car.

It should be no surprise that along with the lack of a drivers training sponsor, that other facets of track handling of the car are also absent - like, what sway bar and settings would be optimal. Something taken for granted as subject of discussion on Mustang forums or in Pro Touring conversation is notably absent here.

The main focus tends to concentrate on the engine - when the reality is that Carroll Shelby spent more time developing the rest of the drivetrain and chassis once the motor was dropped in. It made 350 hp due to the technology of the day, but a reliable limit was needed to survive literally days of harsh conditions at speed. Dropping in a 700 hp motor would have been a disaster simply because they would have never gotten past the broken drivetrain parts to keep it on the track.

Same for today. Drive a 700hp car hard consistently, it's going to take a 700hp transmission, driveshaft, rear gear, axles, hubs and brakes to stop it. Those ain't donor brakes, and with the loss of 1000 pounds of dead weight and the huge increase in performance, even Cobra Mustang brakes aren't going to cut it.

That is the reality of what gets all too readily glossed over. Dropping a 700hp motor in the kit won't be any different than dropping 400hp into a 99 Forester - the allied parts weren't ever designed to handle the load, and it's going to be one breakdown after the other if balance isn't maintained. And that understanding is only a nice to have if 700hp driving experience doesn't go along with it.

Plenty of conversations on record that the 90" wheel base of the Cobra is not conducive to high speed handling. And plenty of owners who report the 427 was more than a handful in normal traffic, much less on the track. Please note, it's a matter of historical record that the improvement in track time from 289 to 427 was often just a second or two. The unbalanced handling and poor response hurt the 427 more than helped.

We seem to celebrate the myth of the 427 S/C more than the facts, and that was the 350hp 289 is what kicked Ferrari out of the FIA Championship. The 427 didn't do that, but for some reason, it's gets the lion's share of attention. What has happened is the typical oneupmanship in male circles - if some is good, more is better.

On the street, almost any kit will outperform 99% of the traffic it's in, but, we just can't. So, we measure ourselves against the others in our class, and that is where the constant drumbeat of being the Alpha male creates the demand for 700hp. Let's not forget that 700hp was an impossible dream not only in the 1960s, but right thru the '70s, 80's and even 90's. Nobody got that kind of power for a hobby car built to just cruise around. That should be recognized and considered before jumping off the deep end into uncharted waters.

As the amount of hp has risen, so has the bar on experience level. And that bar makes it even more important to get the appropriate training and experience. We don't hand an M4 and bandolier of ammo to a new recruit and send him in combat on Day 1, we don't give future surgeon a scalpel and patient first day in class, we don't give a cop a gun and a badge and send him out to catch bad guys on the street as their first homework assignment in Academy.

If we know this, we shouldn't expect to jump into our home built car and go blasting around on the roads with 700hp expecting the car will always respond just exactly the way your daily driver does. It's not going to, and the record is very clear, even with 350hp they can and will do things entirely unexpected when you suddenly slam on the brakes to get out of a bad situation.

Where do I get this stuff? Reading on the forums. You've been telling me about it for , what, over seven years on TOS, and here since the beginning. Plus my own experience driving a Mustang for over 18 years and building it. The car has to have balance, it cannot simply be a receptacle for an engine and do the job it is supposed to do with the focus solely on the powerplant.

The problem is that too many consider that the only topic worth discussion, when the reality is that you depend on everything else to bail you out when the motor got you into trouble. Straight line acceleration is just a small part of the overall picture. Even drag racers have to slow down, do a 180 degree turn, and stop in pit lane. Try that in heavy traffic with intersections changing the right of way every other minute.

It's no wonder we have closed tracks for competition, and even then there's a lot of fender banging and rubbing going on. How do I know? You collectively post the links to video and then comment about the driver's skill level.

I appreciate y'all getting me a realistic picture of what really happens.

The result of your collective wisdom? Build a nice warmed over stock motor with high reliability components, and sort out the car first. Get used to 350hp in a 2200 pound car, which is 6 pounds per hp, more than a 100% change in the daily driver. That is more than just a significant bump, which is the real performance aspect in these cars - the huge loss of dead weight from the typical McSUV's we drive today.

We focus on the engine when in fact the massive improvement in performance is a 35% reduction in vehicle weight. If we don't recognize that, then a balanced view of the car in whole will be misrepresented.

And the trees will come up amazingly faster than we think.

[mikey likes it!]

Ya can't "Hook it up"

[David Hodgkins]

tirod, that is a very thoughtful post.

Balance is truly what will result in a car that you WANT to drive everyday! You must realize that the acceleration is a given with these cars. Getting them to turn without spinning or pushing and stopping without pulling or locking up the back before the front are just as, IF NOT MORE critical.

I did a lot of research before pulling the trigger on my build. I've come to know over time that the key to being truly happy with the Cobra is to create one that is SAFE and is BALANCED! I have 350 fwhp in mine, and it is set up to accept another 125 with a bolt on supercharger. My ride has been on the road since 2009 and I don't have an overwhelming desire for more power. I'm VERY HAPPY with my setup! I have fuel injection (no fumes) CATS and quiet pipes for a nice muted rumble instead of a ear-splitting roar, a Torsen rear end that hooks up both the rear wheels and I can canyon carve all day long without fighting the car and I can still hear at the end of the day.

My advice to you is to take your time and not pull the trigger on your kit until you are absolutely sure of all the components that will give you the end result you desire. A canyon carver is distinctly different than a drag car, and both are vastly different than a road race or autocrosser and the parts that go into each is vastly different. You said this is a one-and-done deal; something I can definitely relate to so take the time to spec EXACTLY what you want. We're here to help, so don't be shy about asking for opinions and advice.

:)

[Mike N]

My car has a little over 360 RWHP / 400 RWTQ and is more than enough for street use, in fact it is enough that you have to be very respectful of the power under your right foot, be paying very close attention and even be a little timid while driving on regular roads. However if you have any intention of drag racing or open tracking your car you WILL eventually want more power, I know I do.....

I have spent a lot of hours on track and even more hours tuning the suspension on the car to get it to where it feels very solid. For a car that has 700HP out of the box I would seriously consider getting one of the experts here to set it up for you. Wayne Presley, Mark Dougherty or Gordon Levy spring to mind.

[edwardb]

As much as we may agree to disagree, this is something that EdwardB is right about. Unfortunately, many don't build balanced cars.

I guess that's a compliment. OK, maybe not. Others commented about your posts, but you chose to name me. So I will choose to respond. This is a friendly forum, which I appreciate, and will try to keep it that way.

When I bought my Mk3 now over five years ago, like many I had been lurking on the other forum for a couple years. Over the years I had tried few engine overhauls and a couple rebuilds and restorations, but frankly didn’t have the skills or patience to deal with what our Midwest weather does to cars. Especially those from some years ago. So building a car from new clean parts – especially a replica of an iconic car I’ve liked since I was a kid – was something I always wanted to do. Plus my career has led me to the Michigan area where the car culture is a way of life with many enjoyable social aspects. Finally I was at a point where it was possible, and off I went choosing a Factory Five Roadster. The other forum, and this one, have been invaluable resources to learn along the way. There are multiple guys here with many years of experience and the patience to share it. Some especially were extremely helpful. Others (and you pretty quickly realize who they are) not so much. Once the Mk3 was done, I drove it as much as the Michigan weather allowed (and love it) and attended multiple car shows and events, joined the local club, etc. Great fun. Plus my wife also enjoys it, so it's something we do together unlike previous hobbies I've had. But I realized I missed the building aspect, so got a chance to build another and have about 1-1/2 years into a Mk4.

What I’ve observed along the way is many forum members having a similar journey as mine. Often asking the same questions or reporting the same issues as I had experienced. Being a detail oriented person (some would call it something else…) I keep records of my build plans, every part used, take tons of pictures, etc. So it’s been easy to be a frequent poster on this and the other forum. I am very careful that I only respond where I have actual experience and can recommend what I found to work. I frequently include specific part numbers, vendors, pictures, etc. I don’t pretend I’m always right. I can only report what works for me. Often there are no “right” answers. But based on the responses I’ve received, and multiple PM’s every week where guys are asking for more details, specific help, multiple visits by forum members to my garage, etc., seems to be making a contribution to the community. Plus I really enjoy doing it. It’s a hobby. I do it for fun and relaxation. It’s a great break from a pretty high pressure work environment. And I've made a lot of great new friends along the way.

Early on, I stepped in it a couple of times responding and giving answers about things I thought I knew about (e.g. thought I read it somewhere, found something with Google, etc.) and was quickly corrected by those with much more knowledge and experience than me. Once even by FFR tech support. I deserved it. I really try not to do that anymore. I don’t respond unless I know by firsthand experience. If someone asks me a question and I don’t know, I say so.

In this thread the OP, a new forum member, asked for the forum’s opinion of his build ideas, specifically related to high HP. I, along with others, responded with our experiences and personal recommendations. Ultimately of course it will be his decision, and I wish him the best as I said to him.

Your posts, on the other hand, confirm you as not having any actual experience with these builds or specific cars (something I’ve suspected all along), and mixed in with seeming knowledge about cars in general are value statements and judgments (among other things) apparently based on forum content alone. Plus I guess we’re not getting it because the Mustang, etc. forums are seemingly so much better. I really try to not comment because it just turns into an argument with no constructive outcome. But I’m sensitive to the new guys who come here to get their questions answered and what they get is something else entirely and maybe they don't know the difference.

In summary, again I will say this is a hobby. We do it for fun. I personally find it very rewarding. Many, like me, are not professional car guys by trade but are attracted to the hobby and often later in life when we can afford to embark on this journey. It is a learning experience. Knowledge comes from hard work and life experience. We aren’t born with it. Sometimes we learn the hard way (I sure do…) but often those are the best lessons. FFR markets these kits as “easy to build” and “no experience necessary” and maybe that is a bit of overselling. Clearly some aptitude and motivation are necessary. But forums like this are fantastic resources to close the knowledge gap. Sometimes the questions are a little scary. I agree. But everyone should have the freedom to ask questions and learn without enduring grandstanding, judging, long lectures, broad generalizations, name calling, being talked down to, questioning motives, condemning the industry, the forum, the members, etc. Ask yourself, is my response contributing with actionable and credible information that the OP can go into the shop and use to further enjoy the hobby? If not, maybe it’s not really contributing to the community.

OK, I'm out. Really.

[Blue MK3]

Why only 700 hp? Go for even more:
http://www.mustangandfords.com/featured-vehicles/1407-1965-shelby-cobra-replica-snail-fed-serpent/

[chopthebass]

Why only 700 hp? Go for even more:
http://www.mustangandfords.com/featured-vehicles/1407-1965-shelby-cobra-replica-snail-fed-serpent/

Even with 345's on the rear I bet he still struggles with traction.

[Erik W. Treves]

Ok, I think I read through this thread and got what you are all saying.... Build what you want in the end...Why don't we all have big horsepower cars....to each his/her own...they are personalized cars. I started a while ago with a Mark1 all stock....then warmed up the 302 with heads and cam, then supercharger, blew the motor up, new motor and more boost and ended up at 460 RWHP ( so that car went from 280RWHP to 460RWHP) over 11 years...sold it cause I want MORE power... Built a Mark 3.1 with a bigger motor and a good size turbo...current setup is running 575RWHP and 790RWTQ. Lights your hair on fire! While I have owned it I built a 1400lbs Locost 7 with 235 RWHP and an 818 with around 260RWHP, both were actually more fun to drive than the 3.1... I am now building another cobra with a target of around 350 RWHP and I believe that will be perfect...funny how things have come around...I must be getting slower in my old age :D I will tell you one thing for sure....if I relax just a second in that car if I am getting after it, it WILL hurt you....whatever you do, approach with caution if go after these HP numbers and remember that you are dealing with a 90 inch wheel base and an extremely light car. Good luck and have FUN!!! It is a hoot to run through the traps at the 1/8 mile with some counter steer in :)

[Mesa Mike]

My question is, why would you even want that much hp? Maybe you haven't driven a Cobra and are trying to compare it to a motorcycle. Not a good comparison and a foolish idea.

[jimgood]

Why only 700 hp? Go for even more:
http://www.mustangandfords.com/featured-vehicles/1407-1965-shelby-cobra-replica-snail-fed-serpent/

Because he was looking at a specific power plant:


The power plant I was looking at was the Edelbrock Supercharged 5.0L Coyote Crate Engine (700 HP & 606 TQ).

[Raceral]

I would strongly suggest for you to go ride in a 350/400 hp car then make your decision.
I had a buddy that had one of the first 392 strokers... took a HP driving class... wrecked it the first lap... rebuilt it.. with same motor.. wrecked it first time out...
This guy was a outlaw turbo motorcycle rider with many time slips at 190 plus mph...

And the beat goes on!!!:cool:

[jayguy]

KolonelKraig, that is a nice power plant, but how about a compromise? Get the Aluminator motor set up to handle a blower first, it's still over 400 hp, then if that's not enough for you, you can throw a blower on the top and tune it to get 700hp or even more. Sure, it's gonna cost a little more to do it in 2 stages, but you might find out (as others are suggesting), that 400hp+ is more than enough to have fun. Or, if you decide it's not, your engine is already set up to take the boost and there are several options available.

http://www.fordracingpartsdirect.com/FORD_RACING_5_0L_ALUMINATOR_LOW_COMPRESSION_COYOTE _p/m-6007-a50sc.htm

[Jeff Kleiner]

Every car and every driver has a limit---arriving at those limits simultaneously is when the big problems occur.

Jeff

[Jester]

FWIW: An older race car driver once told me that for the street it is much more fun to drive a low HP car fast than a high HP car slow. I think there may be some wisdom there.

It is the short wheel base, basic handling, and high power to weight ratio that made these cars such a performer back in the day and although significant advances and improvements have been made on all other aspects of performance, the short wheel base remains constant. The more HP and torque, the faster your reflexes will need to be when (not if) you get into trouble.

I am all for building the way you like and what you can afford but these cars demand respect or someone will get hurt.

Good Luck!

[blueoval_bowtie_guy]

I don't know why, but this post just reminded me of a young man that was over on a BMW forum a few years ago. He was talking about his Dad's M5 and how fun it was to drive it really fast. He got cautioned a number of times about how young he was (in his teens) and just how quickly high-powered cars can get away from you. It wasn't long before we found out that he'd not only killed himself in the car but several others as well. He took it on a runway and opened it up. He couldn't stop in time.

If I had to do it over again, I think it would be more fun to drive it with a small block rather than a bored-stroked 351W. I've had it on the track a couple times, more is not alway better. My old Miata (sold it) was more fun on the track (supercharged, intercooled 204rwhp).

[69Cam620]

Here is my take. Yes, I agree that the roadster has a shorter wheelbase which will make it harder to control, which has lead me to the coupe. I had my heart set on building a challenge car to race in the series, but the more research I do the more I realize that a coupe built how I want it can still be legal in certain SCCA and NASA classes. The reason? I want something I can enjoy daily along with doing the local SCCA autocross, drag racing (which the track is less than a mile from my house), and of course I have to run Mid-Ohio at least once a year to maintain my training (legally). My first Corvette was a base 2006 with the Z06 widebody and suspension with the LS2, F1D Procharger, methanol injection etc. Basically listing the mods is hard to do because, well it's easier to say what was still stock. Running modest boost at 12 psi yielded 650 rwhp. When I first got it I drove it with utter respect because it was to date the most powerful car I had ever owned. Turn off the traction control and nanny systems and it was a complete handful. But after 2 weeks of owning it, 650 rwhp went from being scary to "I need more power". I simply got used to it very quickly. I autocrossed the car, drag raced it and ran it at Mid-Ohio on open track days (not the lead follow stuff, I have my racing license). So I say don't listen to those who will try to scare you away from adding more power, as long as you can control how much of that power you want to apply by controlling your right foot you'll be fine. If you have 700 hp, if you are like me, you'll be planning the next upgrade to make 1,200 hp. If my FFR doesn't run at least low 10s there is no point in it for me...but I think these cars can be an "all arounder" on track and off track. Plus you don't want to spend a ton of time and money in your build and have some kid in a Neon SRT-4 egg you on to race on the highway only to blow your doors off. It happens a lot, if you have a sports car you will get challenged and you can either try and be responsible or you can have enough power to put them so far behind that they would be embarrassed to try you again. To each their own.

So the real question here is: what can the roadster, challenge, coupe, etc frames handle as far as torque and hp? What amount of power would twist them?

[christenfreedman]

700hp sounds good if I want to walk around it and tell my neighbors that I have 700hp...but if you really want to get in and drive the damn thing down the street...stop and use the thing between your ears...