Frame hp/torque tolerances

[69Cam620]

Hello I think I am swaying to the coupe build...but some hard numbers would be helpful.

FFR challenge car frame strength/tolerances etc = ?

FFR Type 65 Coupe frame strength/tolerances etc = ? And what modifications to the frame would make it SCCA/NASA/and NHRA approved?

Basically how much torque/horsepower can they handle as you ship them? And would you be willing to share any information on what would make them stronger (seeing as how you designed the chassis and should have some feedback on the CAD, especially if you used MATlab or another program that will allow you to analyze stress members and shear strength). And yes I have a degree in mechanical engineering and a second in computer science, so this would be great information to have and know in order to plan my build properly. If I build a coupe it will have either a turbo 427 LSX or the new Procharger i series with driver controlled boost mapping. So at a minimum I would need to be able to support 700 hp (maybe 1500 hp max at the flywheel). Boost control is important as I will use the car for drag racing, autocross, and road courses (mainly Mid-Ohio). So the chassis needs to be able to cope with varying stress points. I had a F1D Procharged Corvette that put down 650 rwhp at 12 psi and over 1,000 when raised to 20+...but I was constantly replacing parts and reinforcing the chassis. I sold it to build a car where I could control these variables from the bare chassis and build it to required specs. Any hard numbers, diagrams, etc would be much appreciated to assist me in building my perfect car.

[skullandbones]

I know this is for FFR tech but I wanted to ask about your diff. What are you going to use to transfer the power to the ground on this torque monster? Also, I have a suggestion if you haven't already made a decision. I noticed when I was doing my Watt's link and custom third link that I was adding two lateral supports to this area of the chassis. Of course, they are necessary to support the various links but the secondary benefit is that it is actually boxing in the chassis where there my not be as much support for high hp. I'm using smaller wall tubing (not anticipating more than 425+ hp) but you could go up to 3/16 and get a very substantial improvement on stiffness. I'm using the quad shock brackets and UCA brackets for the supports so I can do a strictly bolt in project. You would probably weld everything in solid. If you use a 9 inch live axle that would be very strong. I'm sure there are after market diffs that are "bullet proof". These mods should work on either project you choose.

Good luck, WEK

[69Cam620]

I know this is for FFR tech but I wanted to ask about your diff. What are you going to use to transfer the power to the ground on this torque monster? Also, I have a suggestion if you haven't already made a decision. I noticed when I was doing my Watt's link and custom third link that I was adding two lateral supports to this area of the chassis. Of course, they are necessary to support the various links but the secondary benefit is that it is actually boxing in the chassis where there my not be as much support for high hp. I'm using smaller wall tubing (not anticipating more than 425+ hp) but you could go up to 3/16 and get a very substantial improvement on stiffness. I'm using the quad shock brackets and UCA brackets for the supports so I can do a strictly bolt in project. You would probably weld everything in solid. If you use a 9 inch live axle that would be very strong. I'm sure there are after market diffs that are "bullet proof". These mods should work on either project you choose.

Good luck, WEK

Great info in there, thank you. Always good to hear from people who have experience with these cars, I haven't seen one in person so I only have others' experiences to work with. I've definitely been scouring the forum and saving pictures of other peoples' frames and their mods, though some technical data would help in identifying what areas need reinforcement for high power applications. Since I plan to exceed what my Corvette could handle, for this I am definitely going with the live axle, most likely a custom built Moser 9", though I have considered going with a custom GM truck based 14 bolt 10.5" rear. I know a lot of guys here love the independent rear suspension, but I can tell you that the Firebirds/Camaros/Mustangs with a live axle and less hp were giving me a run for my money, so to me a well setup live axle can be just as good on a road course and much better when at the drags. On my 1969 Camaro I had a 10 bolt 8.5" built with hardened shafts, but now that is something extra I have to sell since I went from a bored 350 (388) to a LSX 427. Now I have a 12 bolt custom built by Moser and getting the BMR torque tube with coil overs and watts link. So if I could work something similar to that I am basically adding the same strength members as you suggest. The main issue I see is that anything I use will have to be custom for this application since most companies build these types of specialty parts for common makes and models like the Mustang and Camaro. Though I am wondering now if I could get one built for the Mustang (similar to what I have pictured) if that will work for the coupe with some modifications of course. I know this will end up being a much more complicated build, but in the end it will be worth it. One of the reasons I was leaning toward the Challenge car was due to the rule book restrictions and cost...but I know me well enough to know I wouldn't be happy in the long run. Plus I have a hard time trying to play by the rules lol.


This is the pic of what I have coming for my Camaro, it ties into the leaf spring perches, the rear subframe and attaches at the front where the subframe connectors join to the front frame. Which I think will add quite a bit of stability, though the Camaro isn't being built as a race car...just a protouring restomod-restoration.
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Thanks again for your input, as soon as I purchase a kit I will be a super needy information seeker lol.

[skullandbones]

I remember seeing a statement about the roadster chassis being twice as stiff as the originals. I find a detail in the brochure that says it has twice the torsional stiffness due to an added "backbone" and other perimeter supports. The chassis weights more than most of the competitors but the finished product is lighter than most competitors. This is the major reason for me buying this product over other offerings. With price and quality as the main factors, I couldn't find a better project. Since you are an engineer, you want numbers, right? BTW: you may have checked this out already but if you haven't see Gordon Levy's 5 link. He's a vendor on the forum and this would fit your project perfectly as it is guaranteed for high HP applications ( I think 1000+). It's a good value, I think. The main reason I didn't get it was I didn't want to change my electrical system at all so the battery box was a real problem. Also, I liked the watts link mounted on the chassis instead of the pumpkin (just a personal preference). But for your application it sounds like a real winner. See edwardb's build string and you will see what I mean. I guess you can see my bias but I don't think you can find a stronger chassis for your purposes anywhere! WEK.

[Mike N]

The guy that has done probably the most analysis and mods to the FFR roadster chassis is David Borden. Grab a cup of coffee and read the following thread http://thefactoryfiveforum.com/showthread.php?141-David-s-Mk4-Build-Thread I believe that David did the backbone mod long before FFR did.

[69Cam620]

The guy that has done probably the most analysis and mods to the FFR roadster chassis is David Borden. Grab a cup of coffee and read the following thread http://thefactoryfiveforum.com/showthread.php?141-David-s-Mk4-Build-Thread I believe that David did the backbone mod long before FFR did.

You guys are great here, thanks for the information and I will definitely take your suggestions. Now for some good reading and research :)

[69Cam620]

You guys are great! Thank you for the information, all will be very helpful. I am checking out Dave's build page, like his use of Solidworks. And that Levy 5 link looks stellar, very stout.

[Plebeian]

Good info here on the Coupe http://thefactoryfiveforum.com/showthread.php?2324-Frame-Mods-to-Type-65-Coupe&highlight=coupe+roll+bar+modifications