Thoughts on Sequential Transmission for 818

[SkiRideDrive]

Now I know this isn't the most affordable option. But I do think it could be extremely fun and we can all dream. I found this mendeola box which looks like it would fit the bill as it also includes a limited slip differential. It doesn't list a price, but based on some of the other boxes which do list prices, I'm assuming somewhere in the 10K range.

Different models they offer:
http://mendeolamotors.com/trans-proto/index.php?option=com_content&view=article&id=47&Itemid=29

LQ-456 (the one I think would fit the bill):
http://mendeolamotors.com/trans-proto/index.php?option=com_content&view=article&id=53&Itemid=66

It seems to be designed for sand rails but also mentions it can be used for rally cross. It says it can handle 375 hp, which should be enough for ear to ear grins in the 818 and weighs 160 lbs, which isn't too much more than the stock transmission which I believe is a bit over 130, correct me if I'm wrong. I'm not sure about the distance from the face of the transmission to the output shafts compared to the stock tranny, but I would assume any small differences can be accounted for in a bit of drive shaft splay.

Thoughts?

[shinn497]

Maybe you could ask mendeola yourself as I think they are this forum. Personally I love manual transmissions and wouldn't pay for it.

[JRL]

My first thought - you are going to put a $10,000 gearbox in a car projected to cost $15,000 to build??????

My second thought - do you have any idea the maintenance cost on a true sequential box?

My third thought - do you have any idea how much noise straight cut gears create?

Other than that go for it!

[JRL]

If you just want a sequential shifter this might be a better option

http://www.nengun.com/ikeya-formula/sequential-shifter

[leetfade]

If your goal is 375hp (based on the limit you stated on the transmission), I, personally, wouldn't go sequential. It's entirely up to you if you really want to spend that money but it wouldn't be needed for that amount of power. The EJ20/25 transmissions have held to 400whp but it is a known weak point of the Subaru motor. Many have used them successfully for decent horsepower, though.

I MAY go with a sequential dog box but only if I go full-out road race build and, at that point, the $15k is so far out the window anyways that the price point isn't the issue anymore.

[Xusia]

I think the point of the price comment is one PyrraM made in his thread "Low buck, phased in build (http://thefactoryfiveforum.com/showthread.php?5863-Low-buck-phased-in-build)," that if you going to spend that kind of money, there are other options that would probably provide a better platform (i.e. GTM, etc.). I have no doubt it possible to spend $40k on an 818 build. Like PyrraM, I just don't think that's practical because a similarly priced build in another platform would likely yield as good or better performance, AND be able to be built to a higher level of performance (for more money, of course) than the 818 will be capable of.

[crash]

Maybe you could ask mendeola yourself as I think they are this forum. Personally I love manual transmissions and wouldn't pay for it.

I don't mean to offend, but I have no idea what your post is saying. Yes Mendeola is a vendor here, but all they produce are manual tranmissions, at least at this point. Are you talking about loving synchroed transmissions as opposed to dog box transmissions?

For the record, most of Mendeola's boxes are helical cut gears. They do have some straight cut gear boxes for their higher end race stuff, but most everything they offer to kit car builders would undoubtedly be of the helical cut gear variety.

[Evan78]

What else is out there that weighs less than 2000 pounds? Some people seem to focus only on the target price point of the 818, but the weight is pretty low. The experience of driving a light car is hard to replicate, even if the performance numbers of something heavier are equal or better than the light car.

[Etos]

I think the point of the price comment is one PyrraM made in his thread "Low buck, phased in build (http://thefactoryfiveforum.com/showthread.php?5863-Low-buck-phased-in-build)," that if you going to spend that kind of money, there are other options that would probably provide a better platform (i.e. GTM, etc.). I have no doubt it possible to spend $40k on an 818 build. Like PyrraM, I just don't think that's practical because a similarly priced build in another platform would likely yield as good or better performance, AND be able to be built to a higher level of performance (for more money, of course) than the 818 will be capable of.

I don't know about this TBH. It looks like the cost to complete a GTM is at the very least 35k with an actual cost of around $40k+. The kit itself is $20k, a crate motor is $6-16k and the trans is $8.6k(I don't know what the porsche trans costs but I hear it tripled in cost).

I just checked the GTM page FAQ and this is what it says about the completed cost:

How much does it cost to build a GTM?
The price of the kit is not as important as the price of the completed vehicle. Our original target was that a guy should be able to build the GTM for less than $50,000. Most customers spend between $35,000 and $50,000 to complete the car including Chevrolet parts, wheels/tires, paint and transaxle.

So I was right on the money when it came to the cost. Factor in that a GTM weighs around 2,400 as well. TBH I'm damn sure for $40k you can build a much faster 818 then a $40k GTM. 600 pounds is a big difference.

To those saying it doesn't make sense to dump alot of money into an 818, factor in that regular street cars that are modified to be race cars will see over $200,000 spent on a 35k car. Some porsche people spend more money modding their car then what they spent buying it.

Also if you want a cheap way to get a sequential gearbox, drop in a suzuki 1.3l hyabusa motor/trans and you got yourself a high revving sequential. Those things turboed hit 400+ easy.

[carbon fiber]

now your talking! turbo hayabusa engine in the 818! smaller, lighter, built in trans and could use an air shifter. less torque, and don't know what the lightening of the rear would do. would sound awesome though, and the thing will hit 13,000 rpms!

[Evan78]

I've posted this before, but there's been more progress, so check out MotoIQ's Miatabusa project (http://www.motoiq.com/projects/mazda/project_mazda_miatabusa.aspx) if you're into that sort of thing.

[Xusia]

OK, I'm REALLY nit picking here, I know... 400hp perhaps, but easy? No way. I don't know much about Subies, but I know a hell of a lot about bikes and getting a 'Busa engine to 400hp is a feat, and would require a lot of mods. Fitting it into the car and adapting it to a differential are 2 other feats in store for enterprising souls. I know it can be done, but good luck with that. I would weigh less, but that's about it. I think it would even get worse gas mileage.

And don't forget that even at 400hp it will have a lot less torque - probably not even as much as a stock WRX engine.

[JRL]

I don't know about this TBH. It looks like the cost to complete a GTM is at the very least 35k with an actual cost of around $40k+. The kit itself is $20k, a crate motor is $6-16k and the trans is $8.6k(I don't know what the porsche trans costs but I hear it tripled in cost).

I just checked the GTM page FAQ and this is what it says about the completed cost:

How much does it cost to build a GTM?
The price of the kit is not as important as the price of the completed vehicle. Our original target was that a guy should be able to build the GTM for less than $50,000. Most customers spend between $35,000 and $50,000 to complete the car including Chevrolet parts, wheels/tires, paint and transaxle.

So I was right on the money when it came to the cost. Factor in that a GTM weighs around 2,400 as well. TBH I'm damn sure for $40k you can build a much faster 818 then a $40k GTM. 600 pounds is a big difference.

To those saying it doesn't make sense to dump alot of money into an 818, factor in that regular street cars that are modified to be race cars will see over $200,000 spent on a 35k car. Some porsche people spend more money modding their car then what they spent buying it.Also if you want a cheap way to get a sequential gearbox, drop in a suzuki 1.3l hyabusa motor/trans and you got yourself a high revving sequential. Those things turboed hit 400+ easy.

What are you talking about - I mean really?? I have modified and raced a few cars (even a Porsche or two) and never come close to those kind of numbers.

[Xusia]

My comment about the build price wasn't meant to stir anything up or get anyone arguing. I was simply trying to explain what I thought someone else meant. By all means, spend $40k on an 818 if that's your thing. Just don't expect everyone to understand! :)

[kalare]

I don't see the issue about spending more on the 818. Many GTM folks build cars with well over 100k invested and get massive praise. Spending 30k on an 818 or more is akin to someone spending 60-80k on a GTM, which is almost the norm. The whole idea of the 818 is that it can be had at a wonderful entry level price however that doesn't mean that owners shouldn't invest more cash into the car because "it defeats the purpose of the car". I for one don't believe that the purpose of the car is to be cheap, I believe the purpose of the car is for FFR to be able to provide a wonderful handling platform and a reasonable price.

It's a little premature for everyone to be commenting on these dream builds that many are posting up, but, while they may never come to fruition, I do believe they should be encouraged! If someone dreams of building a 60k 818 with all the bells and whistles, I say DO IT! How very cool would it be to have a range of 818's around from the mild to the wild? That's why kit cars are so great, the owner makes it their own.

[jimgood]

These guys seem to have some Subaru gearbox experience: http://www.tunersgroup.com/Products/KAPS_full_sequential.html

[Oppenheimer]

I don't see the issue about spending more on the 818. Many GTM folks build cars with well over 100k invested and get massive praise. Spending 30k on an 818 or more is akin to someone spending 60-80k on a GTM, which is almost the norm. The whole idea of the 818 is that it can be had at a wonderful entry level price however that doesn't mean that owners shouldn't invest more cash into the car because "it defeats the purpose of the car". I for one don't believe that the purpose of the car is to be cheap, I believe the purpose of the car is for FFR to be able to provide a wonderful handling platform and a reasonable price.

It's a little premature for everyone to be commenting on these dream builds that many are posting up, but, while they may never come to fruition, I do believe they should be encouraged! If someone dreams of building a 60k 818 with all the bells and whistles, I say DO IT! How very cool would it be to have a range of 818's around from the mild to the wild? That's why kit cars are so great, the owner makes it their own.

Welcome to the forum. I agree with pretty much everything you said. The one thing that does concern me a little about talk of 'dream builds' is it can plant the notion in a guys head that unless he (or she) can build their ultimate dream, they shouldn't build one at all.

I've heard comments that Roadster guys sometimes get, like, 'what? It doesn't have a 427? If I were ever going to build one of these, it would have to be a 427 or I wouldn't build it at all'. Lets encourage talk of dream builds, but lets just be careful not to end up encouraging 'dream or nothing' thinking.

[carbon fiber]

two of my riding buddies have turbo hayabusas. you can make a quite livable 375-400 turbo engine if you want. i've ridden one. you have to be careful when the boost comes on but it's ridable. the entire bottom end is built, and the heads are ported.

[Etos]

OK, I'm REALLY nit picking here, I know... 400hp perhaps, but easy? No way. I don't know much about Subies, but I know a hell of a lot about bikes and getting a 'Busa engine to 400hp is a feat, and would require a lot of mods. Fitting it into the car and adapting it to a differential are 2 other feats in store for enterprising souls. I know it can be done, but good luck with that. I would weigh less, but that's about it. I think it would even get worse gas mileage.

And don't forget that even at 400hp it will have a lot less torque - probably not even as much as a stock WRX engine.

http://www.hayabusa.org/forum/turbo/

It seems the hardest part about turbo a busa is room. With that not being an issue since it's going into a car the only real problem putting a turbo busa in an 818 is establishing the engine/trans. It's been done before on many cars, smart cars being the most well known. I also don't think torque is an issue. There's far heavier cars with less torque then a turbo busa and do just fine.


What are you talking about - I mean really?? I have modified and raced a few cars (even a Porsche or two) and never come close to those kind of numbers.

And there's people who spend as much as the cost of the car modifying it. Just cause you haven't doesn't mean no one has. Hell I know people who spent $300k on just the transport truck/trailer. Must be good to have money =/

[kalare]

Lets encourage talk of dream builds, but lets just be careful not to end up encouraging 'dream or nothing' thinking.

Thanks for the welcome! I also never intended to encourage people to dream and then quit if their dream is unattainable. I totally agree with your last statement.

[bobzdar]

I think it would be cheaper to adapt a hydraulic paddle shift setup to the stock trans if thats what you wanted. It would require some fabication, but a setup from say an e46 m3 or last gen mr2 should be adaptable with some work and be half the cost.

[SkiRideDrive]

Wow, this got more interest then I thought it would. As for the cost issue, people will do what they want and what they think is worth it to them. I'm not saying this is worth it to me or I would be able to afford it, but I just thought it was an interesting idea. During my days driving for my college formula sae team, we did just what you guys are discussing, and designed a car around a motorcycle engine and that's where I got my idea from. I thoroughly enjoyed driving a car with a sequential transmission. I also ride motorcycles quite often and and am very accustomed to rowing gears in that fashion.

I intended this thread to be more of a feasibility of running that transmission in the car, including any hurdles that would have to be overcome to make it work rather than a philosophical discussion on whether its worth the money. Either way it's good to hear what everyone thinks.

As for a busa motor in the 818, it is an interesting concept but I feel the appeal of the car is that the tube frame is designed around a motor you can purchase fairly readily and doesn't require extensive fabrication at home. While I would love to see a busa motor in an 818, I don't see myself taking on such a project until I have the tools to do so.

And thanks for the other "sequential like" ideas. Both are interesting concepts, especially the nengun unit. That setup is pretty trick although I don't think it would feel like a true sequential box. The appeal to me was the extremely quick no clutch shifts. At least with a bike all you have to do is unload the motor a bit by coming off full throttle and rip on the shifter and your up to the next gear.

Anyone have any comments on the durability of a trans designed for offroad applications being used on pavement or any potential issues with bolting up the mendeola unit?

[carbon fiber]

anyone watch dream machines on syfy? they built a car from scratch (futuristic with giant wheels and questionable aero, but looked wild) that has a motorcycle engine/normally aspirated. not sure what engine or how they set up the driveline to the wheels, but interesting. i saw YEARS AGO in popular hot rodding(i think) a guy that built a open wheel car similar to old indy car with two kz1000 engines in the back. it had a coor's light paint theme, and he had gotten it to legal status for the street. but yes, it would be alot of fab to make a bike engine fit in the 818.

[Thorne]

If your goal is 375hp (based on the limit you stated on the transmission), I, personally, wouldn't go sequential. It's entirely up to you if you really want to spend that money but it wouldn't be needed for that amount of power. The EJ20/25 transmissions have held to 400whp but it is a known weak point of the Subaru motor. Many have used them successfully for decent horsepower, though.

I MAY go with a sequential dog box but only if I go full-out road race build and, at that point, the $15k is so far out the window anyways that the price point isn't the issue anymore.

The subaru 5 speed will not hold 400whp for any amount of itme assuming you actually drive/race the car.

[PhyrraM]

The subaru 5 speed will not hold 400whp for any amount of itme assuming you actually drive/race the car.

So, which is it? Drive or race?

5 speeds can last a long time, with big power even, if all your doing is driving them.

5 speeds can pop in minutes if your racing it, or racing it on the street. Or dropping the clutch, or slamming faster then the scychros are designed for, or.....or.....or....

The never ending tranny debate = free entertainment. :o Let's get a few built and resume after we have some real answers.:cool:

[Oppenheimer]

The subaru 5 speed will not hold 400whp for any amount of itme assuming you actually drive/race the car.

What is known entity for WRX does not apply to 818. Lighter, 2wd only. We simply don't know yet what to expect as far as how much power you can push with the stock 5sp in an 818, and won't until some are built (though it hasn't stopped us from debating here).

[Etos]

The subaru 5 speed will not hold 400whp for any amount of itme assuming you actually drive/race the car.

With a brace it can surely hold 400hp effectively. The only issue still with an AWD application is dumping the clutch even with a brace causes intense shock to the gears. But this isn't an AWD so any excess power from a clutch dump at a stop just causes wheel spin.

[StatGSR]

The subaru 5 speed will not hold 400whp for any amount of itme assuming you actually drive]/race the car.

i think its more of the people that don't know how to drive the car that have the tranny issues... racing (well maybe not drag racing) is about being smooth, not about beating the crap out of your car.

i bet for every 9 out of 10 5 speeds that break, the cause was from a bad driver and not because there was too much power...

[shinn497]

I don't mean to offend, but I have no idea what your post is saying. Yes Mendeola is a vendor here, but all they produce are manual tranmissions, at least at this point. Are you talking about loving synchroed transmissions as opposed to dog box transmissions?

For the record, most of Mendeola's boxes are helical cut gears. They do have some straight cut gear boxes for their higher end race stuff, but most everything they offer to kit car builders would undoubtedly be of the helical cut gear variety.

I think I was half asleep when I wrote this. I was under the impressions the sequential gearboxes are automatics with tiptronic controls. Anyway I pretty much only pay attention to standard manual trannies. Just clarrifying ignore this post the rest of you.

[Evan78]

http://en.wikipedia.org/wiki/Sequential_manual_transmission

[RossLH]

With a brace it can surely hold 400hp effectively. The only issue still with an AWD application is dumping the clutch even with a brace causes intense shock to the gears. But this isn't an AWD so any excess power from a clutch dump at a stop just causes wheel spin.

This post made me cringe. Just.....no, man. It doesn't work that way.

[PhyrraM]

This post made me cringe. Just.....no, man. It doesn't work that way.

Care to enlighten? Or we are just supposed to know?

[RossLH]

I touched on it in the 'Transmission Ideas' thread. Its an internal problem--case flex is a myth that needs to not be spread. Ever. Adding an external brace cannot and will not fix the problem, though doing so can very efficiently waste your time and money. The issue is input shaft flex, an issue brought on by designing a long, narrow, unsupported length of input shaft over the front diff. Put some power through the input shaft and you've got a big 'ol bending moment right there and another right at 2nd gear. 2nd gear on the input shaft pulls away from its output shaft counterpart, and you're left trying to distribute a large amount of power over significantly less tooth surface area.

Note that this effect is not exclusive to shock loading. If 400 crank hp is applied to the input shaft, shock loading and wheel spin* aside, during hard acceleration a lesser, but still dangerous, amount of flex will occur on the input shaft.

*Figured I'd touch on this as well while I'm on a roll. Shock loading and hard acceleration loading occur in every gear. Wheel spin does not. So saying "shock loading isn't a problem because you'll just spin the wheels" is nothing more than a cop out, unless you plan on making enough power to break the wheels loose in 3rd, 4th, and 5th gear. Being 2WD rather than AWD will only help in lower gears. Keep in mind there have been several cases in which 5th gear will crack in a built 5-speed in a high powered WRX or STi.

Hopefully that answers your question. For what its worth, I studied mechanical engineering with a concentration in automotive powertrain (read: a lot of transmission stuff), I have crunched the numbers on the stock 5-speed, and its not pretty even in stock form. These things don't break by coincidence, they survive by sheer luck.

[Evan78]

Do you happen to have a diagram handy that shows the transmission internals that you're referring to? Don't mean to be lazy, but it sounds like you might know one of the top of your head.

[RM1SepEx]

great trans info... how much stronger is the 06 - 07 trans

[PhyrraM]

I touched on it in the 'Transmission Ideas' thread. .......... These things don't break by coincidence, they survive by sheer luck.

Thank you, that was much more productive and useful.

[RossLH]

Do you happen to have a diagram handy that shows the transmission internals that you're referring to? Don't mean to be lazy, but it sounds like you might know one of the top of your head.

I'll find a picture later and put some labels on it. Been running around all day.....almost done running errands.


great trans info... how much stronger is the 06 - 07 trans

Simply put, it isn't. You'll just break 3rd gear instead of 2nd. Subaru said they fixed the 2nd gear issue....well they weren't wrong.


Thank you, that was much more productive and useful.

Sorry if I seemed short in my previous post, this is just an issue that I've gone over dozens of times with various people who insist on the silliest things (such as case flex) being the problem. Subaru even does it--they tried to band-aid the problem in 2002 by making the gears 1mm wider. Didn't help. Fact of the matter is until the real issue is addressed, 5-speeds will continue to be unacceptably weak. Want your 5-speed to not break? Here's what to do:

1. No lightweight flywheels. Ever.
2. Full-faced, sprung clutches only. No 6-puck or 4-puck, they're too aggressive. Multi-disk clutches are fine.
3. Be smooth.
4. Double clutch on downshifting--the synchros in the 5-speed from '02-07 are quite literally the same design that Subaru used in the 80's. They're trash.
5. No budget building. If you break stock gears, you'll break ANY OEM gearset (whether it be Legacy, RA, etc) you drop in there. Cryo treated? Doesn't matter.
6. 300whp is plenty enough to break these gears. I don't care what you've heard or how many anecdotes you can list off the top of your head, whether the car is RWD or AWD. I'm not saying they'll break the first time you step on it, but plan for them to break. If they don't, fantastic, but its much better to be ready than to be caught like a deer in headlights.

[Etos]

I'm going to have to disagree on the case issue. I personally spoke with a subaru engineer a few years back on this subject for a good half hour. He himself brought up the split case design as the biggest design flaw in the 5 speeds for higher horsepower applications. I'm sure you know what you're talking about but so did this guy considering he helped with the transmission ends of things. The only problem with case braces is they have been rare and far between and every company trying to make them always ended up having some financial issues not allowing them to venture further. I don't see Moore going anywhere soon and with some time and testing they should be able to run some more long term testing on the case brace.

[RossLH]

The amount of force either of the shafts would have to apply to the case in order to make it flex is immense. If the case does indeed flex, I can promise you that your transmission was doomed far in advance. We're talking levels of stress only achievable by 600+hp. So yes, the case can flex, but with the power the general population here is planning on making, not a single one of us will ever have to worry about it. It simply wont happen at these power levels.

[Evan78]

It seems like you could measure it relatively easily with a little data acquisition equipment. Couldn't you use a linear sensor like they use on suspension to measure case flex, or lack thereof? If something is worth bracing, you should be able to measure some movement between the points you're reinforcing.

[crash]

The Mendeola works great. See here...

http://www.youtube.com/watch?v=YCrbHt7Ln-Y

[Etos]

The amount of force either of the shafts would have to apply to the case in order to make it flex is immense. If the case does indeed flex, I can promise you that your transmission was doomed far in advance. We're talking levels of stress only achievable by 600+hp. So yes, the case can flex, but with the power the general population here is planning on making, not a single one of us will ever have to worry about it. It simply wont happen at these power levels.

Then explain why even with PPGs input shaft/gears in a 5mt you get breaks?


It seems like you could measure it relatively easily with a little data acquisition equipment. Couldn't you use a linear sensor like they use on suspension to measure case flex, or lack thereof? If something is worth bracing, you should be able to measure some movement between the points you're reinforcing.

I agree 110%.

[RossLH]

Then explain why even with PPGs input shaft/gears in a 5mt you get breaks?

Who uses PPG gears? Generally speaking, people who own cars that make very significant amounts of power. PPG makes some amazing gear sets, but they still have to work with the design of the 5-speed case. They've beefed up that unsupported section, but when you increase the power proportional to the increased capability of the gear sets, you're effectively right back where you started, and in some cases (i.e. retaining the stock 5th gear), you're worse off.

Think of it this way: if at low power levels (300whp or less), the transmission case flexes enough to inflict damage upon the gears, what do you think it would do if you doubled the amount of power going through it? People using PPG gear sets and making over 500whp would be leaving massive chunks of transmission case on the track. Case flex is not unaffected by power output, yet those people making 600+whp with built 5-speeds have zero issues with case breakage.

The input shaft, by design, is the weak link. It will flex first, and when it does, there's nowhere near enough force left over to affect the case.

[Etos]

Who uses PPG gears? Generally speaking, people who own cars that make very significant amounts of power. PPG makes some amazing gear sets, but they still have to work with the design of the 5-speed case. They've beefed up that unsupported section, but when you increase the power proportional to the increased capability of the gear sets, you're effectively right back where you started, and in some cases (i.e. retaining the stock 5th gear), you're worse off.

Think of it this way: if at low power levels (300whp or less), the transmission case flexes enough to inflict damage upon the gears, what do you think it would do if you doubled the amount of power going through it? People using PPG gear sets and making over 500whp would be leaving massive chunks of transmission case on the track. Case flex is not unaffected by power output, yet those people making 600+whp with built 5-speeds have zero issues with case breakage.

The input shaft, by design, is the weak link. It will flex first, and when it does, there's nowhere near enough force left over to affect the case.

Well it's a very compelling point. I still would like to see someone do some tests to see how much(or little) the case flexes with some power put through it.