Help with Mid Engine Design

[Egg Nog]

Well I guess my question now is does anyone know of any Transaxles that can handle around 800HP that can be made to fit a small block chevy V8? This where I am right now and I cant go forward at all until I have some answer to this question, lol it is kind of critical.

Renegade hybrids does an excellent 914/Chevy small block conversion, and use different tranny set-ups for different power outputs. the Porsche 930 Transaxle can be used for street applications of up to around 700hp. They have adapter plates for a variety of choices.

Check it out here, at the bottom of the page:

http://www.renegadehybrids.com/914.htm

[V8turbo4me]

wow, thanks a lot guys, you are super helpful. I know that it sounds kinda rediculous but I don't think that 700HP capacity is going to work, but maybe it will, I guess I could tone it down a bit, but thats not very much fun! I will check out both of those web sites.

I am willing to spend what it takes to do the project well. Emphasis on well and not to the best possible standards. That is not my aim with this project, perhaps once I have completed this car and see how I like it I will move on to greater things but for now I am just having fun here. As I said before though I would really like to have a transaxle that could handle 800 to 850 horses without problems or having to worry about snapping a gear or driveshaft.

I have decided that I will use a twin turbo setup for the sake of keeping a cleaner engine bay and to also keep the cooling situation at hand. I really like the idea of not having to fabricate eight into one headers, lol.

[Egg Nog]

If you can afford it, I found an ideal engine for you... Banks Power's turnkey TT 6.0. 800hp, or if you want more, you can go all the way to 1600hp

http://www.bankspower.com/twin-turbo-engine.cfm


By the way, I'm pretty sure that Renegade Hybrids would be able to set you up with a beefed-up 930 transaxle. They tend to do a lot of custom work, especially when it comes to handling more power.

[V8turbo4me]

wow, Eggnog, you are also an extremely helpful person! I just can't get over how much positive feedback I have gotten. Do you think that Renegade would simply have the components to beef up a 930 transaxle to carry those kinds of loads? Also I am a little curious as to their pricing, it seems like they wouldn't be really high but I've been unfortunately surprised in many instances.

I know it is on a totally different note but do you think that a four wheel drive differential would be easier/cheaper to come across? or is a mid engine AWD/4WD vehicle just not really a feasable endeavour? You have to rember I am going to miss the AWD that my VR-4 runs when that car goes. though the extra driveshafts would add weight it seems like the overall performance of the car would improve.

[Matra et Alpine]

I know it is on a totally different note but do you think that a four wheel drive differential would be easier/cheaper to come across? or is a mid engine AWD/4WD vehicle just not really a feasable endeavour? You have to rember I am going to miss the AWD that my VR-4 runs when that car goes. though the extra driveshafts would add weight it seems like the overall performance of the car would improve.

Definately not cheaper or easier to source and install an AWD drivetrain.
Also if you are mainly tarmac then you won't want to lose the power into the AWD drivetrain when a well-balanced mid-engine RWD will give better traction on all but the very tightest of corners.
To handle 800bhp, the centre diff will take a LOT of loading and will be very expensive to make it slip when required. With that amount of power, you're certainly looking at needing adjustable diffs and now you're into GroupB technology. Want to spend 50 grand on a drivetrain ?
There are plenty of sites and books on the GroupB cars, see what the 6R4, RS200 and 206T16 were doing. Have you thought about buying one of those and saving the hassle

[V8turbo4me]

You are perhaps very correct there Matra. Maybe I should consider turning the power down a bit and get back to what was my original goal of awesome handling and great acceleration and braking. Here is the deal though, I still want to produce about 700-750 hp at around 12psi of boost from dual turbo chargers, though I am considering boost levels from 8-15 psi. I was wondering about what size block and what compression ratio you guys think I should run. I would like to use 93 octane gas in the car which would have dual intercoolers to occumpany the turbos. If you have any suggestions please let me know, I would love to hear them, always looking for input.

[mechanixfetch]

Matra, I have actually heard of a lot of those european auto companies unfortunately their components are not easily obtainable over here in the states so I tend to rule them out for practical reasons

well you seem to be planning on spending a whack load of money so wouldn't the cost of shipping the parts really end up as being inconsequential anyway? Why sacrifice tried and tested performance and use when you want to build the ultimate car?

[V8turbo4me]

Well I'm not really planning on spending a "whack load of money" and I don't intend to settle for a transaxle that will not have the capabilities I need it to have. A transaxle from a renault is obviously not going to have ideal gear ratios for a V8 engine so I don't think I want to go that route either. I also looked into the porsche 930 transaxle and it really isn't that great of a deal, It would be about $8000. That is a lot in my opinion for a transaxle that will be overstressed and out of date reguardless of how much it is updated. So again, I am looking for suggestions on a transaxle.

[Matra et Alpine]

Well I'm not really planning on spending a "whack load of money" and I don't intend to settle for a transaxle that will not have the capabilities I need it to have. A transaxle from a renault is obviously not going to have ideal gear ratios for a V8 engine so I don't think I want to go that route either. I also looked into the porsche 930 transaxle and it really isn't that great of a deal, It would be about $8000. That is a lot in my opinion for a transaxle that will be overstressed and out of date reguardless of how much it is updated. So again, I am looking for suggestions on a transaxle.

First, the Renault transaxle is used by serious racers and is often used in GT40 kits with BIG V8s.
It IS good for lots of power and my A610 manages 0-60 in 5.5 and 165mph in factory condition. So I'd not dismiss it so out of hand perhaps
"out of date" ? for a transaxle. With the exception of computer controlled LSDs then I'm afraid not much has changed in gearboxes in 50 years. So not sure what you are looking for I presume you are still lookign for manual as auto's are the only area of major improvement over the years.
The ZF transaxle range is one of the most widely accepted competition setups and is used in may different formula's/ Not much is diffferent from the ZF' of 20 years ago.
We're trying to help, but I'm not sure of the decision-making and it makes it hard to suggest alternatives.

[V8turbo4me]

I didn't mean out of date as far as technology is concerned I am talking out of date as in out of time, all things wear over time as more and more stress is applied to them. I am planning on putting a lot of strain through whatever transaxle I end up with and I need to be confident in its ability to take that strain without giving due to fatigue in the components. And yes I am looking for a manual, either a five or six speed and preferably with overdrive but not necessary. The renault transaxle is something I will seriously consider if you can prove to me that it can handle the stress, I need to say that I am by no means dissmissing any transaxle at this point. I was even thinking that maybe I could have some work done to a pontiac fiero transaxle, but there again the gear ratios will be horrible for an engine that developes 700+ HP. I am looking for a transmission that has shift points at around 45, 85, and 125 mph at 6000 rpms. Actually I would prefer that first go faster than that because by the time the turbos kick in I will already be going 25, so 0-55 in first would be ideal, but maybe not attainable with anything short of a ferrari gearbox.

[sandwich]

daaaaaaaaaaaaaaaaaaaaaaaamn did i come to this thread late. I could've saved you a lot of time.

I recently tried to build a kit car with dreams similar to yours, albeit significantly smaller in scale. 700-800hp is wacky, and you will likely find yourself playing the "bigger turbo, bigger tranny, bigger turbo, bigger engine" downward spiral until your wallet kills you or you end up bankrupt.

Why don't you aim for a more reasonable 650 hp, or a n/a 550hp ish design? I can promise you this- if you can't afford an 8g 930 tranny, you can't afford anything with 800hp.

the options are:
porsche g50/52, five or six speeds, ~500hp capacity, needs to be inverted with a few mods. You can get them through various places, including ultima, for about 5gs or more, depending on your desires. Chevy's are the engine of choice.

930, from a porsche, 4 speeds, 750hp capacity, good gear ratios. Problem is, you WON'T find one for under $3000 in any good condition, and then you have to give it to renegade to have it converted so you can actually use it in a mid-engine design. Renegade WILL charge you an arm and a leg for anything they do. They can charge you whatever they want because nobody else will do what they do. Good finished project, but expect to spend money, and lots of it.

Audi 5000, 450 bhp, buy an adaptor plate from kennedy engineering, and drop it in. It's not 800hp, but you can drive it, and buy about 30 of them for the same cost of one 930 transaxle with no mods.

The fiero can hold about 450 hp, the ZF is way up there. The problem with the ZF is that you're stuck with a ford and you're looking at 5-8g's. I'm not sure of hp, but i wouldn't put it past 750.

You can probably get something to hold 800, but it'll be custom and it will cost you your firstborn son.

As for the renault transaxles that matra is pimping, the only renault trannies in the us can hold like 150hp, and have no place in a performance car. If you want to pay the 1g or more to get a french tranny shipped, then more power to you.

If I were you...I would try to put the engine of your 3000gt in front of the rear wheels. You can use a suzuki samurai transfer case, with no rear driveshaft, locked, to drive a 3-piece driveshaft with carrier bearings back to the front wheels, flip your rear differential and mount it in front, and you now have a 300hp twin turbo, v6 awd mid-engined car. You will of course have to weld in a firewall, a roll cage, and significant rear end stiffeners, not to mention some custom driveshafts. The actual cost of such a project, lots of time and research, ~1000 in driveshafts, 850 for the samurai Tcase (http://www.high-impact.net/transmission_and_gear/),and maybe 1000 in other parts (eg cable shifter, air intakes, wiring, etc). I thought about doing it to an eclipse, and I almost did it to my old kit car, which I sold for similar reasons, btw. I just don't have the garage space or the experience that you might.

For referance I'll include some other pictures of a few midengined frames. One of them used to be mine. Lots more available http://community.webshots.com/user/dileu16 .

Hope this helps, i have lots more info if you'd like, this is just the summary.

[V8turbo4me]

Thanks alot Sandwich, that was nice of you to come in and contribute albeit late. Do you think there is anyway to strengthen a fiero or audi 5000 transaxle to about 650 hp capacity? I guess I am really big on the fiero because it is so easily accessable for me here in the midwest, so I thought maybe shot peening the components or maybe someone out there does upgrades for the fiero or audi transaxle. Its not that I don't have the money to buy the other transaxles it is just I would rather not waste money that I don't need to waste. I do have lots of garage space and time though, I have a three car garage that is my "big boy play house" I am by no means going to start chopping my poor VR-4 man, lol, that car is going to be a collectors item someday and is a great car now, it doesn't need to go under the knife.

[sandwich]

www.v8archie.com

If there is any question of a fiero transmission's reliability, he can answer it. I honestly do not think the fiero can hold much more than that, but you never know.

I don't think the audi can be beefed up too much. I have heard someone flew all the way to england to do it (someone over there had the ability to machine gears for it) but they wanted like a year to have it done, etc. etc., and it wasn't a very good option.

I still think your best option is to go for a zf or g50, converted. It's a good step, cost is not too high, comparitively. If you get a fiero tranny, the trans itself will cost next to nothing, but expect to put several thousand into building it up. Even then, it's still transverse mounted.

Do a search for ultima gtr, and poke around a little. The g50 can hold 550 easily, and i do believe I heard of one that had 650 or 700 and ran in the texas high-speed cross state race. I got a ride in one, and I can safely say it is an excellent way to go.

I was at the carlisle kit car show this weekend....audi transaxles are the hot sh.t right now, they were even in some very high end gt40s. The top of the line racing ones had ZFs, however. It all comes down to how deep your wallet is...the more you spend, the more you get.

[sandwich]

also, check out some forums and kit car sites.

Ones to note:
www.lambolounge.com
Incredibly helpful, lots of trans info.

There are also a lot of kit car clubs in yahoo groups. I would encourage you to become a member of some, like mantacars, kelmark gt, etc.

You are building a kit car, so keep that in mind. Magazines like kit car will help. You may also want to talk to some gt40 manufacturers, like

era cars,
roaring forties,
lone star motors.

kitcar.com, kitcars.com have some good info.

transaxleengineering.com, kennedyeng.com, have good info.

There are three companies making porsche adaptors, kennedy, renegade, and another, starts with rod, maybe rod simpson hybrids? All are similar in price.
http://www.porchev.com/ (Rod simpson- i was right).

[V8turbo4me]

Just need to say thanks again for all the info and if you find anything interesting please let me know.