Mid Engine Transmissions, I been thinking Options

[andys]

QUOTE (r_towle @ Jan 21 2005, 02:29 PM)

So, Audi/VW tranny is what I am looking for. I want a tranny that is plentiful to get at junk yards, has some aftermarket support, and can realistically handle 450 hp. It seems that once I get over 300 hp, i get into a G50 tranny that will cost a fortune to rebuild. I want a tranny that I can buy several and keep spares around with different gear ratios.. Right now I have like 7 901 trannies, but I may just sell them and get several trannies that can.. A) relialby handle the power (IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif) Be able to handle long drawn out burn outs c) handle drag racing type acceleration d) possibly an automatic if I need that type of shifting. A is the most important with B and C being a subset of A This is not a dream, this is what I want to put in any car...to put all the money into a great motor only to have to baby the tranny seems like a waste of time. The 928 puts out 300+ in stock trim...and it wont stay stock...I have seen 600HP versions out there. I am ready to go down the 928 route with my car, but all the effort to build this and baby the tranny is just stupid IMHO...I know it can handle 300HP, but can it handle me with 300HP, I doubt it. Rich

Once you get into "Be able to handle long drawn out burn outs", and 450+HP, the transaxle choices become pretty slim AND expensive. The 930 is a good choice, not hugely expensive, good ratio's, plenty of adapters, needs flipped ring gear (with machining), or run up-side-down (with minor mod's). ZF takes the cost issue to the next level, as does the G50, and so on (Mendeola, Fortin, EMCO, Quaife).

The Audi stuff will very likely never withstand that burn-out thing. The GT40 replica guys are putting 400HP or so thru the 016, but you must be nice to it. That said, you can probably find an ample supply of them in the junk yards for cheap, but I don't see the point. May as well stick with your supply of 901's.

Transaxle longevity depends much on your driving style, and it sounds as if you're looking for throwing some pretty severe pounding at it. No M22's or Top Loader's in this catagory.

Andy

[redshift]

QUOTE (MattR @ Jan 21 2005, 08:07 PM)

QUOTE (redshift @ Jan 21 2005, 03:58 PM) Draw a line at the rear of the front tires, and another at the front of the rear tires.. That is what I am talking about. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) M Why do the tires define the location of the engine? Would putting smaller tires on the car change its engine location? It should be measured from the center of the tire, where the forces are applied.

I was just saying to section it up, and see that most of the weight to the rear is real close to the rear.

(IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)


M

[r_towle]

QUOTE (redshift @ Jan 21 2005, 04:23 PM)

QUOTE (MattR @ Jan 21 2005, 08:07 PM) QUOTE (redshift @ Jan 21 2005, 03:58 PM) Draw a line at the rear of the front tires, and another at the front of the rear tires.. That is what I am talking about. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) M Why do the tires define the location of the engine? Would putting smaller tires on the car change its engine location? It should be measured from the center of the tire, where the forces are applied. I was just saying to section it up, and see that most of the weight to the rear is real close to the rear. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) M

who cares

[Mueller]

I still stand by my thoughts on the MR2 (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

I'm not the only one...Road&Track and cars.com thinks the same way:

QUOTE

Current mid-engine vehicles include Porsche’s Boxster and Toyota’s MR2 Spyder — though the latter borders on being rear-engine because its motor is directly over the rear axle.

now back to the original post, I think rich is looking for the holy-grail of transmissions (for us "frugal" 914 owners)

I don't think they is going to be a sub $3k transaxle that's going to handle being abused with 450+ hp

one thing to ponder, the size/type of tire can influence how long the transmission will last....sticky wide tires will cause the transmission to see more stress than skinny or harder tires....

[SpecialK]

WOW....for a second I thought I was still on jwalter's "Bus 4 speed" thread (IMG:http://www.914world.com/bbs2/html/emoticons/blink.gif) . Well there you go, how about a beefed up bus tranny?

[Mueller]

QUOTE (Special_K @ Jan 21 2005, 07:40 PM)

WOW....for a second I thought I was still on jwalter's "Bus 4 speed" thread (IMG:http://www.914world.com/bbs2/html/emoticons/blink.gif) . Well there you go, how about a beefed up bus tranny?

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif)

I'd look into that for sure....

[Brett W]

The Audi tranny comes from the 5000 Turbo Quattro. It seems to be logical choice for us. You will have to design a shift linkage and get custom axels, but it will hold 450+ in out applications.

One thing to remember about a tranny and its capability to handle torque, when you are moving 3000+ lbs worth of car your tranny will be under more stress as you up the horsepower levels. So if you drop the tranny from a 5000 or boxster, etc in a teener and lighten accordingly your tranny's HP tolerance should go up.

[cha914]

Yep, seen lots of v8 sand cars use these...pretty cheap to get a beefed up one even...and the axels are bigger right?

http://www.ranchoperformance.com/transaxles/vw.html

[xsboost90]

all these ideas and no mention of a 944/951 trans? a 944 trans is pretty tough and a 951 even more so though gearing is slightly higher. The 928 trans is much bigger IIRC. Either way they sit in the rear and have half shafts. Old 924's have "Thing" halfshafts, should be close to length.

[michel richard]

QUOTE (cha914 @ Jan 21 2005, 07:00 PM)

Yep, seen lots of v8 sand cars use these...pretty cheap to get a beefed up one even...and the axels are bigger right? http://www.ranchoperformance.com/transaxles/vw.html

Don't forget about the side shift thing, though.

[Brett W]

The 944-951 tranny is the same one as the audi box from what I understand. I believe it is wider so you have to either widen the track or get shorter axles.

[andys]

QUOTE (Brett W @ Jan 21 2005, 07:48 PM)

The 944-951 tranny is the same one as the audi box from what I understand. I believe it is wider so you have to either widen the track or get shorter axles.

Brett,

Well they're close to the Audi 016 (Audi 5000), but differ in that the 951 (016R) has no provision for the clutch/TO bearing, and the input shaft is different. The 951 input shaft does have heat treated gears, an integral oil cooler pump, and a 3.375:1 R&P. The trans and R&P ratio's differ from the Audi version. Bummer is, that the parts that matter cannot be swapped with the Audi trans parts for a hybrid. With the right selection of parts, you can swap the R&P.

The Quattro version of the 016 is rated higher simply because you split the torque between two differentials through a Thorsen. This holds true for the newer model 01E 6 speed Quattro trans, though it seems to be somewhat more durable than the earlier model 016 5 speed Quattro.

I like the "out of the box" thinking with regard to the bus trans. There has been a ton of racing development on these, and you (jwalter) just might be on to something very interesting.

Andy

[Brett W]

Yes I thought they would be a little different. You can get the Audi tranny for 150$ all day long, yet the 951 tranny would probably cost you a bit more.

http://www.lambolounge.com/Chassis/Transmi...i-915/index.asp
http://www.lambolounge.com/Chassis/Transmi...n/5000/5000.asp
http://elektro.cmhnet.org/~charlie/photos/.../01E/trans.html
http://webpages.charter.net/jims80/M6B-GT/...nginetrans.html