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Turbo 3.8L Engine (924)?????
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KELSO924  
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PostPosted: Wed Apr 03, 2002 7:15 pm    Post subject: Reply with quote

Anyone ever thought to attempt this? With aluiminum heads/intake, the engine would seem to be fairly light, and are very reliable/potentially powerfull engines...

The problem (besides all the neccesary fab. work) would be all that tourque. The intercooled Turbo Buick motors were putting down Big-Block like tourque figures, and I DOUBT a stock 924 drivetrain could take very much abuse from 400 lb.ft.

Thanks
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Cbass  
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PostPosted: Wed Apr 03, 2002 8:48 pm    Post subject: Reply with quote

I know that 968 6 speeds can handle the torque from a turbo 968 motor. Thats about 400ft lbs.
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turbobob924  
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PostPosted: Sun Apr 14, 2002 4:25 am    Post subject: Reply with quote

Scott in Las Vegas ahs a Buick 3.8 turbo motor in his 944!
http://members.aol.com/grandnational944/

I have a nasty Buick GN engine in my Garage and very seriously considerling a swap!
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Lizard  
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PostPosted: Sat Apr 20, 2002 12:13 am    Post subject: Reply with quote

I was reading on a page that the 4 speed transaxle in the 924 is stronger than the 5 speed as it was created by porsche and can withstand 350 + ftlb at least, not sure if 400 will break it or not but i wouldn't try 400 ftlb with a 5 speed as it was built by audi and cant handle as much power, I know that the torsion tube woulb be able to handle the power though.
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cakemakerman  
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PostPosted: Sat Apr 20, 2002 2:04 am    Post subject: Reply with quote

lol i have a 4 speed trany from a 1978 924 if anyone wants to buy it. I live in washington state.
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Cbass  
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PostPosted: Sat Apr 20, 2002 12:49 pm    Post subject: Reply with quote

There are two basic types of tranny for the 924. The early cars, up to 79, used the Audi 4 speed, and the 5 speed that was based off of the Audi 4 speed. The 5 speed was the same box, modified for an extra gear.

The 79 cars, and most of the 80 cars used a 5 speed from the 911, the 915 tranny. This was expensive to maintain, had a horrible shift pattern, and was very prone to grinding itself apart.

Later cars used the Audi 5 speed, including the early 944s. I think the later 944s used the same tranny, albeit updated. This is my understanding, and I'm probably wrong on several points .

The Audi 5 speed is probably the strongest you're going to find, but if you want big torque, get a 951 tranny. All the V8 and other high torque swaps use it. It's a pretty simple conversion from an Audi based tranny.
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Lizard  
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PostPosted: Mon May 13, 2002 6:34 am    Post subject: Reply with quote

I think that you should look at http://www.windward-perf.com/944turbo.html this is the winward turbo page and they have a tip on this page showing that the older 924 porsche transaxles were strong. I think it is also safe to trust what they say as they have the tools to test these things
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numbers  
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PostPosted: Tue May 14, 2002 8:55 am    Post subject: Reply with quote

Lizard, you are right. The snailshell will take more torque than the Audi box. It is a stronger box in terms of gear strength, but has really crapie synchro's.
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Cbass  
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PostPosted: Tue May 14, 2002 1:29 pm    Post subject: Reply with quote

Yeah, it's plenty strong, until you find out you have 3 worn synchros, and the gears start eating themselves.
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John H  
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PostPosted: Tue May 14, 2002 4:09 pm    Post subject: Reply with quote

Quote:

On 2002-04-20 11:49, Cbass wrote:

The 79 cars, and most of the 80 cars used a 5 speed from the 911, the 915 tranny. This was expensive to maintain, had a horrible shift pattern, and was very prone to grinding itself apart.

This 5 speed is not a 915 gearbox - while soem of the internals (mainly dog teeth) are from the 915 the majority iss custom to teh box. The shift pattern is actually ideal for racing the change from 1st to 2nd is awkward for those not used to it but if you let the lever go by itself it finds 2nd straigh away. I've found in the last few years racing I have yet to select reverse or 4th on a fast start. Once on the move you don't need to go back to first and the gears you use the most on the track are in the H pattern.
The box is strong and I've done over 260,000 miles in mine and we replaced the 1sr gear syncros in 1986/87 and swapped 4th and 5th around in 1989 and since then it has been relible and done many hard miles racing with no problems.
The snail shell is also the better box for racing and handling as it puts most of the weight within the wheel base whereas the other boxes have the gears behind the rear axle line.
A turbo'd Volvo 360 racing sedan over here runs the same gearbox and while the engine puts out over 400hp in race trim the owner has had no problems with the gearbox.
Like most mechanical items if you change oil regularly the box with last for a hell of a long time. If your rough and treat it like shit it will break and so with the Audi boxes.
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Cbass  
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PostPosted: Wed May 15, 2002 7:15 am    Post subject: Reply with quote

It's a better box for racing for sure. On a race track, you'll never see first gear anyways, and if you do, it doesn't matter what tranny you have

Can the stock 924 torque tube take that kind of power though? There is a snailshell in the 79 NA I am buying, and I am replacing it, because I would rather put a 951 LSD tranny in instead.

It's just more practical and reliable for street driving, which is what I'll be doing.

If I get a track car for advertising, then I'll use a snail shell for sure. Or maybe a 6 speed with a Torsen dif.... <stares into space>
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John H  
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PostPosted: Wed May 15, 2002 1:10 pm    Post subject: Reply with quote

I'm pretty sure the non turbo snail shell torque tube has a narrower diameter drive shaft comapred to the 931.
Depending upon how you drive the 931 is a pretty good road gearbox as well. Unless you like to use 1st for slowing down then it's as good as all the others for road use. I have a 79 N/A with the dogleg first and while I have 5 speed box (audi based) and tube from a later car it's not worth the hassle to swap over the ratios are good fro road and it always goes into first when required, secondly it also means I don't have to remeber which car i'm in when I take th ePorsche out inthe morning GT or N/A as they both have same shift pattern.
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Benski  
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PostPosted: Wed May 15, 2002 1:42 pm    Post subject: Reply with quote

According to this, the turbo snailshell transmission can take 600+ hp =)http://cgi.ebay.com/ebaymotors/ws/ebayISAPI.dll?ViewItem&item=1827748669&r=0&t=0
And remember these guys probably had their choice of boxes (951, 968, etc)

I have heard of many 944 racers who use the getrag gearbox - It's certainly the strongest available...

They are often ragged and worn out because of worn shifter bushings that go unreplaced. People hear this, and think the transmission is weak, synchros are bad, etc and so the rumor spreads ...

My dual carb'd 924 (with about 150 hp at the flywheel =) has a rebuilt snailshell and it is just AWESOME... 'clicks' when it shifts ... never miss a gear, never wonder what gear i'm about to go into ... don't have to doubleclutch to second gear... much much nicer than my two turbos (one of which is so bad I won't drive it until I have time to replace the cup at the end of the shift rod)

_________________
76 924 (white), 78 924 (red and automatic)
80 924 (silver), 80 924 (dual carbs, snailshell)
2 80 931's (red + burgundy)

[ This Message was edited by: Benski on 2002-05-15 12:57 ]
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Cbass  
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PostPosted: Wed May 15, 2002 2:28 pm    Post subject: Reply with quote

The parts are expensive though. My big decision is whether to get a new Audi box, or rebuild the snail shell. So far all it needs is a synchro for second, but it could use one for fourth. I figure I might as well do them all, and save having do drop the tranny and crack it open again

What would be the cost to replace all the synchros, and how many hours would it take? I have read the tech section stuff on this, but I'd like to know from someone who has done it recently.
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numbers  
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PostPosted: Thu May 16, 2002 9:44 am    Post subject: Reply with quote

Cbass, I posted some of this on the other thread. If you only replace the synchro rings, it is not too expensive. $100 or less per ring. The big issue is droping and re-installing the box. It will take you two to three hours each way. A real PITA. Once you have the box on the bench, it is not too bad. Just use your Haynes, and be careful to look over the synchros before you disasemble them. There are a lot of small parts that have to be fitted back in their proper places. You will need an impact wrench to remove the nut from the main shaft, but other than that, no special tools are required.
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