Auto to Standard Trans conversion
Thread Starter
Instructor
Joined: Dec 2011
Posts: 120
Likes: 1
Auto to Standard Trans conversion
Anyone done it or is it just whacky to try and do it? I did a track day in Cresson two weeks ago with the Brazos River CC and had the oldest Vette and the slowest Vette! Not saying I drove the slowest but, compared the the C5 & C6... yea.
Anyway, the Auto trans in mine did not shift when I would have liked it to and I didn't have very big expectations but, I listed my car for sale the other night and then took it back off last night after a change of heart on just the auto trans issue. I have put some work into the car with some more to go but, if it's not batsh#t crazy, can I scab the standard pedals and gear off of a car being parted out and are the connection points there in mine? (It's an '88 BTW)
Anyway, the Auto trans in mine did not shift when I would have liked it to and I didn't have very big expectations but, I listed my car for sale the other night and then took it back off last night after a change of heart on just the auto trans issue. I have put some work into the car with some more to go but, if it's not batsh#t crazy, can I scab the standard pedals and gear off of a car being parted out and are the connection points there in mine? (It's an '88 BTW)
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
I'm sure its been done, but I think you would be better served by just getting a manual transmission Corvette.
Hey, you might have been slow but when your down 100 or 150 or 250HP!?!?! It is expected. Kudos for actually using your Corvette like a Corvette.
Hey, you might have been slow but when your down 100 or 150 or 250HP!?!?! It is expected. Kudos for actually using your Corvette like a Corvette.
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
I've seen conversions on here so I know it can be done. The question is, is it worth it?
What have you done to your car?
What would be the cost to replace it with a manual model and do the same to it?
Do you enjoy this type of stuff or would you have a shop do it -if so, I doubt it is cost effective.
I'd figure you could easily be out 3k for the swap so if you are relatively stock, you could probably come out ahead selling and buying a different one, if you can find what you want.
Looks like Keisler now has a T56/45 based option (5 speed) that might be a good way to go (as well as the TKO) though they say the RS is good for 7k shifts.
http://keislerauto.com/gm/corvette/c...-products.html
EDIT: Also if you are going RR, grab an aluminum flywheel for it. Even with TPIs they are a blast.
What have you done to your car?
What would be the cost to replace it with a manual model and do the same to it?
Do you enjoy this type of stuff or would you have a shop do it -if so, I doubt it is cost effective.
I'd figure you could easily be out 3k for the swap so if you are relatively stock, you could probably come out ahead selling and buying a different one, if you can find what you want.
Looks like Keisler now has a T56/45 based option (5 speed) that might be a good way to go (as well as the TKO) though they say the RS is good for 7k shifts.
http://keislerauto.com/gm/corvette/c...-products.html
EDIT: Also if you are going RR, grab an aluminum flywheel for it. Even with TPIs they are a blast.
Last edited by USAsOnlyWay; May 17, 2012 at 11:20 PM.
Thread Starter
Instructor
Joined: Dec 2011
Posts: 120
Likes: 1
Thanks for the input fellas. Yes, a buddy and I would probably do it if the pedal well is set up to accept the equipment. Not sure if I feel like engineering any of the guts down there. It would be cool if it was something that I could scavenge the parts of another car and switch the stuff out over a week or weekend. It would be worth $3K to me in that case. I really enjoy the interaction with the machine.
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
I think the Keisler stuff for a trans swap (already a manual) is in that $ realm, conversions would be worth a call. Might be worth it to just plug it in and go but you won't know till you know the cost.
Other ones that you could swap in are t56, (87bob did the swap from a 4+3 IIRC), zf6, t5 (though I question reliability).
Both will require the third pedal, hydraulics and some work in either swapping c-beams and driveshafts with a manually equipped car or something similar with fabbing up a mount for the t56 (though I know a website sells one too).
Easiest will be Keisler and that RS looks interesting if you are OK with a 5 speed otherwise the t56 and zf6 will take a bit more work but are also doable at probably a lower price.
(For instance, zf6 =700-1200 used, flywheel -300, clutch -300, clutch master - 100, hydrualic TOB- 150 + lines 100, clutch pedal assembly - ?, driveshaft/c-beam from a manual - 300, interior console panel- ?, ~ 2500? You obviously could use factory hydraulics or whatever, just a ballpark figure.)
As a side note, an alternative to the aluminum flywheel option is to use a 4+3 flywheel if you can, they only weigh around 21-25lbs and were a cheaper option that full aluminum(13lbs, steel=~30lbs) for RR/autoX use.
Other ones that you could swap in are t56, (87bob did the swap from a 4+3 IIRC), zf6, t5 (though I question reliability).
Both will require the third pedal, hydraulics and some work in either swapping c-beams and driveshafts with a manually equipped car or something similar with fabbing up a mount for the t56 (though I know a website sells one too).
Easiest will be Keisler and that RS looks interesting if you are OK with a 5 speed otherwise the t56 and zf6 will take a bit more work but are also doable at probably a lower price.
(For instance, zf6 =700-1200 used, flywheel -300, clutch -300, clutch master - 100, hydrualic TOB- 150 + lines 100, clutch pedal assembly - ?, driveshaft/c-beam from a manual - 300, interior console panel- ?, ~ 2500? You obviously could use factory hydraulics or whatever, just a ballpark figure.)
As a side note, an alternative to the aluminum flywheel option is to use a 4+3 flywheel if you can, they only weigh around 21-25lbs and were a cheaper option that full aluminum(13lbs, steel=~30lbs) for RR/autoX use.
Last edited by USAsOnlyWay; May 17, 2012 at 11:56 PM.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Once you do that, then the stock 2.59 or 3.07 rear gears will need to go. For a decent Dana 44 with 3.45s figure $1,000 - $1,500. Another option is 3.73s in your D36 for $500 if you do all but the gear setup yourself.
Cheaper, faster, easier to just buy a 6 speed car. For your car plus the $2500-$3000 your going to spend on a conversion, you can probably get a decent '92 or later LT1 car. Not only do you get the transmission you want, but you get an extra 50hp.
Even if you mod the engine to be equal with or slightly more power than a C5 or C6 (much less any of the Z06s), assuming equal drivers, a stock C5 or C6 will run circles around a C4 on a road course. The later chassis is just that much better.
None the less, it's a LOT of fun! It's also very addicting. As the saying goes, "How do you make a small fortune racing? Start with a large fortune". It's applicable to trying to run with the big dogs at track days as well.
As you get better, be prepared to use better brake pads and to add brake cooling. C4s that are pushed hard boil the fluid or fade the pads very easily.
Cheaper, faster, easier to just buy a 6 speed car. For your car plus the $2500-$3000 your going to spend on a conversion, you can probably get a decent '92 or later LT1 car. Not only do you get the transmission you want, but you get an extra 50hp.
Even if you mod the engine to be equal with or slightly more power than a C5 or C6 (much less any of the Z06s), assuming equal drivers, a stock C5 or C6 will run circles around a C4 on a road course. The later chassis is just that much better.
None the less, it's a LOT of fun! It's also very addicting. As the saying goes, "How do you make a small fortune racing? Start with a large fortune". It's applicable to trying to run with the big dogs at track days as well.
As you get better, be prepared to use better brake pads and to add brake cooling. C4s that are pushed hard boil the fluid or fade the pads very easily.
Pro
Joined: Aug 2004
Posts: 549
Likes: 13
From: Richmond VA
If doing it you will need a lot of changes
D44 rear and driveshaft
Early year clutch/brake pedals + master and slave
the trans kit, if using a zf, kits can be found from some salvage yards
possible requirement for new cluth, flywheel .... the DMF for a zf is no longer available but Spec and others make some SMF that will work
the trans tunnel area around the shifter depending on how "nice" you want it this can be a small or a medium job
shifter plate for the console
It does take a lot of time but the only area you need to "fabricate" is the trans tunnel. The mounting points for the master cylinder is dimpled so drilling that is simple.
I did it, as I already had the D44 already and a lot of other mods on a low mileage car. If you do not have a lot invested or "love factor" in the car I would start over with a zf/6 speed car.
D44 rear and driveshaft
Early year clutch/brake pedals + master and slave
the trans kit, if using a zf, kits can be found from some salvage yards
possible requirement for new cluth, flywheel .... the DMF for a zf is no longer available but Spec and others make some SMF that will work
the trans tunnel area around the shifter depending on how "nice" you want it this can be a small or a medium job
shifter plate for the console
It does take a lot of time but the only area you need to "fabricate" is the trans tunnel. The mounting points for the master cylinder is dimpled so drilling that is simple.
I did it, as I already had the D44 already and a lot of other mods on a low mileage car. If you do not have a lot invested or "love factor" in the car I would start over with a zf/6 speed car.
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Advanced
Joined: Jun 2011
Posts: 70
Likes: 0
From: Rockford TN
A lot of good points here. The biggest issue for most C4 owners is the cost to convert vs. the value of the car. I would of course love to sell you a conversion kit, but for similar money, you could buy a manual car and never have to turn a wrench. A tough call to be sure, especially if you've already got significant $$$ into engine and suspension mods. Rough guestimate on a 5-speed conversion would be about $4500+ which would be everything from the back of the block to the rear pinion, although I don't currently stock a C-4 pedal kit.
Thread Starter
Instructor
Joined: Dec 2011
Posts: 120
Likes: 1
Thanks again for all of your input guys. I am going to have to crunch the data in my head. Shoot, Maybe I just need to find someone with a ragged out later model car with more power and standard and trade my pretty nice '88 auto? I know a co worker has a 93 that looks very similar to my '88 and he hates shifting. He would probably trade but he put a lot of money into the car to rebuild the engine and now has too much invested he won't get out to sell or to trade even. He's stuck psychologically even though he has lost interest in his because it's a standard.
