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Tranny question


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Hi all,

It's been a while since I've been on the boards. Hope everyone is doing ok. The Caddy keeps getting better and better. Just to bring everybody up to speed, I am now running a 950 Holley stand alone engine management system along with a PCS stand alone tranny controller specifically for the 4T80E. The stock PCM controls all the rest of the car as normal. The motor has a Darton sleeve with forged pistons and rods, ARP head bolts and stock crank. It is good to 1000HP. I upgraded the turbo to 70-1 instead of the 62-1 I was running. I also got a Greddy Profec-B electronic boost controler that I mounted in the dash so it looks stock. I still have the Corsa exhaust.

The guy that helped me build the car decided to get a portable "Dyno Dynamics" dyno and I have partnered with him to be the operator to go to events and do tunning. Since I have the dyno at my disposal I decided to experiment. I have a 3" down pipe coming off the turbo going into a 2.5" just in front of the CAT and continuing on back through the Corsa. Turbos don't like back pressure and I know I was choking it by going from 3" down to 2.5". I was only able to get the boost up to 11.5 lbs. so I thought what if I drop the pipe right berfore it rduces and put it on the dyno. OH MY GOD what a differencce. The boost went up to 15.5 and I gained a full 73hp to the WHEELS which is about an extra 100 to the crank. I was at 410 and then it jumped to 483. That is close to 600 at the crank. I couldn't just leave that kind of power on the table so I put an electric cutout on the exhaust so I can pick up that exra 100hp with the click of a switch. Really cool! The car did a 12.25 @118mph spinning the slicks through 2nd gear. If it woould ever hook it would be in the mid 11"s(tough to do on a front wheel drive with that kind of power)

Any...... way as you probably guessed a completely blew up the tranny. It completely fused the clutch packs so I have no 1st or reverse. I know that way back for some of us oldtimers on the original board I rember a link to a place in NY that supposedly made a bullet proof 4t80e. Does anybody know where I can get upgraded parts for the tranny, bigger valve bodies, thicker and stronger clutches, etc.

Now that I have created a monster I would like to see it live for a while so I can enjoy it. That is my weak link right now. Any input would be appreciated.

MARK 99STS

TURBOCHARGED

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Mark, I would send Bruce a PM and see what he can come up with. I am not sure what is available from the original board.

According to my ATRA 4T80e rebuilding manual Maximum Engine Torque is 305 ft lbs (clutches, etc), maximum gearbox torque is 461 ft lbs. You replaced your differential right?

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I would call one of the racing transmission rebuilders such as TCI. I did a web search on "Racing Transmissions" and turned up a lot of links, including a score or so of possibilities. I would start with TCI. They rebuild and sell parts of all the late model GM longitudinal transmissions including the 4L60E, 4L80E, and 4L85E, and most internal parts of the 4T80E should be interchangeable with one or more of these.

Be sure and talk to them about cooling, too. Unless you are already using an external transmission heat exchanger with electric forced air, you should go there just to get through the quarter mile without cooking the tranny fluid.

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I would give these guys a call. They are into building custom racing transmissions and the owner has been featured in several racing magazines. Both my dad and I have had our transmissions rebuilt by them specifically for towing heavy trailers and have had excellent results. What's nice is the owner is friendly and able to think outside the box. If you call them up, ask to talk to the owner. I've forgot the owners name since it has been 10-15 years since I had my transmission rebuilt by him.

Toy Shop Transmissions

1292 E 3rd St

Pomona, CA 91766

(909) 620-5849

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Be sure and talk to them about cooling, too. Unless you are already using an external transmission heat exchanger with electric forced air, you should go there just to get through the quarter mile without cooking the tranny fluid.

Thanks Jim

I am already using an external fan tranny cooler.

Thanks Ed, I will check them out

MARK 99STS

TURBOCHARGED

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