: Tranny Question

06-14-08, 01:30 PM
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 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.



06-14-08, 04:19 PM
Mark, Welcome back....Missed you the last year. Glad to see the car is still trackable.

There have been a lot of questions surrounding your car and work, mainly by brand new members looking for "Northstar Mods".

Would you be willing to put together a brief history in order to detail the blood, sweat, and tears that went into your car?

Within 12 hours this thread will be 600 posts long. Somebody's going to want a kit to put on tomorrow afternoon :rolleyes:.

All the best, Jim

(as regards your turbo boost jump, the "Turbo" muffler got its name from the '64 Corvair Spyder: There was no blowoff so the muffler was created to raise back pressure and limit RPM. You could drop the muffler and easily blow the engine......(2 to be exact....).)

06-15-08, 12:55 AM
Not surprising... 450 is about all they can handle.

I can't remember the name of the place that sold built 4t80e's... something-performance. FWDperformance?

If cost isn't a concern, you might consider a 4t65e. They have been used in 1000+hp 3800 and turbo ecotec cars. You'd also lose 100lbs which would shave off a tenth on your 1/4. You'd be on your own for axle$.

06-16-08, 03:32 PM
The place that was building bulltproof 4T80E's upon request was in Harriman, NY. I've still got the link to their site on my computer at home (at work right now) and will post it. When I had spoken with them a few years back they said they had built a few for some people already, but did not sell individual parts. I guess it was more cost effective for them to combine everything into one package.