twinturbo496

iTrader: (2)

A local converter shop in Portland cut open a 5.7L gas 4L80E converter and made a few changes inside so it would help my car idle better at red lights. I just asked them to up the stall as much as they could, they also installed a new converter clutch disc. I have about 2000 miles of street driving on it.

My question: If I run the car in 3rd, then let off little at about 2500 rpm and lock the converter clutch, will it hold full power? The car has a big engine, but it really doesn't make that much power, most likely less than 500 to the wheels.

I know that the mod's they made to the stock converter aren't the right way to change the stall, but I didn't really want to spend a lot of money on a 80e converter only to find out that my rebuild wasn't good enough.

If the engine/trans doesn't blow up this summer, I plan on putting on a bigger blower and a proper stall converter this winter.

performabuilt

iTrader: (25)

With a stock or any single disc converter there is always some risk locking on the dyno. More than likley I will say you will be ok. But its not 100% I would say tell your dyno operator to watch the input speed to MPH and if it looks like slip stop imediatley.

Circle-D

iTrader: (21)

I think you will be fine for a couple of runs. Just watch out for the slip. The OE converter has a huge piston so it has a lot of area for the fluid to push against. Good luck, be sure to give us a call when you are ready for the new converter. The turbo setup will love my multi disk.

Chris

twinturbo496

iTrader: (2)

Thanks for the input.

Side note, we tried a pair of holset turbos on a 454/th400 in a test vehicle. I decided I'm not ready for that just yet, so I put an 8-71 on instead, it has a lot less power, but the turbo setup was not something I wanted to let my wife drive.

Chris: you built a special turbo for me a few years ago so I could put a 3.3L Mitsubishi Diesel in my S10 pickup, it worked for a lot better than I expected. I will give you a call later this summer for a new 4L80E converter.

Circle-D

iTrader: (21)

Yes I remember that, I think we used a 700R4. Very interesting project, glad it worked out for you. Talk to you soon.

Chris

twinturbo496

iTrader: (2)

For anyone else how might want to try this, my stock converter with a new clutch held 590 tq/520 hp in third gear from 2000 rpm - 6000 rpm.

I had a local shop modify the stock converter to give it more stall speed, it flashes to about 3500 in my 3800# car with 3.50 gears and a spool (28x10.5 tires)

I took it to the track it ran 11.05@125.

01ssreda4

iTrader: (96)

glad it held up, I wouldnt do it though.

twinturbo496

iTrader: (2)

I agree. Trying to use a "stalled" stock converter on a drag car doesn't seem to work as well as I had planned.

In short, the modified converter doesn't work right. It is loose enough for my solid roller cam to idle in gear at 950 rpm, but it doesn't seem to ever actually "tighten up" at higher rpm. At the track I can't even feel the transmission shift at 6000+ rpm, it goes into the next gear but the engine rpm doesn't drop. The first time it happened I was positive that I had burnt out a clutch pack, but when I got home and pulled the pan off the transmission it looked like new, absolutely nothing in the bottom of the pan...

On the bright side, perhaps my car will actually get into the 10's with a good converter.

Also, my transgo-3 kit still has a late 2-3 shift...not sure what to do next, perhaps the TCI trans brake...