mobileman

iTrader: (7)

Car is a heavy 2001 Trans am with a 402 that makes 525rwhp through a 9 in and a 4L80 with the converter locked. Both the tranny and nitrous converter are from very reputable companies and are high end parts but one or the other never seems to never be right. I have had the converter looked at a few times and by more than one place but the results seem the same. The converter seems to slip more than it should NA and gets worse with a 175 shot and is supposed to handle a 350-400 shot. I have make some minor changes to the tranny tune as far as when the converter locks and where it shifts but all other parameters are stock from the segment swap. Lookin for some help with the tuning to see if that may be the problem.

Mavn

iTrader: (3)

What brand converter?

mobileman

iTrader: (7)

Circle D

wht/73

Did you try it unlocked on the dyno? Was the 525 with the shot or N/A?

mobileman

iTrader: (7)

525 is N/A. Never sprayed it on the dyno or ran the converter unlocked on the dyno. Slip #s compute over 15% on the 175 base tune.

MaroonMonsterLS1

Slip in what gear and at what rpm?
Have more details on the converter?

How are you calculating slip? Engine RPM vs input sensor rpm from the 80?

mobileman

iTrader: (7)

Slip in 3rd gear at the track. Going by mph and rpm, also log from hp tuners. Converter is a 3600 billet, tripple disk lock up.

wht/73

525whp you should be well into the 10's

mobileman

iTrader: (7)

Im not sure of the weight, but iron block, braced 9in, 10pt cage, all bmr suspension 4l80,, car still has the air, no weight savings. Car runs 11.10 @ 119 and 1.57 60ft. 175 shot runs 10.45 @ 126 1.45 60ft. Pulling 7 degrees just base tune, trying to figure out what the tranny/ converter is doing.

MaroonMonsterLS1

Have you called the converter manufacturer and described whats happening?

mobileman

iTrader: (7)

Yes they have stalled it twice. I even had another shop look at it and they got it to 60' better but didnt feel it should be that loose either.

MaroonMonsterLS1

What is the converter diameter? Can you share some more info on the specs of the converter.

Also, what are your typical trans temps when testing?
What is cooler line pressure and main line pressure (converter charge pressure is a derivative of cooler pressure and line pressure and can change the way the converter behaves...not super common with 4l80e stuff but it could be indicitive of an issue)
What type of fluid are you using?

watman02

iTrader: (9)

I had a billet 245mm single disk nitrous converter from Circle D that was specd for a 402 ci ls and I put it in my turbo camaro and it seemed really loose as well to me but it stalled right at 3600 just like it was supposed to but wouldn't get efficient till 6500+rpm I never took it past 6800 but my ecu converter slip showed it was getting better and better. Maybe your bot spinning it high enough. I took it out as it didn't work right for my setup but it sounds like a similar situation to yours my car with me in it is almost 4000lbs.

mobileman

iTrader: (7)

245 3c . Dextron/ Mercon fluid, Ill check the exact fluid when I get in the garage. Its a fluid Rossler reccommended. I do not know what temp the tranny is running at but it has a good size cooler and a custom Morrosso pan that holds 2 or 3 quarts extra. I have felt the tranny and cooler in the past and its definitely not getting hot. I was going to check pressures at the tranny now but wasnt sure what the pressires should be and how to change them if there not right. I wasnt sure if there was a setting I needed to check in the tune.

dw456post

If you have HP Tuners, why don't you post the tune? It's hard to tell what the tune is asking for.

mobileman

iTrader: (7)

Here is my tune. Its from last weekend when I tried switching to a 4.10 gear to see if it would help the problem and was also experimenting locking the converter in 2nd.

mobileman

iTrader: (7)

This is what I am seeing too. The higher I twisted it the better the slip got but even shifting at like 7200-7300 it was still loose and wasn't gaining enough to keep the revs that high. If I trusted my lifter more I would experimented even revving it higher.

mobileman

iTrader: (7)

3.73 and not locking the converter
https://photos.app.goo.gl/2mz67uQvX2gy9ddw5

4.10 and locking at the top of 2nd and keeping it locked. It spun the tires and I had to peddle it but still trapped 132.
https://photos.app.goo.gl/zLshznwSZJoKSFjJ8

wht/73

Link doesn't work for me.

MaroonMonsterLS1

About the only 2 ways to change the converter behavior without physically altering the converter...is by converter charge pressure...or fluid type. Both usually only gain about 150-250 rpm on the stall speed which translates to a few percent on the big end.

If anyone else has an easy way to change converter behavior other than those two, please feel free to share. I may just not be thinking of one.

I'm not sure what you're thinking to change in the tune to get the converter to act differently