About to give up on tuning 3800 converter in 6L80....need help

[2000_SS]

Working on a 2012 Camaro SS with a big cam and big converter. I cannot for the life of me figure out how to make this thing shift at WOT. driveability is nice, although fueling isn't finished...we're running MAF only for now until i can get the car back for a day or two. I've only done one other 6L80 with a converter and it was a bone stock car with a 2600 or 2800 Edge, piece of cake.

This car has a Revmax 3800 in it. The car acts like the converter is just too loose. i'm having the owner verify fluid level tomorrow as well, the car had a trans fluid leak for a day and i'm not confident the converter didn't get put in dry.

We thought me made some progress though with another attempt today where i set the shifts to happen pretty rapidly, that file and a log are attached. The root problem i'm fighting is that once you go WOT, the RPM's sail up to the fuel cutoff and the car stutters between gears before continuing on. It hits the fuel cutoff at or just after each shift. I want shifts to happen around 6000 rpm like commanded but the engine just revs so fast & the converter is so loose it misses the shift and hits the fuel cutoff....hence why i tried making the shifts happen in rapid succession but once it finally makes it to 4th, it bogs hard, which i now think may be related to the TCC apply in 4th. I didn't get a chance to experiment further since his woman was needing to go to Walmart before going in to work.....The attached file is the one currently in the car and the log is from that run. The previous WOT shift speed settings i tried were as follows:

1-2 @ 21mph
2-3 @ 51mph
3-4 @ 80mph

also tried like this:

1-2 @ 32mph
2-3 @ 37mph
3-4 @ 44mph

I've also had the shift rpm in 100rpm increments from 5800 to 6250. No matter what happens, i can get the 1-2 shift to happen as commanded but the rpm continues on up to 6500 in 2nd and the fuel cuts in each gear after. It acts like the shifts need to happen very rapidly but the car bogs in 4th. I know my current settings aren't correct and may not be close to what the final result ends up being, its just where i'm at right now and i'm out of ideas. Any suggestions would be greatly appreciated.

Thanks guys.

[jaydubb71]

What size gear?

[2000_SS]

3.27 I believe

[jaydubb71]

Have you tried the Bluecat Trans Tool? I used the numbers from your tune and came up with something different. I also noticed your part throtlle shift MPH was was off from your WOT.

[jaydubb71]

If you want, I saved my BTC file (the result). I can send it to you, if you like.

[2000_SS]

I have the tool and started with the results. Send me what you have and I'll compare to what I had in it. Even with those numbers, it hit the fuel cutoff before shifting. I didn't want to raise the cutoff but I think at this point I may have to. The converter is extremely loose.

I'm still messing with it though. I don't like the shift speeds at wot that I currently have, but that's the only way to make it go through the gears without cutting out at every shift so badly.

[jaydubb71]

When I used it for my G8, I had to lower the 1-2 shift mph by 2 or 3... Inbox me your email address. I cant send this BCT file thru the forum.

[2000_SS]

Thanks, I'll look at it tonight

[jaydubb71]

No problem. Let me know how it works out.

[2000_SS]

Will do

[realcanuk]

I just looked quick but a few things stood out. You should make the WOT shift mph match the mph in the 100% column of the part throttle shift speed. Also zero out all the TCC desired slip tables. Personally, I would run with some torque management to help it shift but some people don't.

Also noticed your full throttle apply release tables are telling it to lock in all gears. Not sure that is what you want to do.

[2000_SS]

Ok thanks, i was actually planning on playing with TM this weekend some. I know some vehicles are very sensitive to removing it and some just flat out won't work without out. As for the TCC slip, i'm not sure what to do with that. I see it's calling mostly for a 20 rpm slip in 2nd through 6th gear. Should i just zero those out or are you saying it needs to slip more? 20 rpm doesn't seem like much either way. I'm honestly not sure how/when to have the TCC lock/unlock. I don't have a dyno or access to one either to see what the car likes on paper. Is there something you'd suggest I read or look at to brush up on the subject? I'd like to get better at trans tuning but i don't get to do that many built autos or big converter cars to practice on. This one i'm working on right now just happens to belong to a friend so i can work on it whenever we both have time to meet up. It's by far the most difficult one I've encountered, although i'm sure it's not that hard for someone who has done it multiple times.

[realcanuk]

I would 0 out the tables and for starters try setting the converter to lock only in 5th and 6th in normal driving. I don't lock mine at full throttle but that is trial and error. Some cares run faster locked, and some don't.

[2000_SS]

Ok I'll try that. Thanks. What's the procedure for determining if the car likes to be locked or unlocked at WOT if you don't have a dyno or an open race track? Would I just take an educated guess at when to lock it and track speed vs time in the scanner, say 20-80mph or something? I'm not too new to tuning but like I said, I don't get hardly any big converter cars to work with, especially a 6L car, so this in new territory for me.

[realcanuk]

Ok I'll try that. Thanks. What's the procedure for determining if the car likes to be locked or unlocked at WOT if you don't have a dyno or an open race track? Would I just take an educated guess at when to lock it and track speed vs time in the scanner, say 20-80mph or something? I'm not too new to tuning but like I said, I don't get hardly any big converter cars to work with, especially a 6L car, so this in new territory for me.

The only way that I know of to really tell is to try both ways at the track, and see what works best.

[Speedmaster747]

Have you touched your torque coefficient tables on the torque management/engine tab?
The Airmass A B C and D?

[2000_SS]

I have not.

Turns out it was just severely low on fluid....so low he wouldn't tell me how low it actually was. He took it for a spin and it shifted fine. It's coming back to me tonight for VE tuning, so I'll refine the shift points with everyone's suggestions.

Thanks for the help, fellas.

[HeavyChevy305]

They probably slapped the converter in the tranny dry lol.

[2000_SS]

That was the very first thing i asked when he dropped the car off. He bought it slightly used from someone else with a warranty still in effect. He said, "it had some fluid in it when I took it out of the box.".....I just rolled my eyes and prayed for the best.

I'm always quick to diagnose a mechanical issue, but slow to get it fixed. It makes me second guess my tuning abilities when something isn't going my way. I hate to look stupid in front of the vehicles owner, especially when he's a GM tech. I do enjoy a good "I told you so" though, lol

[04blackgmc]

I can work you up a tune for the A6 let me know.


Also The A6 is highly sensitive to fluid level being low, I've been dealing with this for years. I wonder how many shops tell customers they need a trans when it's just low fluid level.


I always overfill by .5-1quart