[wnta1ss]

Originally Posted by Immoralus

So while I was perched on my porcelain throne a thought scampered through my
Mind.. What if Chevy implemented a major TQM program from 4th to 5th gear to ensure that the corevette will always dominate top end?

Think you're barking up the wrong tree with that thought. 6th gear is the top speed gear for a stock A8 Camaro SS. The Corvette is lighter and sleeker so it will accelerate quicker and run a higher top speed if the computer allows it. Meaning there is no reason for them to fear the Camaro keeping up if both were completely unrestricted. The Camaro SS Coupe does have a governor set at 180 in the ECM, don't know if the Corvette has such a setting in it.

[jaysonstuart]

Originally Posted by Megahurtz

I definitely do not have a violent shift in 4-5. My canr only shifts hard in 1-2 and then every other gear is perfect. Except for 4-5 where it shifts fast but that stupid TMA hanging around making it feel sluggish.

I will say that once I had the triple flush and TCM reprogram at dealer, the random harsh shifting was gone. And I took it in for the "rumble strip" vibrations.

Yeah mines a very hard shift, sometimes it even slips from 4th to 5th. It's only when the tranny is at operating temp. I also see the traction control/stabiltrak lights flash when it does it.

It's at the dealer again now. I told them to keep it as long as they need to figure this out. I have a full kooks exhaust sitting in my garage waiting to be installed and then it's going to get tuned.

Before I trash my warranty this needs to be taken care of.

[Megahurtz]

Originally Posted by Immoralus

So while I was perched on my porcelain throne a thought scampered through my
Mind.. What if Chevy implemented a major TQM program from 4th to 5th gear to ensure that the corevette will always dominate top end?

Thats a bit far fetched lol. But maybe thats why the manual Camaros did not get 7 forward gears either haha.

I really think its happening due to the converter failing to lockup quickly enough after the shift. It's so weird though that it doesn't affect any other gear. I mean I assume its not happening on the 5-6 shift but how often can you do 140mph+ on the street to test that?

[Immoralus]

Ok maybe a bit farfetched but regardless there is something funky going on. Someone was telling me that the gear ratios change drastically from 4th to 5th but not something that would make it appear as if the TC is slipping...

[PRAY]

Is the TB blade staying open? Or I should say re-opening after the shift at the proper point. I put one of my ported IM/TB combo's on a 17' C7 GS the other day and we were exceeding the TQ tables in either the Driver Demand, ECM, TCM. It was closing the blade. It took a bit of tuning to get it out. With just the IM/TB and a tune we dropped .4 in the 1/8 and .5 in the 1/4. We gained 4+mph. But on the stock tune it would close the blade bad with TM and went slower than stock. That car is sensitive. Check your logs for blade closure.

[PRAY]

Originally Posted by Immoralus

Ok maybe a bit farfetched but regardless there is something funky going on. Someone was telling me that the gear ratios change drastically from 4th to 5th but not something that would make it appear as if the TC is slipping...

Shift recovery from 1/2, 2/3, and 4/5 are the same 1,500 rpm drop. The 3/4 only drops about 1K rpm. So the 3/4 feels much harder than the 4/5. The trans pressures seem to be set up to compensate for this though. Most people say the 4/5 feels like the hardest shift. It could be possible also that if the trans is slipping or the converter isn't locking that you are hitting the limiter during the shift and that is shutting you down for a sec also.

[Megahurtz]

Originally Posted by PRAY

Is the TB blade staying open? Or I should say re-opening after the shift at the proper point. I put one of my ported IM/TB combo's on a 17' C7 GS the other day and we were exceeding the TQ tables in either the Driver Demand, ECM, TCM. It was closing the blade. It took a bit of tuning to get it out. With just the IM/TB and a tune we dropped .4 in the 1/8 and .5 in the 1/4. We gained 4+mph. But on the stock tune it would close the blade bad with TM and went slower than stock. That car is sensitive. Check your logs for blade closure.

Pray would you mind checking out my logfile? I don't recall seeing the TB closing in my logs. Right now the car is running a tune from Tim @ EFI but he did not see it necessary to touch any of the Torque Model or Driver Demand tables. I reached out to him but I think he's been buried. Haven't heard back.

I had to email it to you separately as I could not attach on here.

[PRAY]

Originally Posted by Megahurtz

Pray would you mind checking out my logfile? I don't recall seeing the TB closing in my logs. Right now the car is running a tune from Tim @ EFI but he did not see it necessary to touch any of the Torque Model or Driver Demand tables. I reached out to him but I think he's been buried. Haven't heard back.

I had to email it to you separately as I could not attach on here.

I will take a look at it as soon as I get a chance. May be tomorrow before I can get to it.

[Megahurtz]

Originally Posted by PRAY

I will take a look at it as soon as I get a chance. May be tomorrow before I can get to it.

Thanks Bret, I'm actually going to try to turn traction control off and datalog/test again. I spoke to my service adviser and tech today at the dealer and the tech asked if I could test that for him. He thinks the ECU is seeing something to keep TMA active rather than the torque converter having an issue.

[PRAY]

Originally Posted by Megahurtz

Thanks Bret, I'm actually going to try to turn traction control off and datalog/test again. I spoke to my service adviser and tech today at the dealer and the tech asked if I could test that for him. He thinks the ECU is seeing something to keep TMA active rather than the torque converter having an issue.

If TC is on then that could be the issue. You could also try to getting rid of TM in the trans and see if that does it as well.

[PRAY]

Originally Posted by Megahurtz

Thanks Bret, I'm actually going to try to turn traction control off and datalog/test again. I spoke to my service adviser and tech today at the dealer and the tech asked if I could test that for him. He thinks the ECU is seeing something to keep TMA active rather than the torque converter having an issue.

I looked at your logs and sent you some emails.

[jaysonstuart]

Originally Posted by Megahurtz

Thanks Bret, I'm actually going to try to turn traction control off and datalog/test again. I spoke to my service adviser and tech today at the dealer and the tech asked if I could test that for him. He thinks the ECU is seeing something to keep TMA active rather than the torque converter having an issue.

Well I got my car back today and after some dinner took it out for a test run to see if the shifting issues were resolved. I must say I'm in shock how fast and smooth it shifts now.

I took it WOT (in mexico of course) all the way to 5th gear and the car shifted perfectly.

No more lag or abrupt hard shifts at all. I spoke to the tech that worked on the car and he said he data logged the car while driving it around for a few days ( I gave them permission) and he found some issues with the shift points in the ECU. He didn't go into specifics with me but said it was all fixed by making some adjustments to the way the transmission shifted in the ECU.

So far it seems like my nightmare has ended and the mods can finally begin. I'm going to hold off for another few weeks just to make sure it's solid. If all goes well headers and a fulll kooks exhaust with the dyno tune after.

[Immoralus]

Thanks for you all's input regarding this. Is there some type of direct troubleshooting I can do to figure out which is which? My car barks 1/2, 2/3,3/4, and slurs like Jack sparrow 4/5. I do have your Ported tb/im as well as a dry rotofab running on the stock tune.

[PRAY]

Originally Posted by Immoralus

Thanks for you all's input regarding this. Is there some type of direct troubleshooting I can do to figure out which is which? My car barks 1/2, 2/3,3/4, and slurs like Jack sparrow 4/5. I do have your Ported tb/im as well as a dry rotofab running on the stock tune.

Megahurtz, his is slipping the 3/4 and 4/5. However, on the 3/4 the timing comes right back. But his 4/5 the spark does not recover for a sec and then it dips out during 5th. We are trouble shooting it.