09-16-2019, 07:37 PM | #1 |
Drives: 2018 Red ZL1 Join Date: Mar 2018
Location: Spring grove IL
Posts: 190
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A10 shifting problem after mods
Just completed second set of mods giving me a little over 700 whp. List of mods in signature.
No changes or tuning done to the transmission. Had car back from tuner and drove 4-5 times. Did plenty of manual shift WOT sessions and in “D” WOT hits w/no issues. Was giving buddy a ride and had in manual mode near redline and car had an “event” that lost drive and over revved engine. Did multiple times. Majorly scary. Thought blew something up at first. Car idled, ran and shifted fine immediately after while driving easy. No leaking fluids, mechanical noises or service lights. Let it sit to cool down at work and on trip home figured I’d give brief WOT run in D and see what happens. Was in D, going about 25, then went WOT. Didn’t make it to next shift point and had same event. Took to tuner and it repeated for him. Says car is actually downshifting instead of upshifting while near red line. Said rpms flashed to 7500 then rev limiter takes over and tries to shut down. Certainly VERY concerning. He is going to try and trouble shoot. Has anyone had any experience like this? Almost seems like a transmission programming thing gone wrong.
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Mods: RotoFab Big Gulp, 2" Kooks, Metco 9.1" pulley, Green belt, 103 NW TB, Tune, WeapX Boost Chiller, ADM Coolant reservoir, Jokerz Full Tilt SC Port, Elite E2X Can, Corsa Sport Catback, LED markers, 1LE Tail lights, HO reverse LED's, Red SC Lid, Forgestar 17x11/MickeyT Street R's for Drags
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09-16-2019, 07:47 PM | #2 |
Drives: 2017 ZL1 Convertible A10 Join Date: Aug 2017
Location: San Gabriel, CA
Posts: 992
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pretty basic mods... sounds like your tuner messed something up.
Where did you take it, and do they have a lot of history tuning the LT$ and the LT4 A10 combination?
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'17 White ZL1 A10 Convertible - TM ported TB - RotoFab CAI - 2.3" griptech upper pulley - Kooks 1 7/8" Headers with High Flow Cats - Borla S-type Catback - Audio Overhaul - NavTV M650-GM - 20" BlackDiForza- Michelin Pilot Sport4S - Tuned at BRC Raceworks (606rwhp/675trq)
'14 CTS-V Coupe - ZL1 lid - Ported TB - Ported Snout - AirRad CAI - 8.66" lower - 2.55" upper- Greenbelt - SW Headers - SW Catback - Varimax Intercooler Pump - Track Attack Intercooler-Tuned at BRC Raceworks (551rwhp/516trq) '17 Maserati Levante- STOCK |
09-17-2019, 08:10 AM | #3 |
Drives: 2018 Red ZL1 Join Date: Mar 2018
Location: Spring grove IL
Posts: 190
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Yes, he has. The Trans CM wasn't touched. It also drove OK for a brief period after i picked it up. Can something in the ECM Tune make the tranny downshift instead of upshift? Not sure where the Programming resides that makes the A10 shift...
The weird thing is it shifts normal under light and normal acceleration, but only does this up at the big end...
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Mods: RotoFab Big Gulp, 2" Kooks, Metco 9.1" pulley, Green belt, 103 NW TB, Tune, WeapX Boost Chiller, ADM Coolant reservoir, Jokerz Full Tilt SC Port, Elite E2X Can, Corsa Sport Catback, LED markers, 1LE Tail lights, HO reverse LED's, Red SC Lid, Forgestar 17x11/MickeyT Street R's for Drags
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09-17-2019, 10:37 AM | #4 |
Drives: A10 LT4 Join Date: Aug 2016
Location: Deep South TX
Posts: 1,094
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I don't know much about modding but would think everything that can be tuned should when going up in significant hp??
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09-17-2019, 10:55 AM | #5 |
Drives: 2018 Hyper Blue ZL1 1LE Join Date: Dec 2018
Location: CA
Posts: 1,360
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Seems like 7500 is pretty high for this motor, 1000+ over. If it does it again, dont let it repeat, stop revving anywhere near red line until it's fixed. You will bend valves from float. I dont understand why OEMs dont always use high rev springs with 9-10K RPM capability on car like this to avoid that kind of damage, keeping rev limit 3k RPM below the spring's capability. This might cost them an extra $100 to include.
I'm surprised you're able to rev that high and it sounds like you're saying it does it while holding full throttle/load past 7000 RPM. My rev limiter always kicks in immediately at 6400 RPM when I hit it with my manual, and the RPMs fall immediately with no power. My ECU shows no over-revs. |
09-17-2019, 11:26 AM | #6 | |
Drives: 66 Chevelle SS Join Date: Mar 2013
Location: SoCal
Posts: 1,347
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Quote:
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66 Chevelle SS 396
91 octane Driver n/a 6.44@105.78 1/8th mile |
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09-17-2019, 12:24 PM | #7 | |
Drives: 2018 Hyper Blue ZL1 1LE Join Date: Dec 2018
Location: CA
Posts: 1,360
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Quote:
Even if the engine isn't designed and tuned to go to 7500-8000 it would be good to have a safety buffer if it did. |
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09-17-2019, 12:25 PM | #8 |
Thank you Al Oppenheiser!
Drives: Red Hot A10 ZL1 Convertible Join Date: Jun 2017
Location: Sarasota, FL
Posts: 4,966
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99% chance this is on the Tuner. 1% bad Tranny.
There's been reports from the 1/2 milers with 3-4 and 4-5 hangs (doesn't shift, bounces off limiter) but this is the 1st I've ever heard of a money-shift from an automatic. |
09-17-2019, 02:38 PM | #9 |
Drives: 2017 ZL1 Convertible A10 Join Date: Aug 2017
Location: San Gabriel, CA
Posts: 992
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'17 White ZL1 A10 Convertible - TM ported TB - RotoFab CAI - 2.3" griptech upper pulley - Kooks 1 7/8" Headers with High Flow Cats - Borla S-type Catback - Audio Overhaul - NavTV M650-GM - 20" BlackDiForza- Michelin Pilot Sport4S - Tuned at BRC Raceworks (606rwhp/675trq)
'14 CTS-V Coupe - ZL1 lid - Ported TB - Ported Snout - AirRad CAI - 8.66" lower - 2.55" upper- Greenbelt - SW Headers - SW Catback - Varimax Intercooler Pump - Track Attack Intercooler-Tuned at BRC Raceworks (551rwhp/516trq) '17 Maserati Levante- STOCK |
09-17-2019, 03:13 PM | #10 |
Drives: 2018 ZL1 Garnet Red A10 Join Date: Mar 2015
Location: Nashville, Tennessee
Posts: 137
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Isn't this pretty simple to test? Have tuner flash ECM back to stock...see if issue goes away.
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2018 ZL1 Red Hot A10 (SOLD 1/21)
2001 Corvette Z06 Quicksilver Heads/Cam/Longtubes 443rwhp (SOLD 5/23) 2018 ZL1 Garnet Red A10 (BOUGHT 2/23) |
09-17-2019, 07:49 PM | #11 |
I private message you I have exact problem n can not figure please let me know what you come with
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09-18-2019, 06:49 AM | #12 |
Drives: 2018 Red ZL1 Join Date: Mar 2018
Location: Spring grove IL
Posts: 190
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I've talked w/SUPER SS and our issues are almost exactly the same. Very similar mods, his didn't happen right away after the last tune, he gets a "money shift" in manual or "D" mode...All the same. His is a '17 A10 and mine is a '18 A10. Obviously different Tuners. SUPER SS hasn't figured out a fix yet, same as us, but just putting it out there, there are 2 instances of this...
Don't know what's causing it yet so could be a ton of things (Tune, Trans, programming, etc). Obviously there are a ton of people on here who have similar mods w/no problems, so going to be tough solve I think. Once we find a fix, will post to potentially help others.
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Mods: RotoFab Big Gulp, 2" Kooks, Metco 9.1" pulley, Green belt, 103 NW TB, Tune, WeapX Boost Chiller, ADM Coolant reservoir, Jokerz Full Tilt SC Port, Elite E2X Can, Corsa Sport Catback, LED markers, 1LE Tail lights, HO reverse LED's, Red SC Lid, Forgestar 17x11/MickeyT Street R's for Drags
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09-18-2019, 09:08 AM | #13 |
Drives: 2018 ZL1 1998 SS 1992 Typhoon Join Date: Nov 2015
Location: RR
Posts: 262
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Thanks for posting so we can all learn. What is your next step, unlocking/tuning the trans?
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09-18-2019, 09:48 AM | #14 |
Drives: 2018 Red ZL1 Join Date: Mar 2018
Location: Spring grove IL
Posts: 190
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Not 100% sure at moment, although he's talking w/others in Tuning community, GM Tech contacts and possibly TCM Tuning...
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Mods: RotoFab Big Gulp, 2" Kooks, Metco 9.1" pulley, Green belt, 103 NW TB, Tune, WeapX Boost Chiller, ADM Coolant reservoir, Jokerz Full Tilt SC Port, Elite E2X Can, Corsa Sport Catback, LED markers, 1LE Tail lights, HO reverse LED's, Red SC Lid, Forgestar 17x11/MickeyT Street R's for Drags
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