SoundGuyDave
This Space For Rent
- Joined
- Apr 9, 2007
- Posts
- 1,978
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Okay, a little background. The car in question is a 2006, formerly automatic, currently stick, running the VDX-1 auto computer with a 2006 manual strategy flashed in. There are NO DTCs, either with the Xcal2, or a Snap-On code scanner. Now that we have that out of the way...
Mods are basic bolt-ons: 1.75" ARH long-tubes, offroad H pipe, C&L Racer intake, electric water pump, Roush underdrive pulley with short belt, Steeda billet delete plates, 3.73 gears, aluminum driveshaft, and that's about it for the drivetrain. I have extensive oiling-system mods, but all external to the engine, which has never been touched below the level of the valve covers. At the same time I swapped the trans, I also re-did the interior with race seats, rollbar, harnesses, etc., partially disabling the SRS.
Prior to the trans swap, the car ran 12.9-13.2 at around 108mph like clockwork. Swapped the trans, updated the tune to reflect that, and then it ran like ass. Changed to a different tune provider, and drivability is much better, but it's still dog-turd slow. Datalogging shows that it's throwing a torque source of 1 (transmission), and basically not wanting to come out of open-loop for some reason. This is with a tune having both torque management and adaptive functions turned off. 0-60 times are almost 8 seconds, and 0-100 is almost 17 seconds. Air/fuel is running very lean at WOT up to 4500RPM or so, despite retune after retune, but there is no knocking or knock-sensor source codes in the timing data. Again, remember that scanning with the Xcal and a Snap-On scanner report ALL sensors good, so I can pretty much rule out mechanical and electrical. I'm convinced that it's in the tune. My previous tuner (highly respected) just stopped answering emails after the first round or two, and my new tuner (also highly respected) is working diligently, but I'm trying to offer whatever help I can to get this resolved. I had an open track day on Monday that was miserable: I was pulling on most cars through the corners (!), but got eaten on the straights by everything in sight: Mini Coopers, 350Z's, a 4-door infinity, even a NA Miata! On a track that I could hit 125mph with the automatic, I was struggling to hit 100mph with the manual. And no, there's no clutch slippage or lack of ability. Just no grunt out of the motor. Also, please do not recommend a different final-drive ratio; for the tracks that I run, a taller gear won't work unless I can up my redline productively to 7400 or so. The gear is right.
The only things that I can think of are:
1) lack of a clutch-pedal switch is causing the car to think it's in neutral at all times.
2) The SRS system is inhibiting the tune.
Does anybody know FOR A FACT that either of the two above situations would be valid? Does anybody have any ideas BASED IN FACT OR EXPERIENCE that might cause the tuning problem? I leave for yet another track weekend tomorrow, and I'm already tired of getting passed by grandmothers on bicycles. I need help.
Mods are basic bolt-ons: 1.75" ARH long-tubes, offroad H pipe, C&L Racer intake, electric water pump, Roush underdrive pulley with short belt, Steeda billet delete plates, 3.73 gears, aluminum driveshaft, and that's about it for the drivetrain. I have extensive oiling-system mods, but all external to the engine, which has never been touched below the level of the valve covers. At the same time I swapped the trans, I also re-did the interior with race seats, rollbar, harnesses, etc., partially disabling the SRS.
Prior to the trans swap, the car ran 12.9-13.2 at around 108mph like clockwork. Swapped the trans, updated the tune to reflect that, and then it ran like ass. Changed to a different tune provider, and drivability is much better, but it's still dog-turd slow. Datalogging shows that it's throwing a torque source of 1 (transmission), and basically not wanting to come out of open-loop for some reason. This is with a tune having both torque management and adaptive functions turned off. 0-60 times are almost 8 seconds, and 0-100 is almost 17 seconds. Air/fuel is running very lean at WOT up to 4500RPM or so, despite retune after retune, but there is no knocking or knock-sensor source codes in the timing data. Again, remember that scanning with the Xcal and a Snap-On scanner report ALL sensors good, so I can pretty much rule out mechanical and electrical. I'm convinced that it's in the tune. My previous tuner (highly respected) just stopped answering emails after the first round or two, and my new tuner (also highly respected) is working diligently, but I'm trying to offer whatever help I can to get this resolved. I had an open track day on Monday that was miserable: I was pulling on most cars through the corners (!), but got eaten on the straights by everything in sight: Mini Coopers, 350Z's, a 4-door infinity, even a NA Miata! On a track that I could hit 125mph with the automatic, I was struggling to hit 100mph with the manual. And no, there's no clutch slippage or lack of ability. Just no grunt out of the motor. Also, please do not recommend a different final-drive ratio; for the tracks that I run, a taller gear won't work unless I can up my redline productively to 7400 or so. The gear is right.
The only things that I can think of are:
1) lack of a clutch-pedal switch is causing the car to think it's in neutral at all times.
2) The SRS system is inhibiting the tune.
Does anybody know FOR A FACT that either of the two above situations would be valid? Does anybody have any ideas BASED IN FACT OR EXPERIENCE that might cause the tuning problem? I leave for yet another track weekend tomorrow, and I'm already tired of getting passed by grandmothers on bicycles. I need help.
