Speedometer vs. Rev Limiter PCM Tuning
Speedometer vs. Rev Limiter PCM Tuning After installing my 3.91 ratio 12 bolt, with my EFI Live V1 Software, I inputted the new gear ratio & 25" tire diameter. Trans is M6. Now the rev limiter cuts in @ 4500 -5500 rpm [varies]. That was the only change I made. It was not a new file [i.e.: I uploaded the PCM, changed only that, saved the file & downloaded]
If I set it back, all returns to as before. Does anyone know what I missed?
If I set it back, all returns to as before. Does anyone know what I missed?
After installing my 3.91 ratio 12 bolt, with my EFI Live V1 Software, I inputted the new gear ratio & 25" tire diameter. Trans is M6. Now the rev limiter cuts in @ 4500 -5500 rpm [varies]. That was the only change I made. It was not a new file [i.e.: I uploaded the PCM, changed only that, saved the file & downloaded]
If I set it back, all returns to as before. Does anyone know what I missed?
If I set it back, all returns to as before. Does anyone know what I missed?
I guess my issue is "unique". After searching several other forums I find no other references to this problem. Maybe I'm the first one ever to change a Camaro speedo with EFI Live and have it affect the rev limiter.
My trans is not automatic so shift point tuning should not be an issue. But I am curious why one would want to modify auto trans shift points when adjusting the speedo meter.
Since the tranny shift point are controlled by the PCM and it is determined by the vehicle speed. if you had a 4.11 rear end, you certainly wouldn't want it shifting at the same MPH if you had 2.73's, since the engine speed would 50% higher
Another thing to remember is the LS1 PCM shifts primarily off mph at WOT. If you changed the speedo settings, but not the mph shift points, you will be shifting at a much lower rpm setting.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
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Bump the rev limiter 500 RPM and see if it quits......look at you MPH also, and see what it changes between the two files, if at all. Car is a standard, so no shift timing would be affected.
Seems to me you are getting to the limiter quicker, with the taller gear. Go through it one and compare set points, by process of elimination.
T,
Seems to me you are getting to the limiter quicker, with the taller gear. Go through it one and compare set points, by process of elimination.
T,
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Are you sure it isn't the speed limiter kicking in rather than the rev limiters...? What does H0109 (speed limiter, non ETC) say...?
If I leave Traction Control on I feel it kick the pedal like normal. With TC off, the rev limiter seems to cut in early, but not always the same RPM. Seems like sometimes~4500, sometimes~5000. If it's the speed limiter, wouldn't I feel it in the pedal?
I'll go back and check the settings you guys suggested.
It a manual trans car, but I never knew the auto trans cars shifted on MPH, thanks for that.
