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?

 

with HP Tuners, there is a table to change your tire size and gears, which will then automaticlly change your shift points..

It saves a tuner like me a ton of work

 

Change one of them at a time and see what causing the issue

 

Thanks for the input. There is a "Speedometer" table in EFI Live to change tire diameter, gear ratio, trans pulses/mile, change by percentage, & more. From reading around it appears that inputting a new tire size could cause a problem with the ABS, although I don't understand why since the ABS Controller is a different PCM reading the same sensors, requiring a tech-2 programmer. From what I've gleaned, it may be better to change percentage rather than the hard numbers like ratio & tire size.

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.

 

The ABS system doesn't read the same sensors, it get the reading for the rear tire speed from the high speed output on the PCM, which means if the tires size or rear end ratio is set wrong, it is going to send the wrong speed signal to the ABS

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

 

Are you sure it isn't the speed limiter kicking in rather than the rev limiters...?

What does H0109 (speed limiter, non ETC) say...?

 

Beat me to it. Very possible cause.

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.

 

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,

 

Thanks for all the input!
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.