GTO Speedometer Problem w 3.91's

[Moparth]

I'm probably overlooking something very simple, but can't get my speedometer corrected after installing 3.91 gears yesterday. Using HPTuners, I changed my final drive ratio to 3.91 and reflashed the PCM, speedometer is around 8 MPH off at 60 MPH, tried the auto calculate thing and all it did was round up my Tire revs / distance value. What am I doing wrong ??? This is a 2005 GTO with a M6, any help for my stupidity would be appreciated, attached is a pic of the speedometer settings.

[S2H]

when you changed it did you manually enter values for final drive??
or did you enter tire size and gear ratio and hit commit...cause as far as I kno wyou gota do it that way...
I have looked at a 2005 gto file...but havent put one in a car yet....
and it looks to me like the vss dist and err are the same when I do it in the file I have...so maybe that is causing some issues

[Moparth]

I tried it both ways, first time I entered tire size and ratio, then hit commit, after that didn't work, I took the old file and just changed the ratio, still way off.

[Chris@HPTuners]

are you using version 2.1.6 or 2.1.8? There was a bug in earlier versions for the LS2 speedo

[Moparth]

I had been using v2.1.6, but just upgraded to v2.1.8 and it's still off, guess I might try to cheat by using a false tire size and see if that will make it right.

[Moparth]

Got it working now, it was the 2.1.6 that was the problem, noticed after trying it with 2.1.8 that the output pulses/mile didn't change between an older file and the one I tried yesterday, so went back to previous file before 3.91's were installed, changed to 3.91 and the pulses/mile changed accordingly. Thanks Chris !!!