PCM Diagnostics & Tuning - What changes for 3.73 gears (Yes I Searched)



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98Blubrd
03-21-2006, 03:10 PM
My friend just got a 98 trans am A4 with 3.73 gears (So he already started bugging me for free tune stuff since i can work on any 98). What do I need to change on HP Tuners for the gear swap. I took a quick look in HP Tuners and could only find something like axle revolutions per mph or something like that. Where and what do I do to make the changes for the gears? Thanks.

2xLS1
03-21-2006, 03:23 PM
Under the Speedometer tab, enter 6.68 in the box under New. Make sure Auto Scale Transmission Tables is set to Yes. Click on commit. Save file. Flash file.
98Blubrd
03-21-2006, 03:59 PM
Under the Speedometer tab, enter 6.68 in the box under New. Make sure Auto Scale Transmission Tables is set to Yes. Click on commit. Save file. Flash file.


Is that for HP Tuners? All i have under speedometer is

VSS Pulses Per Mile
VSS Pulses Per Rev-Trans and
Trans Output Revolution per Mile

2xLS1
03-21-2006, 04:08 PM
Yes, HPT. What version do you have?
98Blubrd
03-21-2006, 04:13 PM
Version 2.0.17.0
98Blubrd
03-21-2006, 04:18 PM
OK Got it. Thanks. I was looking in the navigator area. Dont ask me why.
Bad30th
03-21-2006, 07:47 PM
Under the Speedometer tab, enter 6.68 in the box under New. Make sure Auto Scale Transmission Tables is set to Yes. Click on commit. Save file. Flash file.


6.68 ? :confused:

When I switched from 3.23's I put 3.73 in the "new" Gear Ratio box and hit "commit", with the "Auto Scale Trans Tables" set to "yes".

Did I do it wrong ? I've been driving like that forever and the speedo is correct... Seems to shift correctly as well...

Rob (Bad30th)
2xLS1
03-21-2006, 08:08 PM
98s do it a bit different than 99s and up.
Larry
03-21-2006, 08:17 PM
6.68 would only be correct if you have a 24.92" diameter tire.
2xLS1
03-21-2006, 08:25 PM
That is the size GM uses for all the stock F-body files whether they came with 16 or 17inch wheels. You'll see 24.91 or 24.94 in all the files that list the gear and tire size separate.
Larry
03-21-2006, 08:36 PM
That is the size GM uses for all the stock F-body files whether they came with 16 or 17inch wheels. You'll see 24.91 or 24.94 in all the files that list the gear and tire size separate.Yes, but if you have a larger or smaller diameter tire and want your speedometer correct you would have to adjust the value slightly.
Bad30th
03-21-2006, 08:39 PM
98s do it a bit different than 99s and up.

Thanks for the info. Man, those 98's have it rough. :jest:

Cheers,
Rob (Bad30th)