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Discussion Starter #1
I have a 94 AWD Oldsmobile Bravada with C4 corvette wheels I’m putting a 350 in it but at 95mph is redlines and I can’t go any faster. Is there a cheaper way to increase the top speed without buying a $4k 6l80e lemme know
 

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Moved to Transmission/Rearend.
 

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Are you saying at 95 MPH youre turning 5500RPM?
PCM is speed governed for tire speed ratings that came factory equipped.

AWD Bravada is most likely set up with 3.73 gears
what height tire are you using?
 

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Find some one with HP Tuners. You'll likely have to pay for the license for your truck ($100) but they can disable the top speed limiter. They can also correct your speedo at the same time since it's likely off around 10%.
Theoretically at 95 you should be only turning 4640 rpms in 3rd and 3230 in OD with 3.73 gears and stock C4 275/40R17 tires.
Unless the program has been corrected to reflect the new tires and thinks you still have 235/70R15 tires what you see as 95 is actually only 87MPH because the shorter tires do travel as far per revolution.
For your speedo to remain accurate w/o altering the PCM you'd need to run 255/55R17 tires which are the same height as you original tires, but wider. Bridgestone and Pirelli make some that size, but they're all season radials, not performance tires.
 

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Im running 275-55x17 with vette wheels on a 2WD blazer 2dr
diameter is about 3/4 inch higher than the 235-70x15 mine came with,but the same diameter as the 235-75x15 that 4WD came with
 

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Did you need 2 or 2-1/2 inch spacers to run Vette wheels on a 2wd?
 

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Discussion Starter #8
Are you saying at 95 MPH youre turning 5500RPM?
PCM is speed governed for tire speed ratings that came factory equipped.

AWD Bravada is most likely set up with 3.73 gears
what height tire are you using?
The tires are 245s and the wheels 16s, it used to have 18s witch I think is what killed the top speed
 

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Those early C4 16" wheels are bit of an oddity. They only have 38mm offset. About 1/2" less than the 17's. Probably 1" narrower wheel than the 17". That would explain the difference in offset.
If you speedo is close to accurate you'll need the speed limiter disabled in the PCM. Don't know as I'd want to be with you in a 94 Bravada over 95 mph. GM put that limit on them for a reason. SUV's aren't meant to run at Bonneville and don't know anywhere I'd do that on the street. If a critter jumped out in front of you and you had to swerve you'd roll and roll and .... You get the point.
 

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Discussion Starter #12
Find some one with HP Tuners. You'll likely have to pay for the license for your truck ($100) but they can disable the top speed limiter. They can also correct your speedo at the same time since it's likely off around 10%.
Theoretically at 95 you should be only turning 4640 rpms in 3rd and 3230 in OD with 3.73 gears and stock C4 275/40R17 tires.
Unless the program has been corrected to reflect the new tires and thinks you still have 235/70R15 tires what you see as 95 is actually only 87MPH because the shorter tires do travel as far per revolution.
For your speedo to remain accurate w/o altering the PCM you'd need to run 255/55R17 tires which are the same height as you original tires, but wider. Bridgestone and Pirelli make some that size, but they're all season radials, not performance tires.
Thanks for the help, it really means a lot
 
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