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wont go over 125mph?

1025 Views 8 Replies 6 Participants Last post by  tripleblack
Can someone tell me if a 99 gt has a factory top speed limiter?I just had 373 gears installed recently and was out on a old country road and opened it up and at the top of 4th gear at about 125mph it acted like it was running out of fuel but no problem at speeds under 125mph also i have not put a programmer on it to correct the speedometer yet so the 125 mph is probly more in the 115mph range.Thanks Jason
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Yes it has a factory speed limiter.
The only GT with a speed limiter, is one that came with 16 inch tires due to the performance rating of the tires, but the 17 inch ones do not. They all have a rev limiter though.
Depends on the wheel/tire combo

Your car's speed limiter is preset at the factory to match the wheel/tire combo. If you're running the good wheel/tire setup, you're good to 150mph.

The cheapo 16" versions pull you up short at 125.

You can change this with a tuner (SCT or Diablo), but don't do that unless you know your tires can handle the freight...

Cheap tires + high speeds = parts car + ambulance ride

Think of it like this, your tires are what is actally touching the road. Make sure your treads are up to the task before you go breaking the sound barrier! :cool: Mine are W rated, good for 168!! :happyhapp
All of the 99 GT's came with 17's so you don't have a speed limiter. But, you said you have gears and you were doing 125 in 4th gear. What rpms were you at? Sounds to me like you hit the rev-limiter. Solution: SHIFT INTO 5TH GEAR!
I will try again but i did go to fifth gear and the same results so it was not on the rev limiter if i recall it was about 4500 to 5000 in forth when this happens and was pulling strong.The car does have 17in wheels.
There's no need to try again just for us.....sheesh.
In the clutch

Could be a slipping clutch - a sick fuel pump - partially clogged fuel filter - or your gear install trashed your speedo gear, which no longer works properly.

Also could have been a 60mph headwind, but I bet you would have noticed that. This wasn't in the middle of Katrina, was it...

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