Just trying to get some input on raising the Rev Limiter. I believe on the stock ‘06 GT the limiter is set just above 6k. When I’m running the car at the track or street, it seems to bog down a bit every time I shift, I just feel like I could get a couple hundred more RPMs to keep the power going strong throughout the whole run. Has anyone raised the limiter and had success, and if so what did you raise it to? I have whipple supercharger, CAI, headers, upgraded fuel system etc.

 

Since your car has all those mods, the ECU must have been reflashed with a custom tune. Contact your tuner and ask him to raise the rev limiter; 6500rpm would be safe enough.

 

Better yet, since you're in AZ, go to a dyno shop. Most remote tuners don't understand about how much heat soak you get during the summer. That will lead to preignition/pinging and eventually detonate the motor.

That could also be why the rev-limiter is dialed back a tad. If you do get it pushed up definitely don't forget to dial it back when it starts hitting 100's in May/June.

 

Abigail Frymier, everything the fellows have suggested is absolutely true. I have been told everything from 6000 to 6800. Only a horsepower rating on a good dyno will give you the answer. That being said, all the fellows on this blog know I am "old school" and come up with some crazy suggestions. But one area I would pay attention to is your rear end gearing. Again the dyno will give you a idea as to optimum gearing. My nephews 87 fox body with a 331 stroker would fall on its face during shifts. I installed a set of 4:10x1 gears and the car ran like a raped ape. Just input from past experiences.

 

I bet it's falling on its face because you are shifting at the rev limit when the fuel shuts off suddenly. There is no way a supercharged 06 is bogging down when you shift because the rev limit is too low. I know because I had one. When I started shifting a tich earlier, the car just kept pulling. When I timed the shift to the last rev I almost always bogged down as you say. That RPM comes in a hurry when you are supercharged.

 

Abigail Frymier, yes proeagles maxes a excellent point. I don't want to get to technical here but there are a few issues. The first is, if you are still running through your OEM rev limiter, the car is "DEDICATED" at that rev limit. You can put a 10,000 rpm chip in it and it will only shift at the designated OEM R.P.M. The only solution to this rpm problem is switching over to a different system so you can chip, say, a MSD control box. I also had installed in our 331 stroker , a 150 hit of juice. Not that I am disagreeing with proeagles statement about the importance of constant boost. My only experience is that gearing affects shift patterns weather aspirated or non aspirated.

 

Abigail Frymier, sorry, but I forgot to mention that changing over to, say, a MSD system still won't override the OEM rev limiter. You have to completely eliminate the OEM, rev limiter, system. You can have your OEM engine management system modified, or replace the complete OEM system with a third party system. If I am in a hurry, I will eliminate the whole OEM engine management system and go carbureted, with a ton an nitrous. P.S. our 87 foxbody 331 stroker, carbureted, with a 150 hit of juice, is running in the standing quarter, in the high 10's.

 

You don't need to do anything as drastic as that. I have a custom 91 octane tune from Brenspeed with the rev limiter raised to 6500rpm.

 

Dino, as usual, you are absolutely correct. Sometimes I forget I am sponsored and get crazy with my modifications. Just for peace of mind I change the complete engine management system,weather carbs or injected, to a complete MSD system. As you say. there is no need for all that expense when a aftermarket tune gets the same results. Sorry for suggesting the overkill.

 

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You have a " file tune ", altered to suit your needs,......................custom tuning is done @ a shop, can't be ordered via the net or by phone..
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