Tyler N Tkachuk

Now, I realize I'm just chasing my tail here because I have a v6, but I was wondering if there is anyway that I can just take out the rev limiter. Instead of stopping at 4,000 rpm standing still, I was wondering if there was a way to break that, and hit 6,000? If so, please help. If not thanks for trying. Main reason for this, is at shows, instead of stopping at 4k, it would sound better at 6k now that i have a different muffler on.

Lethaldosage423

http://www.americanmuscle.com/x3-cus...er-0510v6.html

That will do it, it's a tuner. Get tunes for it too and you'll have a whole new car on your hands

2005Redfire6

+1 on needing a tune/tuner to get rid of that....

Nuke

The factory setting on the 4.6L is 6250 PRM. I have mine at 6500, down from the 6800 that Brenspeed set it at. But I was pretty sure the 4.0's factory rev limiter setting is higher than 4k...

rls82959

I wouldnt want to rev higher than 4k in neutral.
There's no load on the engine.
My rev limits are Neutral 4000 , Drive 6150

But yes you can raise the neutral rev limiter with a tuner.

2005Redfire6

It is higher than that, for some reason while the car is in neutral it will only rev to 4000k. My car did it stock.

Derf00

The Neutral Rev Limiter is there to keep you from floating a valve either from just sitting there reving the engine at a stop light that high (like an idiot) or if you miss a shift... Ever floated a valve that hits a piston? It's not pretty, it will take the cylinder, the valve(s) that get hit and possibly blow a head gasket.

When the engine is not under load and just reving, there's no momentum/inertia to make the valves close faster so you end up with valve float... If it happens at just the right time, it smacks the top of the piston and that's it, you are done.

Unless you have strong valve springs I would never mess with the neutral rev limiter (raising it).

2005Redfire6

I am sure that is the case with some motors, never heard of that out of the 4.0, 4.6, or even the 5.0 though.

Derf00

All of these motors are interference motors meaning under the right conditions it will happen. Most people don't blow their heads from free revving. Instead you hear of people blowing their motors out the bottom from excess FI pressure or too high of an RPM at WOT.

The rods in these cars are weaker than the valve train so yes, it is not likely to happen to these cars. It is still possible.

Norm Peterson

You're into it for at least one head gasket no matter what else happens. But a gasket is such a small part of what you're in for that it's hardly worth mentioning.


If the valve is hung open far enough when it gets "kissed" . . . ↓↓↓







That bent valve stem in the first picture belonged where you see a "good" exhaust valve in the head section picture. Pieces of the missing valve head took out the missing stuff in the red circles on its way to wherever it ended up at. A few bits are embedded in the top of the piston


Water will pour into the cylinder, hydro-locking it (which bends rods) and the sudden quench will probably crack the cylinder wall in addition to the above damage.


Norm