What RPM limit should I have?

[darebren]

presently I'm running without an RPM limiter on Dennis' chip. What limit should I have put back on if I don't want to hurt any of my shift points or WOT shift points, but just want a little extra insurance in case I hammer down on the throttle in first gear too hard.. would 6800 work? or 7000? what is the stock limit by chance?

[FordNut]

6800 or 7000 should be safe. I believe that is what the Mach 1 uses, at least on the ones with a manual tranny. The Mach 1 has the same engine as the MM.

[Stephen Soulsby]

6800 or 7000 should be safe. I believe that is what the Mach 1 uses, at least on the ones with a manual tranny. The Mach 1 has the same engine as the MM.

I remember reading something about the Mach 1 with autos having to be limited to 6500rpm due to the torque converter bulging. I think it was due to possible rupture of the torque converter. I would go with 6500. Better safe than sorry.

[FordNut]

I remember reading something about the Mach 1 with autos having to be limited to 6500rpm due to the torque converter bulging. I think it was due to possible rupture of the torque converter. I would go with 6500. Better safe than sorry.
Good point. But if you have the Stallion that's a different story. I'll be getting mine set to 6800 since there's not much power being made above 6500 anyway.

[Stephen Soulsby]

Good point. But if you have the Stallion that's a different story. I'll be getting mine set to 6800 since there's not much power being made above 6500 anyway.

Just in case you misunderstood what causes the supposed bulging and rupturing, it is not how much power you're making at that RPM, but rather the centrifugal force exerted at that rotation speed.

[FordNut]

Just in case you misunderstood what causes the supposed bulging and rupturing, it is not how much power you're making at that RPM, but rather the centrifugal force exerted at that rotation speed.
I understand. With the Stallion I should be safe at 7k or more without bulging. But for another reason, the fact that there isn't much to be gained above 6500, I will set mine a little safer than 7k, say at 6800.

[SergntMac]

Just adding my .02C...

The Mach I with a manual tranny redlines at 7K, but it has the 8 bolt Cobra crank too. Autos are factory limited to 6500 RPM.

If I remember my numbers correctly, the MM engine's power peaks at 5800-6000, so, why go any further? AIRI, the chip will shift the car at 6000 RPM, so, if you let the car do it's own shifting, you shouldn't be anywhere near your redline.

A professional dyno tune will show you exactly where your power peaks on your MM, and the shifting can be tweaked accordingly. The bottom line here, is that you shouldn't need any rev limiter if your tune is set up correctly, and you drive the MM as most of us do.

If you like hitting that 1-2 shift yourself, set your limiter to 6200.

[BillyGman]

That's an interesting point about the mach 1 crank that MAC made. I didn't know about that. Good 411. One thing to keep in mind is that if you ever decide to do enough mods to it like I have done to my car, (or more)in order to leave some serious rubber from merely a dead punch, then you'll find (like I have found) that by having the rev limiter set at 6200 RPM's just isn't high enough because the engine will be bouncing off the rev limiter the whole time during first gear well before the transmission hits second gear.

Then what happens is the RPM's in first gear drop significantly right before it goes into second, and then once it does shift into second, it compromises the burnout since the revs aren't high enough. With my car, the tires will still spin in second gear, but not like they would if the RPM's were kept up near 6000 in first gear until the 1-2 shift occurred. Not to mention that the engine exhaust note just sounds terrible while you're in first gear w/the rev limiter kicking in.

This might not matter to you like it does to me, but incase that it would matter, it's something to keep in mind. I think that setting the limiter to 6500 RPM's might very well prevent that from happening during a buirnout that's being left w/out the brakes (from a dead punch). keep in mind also, that this is the only time when my car gets into te rev limiter. When I have the thing pegged in first gear (or any other gear) and the tires have traction, It never hits the rev limiter and always shifts at 6000 RPM's. It's only in first gear w/the tires spinning that the revs go higher, and the rev limiter is activated that this happens.

If the rev limiter was set higher, I believe the transmission would hit second gear BEFORE the rev limiter is activated EVEN during tire spin.