Safe RPM for rev limiter???

[BillyGman]

I'm looking for some educated opinions about exactly what is the highest RPM that would still be safe to have the rev limiter set at in our Marauders.
The reason for my question is simply that once in awhile when I get a little crazy behind the wheel, and I decide to make a spectacle by leaving rubber from a dead punch, my MM spins the tires right up to 6200RPM's in first gear and I hear the engine breaking up indicating that it's getting into the rev limiter just before it hits second gear.

So I was considering having the chip re-burned in order to reset the rev limiter to 6500 RPM. But I'm wondering if that would be high enough to avoid getting into the rev limiter while doing a burnout. So I've been thinking about having it set to 6800 RPM instead. However I'm not sure if 6800 RPM would be safe. I'm wondering if anything over 6500 would open up the possibility of valve float.

[Fourth Horseman]

Yikes! I'll be the first to admit that I'm a big sissy, but I turned my motor to 6000 once and swore I'd never do it again. Even when goofing off I keep my RPMs to the low 5000s. You're a braver man than I am.

[BillyGman]

Originally Posted by Fourth Horseman

Yikes! I'll be the first to admit that I'm a big sissy, but I turned my motor to 6000 once and swore I'd never do it again. Even when goofing off I keep my RPMs to the low 5000s. You're a braver man than I am.

Well thanks for your honesty. I've had my 73 Vette for 6 years, and over those 6 years, I've done countless 6000RPM burnouts. The engine now has well over 100k on it, and I've never done any engine damage to it driving it hard like that. I recently blew my clutch doing that, but because it also had over 100k on it, then it had seen it's better days anyway.

This isn't something that I do every day,or even every week, but when I do show off w/my car, I don't want it to be limited because it's getting into the rev limiter.

Anyone else on the rev limiter question?

[Fourth Horseman]

Wasn't trying to say you're doing anything wrong. I just don't have the cajones for the high-RPM stuff. If it wasn't my daily driver that I depend on I'd probably feel differently.

[BillyGman]

Originally Posted by Fourth Horseman

Wasn't trying to say you're doing anything wrong. I just don't have the cajones for the high-RPM stuff. If it wasn't my daily driver that I depend on I'd probably feel differently.

It's all cool FH. I wasn't offended at all by your comments. I understand and respect your viewpoint on that. As for me, my Marauder is my daily driver too. But if I didn't want to use ALL of the power this car has to offer, then i would've just purchased the Black crown Vic that I test drove just before I purchased this car. And if you look at the list of the modifications I've made to this car, then maybe you can see where I'm coming from.

my viewpoint is that I wouldn't have bothered spending $800 for an aftermarket Torque converter, $1600 for Headers, and aftermarket exhaust system, and another couple hundred for 4.56 ratio rear end gears, if I simply wanted to drive my MM mellow.

That isn't to say that your viewpoint is neccessarily wrong. It's just that some of us are more performance oriented than others. That's all. Thanks for your opinion. Nuthin wrong w/sharing.

[Fourth Horseman]

Originally Posted by BillyGman

my viewpoint is that I wouldn't have bothered spending $800 for an aftermarket Torque converter, $1600 for Headers, and aftermarket exhaust system, and another couple hundred for 4.56 ratio rear end gears, if I simply wanted to drive my MM mellow.

All good points. I'll probably romp on it more once I get out of warranty and start to mod my power train. I now return your thread to it's intended subject matter.

[BillyGman]

Originally Posted by Fourth Horseman

All good points. I'll probably romp on it more once I get out of warranty and start to mod my power train. I now return your thread to it's intended subject matter.

LOL.........

[cyclone03]

Billy,
You,like I,have removed the reason for the 6200rpm rev limit,the Torque Converter.Our new ones are now good to 9500rpm(!).
The Mach 1's with stick shifts are limited to 7200rpm but they have steel cranks too(Cobra).
Being the top end is the same as the 5spd Machs I dont think the valve train is the limit.
I too would like to raise the rev limit in the search for improved ET's,I know slightly less vain than your reason,but thats just me.I think with our exhaust there is power to be had above 6000rpm,and improved ET.

I don't know if the best way to find the best upper limit is at the track or on the dyno.
I also don't know when the crank and rods will come flying out either,but my GUESS would be about 7500rpm.
So I'd go with 6800 to be safe and shift at what ever gives the best ET.

[BillyGman]

Yep, I'll admit that my reason is more vain like you said. Those are some interesting viewpoints you've shared about the mach I. What 'm interested in doing is to raise the rev limiter w/out raising the shift points. I'm pretty sure that can be done. I'm happy w/my ET's(atleast until marty beats them!), so the shift points I have no are fine. I just don't like hitting the rev limiter in first gear during a dead punch burnout. (call me Mr. Vanity....LOL).

[prchrman]

Billy if you have done a dyno...and see where you quit making power this might be a good rpm to set your limiter at because that is where the motor is starting to strain...my dad a master machanic always said it was not USUAL high reving that got motors and such but sudden jerks (like we all did in our younger days, neutral drops, reverse to forward or vice versa) is what kills motors, drive train and such...willie

[merc406]

I don't think you have to worry about valve float with OHC motors, and they are capable of higher RPM's in general.

[RF Overlord]

Gman:

I'm with Fourth on this one...I rarely run mine up that tight, but I understand your question...I think Dennis or Lidio would be the ones to answer it, though...

Would raising the rev limiter really buy you that much? I'd have to see a hp/torque curve...perhaps it falls off rapidly at much above 6200...

The other question is: will the lower end handle the increased revs? Remember, this motor has powdered-metal rods...

I know this isn't much help...just thinking out loud...

[FordNut]

Billy,
Good question and something I've been thinking about too. After I get the headers installed I may have the rev limiter set to 6500. I would like to do some experimenting with my chip's shift points too. If only I could setup 3 different programs. Maybe a flash on the PCM plus my delta chip with two different programs! Then one program to shift at 5800, another at 6000, and another at 6200. If the best times are at one of the end settings, I would try again at a 200 rpm change. I believe the shift points should be slightly higher than the peak power RPM so you don't drop off too many RPMs below the peak. But I don't know that anybody has done the dyno test at very high RPM (like 7000 or so) with the headers.

[Zack]

My rev limiter is set at 6500 with a S/C.
No problems yet.

And the Mach 1 crank is not steel, its cast and has a 7200rpm rev limit.
A good tune save you from a lot of potential problems.

[SergntMac]

BillyG...What are you trying to accomplish here? Looking for a better launch? Or, putting on a smoke show?

You can perform an impressive smoke show easy enough by locking the tranny in 1st gear, brake torque until the rear tires break loose, and ride on up to 4K RPM holding the brakes. You'll smoke 'em just fine right there, my friend, and not move too far forward while doing it. This is exactly how we clean and warm up our tires/slicks at the track, just before runnig a quarter mile race. Folks watching you will be coughing up rubber for hours, anyone passing by will want to dial 911...LOL! If this is your quest, Billy, go for it!

BTW y'all, I have 3 sets of Pirelli tires just waiting for this honorable epitath. Free too, but I need 40 bucks each tire for shipping anywhere in North America. Write to me at SergntMac@aol.com if your looking to put on a show.