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[Z06] Safe rev limit for my set up?

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Old 11-25-2014, 11:33 AM
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95Z28M6
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Default Safe rev limit for my set up?

Well, Ive done quite a bit of reading on the subject and of course have found different answers. I've seen anywhere from stock (6600) to 7000, and even a few 7200's.

Right now I have Trick Flo Chromoly pushrods, Comp Cams truniun upgrade and PAC 1218 springs. Along with a vararam and Borla stingers.

Over the snow season I will be doing TSP long tubes with an ORX and a stock Ti axle back. Along with a tune of course.

Would I be safe bumping the limiter up to 6800 or 7000? Personally I think so, but doesnt hurt to double check opinions/ reasons.

I want to do this because I find it hard to watch the tach and try to get consistant shifts by 6500 without clipping the stock rev limiter, especially in the lower gears.

The car is mainly a street car but has and will see the 1320 a few times a year and I plan on doing a track day or HPDE next summer.

Also, is the stock limiter a fuel cut off or an ignition cut? Thanks in advance.

Last edited by 95Z28M6; 11-25-2014 at 11:36 AM.
Old 11-25-2014, 05:40 PM
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4XLR8N
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In most street engines, the valve train is the limiting factor for redline. Of course, it is theoretically possible to build such a stout valve train that the bottom end becomes an issue, but that does not appear to be the case here.

If you want the best information possible, you should contact the manufacturers of the aftermarket valve train pieces you have installed.

My seat of the pants opinion is that you could probably go to 6800 w/o major issues - if you use the car as described - and don't plan on spending much time at redline.

Good luck!
Old 11-25-2014, 06:07 PM
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I believe that Forum member "Whtknt" who is a multiple time C5 Z06 champion described our LS6 engines as "Bulletproof" and also suggested that raising the rev limit to 6800rpm had no bad effects. Some here have raised to 7000 rpm, but I don't remember any other details, either positive or negative. If you raise yours, please post your results
Old 11-25-2014, 06:48 PM
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Last C5
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Originally Posted by 95Z28M6
Right now I have Trick Flo Chromoly pushrods, Comp Cams truniun upgrade and PAC 1218 springs. Along with a vararam and Borla stingers.
Would I be safe bumping the limiter up to 6800 or 7000? Personally I think so, but doesnt hurt to double check opinions/ reasons.
.
Trick Flo push rods, Jessel rockers, AFR heads with dual springs, and a 7,000 red line. The new engine will have a shift light set at 6,200.
It seems that when you're on the track you'll use what ever rpms are available to you.

Old 11-25-2014, 07:00 PM
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Originally Posted by Last C5
Trick Flo push rods, Jessel rockers, AFR heads with dual springs, and a 7,000 red line. The new engine will have a shift light set at 6,200.
It seems that when you're on the track you'll use what ever rpms are available to you.

Ouch.
Old 11-30-2014, 07:14 PM
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95Z28M6
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Originally Posted by Last C5
Trick Flo push rods, Jessel rockers, AFR heads with dual springs, and a 7,000 red line. The new engine will have a shift light set at 6,200.
It seems that when you're on the track you'll use what ever rpms are available to you.

Did you figure out what led to your piston failure? That's doesn't look like an rpm issue since the rod is still connected. Unless it dropped a valve, or burned the piston up lean.

I'm confident in my valvetrain parts to 6800 or so, just wasn't sure how well the bottom halves hold up at that rpm. Minus the several #7 piston issues that are out there.
Old 11-30-2014, 07:42 PM
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To each thier own, my shift light is at 6800, limiter at 7200. Been shifting between 6800-7100 for the past 50k miles. Stock heads,.600+ lift, I replace valve Springs every 15k-ish miles. I is correct? I don't know, is it broken? No
Old 11-30-2014, 11:21 PM
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Originally Posted by 95Z28M6
Did you figure out what led to your piston failure? That's doesn't look like an rpm issue since the rod is still connected. Unless it dropped a valve, or burned the piston up lean.

I'm confident in my valvetrain parts to 6800 or so, just wasn't sure how well the bottom halves hold up at that rpm. Minus the several #7 piston issues that are out there.
It dropped a valve. Same as the engine before that. The bottom ends never seem to be a problem, but valve trains always seem to develop some flaw along the way. These engines were in a dedicated track car and both saw several years of hard use. Springs were changed, guides, lash, and stem pattern were all checked routinely, but even the best valves available seem to fail over time. I don't know if reducing my shift level on the new 408 stroker is going to help, but it's something to try this time.
Old 12-01-2014, 12:21 AM
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7000 on both my LS6 and LS7.. I shift around 6700-6900.. No issues.
Old 12-01-2014, 11:17 AM
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95Z28M6
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Thanks everyone, I think I'm gonna go with a 7000 rpm limiter. Stick to 6500-6600 shifts with the stock cam and just use the extra cushion if needed. Until I decide to swap cams and/ or get a dyno sheet showing peak and drop off.

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