Max RPM

zoltan99

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What's the maximum RPM you'd run your engine at? I have my redline set at 7k and run it close to that occasionally, do you think I'm hurting my car? What do you guys run?

Thanks
 

BruceH

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What's the maximum RPM you'd run your engine at? I have my redline set at 7k and run it close to that occasionally, do you think I'm hurting my car? What do you guys run?

Thanks

What motor is in the car?

With a 3v I wouldn't go above 6300 with stock valve springs and powdered rods. I've ran mine up to 7200 and the current redline is 7k. It's also a good idea to have a good balancer for high rpm. High rpms exponentially increase stress and can lead to valve float.
 

BruceH

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7200 rpm on the stock crank Bruce?

Yes. It wasn't on purpose but it happened. 7k isn't all the time but it has been hit numerous times, well over 200.

SD is the one who came up with a 7k redline for the stock crank. IIRC he said they had one that had been lightened and destroked that they found spiderweb cracking on during tear down after numerous passes.

It's another one of those things nobody really knows because one hasn't failed yet. That is probably more because most people go with a Kellog crank for big power projects.

AFAIK Jeremy and myself are the only stock cranks over 650rwhp. At least that I'm aware of. That doesn't mean it's safe to do, we might just be lucky. It's something I wonder about from time to time.
 

JoshK

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Yes. It wasn't on purpose but it happened. 7k isn't all the time but it has been hit numerous times, well over 200.

SD is the one who came up with a 7k redline for the stock crank. IIRC he said they had one that had been lightened and destroked that they found spiderweb cracking on during tear down after numerous passes.

It's another one of those things nobody really knows because one hasn't failed yet. That is probably more because most people go with a Kellog crank for big power projects.

AFAIK Jeremy and myself are the only stock cranks over 650rwhp. At least that I'm aware of. That doesn't mean it's safe to do, we might just be lucky. It's something I wonder about from time to time.


That won't be for long! I am not going to be revving mine that high, at least not until I get rid of the stock crank damper.
 

hamish

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The guy who tuned my car said he'd have no problem running it to 7000rpm.

According to the dyno sheet it pretty much flattens out at about 6200ish.
No real point going to far above that.
 

fdjizm

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^there sure is a point in going above that, it's called the next gear :)
 
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