Maximum Safe RPM?

[Jetnoise]

In reading and searching I’ve seen people post they’ve spun 7500 RPM on a stock engine, tuned, typically with a better intake manifold.

Does anyone know what the truly safe limit to spin a stock internal, naturally aspirated engine is?

Also, what is the weak point? Valvetrain? Rotating assembly? Oil pump gears?

I’m sure it’s been posted, I just couldn’t find it.

I think Ford has already answered all your questions, but i’m Sure there is better advice here on G6

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[BmacIL]

Now did they blow their OPGs simply because of high RPM or because they were constantly bouncing off the rev limiter which tends to be a common occurrence on autox runs?

My guess is the latter, as pure RPMs (especially on an NA car) have very little to do with breaking OPGs. What breaks OPGs is harsh vibrations and harmonics caused by hitting the rev limiter amongst a few other things.

This. The best thing to do being NA is to set the limit well above where you want to rev (so you don't bounce on it) and get an ATI balancer.

 

[EFI]

This. The best thing to do being NA is to set the limit well above where you want to rev (so you don't bounce on it) and get an ATI balancer.

Remember, the GT350 has the same exact gears in its oil pump...yet they rev to 8250 stock.

If you're breaking OPGs in a naturally aspirated stock 5.0 at 8000rpm it's not because of rpm.

EDIT: I should say in a near stock NA 5.0 at 8000rpm

 

[armykyle1 [HACKED ACCOUNT]

Remember, the GT350 has the same exact gears in its oil pump...yet they rev to 8250 stock.

If you're breaking OPGs in a 5.0 at 8000rpm it's not because of rpm.

This right here

 

[Shifting_Gears]

So what breaks the pump gears? What I have gathered is boost, spray or anything that alters the engines harmonics at high RPM.

When the gears break, are we talking bottom end destruction from debris and lack of oil flow? Or is it one of those things that when it happens, if you shut the motor down ASAP damage is usually limited to the pump itself?

The crank and rods are forged correct?

 

[Bluemustang]

This. The best thing to do being NA is to set the limit well above where you want to rev (so you don't bounce on it) and get an ATI balancer.

I plan on having mine set to 8200 at least (so I don't bounce off the limiter) once I get the 18 manifold and shift at 7800.

 

[Turbolag87]

its harmonics at high rpm that cause it to break.

 

[BmacIL]

its harmonics at high rpm that cause it to break.

At excessively high rpm yes, but the cars that break them when NA are bouncing off the limiter or inducing driveline shock back into the crank at high rpm. Boosted it's a different animal, as the crank sees MUCH higher forces.

 

[ahl395]

I rev to 8k, boosted with an 18 manifold. Personally I initially kept it below 7500 before, but after taking it up to 8k it just felt incredible and more than happy up here. Lots of people running them that high without problems.

But as with anything else, you never know. Rev it 100rpm over stock and it could break or you could rev it to 8500 without issue. It's always taking a chance modifying things. Take it from me, 6R80 failures are few and far between yet I've broken mine 4 times at reasonable power levels.

So what breaks the pump gears? What I have gathered is boost, spray or anything that alters the engines harmonics at high RPM.

When the gears break, are we talking bottom end destruction from debris and lack of oil flow? Or is it one of those things that when it happens, if you shut the motor down ASAP damage is usually limited to the pump itself?

The crank and rods are forged correct?

Crank is forged, rods are "sinter forged" IIRC. Basically, better than cast but not as good as real forged.

Generally if the OPG goes it's taking the engine with it.

 

[Ghost50]

Good question.

I've got 1600 miles on mine and the few times I've let it rip I've shifted in the 7300-7500 range.

 

[growler]

if I can get a thousand people to give me 15 bucks...i'll go find out definitively and post up

 

[kz]

Good question.

I've got 1600 miles on mine and the few times I've let it rip I've shifted in the 7300-7500 range.

That's great but of course 7500 is safe on a car that has 7500 (or whatever it is) redline from factory. What they're talking about is elevated redline on previous generation (15-17) Coyote.

 

[Turbolag87]

ive hit 8k on my car a few times by accident. MY18 stop pulling around 7500 so i have to shift around 7800 at least.

 

[V8EATR]

My car has been revved to 8k for the last 2 years, probably 8-10k worth, its fine.

 

[65sohc]

When I had a Boss I read everything I could find about it. I once read that it is Ford engineering's policy to design a 600 rom safety cushion into all their engines.

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