Maximum Safe RPM?

[Shifting_Gears]

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.

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[bluebeastsrt]

8000 is safe. I changed the oil pump gear and timing sprocket on my supercharged GT. And it shifts at 7900. Due to the supercharger being maxed out on its RPMs. 7500 is where I shifted when I was stock mani and bolt ons.

 

[Shifting_Gears]

That’s wild! Is 8,000 safe without changing the oil pump gear on an NA car?

 

[bluebeastsrt]

People have done it. How much risk your willing to take is up to you. But if your still on the stock manifold. Power starts to drop off around 6500. So 8000 is a waste til you step up to a good flowing mani like the gt350, 18, or cobra jet.

 

[Grimace427]

Don't expect a hard number. There will be guys who spin to 8k+ all day without issues then one guy who spins to 7,500 once and it blows. There are far too many variables to have a definitive answer. Stick to what your tuner is comfortable setting it to and tuning around.

 

[bluebeastsrt]

Don't expect a hard number. There will be guys who spin to 8k+ all day without issues then one guy who spins to 7,500 once and it blows. There are far too many variables to have a definitive answer. Stick to what your tuner is comfortable setting it to and tuning around.

While I agree with everything you typed. Even that presents a conundrum. For instance. I recently did a dyno tuning session after a supercharger install. The owner of the dyno. Wanted to push the car a little harder than Lund. Who I paid to do the remote tuning. The shop that I paid for the dyno time. Is a reputable shop with a good reputation. He thought the car could handle a little more RPM. Two tuners. Both with good reputations. Differed on how to tune the car.

 

[SJulian10mm]

Ford Performance spins it up to 7450 with a GT350 manifold (PP3), so id say that's what Ford Performance feels is "safe".

 

[kz]

That’s wild! Is 8,000 safe without changing the oil pump gear on an NA car?

No, no, no. Multiple failures due to that. At least two well known autocrossers (in autocross world) ended up blowing up their engines for that very reason.

 

[thehunterooo]

My tune is set at 7850 and I have been going there off and on for the past year plus.

 

[EFI]

No, no, no. Multiple failures due to that. At least two well known autocrossers (in autocross world) ended up blowing up their engines for that very reason.

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.

 

[SVT-DADDY]

I always cut off my logs at 7500 and get yelled at for not taking them to 7800.

 

[Ebm]

OP, it's a crap shoot. Literally every car is different.

 

[Grintch]

Ford Performance spins it up to 7450 with a GT350 manifold (PP3), so id say that's what Ford Performance feels is "safe".

Right with just intake changes and a tune. No mechanical changes to rpm sensitive items.

2018+ also has a 7500 redline. Does it have any changes to the valve train, etc. over a 2015-2017?

I read some where that the 2015-2017 had the same valve springs as the BOSS 302, which had a 7500 or 7800 redline.

I strongly suspect that a bone stock car would be faster shifting 400-500 RPM higher based on my favorite method of calculating optimum shift points.

 

[w3rkn]

Do a few dyno runs. look at the plots, rpms and also tq curve. Depending how YOUR engine runs & is tuned, max/threshold RPMs may not be necessary.

 

[Silver Bullitt]

I've seen 7700 a couple times on stock tune. I usually try to shift at 7400 on spirited runs. This thing just doesn't feel like it runs out of steam. Need to get a baseline dyno. My cammed LS2 would really lay down about 6600 to the point where you could feel it (rev limiter was set to 6800), so I was usually shifting about 6300-6400. Winding out another 1000 is taking some getting used to. But, I like it!

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