Question about rev limiter

[BkaayRandy]

I have a 17 5.0 with gt350 intake mani and the rev limiter is tuned at 8.2k rpm, what type of damage should I expect if any if I continue to shift around 8k? & what exactly happens to a car when you start going past the red line?

Sponsored

 

[ice445]

It's harder on the timing chains, it can cause stretch and tensioner failure earlier than intended. It's also harder on the rods because of the higher angular acceleration, but since they're meant to handle it it's not as big of a deal.

If this is wrong, someone feel free to correct me.

 

[Bikeman315]

I have a 17 5.0 with gt350 intake mani and the rev limiter is tuned at 8.2k rpm, what type of damage should I expect if any if I continue to shift around 8k? & what exactly happens to a car when you start going past the red line?

Regardless of what your rev limiter is set for consistently exceeding the engines limits will result in severe damage.

What type of damage? Take you pick. Block, heads, pistons, rods, crankshaft. Honestly it’s like asking which bones will I break if I jump off a building.

By the way, why don’t you just reset the limiter?

 

[BkaayRandy]

Regardless of what your rev limiter is set for consistently exceeding the engines limits will result in severe damage.

What type of damage? Take you pick. Block, heads, pistons, rods, crankshaft. Honestly it’s like asking which bones will I break if I jump off a building.

By the way, why don’t you just reset the limiter?

Ah ok, yeah I had a feeling the effects wouldn’t be good. I really only go past redline when I race, so I haven’t thought about resetting the limiter for that reason. I appreciate the info though, I’ll definitely keep all of that in mind the next time I think about running my car

 

[Bikeman315]

I really only go past redline when I race,

You might want to keep this link handy. You may need it.

http://www.fordracingbyspeedshopdir...435_HP_MUSTANG_CRATE_ENGINE_p/M-6007-M50A.htm

 

[Norm Peterson]

Dunno, maybe

I have a 17 5.0 with gt350 intake mani and the rev limiter is tuned at 8.2k rpm, what type of damage should I expect if any if I continue to shift around 8k? & what exactly happens to a car when you start going past the red line?

Dunno, I might be a bit wary about things like valve spring fatigue/loss of spring load and possible increases in transmission gear tooth wear rates. That's just off the top of my head; there's probably more.

Having built up a few engines myself, I'd personally want to know a good bit more about production balancing and clearances.


Norm

 

[tom_sprecher]

Having raced SCCA for quite a few years I can say constantly red lining and abusing an engine will rapidly destroy it. For us it wasn't a big concern because we would regularly rebuild/refresh an engine every 2-3 years. It you have the time and budget for that, then feel free to thrash the $h!t out of it.

 

[Elp_jc]

I would NEVER, EVER rev my stock engine above the stock rev limiter (ever after bolt-on mods), let alone that much more. Remember your 2017 revs less than our 2018+ engines (7,000?), which redline at 7,400, with a rev limit of 7,500. So you're over-revving the crap out of your engine man. It's just plain stupid. And it's probably worse than just shifting earlier anyway. But it's your car.

 

[luc]

Ford performance packs 1, 2 and 3 raise the rev limiter up to 7400 on the 3 and 7200 I believe on my 2
So, being warranted, I will assume that 7400 is a limit that Ford believe to be safe

 

[Norm Peterson]

Ford performance packs 1, 2 and 3 raise the rev limiter up to 7400 on the 3 and 7200 I believe on my 2
So, being warranted, I will assume that 7400 is a limit that Ford believe to be safe

If so, 8200 rpm is still about 11% higher than that. Meaning that the accelerations and resulting inertial forces involved would be about 21% higher. That's way too much to just hand-wave away on the basis of 7400 being "safe".

And that doesn't really address the matter of fatigue.


Norm

 

[IrishStallion]

I’m 7100 shift in D and 7500 shift in S on gear shift lever. ;).

 

[racingandfishing]

The coolest bit may be the remnants of adhesive on the right side of the tachometer. This, we’re told, is where Balchowsky taped a note indicating the engine’s new redline. “Little pieces,” it read.

 

[CrackedHorn]

There's a difference between driving at 6k7500k and shifting at 7500k-8k.

The 5.0 can spin pretty well compared to several other designes. Especially pushrod engines

 

[Nickel]

In reality, the internals of the gen 2+ coyote can handle 8k rpms. It's the oil pump gears that would probably go first. Get yourself some billet oil pump gears, drive it the way you want to, and then report back to us.

 

[BkaayRandy]

I would NEVER, EVER rev my stock engine above the stock rev limiter (ever after bolt-on mods), let alone that much more. Remember your 2017 revs less than our 2018+ engines (7,000?), which redline at 7,400, with a rev limit of 7,500. So you're over-revving the crap out of your engine man. It's just plain stupid. And it's probably worse than just shifting earlier anyway. But it's your car.

Yeah man, the 17’s rev limit is 6,500 so going that far into the red zone worries me, after reading what everyone has to say I’m just going to reset the rev limiter back to 6,500 and be more careful, I really want this car to last a lifetime.

Sponsored