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rev limit?


Guest BadKarmaCreepin

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I think the redline on the tach was 6250 for my 77 280Z. The 82 Turbo engine I put in it regularly saw 7000 rpm and didn't come apart. I know from doing some work at Ford that a lot of times now days the redline is set by accessories, alternator, A/C compressor, P/S pump, more than bottom end strength. This certainly is not true for everything though so don't think I am telling you it is definetly safe to overrev. I don't mind the thought of having to rebuild so I rev 'em as high as they'll make power, and I have never had one come apart.

Perry

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It is normally considered safe to turn one to 7000, beyond that somewhat with mods like ARP rod bolts and good machine work.

 

I have found that I tended to break rings and ring lands when I exceeded 7k on stock engines, and have my turbo one limited to 7k by the ecu.

 

When I had my 240 with a 2.8, cam, header, light flywheel, and 3 two's, I could routinely rev the engine right off the tach in first gear when doing a burnout. That was pretty cool. Leave two nice straight black marks, and then a space of about 5 feet for shifting to second, and then more black marks.

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Guest BadKarmaCreepin

i don't know what it is, but this car feels pretty damn fast. not quite what the v8 was, but close....has anyone heard of jiffy lube letting you run on their dyno for free when you get an oil change? one of my friend's was telling me this and i haven't had the chance to call over there yet.

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Originally posted by BadKarmaCreepin:

i don't know what it is, but this car feels pretty damn fast. not quite what the v8 was, but close....has anyone heard of jiffy lube letting you run on their dyno for free when you get an oil change? one of my friend's was telling me this and i haven't had the chance to call over there yet.

That's a new one, Jiffy Lube has a dyno?

 

I guess it doesn't matter, I wouldn't let one of their monkeys touch my car, let alone drain the oil.

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  • 2 weeks later...

Revs will eat bearings/rings etc faster, plus causes more harmonic distortion, which is often why its not recommended.

 

2 bolt mains on an SBC for instance, wont like seeing above 7k. I've done 7k in an LT1 which is a 2 bolt main (except for the LT4/Vette block).

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Guest norm[T12SDSUD]

The hamonic balancers tend to come apart on 2.8L motors when spun above 6200 rpm.

If you are gonna spin it to 7K watch your balancer constantly as well as going ahead and loctiting the crank bolt and torqing it to 150 ft.lbs.

 

Once your balancer starts coming apart, go ahead and get an earlier 240 harmonic balancer or a new performance one from Nissan Motorsports.

 

Later,norm

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Yep, look into a Fluidampr/ATI etc

 

Most of the stockers just use rubber on a steel base. If you hunt around you will find resonance readings, I think the Fluidampr was better under 7k (and find @ 7k), and the other was better for all out 10k RPM racing etc

 

The info is listed somewhere on www.go-fast.org for the lower RPM setup which is obviously used on most street V8 setups, especially since the stock PCM is only good to 7k (8bit setup).

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Originally posted by Mudge:

Revs will eat bearings/rings etc faster, plus causes more harmonic distortion, which is often why its not recommended.

 

2 bolt mains on an SBC for instance, wont like seeing above 7k. I've done 7k in an LT1 which is a 2 bolt main (except for the LT4/Vette block).

True but you know L6 got more main caps than V8? more counter weight on the crank too. Also with forged rods and crank, I think it'll be okay in higher rpm than V8 ;)
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If harmonic vibrations are not kept under control, the engine can still eat itself most definately. Usually a more powerfull non-NA motor will be easier on mains than a higher RPM engine, especially if vibration can't be controlled.

 

Many Chevy cast cranks can be taken to 7k, beyond is generally not safe (sorry I don't know more about the Z stuff yet). Usually this is where people go forged for high RPM, the crank, rods, and beefier mains and good studs or just beefier bolts throughout.

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I gotcha dude, I didn't know to comment or not, then figured I shouldn't fill up the board :D

 

I still figure that to some extent these are things that hold true to any car, but I do not know the natural 'safe' limit for L6 engines in stock bottom form, don't know.

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