what stock RB20DET redline?

[sil820]

anyone know the stock rb20det redline?? i still really havnt taken my car up yet.. b/c i didnt know what the fuel cut off is or the redline... thanks

[PROJECTRB240SX]

I can rev up to 8500 rpm.

[rbsileighty]

I've been told not to go over 8250, but the stock redline should be ~7400 (depending on what is reading it... ie stock tach, S-AFC etc).

[sil820]

coo thanks ima set my rev/speed meter warning to 8000 then. thanks

[rbsileighty]

What did you do to make it rev out that far?

[wga240]

I've got the RB20 tach in my 240, so I can take a look for you tomorrow to make sure of what it is. I think 7400 is about right though.

So far I've had mine as high as 8700, but that was when I was watching the boost gauge and forgot to shift out of 3rd gear. I'm not sure if I have a fuel cutoff or not, but it sure seemed to pull well even that high. I know it's not good for the engine though

[sil820]

k thanks

[rbsileighty]

Sounds like there is no rev limiter on your 20... should have reworded that... rev cut is suppose to be about 7400-7500.

[PROJECTRB240SX]

MY CAR IS LIKE THAT BECAUSE WE BY PASSED THE TACH INPUT ON THE ECU.

I HAVE NO LIMITERS:REV LIMITSPEED LIMITBOOST LIMIT

[Wulfgang]

What tach input? The ECU determines revs by counting pulses from the CAS. There is no tach input, just a tach output. Do you mean that someone reprogrammed your EPROM to bypass the rev limit?

And what boost limit? RB20's don't have a boost sensor (except for the one that goes to the boost gauge).

[PROJECTRB240SX]

ANYWAY, I'VE ALWAYS BEEN TOLD THAT THE RB20DETS WERE LIMITED 7400 RPM AND 112MPH, I HAVE NONE OF THESE LIMITS. I ASSUMED THE RB20DET WAS ALSO LIMITED 14.7PSI LIKE THE OTHER ENGINES BUT I GUESS FROM RE-READING WHAT I THOUGHT TOLD ME THAT I WAS WRONG.

EDITED: I SEE WHERE I AM WRONG I WAS READING THE WRONG PAGE.... MY BAD, THE RB20DET ISN'T BOOST LIMITED. I HONESTLY DON'T KNOW WHY MY ECU ISN'T LIMITED ANY MORE WE THOUGH IT WAS HOW WE WIRED IT BUT I GUESS ITS SOMETHING ELSE.

[WDRacing]

Be very careful taking the RB20 close to 8000. The tensile loads on the rods are almost doubled every 500 rpm over 7500. Luckily the RB20 has a short stroke, so you can go to 8000, I just don't recommend doing alot.

Also, unless your running a decent sized turbo, your not making much more real power anyway.

WD

[Wulfgang]

Not be anal, butt....

Tensile loads increase proportional to the rpm squared. To say that they double every 500 rpm at 7500 rpm is a bit far-fetched. To double the tensile load the rpms must increase by a factor of the square root of 2, which is only about 1.414. So a 40% increase in rpm would double the tensile load.

Thus, to double the tensile loads that the engine sees at 7500 rpm, you would need to rev to just over 10,000 rpm.

[goofynick6]

Worrying about how high you can rev a stock engine is a ricer thing anyway. It's not like a stock turbo is gonna do anything over 7 grand anyway, and even with a good turbo, what's the point of going to 8000 if the cams and gearing, etc, make it more beneficial to just shift and stay in the power band?

Save your engine and keep it below 8k rpms.

Nick

[sil820]

ya thanks.. the other day i took it up 2 7900, just to see what it feels like.. and it felt like crap.. i can feel a big loss in power past 7rpm. i got the car dyno'd 2day and the power band peaks at 6.5 after that its all down hill...

[Yellow4g63]

Worrying about how high you can rev a stock engine is a ricer thing anyway. It's not like a stock turbo is gonna do anything over 7 grand anyway, and even with a good turbo, what's the point of going to 8000 if the cams and gearing, etc, make it more beneficial to just shift and stay in the power band?

Save your engine and keep it below 8k rpms.

Nick

Well not just the turbo but also the stock cams. 6700-6800 usable power I guess since it's stock.

[WDRacing]

Thx for the physics refresher...8)

[rbsileighty]

From the Aussie tuners I've spoken to... it's the pistons that can't limit the motor past the 8250+ rpm mark for very long.

[WDRacing]

Hmm...if your not detonating then the rods or wrist pins will go before the pistons will.

[rbsileighty]

I'm not sure, but it might have something to do with the weight and not the strength (just an assumption).