How many RPM can you safely spin on a stock internal RB25DET

[240z4u]

Hey guys, I have not had a stock ecu in my car forever. I set the rev limit to 6800 and I am thinking that might be too low. Car still pulling really hard when it hits rev limit.

Where is the stock setting? and at what point do the valves start to float with stock springs etc??

Thanks guys, I did search but could not find the answer to this question.

Evan

[Carl H]

stock is 6800.as far as revlimit i was revving my 20 to 8.5 on stock springs with no float...your mileage may vary.

[240z4u]

Alrighty. 8500?? damn i dont know that i have the balls!!

Thanks carl

[Joe]

you wont make power much above the rev limiter unless you have a bigger turbo, cams, etc.

[240z4u]

Yeah I know. I have a big turbo, just no cams.

I was just wondering if I could bump it up some because car is still pulling really hard when it hits the rev limiter. I was not sure what the valve train could handle.

That power should be dropping off in the low mid 7ks I would guess.

Evan

[Carl H]

strange that it keeps pulling till redline, on the 20 the cams are a huge hinderance in making power.goofynick's dyno showed it it would pull hard till about 6,3-6,5k and then it would take a nosedive.add cams and springs before changing the revlimiter.

[Joe]

its because its a rb25 ya noob.

bigger cams i believe i read somewhere.

[rustbucket]

My best 1/4 mile times came from shifting at 7200 on the stock rb25, seems to put it in a sweet spot with the nvcs and boost in the next gear. But I guess it also has to do with tire size and rearend gearing as well.

[Justin Duncklee]

Mine is set at 8100rpm when I'm at 19psi.

Muaha ha ha ha. No valve float or anything.

[Carl H]

nah if anything the 25 has the same cams as the 20.fwiw vtc is only engaged between 1050-4800, so yeah.

[matafied]

sweeeeeeeeeet!! cant wait to push mine to 8K

[rustbucket]

nah if anything the 25 has the same cams as the 20.fwiw vtc is only engaged between 1050-4800, so yeah.

oh, my bad for puttin out the bad info Carl. Yeah, I looked it up, it says 1500 - 4200 for the RB25 (assuming the internet source is correct).
Modified by rustbucket at 1:56 PM 6/7/2007

[lucky7]

ive only had mine a couple days now. i just shift at 7k if im getting on it.

[Shocker]

bobnissan was taking his to almost 9 grand with a stock head. Now I dont recommend this if you want it to last with standard hydrolifters.. he was also running a pt67...

Don't take it much higher than you make power, after that its decently pointless unless your going to fall out of your powerband after you shift.

Stock turbo rb25's run outta breathe after 63-6400 rpms soo no need to rev past the stock 6900.

[eh?]

bobnissan was taking his to almost 9 grand with a stock head. Now I dont recommend this if you want it to last with standard hydrolifters.. he was also running a pt67...

also why he destroyed the motor..

Unless you have modified the oiling system keep your RPM below 7500. I wouldn't worry about valve float.

[Carl H]

oil pump assplosion!

[midnightsliding]

i dont have a rev limiter, my safc has recorded 8100rpm more then once.

[StricNyne]

aussies say with hydro lifters dont go over 8400, i am gunna be bringing my motor to prolly 8100 ish but i upgraded valve springs just need to drop in cams, also u only need to rev as high as you make power no need to rev to 9k when yer stocker turbo stops pumping out air at damn near 6800, but basically the rb25 rev limit is hindered by the hydro lifters and looking at the work i would need to run those i opted to look into turbo applications that dont require me to rev ultra high and use solid lifters

[Carl H]

remember all those threads we had about changing out the oil pump and collaring the crank, yah thats another limiter to how high you can turn the motor.

[240z4u]

I did the stage eleventeen package. I set my limiter to 12,000 but usually only take it up to 10k. lol.

I did fix the oil pump collar issue while I had my motor apart.

Great replies guys. Thank alot.

Evan

[StockAsFuhS14]

i wish this thread had some mechanical specs..i cant seem to find any

[Darius]

What kind of mechanical specs are you looking for??

[chad b.]

A buddy of mine made 650whp on a stock RB for years spinning it to 7500 MAX. He moved the limiter to 8000 and it lasted 2 weeks. The rod bolts stretched and sent the rod through the block. That being said, on stock rod bolts, I'd set the limiter somewhere between 7200 and 7500. With the stock head and cams, you're not gonna see any real benefits to spinning it another 500-600 rpm anyway. The last thing you want is a hole through the block.

[RRRRB]

i revved mine on a stock rb25 head and cams to 7800 for over a year like that.. never had an issue...

with a GT30R it held power out that far as well

[klh6686]

Ha funny to see this thread back from the dead. I can confirm what CarlH said, I ran a rb20 to 8.5 stock longblock w/o issues for probably 3 years straight, and she was bouncing off the rev limiter most of that time.

[240z4u]

Chad, are you talking about Jons 280z?

Man this thread is OLD.

[breadbox]

Now that thread is kinda back. I picked up an ECU for my upcoming RB20 S13 project. Nico members are awesome. He sent me info that I am posting here more for me than you all, but from the sound of it I should be perfect on this tune with a pretty stock set-up.

Ok, the full story on the ecu is that I acquired it with my half cut so it is a JDM tune. I have a chip reader and burner that I was able to take the chip and read it to compare it to an OEM tune. What I found were:

Fuel map: Minor changes, mainly to help spool
Ign map: slightly more aggressive to help spool
no speed cut and rev limiter raised to 8300 (i would not recommend revving above 8k personally unless rod bolts are upgraded)

It is still tuned for the stock injectors and maf which are the main points of a tune.

My personal experiences with the tune were with the stock turbo at first, but then i switched to a RB25 NEO turbo (which is slightly larger than a normal RB25 turbo)

I compared the tune w/ a stock tune and noticed these traits:
on WOT tip in (from cruising speed to WOT) the car picked up very aggressively vs OEM.
Also the car pulled harder throughout the rev range and most noticeably up top.

With this setup I was side by side w/ a WS6 trans am that traps ~108mph in the quarter.

[chad b.]

Chad, are you talking about Jons 280z?

Man this thread is OLD.

yep. He told me that's what he felt was the culprit.