Rb25det Rev limit?

[rb25drag]

What is the Stock valve spring/cam setup able to Rev without floating a valve and get max power?

I have heard 6400 and 7000?

I usually shift at 6 and it revs to about 6500.

Feels to me like it lays off about 6000 in power, but I have heard people talking about running 7000?

Just wondering if im running mine 100% of its capabilities of if im lagging some?

[Cjmartz2k]

I don't know who you were listening too, but they are an idiot. I rev mine to 7500k every time with no problems. With a stock turbine, however, it probably won't do any good to spin it past 7k. If yours stops pulling around 6k, sounds like something aint right.

[sil_eightyRPS13]

What is the Stock valve spring/cam setup able to Rev without floating a valve and get max power?

I have heard 6400 and 7000?

I usually shift at 6 and it revs to about 6500.

Feels to me like it lays off about 6000 in power, but I have heard people talking about running 7000?

Just wondering if im running mine 100% of its capabilities of if im lagging some?

8300 before u have to switch to to solid lifters..

[rb25drag]

Sweet thanks,

Ya I think my turbo runs out at 6000. Doesnt stop pulling but levels out about then.

[Darius]

Yep there are dyno plots out there that verify that the stock turbo peters out at about 6500 rpm, so there's really no point in revving above that because you're just creating heat. Without an upgraded turbo, revving that high is pointless. The stock valve train can handle MAYBE 8400, but I wouldn't try it on stock springs. Hell, I'm not even going to try 8400 on my fully built head minus the stock hydraulic lifters.

[Chaos the Xile]

I use to shift mine at 8K, no problems til now, collapsed lifters and such

[rb25drag]

Ya I would say I can bump it up to about 7 and be alright.

Least now I know what there capable of.

Thanks for the info!!!

[Jo240sx]

I was reving around 7400 with stock turbo........had plenty of pull

[Shocker]

Bob Nissan used to rev his to 9+ stock head, built bottom end. Lol I dont condone this, but sure it will do it for a bit... 7700-7800 is all I will end up reving mine to, granted its not stock. However unless your tuning for it, and have a/m cams, theres no need to go about stock Redline of 6900, it stops making power around 6400 anyways.

[rb25drag]

Ya im thinking its pointless to go over 7000. But this gives me a good idea of what I have to work with. Thanks for the posts guys!!!

[rb25drag]

Well Since I have finally got to make some WOT pulls @15PSI, I have noticed the car stops pulling around 6500 RPM's If I shift any higher it just seems to fall on its face. But if I shift around 6400 it pulls like a Scalded dog through 3rd gear ( I haven't hit 4th yet).

[sepulchralx]

I know this is an old thread..

Can I raise my rev limit to 8k and safely get away with it? My power band really pics up at high rpm and I coudl probably make about 30hp-40hp more just with the extra 700rpm

rb25det series II

[Largekid]

I wouldn't rev it past 7500...that is where RB's have tendencies to float valves and such. I've read of multiple people reving to 8k or so, but I'd be scared find shrapnel in my motor. my .02

[Cjmartz2k]

I know this is an old thread..

Can I raise my rev limit to 8k and safely get away with it? My power band really pics up at high rpm and I coudl probably make about 30hp-40hp more just with the extra 700rpm

rb25det series II

What turbo and cams do you have? Stock stuff isn't going to make more power past 7krpm. I shift around 7.5k, but I've got 264 cams and a *slightly* bigger than stock turbo. I'll bang it off the rev limiter at 7.8krpm all day doing a burn out before a run though.

Safety of the motor, I would think shifting before 8k and you should be good. Performance, depends, but I'd say not much past 7k for stock stuff.

[meet07]

revive from the dead. I dynoed mine and i was making power all the way up to redline(68-6900) with the stock turbo. only thing i have diffrent than most is the intake manifold and q45 tb. im sure that i could make an extra 10whp if i could red to say 7300.

[Cjmartz2k]

Interesting. I wouldn't have expected that. Mine leveled off around 6500 and was flat until 7k when I ran the stock turbo (and when they still had a dyno on Oki).

[stevespeed]

Dont RB26's going to 9k?

[coreansurfer]

[meet07]

Revive from the dead

I have a question. Would more power be made on the stock head with aftermarket cam gears?? gears and bumping up the rev limit on stock turbo?

Meaning if you use the gears and increase the overlap( aka: tightening the lobe separation angle (LSA) wouldnt that give a lil more power up top??

[Cjmartz2k]

I think it's more a function of the turbo being the choke point, not anything in the head at that power level. That being said, yes, I could see the stock cams providing better top end at the expense of power somewhere else. Keep in mind if you are keeping VCT, you can only use one adjustable came gear. I think you should be adjusting (or keeping) the cams right in the middle of your power band on a stock set up because that's where the undersized RB25 turbo is making most of it's money.

Size and adjust your cams to where you want to make the most power. Putting huge cams (or adjusting cams for the most top end) on a small turbo'd car where the turbo is choking it out anyways kills low end and doesn't help top end. Now if you had a big turbo that pushed a lot of air up top (6k-8krpm), and was a little soggy below 5k rpm, then stock cams would be the limiting factor. Adjusting them towards the top end of the power band would help some I think (more than on a stock turbine car), but bigger cams would be the best answer.