Rb25 Breaking Point

[Elliotws]

I've been building my r33 up for some time now. im pushing 300+rwkw now and im starting to worry about the reilabilty. what are peoples experiances. what power figure seems to start killing an rb25 with stock internals?

[Strik3r]

270-280rwkw is considered the 'safe limit'. I'd be looking at doing the internals pretty soon if you like your car

[cheez]

id be sticking to around 260rwkw. thats safe and it will extend the life more than 270-280rwkw.

[R31Nismoid]

Hi.

There are plenty of threads on this topic, and its basically no set answer.

No-one can tell you as there are so many factors in a motor holding together that its impossible to put a number to it.

If the tune is good, the motor is in good condition and not sitting on high/big RPM for extended time (ie, circuit), then it will last.

If the tune ir crap, or motor a bit old, or it's seeing constant big/high RPM, then its likely it wont last.

But either way, the motor is seeing over double what power it was designed for. Expect it to die eventually.

[Elliotws]

yeah 280rwkw is what i was thinking too. im picking it up tomorrow, just had a hks gt30r stuck on it. but yeah to strengthn my engine the way i want will cost me 8-9grand. That will deffinatly be the next mod i do tho, sooner rather than later is the key or i reckon i may be back to the workshop

[BHDave]

how long is a piece of string?

It depends on lots of things, tune being the most important. Personally, if you keep your revs within reason so you aren't overly stressing the rods and you keep the boost reasonable so you aren't floating valves, and you keep your knock levels down, it will just keep going until the rings and bearings wear our and it gets a bit breathy, same as a built engine.

Don't bounce it off the limiter either or you will kill the oil pump drive.

Otherwise, happy driving.

[STATUS]

depends on the tune and the setup and routine servicing, i have a customer running 320-odd rwkw for nearly 18months now and it is canned on a daily basis.... im interested about your HKS GT30r..... sure it isnt just a generic garret

[joeyjoejoejuniorshabadoo]

i have a customer running 320-odd rwkw for nearly 18months now and it is canned on a daily basis....

[abu]

depends on the tune and the setup and routine servicing, i have a customer running 320-odd rwkw for nearly 18months now and it is canned on a daily basis.... im interested about your HKS GT30r..... sure it isnt just a generic garret

Is that Justin's car!!!?

Thanks,

Abu

Edited August 21, 2007 by abu

[RRob]

One of the DA cars i help with has 460+rwhp. Has baby cams but being a DA car it never gets driven nicely.

[TTT]

there is a LOOOOOOOOOOOOONG thread on here about an internally stock RB25 and how much power it made..

started off rocky but turned out to be a good thread.

I can't remember the user id of the guy who started it though.

someone else will remember and reply here soon.

but yes..

your thread is very much a "how long is a piece of string" type thread.there is noway of knowing.

there is always a general consensus though.

and as said, between 250-270rwkw on a good tune with fueling and oiling well looked after, it should be good for a while..

if you are looking to spend $8K-$10K on a rebuild, why not rebuild an RB26 or 26/30?

same price, much more torque and power.

[GOT04]

i have 280kws now on 14psi with a standard engin and its fine bashing it round a track, im putting a bigger plumium and throttle body on it next too, im not worried bout the engin....

mate of mine has 310kws standard engin....

a well looked after rb25 with all parted matched with a perfect tune on it can handle any power it makes, its just the boost u have to keep low

xoxoox

[R33GOD]

so should i be fine at 16-17 psi when i tune my car. is that considered high boost? im chasing about 240ish rwk.

how long should i expect it to last on that boost? (with all the supporting mods ofcourse)

abit off topic but does a z32afm help increase your power figure? how?

i dont know much about them.

cheers

Edited August 21, 2007 by R33GOD

[joeyjoejoejuniorshabadoo]

should be fine with a good tune

[LatinR33]

there is a LOOOOOOOOOOOOONG thread on here about an internally stock RB25 and how much power it made..

started off rocky but turned out to be a good thread.

I can't remember the user id of the guy who started it though.

someone else will remember and reply here soon.

but yes..

your thread is very much a "how long is a piece of string" type thread.there is noway of knowing.

there is always a general consensus though.

and as said, between 250-270rwkw on a good tune with fueling and oiling well looked after, it should be good for a while..

if you are looking to spend $8K-$10K on a rebuild, why not rebuild an RB26 or 26/30?

same price, much more torque and power.

I support the above comment, rebuilding an RB26. Never enquired on how much the conversion would be to put in a GTS-T but if its a reasonable amount then that would be the way to go. Even a reasonably mild rebuild with decent turbos

[joeyjoejoejuniorshabadoo]

its kinda harsh after you put well over 5k into your 25 tho, as so many of us have...

[TTT]

so should i be fine at 16-17 psi when i tune my car. is that considered high boost? im chasing about 240ish rwk.

how long should i expect it to last on that boost? (with all the supporting mods ofcourse)

abit off topic but does a z32afm help increase your power figure? how?

i dont know much about them.

cheers

Like it's been said mate..

just because someone is making 300rwkw with no problems, that doesn't mean that you will have the exact same outcome.

you might, but there is always the chance that you will lunch your engine.

yes - both engines are RB25's.

but who knows what kind of life they've had.

what kind of servicing they've had in the past 15 years before it came to you.

If you want a "better" idea of how healthy your engine is, you should get a compression and leak down test done.

if the results are all good, then you should then do safety precaution maintenance.

new belts, injectors cleaned, new filters, new oils, etc.

x psi or y psi doesn't mean shit.

to get 240rwkw, the stock turbo (for example if it could stay together) would need to be pushed to massive PSI.

a hiflow stock turbo will need like 15 psi.

a Garrett GT30 would need only 10 psi.

All examples above.

the point is, saying, will x psi to make y power make my engine last long is useless.

Boost pressure is just a measure of restriction.

if you remove the restrictions, you can use less boost to make the same or more power.

a large turbo is less of a restriction than a smaller turbo.

therefore it needs less boost to make the power.

Z32 AFM alows an aftermarket computer to be tuned at higher air flow levels.

it converts air flow to VOLTS.

it can measure up to 5.1V where as the rb25 and rb20 ones measure to 4.7V (I think)

so essentially, there is more room for tuning at higher levels of air flow which in turn means more power (if you have the fueling to go with it)

"GENERAL CONSENSUS" is that the RB25 is good for the power you want.

the usual remarks about RB25 weak points are the piston ringlands.

these seems to not like too much boost.

[TTT]

its kinda harsh after you put well over 5k into your 25 tho, as so many of us have...

we're talking once it blows though.

if you have a stock rb25 that you have spent $5K for bolt ons, and it pops, and you are about to bite the bullet for forged bottom end, N1 pumps, head porting etc where you are going to end up spending about $10K to have an internally tough rb25 and bolt your $5K worth of goods to it, you could spend that $10K to buy and build an RB26 (which has a much better head to start with) or an RB30 bottom end and RB26 head

then bolt your $5K worth of goods to that.

it ends up costing the same to build a forged RB of any kind.

might as well go for the best you can get for the money.

and for $10K, rb26/30 combo can't be beat.

[joeyjoejoejuniorshabadoo]

tis true.... wasn't thinking about it being blown...

[Elliotws]

yes there is alot of variables with different engines and how they have been treated, tuned ect. 270rwkw im guna keep it at i reckon. but about the turbo i find it hard to find any info on the hks gt30r. morpowa said that it was obviously garret running gear in the turbo, but hks flow it differently and lable it as a hks item. i would really like to hear from someone with a hks gt30r