Rb25DET lacking in performance gains?

[Guest DON91E]

Hey there ppl,

I drive a R33 GTST, (auctually this is my 2nd one) Now chasing big power would you say theres a limit the Rb25det could handle??

Im saying this compared to a Sr20det, which can make HEAPS of power without changing the head or block it self.

I see big gains in R33 but i hear of VL 3.0L bottom ends or Rb26 heads.

So would you say the RB25det is limited in making big horsepower??

I would like to see one with standard motor(i mean rb25) make more than 300kwrw.

Don't flame me, its just a thought iv had??

What do you guys reckon??

Donnie

[Guest Nismo_Freak]

SR20s can only handle about 400rwhp (300rwkw) before you must sleeve the block and rework the internals. Even then they are not too reliable above 350rwhp. I have no idea about the RB25's strength other than the block should easily hold 600+ rwhp. Only problem is the headgasket on the iron block/aluminum head motors as aluminum and iron expand at different rates causing greater stress on the headgasket. Copper headgasket should solve that mess. Get some forged internals in there and look for 500whp!

[whatsisname]

The stock Nissan head gasket has been used in RB25DET's making in excess of 300rwkw. Martin (Donnon) mentioned a motor making 330rwkw on a stock gasket! Detonation will kill them quickly though.

The JMS R33 GTS25t still runs standard internals (HKS 1.2mm head gasket & ported head) & has made 308rwkw (1.5bar) And if there's a car likely to be driven HARD it's one driven by Danny! (HPI Aussie drifting videos)

[Guest Nismo_Freak]

I wasnt downtalking the headgasket on the RBs ... I was just noting that the headgaskets on the iron block/alum. head motors are under more stress cause of the different expansion rates of the metals. :burnout:

[Guest DON91E]

Hmmm,

Porting polishing?

Could this be a solution to not go down the RB30 block way??

Donnie

[SLY33]

i have also considered the RB30 block road..

but if you really think about it, its gonna give you a stack of extra torque right? Especially down low and mid range. The problem is, even a decent modded RB25 will have traction probs on the street, while still making killer top end power. If you had an RB30 bottom end, and say 250rwkw, would you be able to get traction?!

This only became apparent after riding in whatsisnames car. when it had 230ish at the rears, 1st and 2nd gears needed serious throttle controll to stop the rears baggin! Awesome. 2.5litres is enough for street -i reckon:burnout:

- i dont think his car has any head work done to it? Definitly a reason not to bother with your 30 bottom end. This has to be a great thing about skyline RB motors in general - you dont so much as have to remove the rocker covers let alone the head, to get SERIOUS street power.

[Warpspeed]

It is probably not that hard to get serious power from a RB25DET, the problem, as whatsisname says, will be keeping it alive for long enough to make it worthwhile.

Any serious detonation is going to kill it real quick, slight timing change, leanout, hot day, a tank of dodgy fuel. RATTLE - BANG.

So what is the point. If some hero can screw 400KW out of one and it lasts one week? Nitrous oxide is a good example of how to get huge power gains and blow up your motor on the dyno.