Rb25/30 How Long Will It Last?

[VB-]

what valve springs were you using cubes? what were the issues?

[Cubes]

Standard R32 RB25DE springs + high oil pressure = onset of float.

They are 'ok' with the low pressure rb20det pump.

[Shaun O]

What kind of setup would you need to pull 7500-8000 rpm just out of interest?

[Adriano]

Do you just want to rev it to that, or make efficient power at 8000? If so you are looking at making about 8-900hp, with the associated costs.

[MBS206]

Personally, I'd be going for a stock turbo if you don't want to break things...

I'm running a T04R on the same setup as you, except for ceramic coated pistons, and a flowed head...

I hit 4000RPM and just snap into massive amounts of torque...

Off boost drives really well, but once above 4000RPM it REALLY Hauls ass...

[Cubes]

I'm not sure a stock turbo on the rb30det is a wise thing for reliability as they choke up way too much.

Mine used to ping so damn easily and ran bugger all ignition timing.

The tune with the GT30 is much less highly strung. The stock turbo was right on knocks doorstep even though we were running next to no ignition.

As a comparison the stock turbo running 12psi tailing off to 9psi saw a peak of 13-14degree's.

Drop the GT30 on and an instant 20degree's through out the rev range.

[MBS206]

I'm not sure a stock turbo on the rb30det is a wise thing for reliability as they choke up way too much.

Mine used to ping so damn easily and ran bugger all ignition timing.

The tune with the GT30 is much less highly strung. The stock turbo was right on knocks doorstep even though we were running next to no ignition.

As a comparison the stock turbo running 12psi tailing off to 9psi saw a peak of 13-14degree's.

Drop the GT30 on and an instant 20degree's through out the rev range.

The advantage though of running the stock turbo, is the ability to drop the revs, and still have just as much useable power.

And we know revs also kill motors.

I've heard of a few 26/30 combo setups (Not in australia) running twin RB20 turbos, and cranking out over 300RWKW without blowing turbos.

[Cubes]

The advantage though of running the stock turbo, is the ability to drop the revs, and still have just as much useable power.

And we know revs also kill motors.

I've heard of a few 26/30 combo setups (Not in australia) running twin RB20 turbos, and cranking out over 300RWKW without blowing turbos.

What sort of rev's are you talking about?

The usual 7000rpm is fine for the rb30det.

With regards to the rb30dett running twin rb20 turbo's.. You've missed my point.

A 'single' rb20 or rb25 turbo on the rb30det's chokes them up reduces the available rev range. Causes detonation and has them living on the edge. You have to pull a heap of ignition timing out of it and even then it still pings so damn easily as soon as the weather warms up.

Mine with its stock turbo made its peak power at 4400rpm and felt like you hit the brakes at 5500rpm. Definitely not fun nor did it accelerate quick. Possibly with a 3.45:1 diff ratio but with the 4.3:1 diff ratio the lack of rev's absolutely killed its acceleration. The power band was compressed not widened.

No point having 110rwkw at 2000rpm unless your towing or pulling stumps.

[Tony1981]

Cubes, I am need of a turbo for my conversion and I was thinking something like this would be good,

http://www.turbobygarrett.com/turbobygarre...T30/GT3071R.htm

With a .63 or .82 A/R,

Thats not to small is it?

[WHITER33GTS-T]

Im running twin T3/T4s on my 25/30 and they are awesome. It hasnt been tuned yet as i need to upgrade the ignition. But they will be making way for something much bigger soon.

[Cubes]

Cubes, I am need of a turbo for my conversion and I was thinking something like this would be good,

http://www.turbobygarrett.com/turbobygarre...T30/GT3071R.htm

With a .63 or .82 A/R,

Thats not to small is it?

Definitely don't go with the .6 on the rb30.

I personally wouldn't go any smaller than the GT3076 .82 on the rb30det which is what I went.

Mine recently made 302rwkw on 17psi. 200rwkw by 3.5k and 256rwkw by 4k. The cams really woke the motor up.

I must be dyslexic as I typed 265rwkw at 4k in other threads :S. Its actually 256.

It has heaps of mid range a perfect street setup. I can click third gear from 60km/h and torque away from rb25 and 26's making similar power that are sitting in second from 60km/h's without any problems.

And surprisingly as power is so linear traction problems are very little. Not lag lag lag and then hard snapping power delivery.. Just brute mid range when you put your foot down.

The GT3582r with a .6 rear will push 340-350rwkw spool slightly later than the GT3076r .82 and have slightly decreased throttle response. Which is most noticeable in the lower loading quicker reving gears.

Up from there is the Gt3582r .82 for another 40-50rwkw cams then GT4088r etc etc

IMO

[Tony1981]

Mine recently made 302rwkw on 17psi. 200rwkw by 3.5k and 256rwkw by 4k. The cams really woke the motor up.

I must be dyslexic as I typed 265rwkw at 4k in other threads :S. Its actually 256.

Its called a transposition error, you can tell because the difference is divisible by 9, ie...265-256 = 9 or example.........1170 or 1710, diff = 540/60 = 9, whenever the difference is equally divisbled by 9, its called a transposition error, common mistake in bookkeeping - I studied Commerce at UNI :-)

And surprisingly as power is so linear traction problems are very little. Not lag lag lag and then hard snapping power delivery.. Just brute mid range when you put your foot down.

Thats exactly what I am looking for, for the moment I am running an N/A RB30 5spd, and old uni'd half-shafts and 27spline'd stub axles, dont want the power delivery to come slammin on at 4000rpm!!!

[Tony1981]

Just curious about manifolds as well Cubes, those turbo's dont have internal gates and I cant fit in a high mount manifold - absolutely no way does it fit under the bonnet of my Z,

Are you modding the stock low-mount and sticking a blow-off valve on top?

[Adriano]

These are internal gate turbos