Advice Needed - Rb25det Neo Vs Rb25/30

[bubba]

Yay!

Got any engine bay pics Titan?

[cactus]

I used to run a built RB25 in my HQ (auto box) making 280ish rwkw @ 20psi. It was very fast once on boost (GT3082R) but it was still relatively laggy with this turbo. I then built a RB30 bottom end and matched it to the same turbo, the car made more power @ 18psi and 1000ish RPM earlier. It was the best decision I ever made and I absolutely regret wasting my money on building the original RB25. The 30 is just so much smoother and nicer to drive. So much power and torque down low and it just pulls and pulls and pulls. If I could do it all again, I would go straight to an RB30 bottom end... Especially on a street car when low RPM cruising is essential. I'm now running a GT3540 and it still makes boost earlier than the 25 with small turbo and its a billion times better to drive. Thats my experience

[QRI05E]

How about all those Supras, RX7's and Big V8's running 800rw/hp with 9-10sec passes that are all RWD?

I think it comes down to decent suspension, tyre setup and launch control.

From what I have read, the RB25/30 will be a great street/drag combo however just waiting to take a drive in Dave's car to see how the new RB25 + turbo setup goes

Edited January 30, 2010 by QRI05E

[drift_dingo]

Hmmm I await your impressions QRI05E, I'm in the same boat as ya, got a r33 gtst s2 bone stock (engine wise) and looking for idea's xD. alas the age old debate, rb25 or rb30/25....plus being in nrth qld limits my engine builders down a bit.

[TiTAN]

Nothing stopping you shipping the engine/bits down to them to get it built.

Bubba, missed that post will pm you some.

[drift_dingo]

any suggestions onto who does 'mail in' engines? I'm doing research ^^;

Nothing stopping you shipping the engine/bits down to them to get it built.

Bubba, missed that post will pm you some.

[TiTAN]

rips will send you a prebuilt engine. most engine shops if you ask will more than likely allow do it.

[bubba]

Bubba, missed that post will pm you some.

Cheers

[QRI05E]

Spoke to Adam my tuner today and here is what we have decided.

Stock RB25DET Neo

- High mount twin scroll manifold

- Garrett GT35R with .82 rear

- Bosch 040

- 800cc injectors

- SARD FPR

- FMIC

- Greddy Plenum

- Q45 Throttle

- Full exhaust

- Haltech E11v2

Should see easily 300rw/kw

Drive around for a while... then when I need more power... RB25/30DET with the same setup should see 400rw/kw

[TiTAN]

twin scroll manifold with non twin scroll rear housing on the turbo?

i am not sure if a 040 will support 300-400kw, you may want to look into using a 044 instead.

forget the sard fuel pressure reg waste of money, 800cc injectors will outflow a GT35R @ stock fuel pressure.

[MBS206]

twin scroll manifold with non twin scroll rear housing on the turbo?

i am not sure if a 040 will support 300-400kw, you may want to look into using a 044 instead.

forget the sard fuel pressure reg waste of money, 800cc injectors will outflow a GT35R @ stock fuel pressure.

Agreed.

That, and with that turbo, why not throw an RB30E in there, run less boost, make more torque and earlier, and have a much more streetable setup?

[QRI05E]

I will be throwing in the RB25/30 in there eventually... just didnt see the point of ripping out a perfectly good engine. The reason for the GT35R is to that when I do decide to build the RB25/30 I wont need to update the turbo.

Would a T04Z be overkill? Im thinking about the new Garrett GT3788R... Any ideas?

[R31Nismoid]

What's the resoning behind changing the throttle body exactly?

All it'll do is hard throttle control. Not like the factory unit doesn't flow enough, everyone else has made 380rwkw out of it easily enough.

[QRI05E]

From what I have seen, all the 400kw+ RB's switch to a larger throttle but we'll see how we go.

Will I run onto any issues with the RB25 Neo head on the RB30? I have read a few posts with people running into a few issues such as the bolting up a Greddy plenum with the factory thottle body.

Edited February 4, 2010 by QRI05E

[QRI05E]

What would a factory RB25DET + GT35R or GT3788R be like with supporing mods? Streetable?

Edited February 4, 2010 by QRI05E

[QRI05E]

EDIT: Double post

Edited February 4, 2010 by QRI05E

[R31Nismoid]

From what I have seen, all the 400kw+ RB's switch to a larger throttle but we'll see how we go.

Where have you seen this exactly?

Just because people change a part, does not mean it's a requirement or needed. Some people just get caught up in what they get fed.

recent thread come up about this actually!

http://www.skylinesaustralia.com/forums/La...dy-t291471.html

[QRI05E]

R31Nismoid - Thanks for the info, like I said, i might just wait and see how we go.

Anyone used a GT3788R on a RB25 yet?

[MBS206]

R31Nismoid - Thanks for the info, like I said, i might just wait and see how we go.

Anyone used a GT3788R on a RB25 yet?

If youwant streetable response, look at the GT3076 or the 3082.

When that gets thrown on the RB25/30, you'll have an unreal combination that will NOT have to be revved, but will be able to when needed.

[QRI05E]

I love the way the GT3076 sounds when it spools up... and have seen them make over 360rw/kw on an RB25DET

Should I go IWG or EWG?