the rb25 and the gt30

[MOB240]

anybody running the gt3076r on their rb25? i asked this question awhile back and a few people said they were planning on it. any updates? im looking into getting this turbo. for people that have actually drove w this turbo, how was it?

[cdorhout]

Yes, I run the GT3076R with .63 A/R, internal gate.I bought mine with the custom RB Downpipe flange from horsepowerinabox.com.

It's a little laggier than I was expecting. It probably wouldn't be a good drifting or autocross turbo. Would make an excellent drag turbo though. I'm still tuning it though, so I may be able to improve the spool time somewhat.

I just installed it a couple weeks ago.

Here's video of it installed: http://www.youtube.com/watch?v=AFe8gkUFikY

[Carl H]

gt30r = fun.

[Bluefire]

Yes, I run the GT3076R with .63 A/R, internal gate.I bought mine with the custom RB Downpipe flange from horsepowerinabox.com.

It's a little laggier than I was expecting. It probably wouldn't be a good drifting or autocross turbo. Would make an excellent drag turbo though. I'm still tuning it though, so I may be able to improve the spool time somewhat.

I just installed it a couple weeks ago.

Here's video of it installed: http://www.youtube.com/watch?v=AFe8gkUFikY

Boy if you think the gt30r with .63 a/r on 25 is laggy... I don't know if you'd be satisfied with any turbo out there. I think the 30r is the perfect turbo for the 25, great response and high numbers...

-Bluefire

[Carl H]

laggy is when you loose half of your powerband or more...my 30r comes on full song at 4k, revving to 8 its on the verge of being too big on the 20...but meh on the 25 its perfect especialy if you have the .63a/r exhaust housing, it should be insane.

[cdorhout]

I'm satisfied with this turbo, it's great and the power is insane. But I just noticed that drifting would be a lot harder with this bigger turbo.

If I was building a drift or auto-x car, I'd get a smaller one or .53 A/R. But my car is primarly used for street and drag racing, so I'm more than happy with it.

I agree, reving to 8k would help alot, but I don't have the supporting mods to do that yet. I'm running stock pistons, valves, springs, retainers, and head gasket.

[Tripz]

Hey cdorhout, was there any major modifications for you to fit that gt30 on the stock manifold? Also, are you using that am-performance dp along with this turbo? How does it fit overall? Do you know how much whp your pushing?

[cdorhout]

No, not any major modifications. I did have to put a spacer in between the turbo and the manifold so the compressor wouldn't hit the manifold. I got a 1/4" spacer, and running two gaskets bumped it out about 3/16" more.

I had to fabricate a new hot pipe.

The turbo came with new water lines. I had to buy a new oil feed line from a local speed shop as well.

The AM Performance downpipe did still fit around the steering shaft (even after bumping the turbo towards the steering shaft 7/16"). I am selling my AM Performance downpipe now though, because the main tube in my downpipe was sized perfectly for a stock turbo, and this GT30 has a much larger opening.

I'm in the process of fitting a Syko Performance O2 housing and SR20 downpipe, so we'll see how that goes.

I'm not sure how much power I have now. I'm still tuning it. I had to go through 3 sets of spark plugs to find a set that were cool enough to not detonate at the 18psi I'm tuning for right now. I'm hoping to throw it on a dyno within a few weeks though. I'm hoping close to 400whp.

[MOB240]

why would i want .63 a/r as opposed to .82 a/r? whats the difference? .63 a/r would spool faster or what? cdorhout: what are your mods? how long did the rb25 swap take you? also what kind of exhaust do you have?


Modified by MOB240 at 1:59 PM 5/30/2007

[cdorhout]

Yes, generally the lower the A/R, the quicker the spool. But also, you lose top end with a lower A/R as well. A GT30 is big enough in my opinion to give up some top end for a lower A/R. But that all depends on what type of racing you're doing.If you don't know how, figure out how to read turbo maps. It's pretty cool to see how different A/Rs affect the efficiency of the turbo.

ModsGreddy intakeQ45 TBNisom FPRPowerFCGreddy VSPL FMICBlow-thru Q45 MAFHKS Hi-Power 3" Exhaust

[l0nestar]

cdorhout,

your car looks pimp-tabular! Did you get that knocking sound fixed in your video?

[cdorhout]

Thanks!LOL, yeah the knocking you hear in the video is a flat spot in the front tire. My brother and I were trying to do burnouts ealier, and now that I have 300zx brakes on the front, they lock up very easy. I need to get my 300zx master cylinder on to get the correct brake bias again.

At the end of the video, when I say "Something's wrong", is because I noticed a ton of knock spikes on the PowerFC Commander. I thought I'd tuned all the knock out of it by then, so I was pissed. I still haven't tuned more. I think I need to pull some timing out at high RPM as I heard the base PowerFC IGN map is too aggressive for high boost. We'll see I guess.

[Carl H]

how much knock are you seeing at full boost?i see at most 30 on hot days at 18psi...

[cdorhout]

It's weird, but at 6k rpm, knock just starts going all over the place. It hits 100 at some places. It's not predictable at all. It's not progressive either, I would assume knock would "build" as you climbed in rpm. But it all of a sudden spikes to 100 back to 0, then back to 100. Whatever it is, it's not good.

[bumblebtuna]

nice vid
Modified by bumblebtuna at 12:21 PM 12/20/2007

[MOB240]

where did you get your intercooler from? and where did you get your engine?

[cdorhout]

I got my skyline front clip and my Greddy FMIC from Phase2 a couple years ago.

BTW - I got my car running great this weekend. I street tuned it for an hour and a half and it's running perfect now. I had to pull back a few degrees of timing at the top end and that took care of all the knock. Then I tweaked the fuel curve and now the car pulls HARD all the way to 7k with no hiccups. It's nice.

[MEclipseGSX2G]

Yes, I run the GT3076R with .63 A/R, internal gate.I bought mine with the custom RB Downpipe flange from horsepowerinabox.com.

It's a little laggier than I was expecting. It probably wouldn't be a good drifting or autocross turbo. Would make an excellent drag turbo though. I'm still tuning it though, so I may be able to improve the spool time somewhat.

I just installed it a couple weeks ago.

Here's video of it installed: http://www.youtube.com/watch?v=AFe8gkUFikY

damn nice vid, how much boost u gettin?

[cdorhout]

18psi right now. Now that I've got it tuned, I think I'll turn it up a little more. 20psi max.

[MEclipseGSX2G]

nice

[MOB240]

more vids more vids inside and outside shots!!!! lol

[sil_eightyRPS13]

Yes, generally the lower the A/R, the quicker the spool. But also, you lose top end with a lower A/R as well. A GT30 is big enough in my opinion to give up some top end for a lower A/R. But that all depends on what type of racing you're doing.

a .63 on a 2.5 ltr....? what a waste... the .86 should have been your choice...ppl run the .86 on there sr20's with no issues while drifting...maybe u should get your car tunned right...u should see full boost a 3500 no problems on a I6 2.5ltr...

[cdorhout]

a .63 on a 2.5 ltr....? what a waste... the .86 should have been your choice...ppl run the .86 on there sr20's with no issues while drifting...maybe u should get your car tunned right...u should see full boost a 3500 no problems on a I6 2.5ltr...

Yeah, I do see full boost alot earlier now that I've street tuned it this weekend. I'm a novice tuner but I'm learning more all the time. I need to figure out how to tune the lower cells to try to minimize spool time. Right now I'm tuning for maximum power up top. I'm sure there are some tuning tricks to get turbos to spool faster. I see full boost at 4k right now.

I might take your advice and take it to a professional "tunner" and get it "tunned".

[Carl H]

how are you seeing full boost at 4k?ive got a 20 and the .63 ar and i see 14psi at 4k...somethings not right.

[cdorhout]

I'm seeing 19psi at 4k right now.How early should I expect to be at full boost? 3.5k? or sooner?

I'm willing to bet my slower spooling turbo is due to the fact that I'm running the factory cast exhaust manifold.
Modified by cdorhout at 11:24 AM 6/5/2007

[240sxr33]

Nice setup.What spark plugs did you end up using?

[JPsNissans]

I might take your advice and take it to a professional "tunner" and get it "tunned".

Nice setup, glad it's coming together.