Jump to content
SAU Community

is anyone running hi-flow rb25 by gcg?

bigcarl

By bigcarl,
in Engines & Forced Induction

 Share

Recommended Posts

Lepperfish Mentor

Lepperfish

Posted
Posted

Hiya. Yep im using a rb25 highflow from cgc...

Stage 1 450hp build... At the moment running 1 bar and full boost comes on by 3500rpm... Currently pushing out 232rwkw with usual mods, Fuel system, ECU, FMIC ect...

Does anyone know how much the turbo will flow boost wise?

LePpErFiSh.........

Sydneykid Grand Master

Sydneykid

Posted
Posted

Hi Carl, we have 2 GCG Hi flow RB25 turbos, both Stage 1. One is on an R34GTT (RB25DET NEO) and the other on a R32 GTST (RB20DET). The R25DET has 240 rwkw at 1.1 bar and the RB20DET has 220 rwkw at 1.3 bar. The full weight R34GTT did a 12.4 for 1/4, and is used daily, in city traffic, freeways etc and has been that way, totally reliably for 20 months. The R32 is used for circuit racing and the turbo is very responsive in the RPM range we use, it isn't lag free but it's pretty close.

The RB25DET power band looks like this

7000 rpm 240 rwkw

6500 rpm 220 rwkw

6000 rpm 205 rwkw

5500 rpm 195 rwkw

5000 rpm 180 rwkw

4500 rpm 160 rwkw

Average 200 rwkw

There are plenty of 240 rwkw turbos around, but not many that average 200 rwkw from 4,500 rpm to 7,000 rpm. That's what performance is all about, a single hi maximum power at one rpm is point is next to useless. Unless you have a close ratio gearbox or an auto.

Our experience with Stage 2's is that they have to be tuned very carefully as they are very close to the compressor surge line on a 2.5 litre engine (OK on 3.1 litres though). I am personally not convinced that the few extra kw's is worth it on an RB25 and I wouldn't even think about it on a RB20.

Hope that helps

B-Man Grand Master

B-Man

Posted
Posted

Hi Sydneykid,

What does this mean to us laymens ???

Our experience with Stage 2's is that they have to be tuned very carefully as they are very close to the compressor surge line
bigcarl Experienced

bigcarl

Posted
  • Author
Posted

thanx for that sydney kidd , very useful info. my st1 pulled 204rwkws at 6300rpm at 1.2bar and that is before i change to a hi flow cat , split dump pipe, cam gears etc. at 7psi boost my peak power was 140rwkws at 6600rpm, why such a difference in peak rpm? would this be because of my restrictive dump/cat? thanx for the great advice, awesome thread!!! did the r34 use aftermarket cams to reach peak at 7000rpm?

BOOSTD Mentor

BOOSTD

Posted
Posted

7000rpm 253kw

6500rpm 250kw

6000rpm 245kw

5500rpm 227kw

5000rpm 220kw

4500rpm 191kw

Average= 231kw

This is my Hybrid VG30, still going strong with the ceramic wheel and T04 Vtrim comp. This turbo is not yet totally sorted as it will surge in 4th and 5th. Boost must come on after 4000rpm to eliminate surge, I am currently controlling it by dual stage boost controll which automatically switches from 11 to 14psi at 4000rpm.

How long it will last is another issue, been running with it for a few months now. Happy with the $350 outlay so far. :)

Heard alot of good things about GCG. Big outlay tho ,but, just the same as buying a brand new turbo....which is cheaper than any HKS, APEX, TRUST etc.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Lithium
      Garrett G Series

      By Lithium · Posted

      Oof. One of my mates has an R34 GT-R that he initially was a "I want to go twins for response and convenience" on his stock 2.6 with Kelford 272 cams, but his friends are pests and were always in his ear about their place being in the bin.   Eventually one of the 2860-5s decided to add it's own input and force his hand, so he conceded and went for a Pulsar 6262G ("G35 900") with T4 0.85 hotside.    Here's an overlay of the results, same cams, same stock bottom end, same boost, same fuel, just from a pretty tidy 2860-5 install to a Pulsar turbo on a 6boost maniifold on BP98.   Worth mentioning here, it may seem like a dead horse thing but the dyno plot doesn't tell the story of how much better it is to drive - transient response has completely changed the car, he used to have flat foot shifting to stop it having to wind up again on gear changes even at >7000rpm... now it builds boost faster than that even short shifting.   It's 100% transformed the car before you even consider how much better it holds on: Pulsar and Garrett aren't the same, but from our experience if you're just looking for a better drive and the ability to make the same or more power I think the divided G30 770 would probably be the smallest I'd go to.
    • robbo_rb180
      Neil's R33 Gts-t Build

      By robbo_rb180 · Posted

      Great work Duncan, any events local you will give it a test once all done? 
    • robbo_rb180
      Rob's S Chassis track cars. Now with more s15 and less 180sx

      By robbo_rb180 · Posted

      Sweet, yeah hoping stock gears will hold up. May use the transbrake feature on hill climb starts so that will test it.
    • GTSBoy
      What Bucket Seats Do You Have In Your R34 Gtt?

      By GTSBoy · Posted

      Yeah, the thread is only nearly 20 years old.
    • Duncan
      Neil's R33 Gts-t Build

      By Duncan · Posted

      Been down in Tassie for 2 weeks (a cruise, not a race for once) but spent a little time on her when I got back. I worked out the injector settings in the PowerFC were not correct for nismo 555s, set those to 66% +10ms and added a little air at closed throttle, set the timing (approximately, because it has some weird non 15o cells around idle) and now she starts and idles properly. She purrs like a kitten (ignore the co2 alarm in the background, I did  ) 20250518_171052.mp4 Next step, off for run-in, tuning and alignment!
×
×
  • Create New...