is anyone running hi-flow rb25 by gcg?

[bigcarl]

just wondering if anyone on this forum is running a highflowed rb25 turbo from gcg turbos in sydney ? and if so what kind of performance are you getting; ie: rwkws along with othermods. has anyone got the st1 or st2 versions? are they any good?

[Lepperfish]

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.........

[B-Man]

240rwkw until engine let go !

[benm]

Been afew good discussions about these turbo's. Do a search for 'gcg' or something.

[bigcarl]

true benm but i like to here unbiased opinions from customers of gcg not the bloke trying to flog his product.

[Ronin 09]

bigcarl, search it - it really has been discussed extensively already.

[Sydneykid]

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]

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

[Guest RedLineGTR]

those turbos sound sweet upgrade..

[bigcarl]

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]

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.