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Gcg Highflow On Rb25, How Much Boost?

Rolls

By Rolls,
in Engines & Forced Induction

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Rolls Grand Master

Rolls

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Posted (edited)

I've got a gcg highflow on a series 1 rb25det (rebuilt with forged pistons etc) how much boost should I be trying to pump out of this turbo? I've heard they are good for 18psi on a 25, will it make more power if I go higher? or is this the limit with the internal wastegate? Just going to be using a cheap bleed valve.

Also with stock cams where will the power start to drop off, I've had a look at the dyno thread but it is a bit hard to tell, I get the feeling around 7k though?

Cheers.

Edited by Rolls
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R31Nismoid Grand Master

R31Nismoid

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Posted

Will it make more power? It's anyone's guess :(

just screw boost in until it stops making power/intake temps get too high etc.

Stock cams - never. I ran factory cams with a 600hp GT30, power held till redline (8000rpm) everytime

andymoocow Grand Master

andymoocow

Posted
Posted

i have a GCG high flow on My series 2 R33, with all supporting mods injectors, PFC, Profec B Spec 2 boost controller etc etc and it runs 20psi and tapers off to 18psi higher in the rev range. Tuned by UNIGROUP engineering in Sydney, who did an amazing job, and the car drives with almost stock like response down low.

still stock CAMS as well. If that helps.

Rolls Grand Master

Rolls

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Posted (edited)

Nice I had a look in the dyno thread and looks like people are pulling about 250rkw with that kind of boost starting to taper off at 7k. What power does yours make and where does it start to drop off ?

I agree it is a lovely turbo to be able to make that sort of power but still drive around like a stock rb25 in the low revs, soon as you get any boost it is much quicker.

Edited by Rolls
R31Nismoid Grand Master

R31Nismoid

Posted
Posted
Is a hyper gear high flow anything at all like a gcg highflow though?

In most cases no :thumbsup:

They are the bush bearing version, so half the price. Wheels could be different too, without specs of each hard to say

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