GCG Hi Flow for GTS25t

[RedDrifter]

What sort of boost response would the 450 HP highflow have on an RB20DET?

[R33NT]

Call em and ask

[Guest INASNT]

I am told that the new hiflowed turbo they do for around $1800 is equivelant to a GT3040

I dont think so.

U can only machine out the housing etc on the stock turbo so much, it dont even come close to a 3040.

[Roy]

I am told that the new hiflowed turbo they do for around $1800 is equivelant to a GT3040

See the posts by B-man, he had a GCG rebuilt turbo that was meant to be a rough generic equiv to a 3040. It made great power up to 250rwks with a wack of boost...but then bolted on a HKS (ok so different to Garret but...) and got an extra 50-75rwks, so i dont think it is really an equivelant.

Good power, but 3040 power maybe falls a bit short... check B-mans posts

[BHDave]

What sort of boost response would the 450 HP highflow have on an RB20DET?

I dont have a stage 1 but i have a stage two on RB20 with no tuning so you can atleast get an indication.

Mine starts to gradually build boost from about 3k, has 5psi by 4k, hits 7 by 4200 and then rockets to 11psi (i haven't upgraded fuel yet so am pegging it there at the moment) I have exhaust, cooler and pod.

It's a fair bet that the stage 1 will make good boost slightly earlier than this and the boost response will be less peaky.

[Guest INASNT]

I dont have a stage 1 but i have a stage two on RB20 with no tuning so you can atleast get an indication.

Mine starts to gradually build boost from about 3k, has 5psi by 4k, hits 7 by 4200 and then rockets to 11psi (i haven't upgraded fuel yet so am pegging it there at the moment) I have exhaust, cooler and pod.

It's a fair bet that the stage 1 will make good boost slightly earlier than this and the boost response will be less peaky.

Thats a very unresponsive turbo. I can get 1 bar by 4000rpm with a 600hp GT30 Garrett.

[BHDave]

Thats a very unresponsive turbo. I can get 1 bar by 4000rpm with a 600hp GT30 Garrett.

No shit.

I know why GCG don't recommend them for rb20s

[R33NT]

With regard to the GT3040 comment as i said is was told it was close to a GT3040 in one conversation and in a later conversation they said it was close to a GT3530???

BHDave how long ago was it that you got your stage 2?? Have you got a turbo from a RB25DET and bolted it to your RB20DET?? When i talked to GCG they said that the reason they didnt push the stage two is the reason yours is so laggy (i am guessing). They said as per SeriesIIGTST's post on page one that all those mods where necessary to get enough air flowing to booth spool the turbo and not restrict the flow of the air it is compressing otherwise it would be laggy.

[BHDave]

I got mine second hand and it was about 4months old at the time, probably closer to 7months old now. Came off an sr20 actually. I'd killed my turbo and it came up for a good price so i got it as a bit of a stop gap.

Id reckon they may also run into surge problems on the rb20 due to the engine not being able to flow as much as the rb25 though i haven't got to that stage yet. Gimme a couple of months.

[Guest INASNT]

With regard to the GT3040 comment as i said is was told it was close to a GT3040 in one conversation and in a later conversation they said it was close to a GT3530???

BHDave how long ago was it that you got your stage 2?? Have you got a turbo from a RB25DET and bolted it to your RB20DET?? When i talked to GCG they said that the reason they didnt push the stage two is the reason yours is so laggy (i am guessing). They said as per SeriesIIGTST's post on page one that all those mods where necessary to get enough air flowing to booth spool the turbo and not restrict the flow of the air it is compressing otherwise it would be laggy.

They will say anything to sell a product!! Have u seen the size of a 3040??? The stock turbo is half the size.

The high flow is so laggy coz u r still using the stock cast manifold which is a piece of shit!!

[SLY33]

but the highflow std turbo is still a pretty small turbo, i wouldnt think that the stock exhaust manifold is too bad for such a turbo. My 2530 is roughly equivalent in size to a highflow stock turbo, and there is pretty much no lag.

I can understand on big phat turbos like 3040's that an aftermarket exh manifold would help, but im not so sure its worth the money on small GT25's or highflow standards???

[BHDave]

I'm in agreement with Inasnt on the advantages of the A/M manifold.

Even on a small turbo the improved flow of the new manifold will give a reasonable gain.

Only problem with getting a decent manifold on an RB that I see is that the turbo will have to be moved from it's stock location in order to get a decent manifold in there so you will need custom oil & coolant lines, intake pipe and dump.

Not a huge problem, but enough of a pain in the arse that i'm leaving it for a while longer (it also has something to do with not having enough cash to do what i want when i want)

[PHaT MR30]

Which is why you port match the manifold to the head and the turbo and then have it power ported to remove the shit you cant get to. this drops the zorst temps down 40deg. having the exhaust housing done also help with efficiency.

watch the boost rise though!!!

sorry but i am a big believer in power porting

some ppl can't afford big turbos and A/M manifolds. been down that route.

They will say anything to sell a product!! Have u seen the size of a 3040??? The stock turbo is half the size.

The high flow is so laggy coz u r still using the stock cast manifold which is a piece of shit!!