GT2530 - Not impressed

[TokyoTaxi]

Well,

For those of you out there who remember, I was having turbo surging problems with a T3/T4 GCG High Flowed turbo on my RB20. Well after heaps of F***ing around I've now got a GT2530 fitted. Yes the surging is gone but so too has the power.

Where the T3/T4 would start making power and then pin you to your seat until rev cut, the GT2530 at 1.2bar just doesn't have the same "nailed to your seat" grunt.

I'm posting this for 2 reasons.

1. So people can learn from my stupidity ( happens a lot ).

2. Has anyone out there fitted a GT2535 or GT2540 to an RB20 and what are your opinions ?

[DREMEN]

Have you seen the differences on the dyno? Did the T3/T4 make more power then now?

[TokyoTaxi]

Not yet but you can feel it by just driving it. It's that obvious !

[predator]

Could be a number of reasons other than just less power and maybe other components need to be matched differently to that turbo to get the most out of it.

[TokyoTaxi]

This is true but that's also what I wanted to avoid

I don't want to have to put vernia cam gears etc, etc on to make the 200rwkw's that I was making. Oh well, GCG say that will make 200+rwkw's so here's hoping after the dyno tune it dose cause if it doesn't I'll probably get the sh!ts and take the car back to standard then sell off all the modified parts and the car itself and buy a Daihatsu Midget 2

[Cubes]

So what did you end up getting in the end the Stage 1 450hp GCG turbo?

Did the GCG turbo make boost earlier or later than the GT2530?

The only thing I can think of that is giving you that feeling is possibly the GT2530 is more progressive in its power delivery.

Very similiar to having a Non-BB turbo then fitting a BB turbo.

The BB turbo comes on relatively smooth where a the non-BB comes on hard.

?!?! - That Sucks, don't return the car back to standard however.

Just slap a RB30 in there.

[TokyoTaxi]

I was only making 200rwkw with the T3/T4 ( Very Conservative Dyno so about 215rwkw on most ) but I knew that I needed injectors which I now have. The T3/T4 came in mid-range and nailed you to the seat up until the 8k rev cut.

The GT2530 comes in low and pushes up but just doesn't plant you and hold you. It really feels like a drift turbo but still it just feels under powered.

I just want to drive it without problems for 1 measly year

[EVOIV]

Sorry to hear about the GT2530. Is the T3/T4 turbo much larger than the GT2530? It's all up to personal preference. Some people like a small, quick response turbo - better for street driving and drifitng. Whereas other people (including myself) prefer the larger turbos with a more peaky power curve - where you can actually feel the turbo. To me, standard turbos/small turbos just feel like a NA car but with more power. The power is very linear and nothing exciting at all. I prefer the thump in the chest, then the loud bark of the external wastegate

Why not go get yourself a huge T-88 for the RB20? Probably an overkill. Or what about a GT2835 PRO-S? They are VERY nice. Reasonable response for street, and a fair bit of top end too! Rated at 420PS.

[TokyoTaxi]

I hear ya ! Maybe I'm just used to that big push back in the seat and that's just not there any more.

Only problem is a GT2835 PRO-S = $$$$$$$'s that I ain't got.

There's still one last option which is getting GCG to change the bearing core from a GT2530 to a GT2540 for under $2k now that the hard work's been done.

[Steve]

Should be getting well over 200rwkw with that turbo! What support systems do you have.

Honestly, I have been in a RB20/HKS 2530 powered car that was putting down 230rwkw @ 1.2 bar and it pulled like whore.

Another thing that it may be is have you replaced the pipe from the AFM to the turbo as these can suck shut as you start getting up in power. you should DEFINATELY be getting alot better power than 200rwkw. To get a pipe made wouldnt be more than $100 cos that is what mine is costing new.

[rev210]

the efficiency range on that turbo begins at 1.3bar and goes to 1.7bar from memory.

[TokyoTaxi]

Steve,

Just the normal stuff, GT-R Fuel Pump, NISMO Fuel Pressure Reg, Pod Filter, re-chipped ECU. I think I might have to try the new pipe between the AFM and the turbo as it could be a possible cause. Are you getting yours made for $100 ?

[Merli]

Did you get an HKS GT2530 or a Garrett GT25?

Because:

1. If it's an HKS GT2530, you're going to want to run about 1.5-1.6 bar through it to make it sit in it's efficiency range.

2. If it's a Garrett GT25, 210-215rwkw is probably the absolute maximum you'll get out of it, if you're set it up properly.

[TokyoTaxi]

Merli,

Dunno. I was told that it's a Garrett GT2530 core as sold to HKS but I don't know if that's factual since GCG "COULD" simply stamp a plate with whatever they want it to read and rivet it to a core. I'm not saying they do but it is possible.

[DoughBoy]

Rev/Merli, you say that the HKS 2530 is in it's efficient range at 1.4-1.7 bar - at what sort of CFM/lbs O2? Do you have anything on paper to show this? Not having a dig, but scouring around looking for comp maps (heh no such luck) or some "real" data/facts regarding the HKS lineup - and I don't mean my uncle's neighbour's daughter's boyfriend's friend said xyz. By what measure are you quoting these figures?

[DoughBoy]

Oh and Fat32, does the exhaust have "HKS" cast into it?

[TokyoTaxi]

DoughBoy,

The Turbine and Compressor housings are both new R34 GT-T housings machined to suit as HKS Turbine housings were hard to find new. It just might be that they have something to do with the power decrease but Brett from GCG assured me that they were close enough to the HKS ones that the difference would be negligable.

[DoughBoy]

woila

EDIT: what about the wheels? Are the genuine HKS items or Garrett bits?

[TokyoTaxi]

I'm told that the "cartridge" ( wheels pre-assembled in bearing housing ) are from Garrett.

[raist60]

what housing a/rs on t3/t4 and what a/rs on gt2530