Hks Gt2530/2535

[SLY33]

I know a lot has been written about HKS turbos, done the search and read whats been said,

but, so much of whats written is stuff like "ive heard" or "so and so's car makes xxxkw" Mostly hear say info on these turbos.

Please post only if you've had direct experience with these turbos, and facts not hear say:-

1. On an RB25 what power can you make at the wheels, whilst running "efficient" boost ie, not stretching to the limit, with a 2530 and the 2535? -plz post boost with power figs.

2. When does boost start, and when is full boost hit for each of these turbos?

3. I hear that the 2530 is a really good turbo for street, is this still the same for the slightly bigger 2535? (as i hear that the 2540 is a bit too laggy).

I'm trying to get all the facts sorted as i'm about to purchase one or the other. (yes i've thought about high flows, GCG etc, but am going for HKS)

THANKS, SLY33

PS, REV210- not interested in hearing that these turbos will only make their "rated" power at the engine, as there are too many of them making way more than that -but by the way congrats on your time!

[Cubes]

JMS has a GT2510 on a R32 making 220od RWKW 1.3bar.

Tilbrook has also had a GT2530 on a RB20DET making 220rwkw at 17psi Tilbrooks told me the GT2530 made full boost at around 3700rpm on the RB20DET.

The HKS turbo's are more efficient at higher boost levels compared to the same HP Garret unit. Hence why the HKS make more power.

My info is probably useless to you but may give you some idea.

[Sydneykid]

Hi SLY33, no experience with 2535's, but we find 2530's to be really good. Single for 230 rwkw or twins for 390 rwkw has been our exerience and good power spread as well.

If you are going to run a fair bit of boost (more than 1.3 bar) then HKS turbos are very hard to beat. But you will have to do a lot of support systems upgrading to take advantage of their good performance at the high boost levels. I strongly suggest you think about how much power you are targeting at what boost and then work out the budget for the project. You may find that you are spending money on a "high boost" turbo and that the support systems to take advantage of that turbo are outside your budget.

We see this lots of times with uncompleted projects where the owner has run out of money to finish the job and ends up with a dog of car that doesn't run properly.

Hope that helps.

[TokyoTaxi]

I'm also very interested in this topic as I'm running an RB20DET with a T3/T4 GCG modified R33 turbo and am having surging problems. I'm sick of messing around and am now looking into a HKS GT2530 as I'm told ( by all in Japan ) that it's the perfect turbo match for the RB20DET and the HKS GT2535 for the RB25DET. Unfortunatley I too have heard nothing while in Aus about the pro's and con's. P.S. What's a good price for a GT2530 new?

[Cubes]

I've seen them from $1500 right up to $2500 second hand.

$4000-$4500 new.

[Steve]

FAT32, RB20 + HKS2530 = slightly off topic being a RB20 (SLY want RB25) so pm sent, cost definately under 4K new in australia if you know where to look:)

[Sydneykid]

Hi FAT32, I am really concerned with your comment "I'm running an RB20DET with a T3/T4 GCG modified R33 turbo and am having surging problems". We have around 10 cars (both RB20 and RB25) running GCG hi flow RB25DET turbos and none of them exhibit any surging. They range in output from 190 rwkw to 260 rwkw and have a multitude of different support systems for the turbo's (big I/C', std I/C's, hi lift camshafts, std camshafts, split dumps, combined dumps, Power FC's, Chipped Std ECU's etc etc).

Consequently I would be most interested in your set up as there must be something/s unique causing this problem. I also suspect that if you are having a surging problem with your hi flow then it will still be there with a 2530.

Further details would be a great help.

[Cubes]

What do you consider to be surging FAT32?

[R32 Zilla]

I bought my 2535 2nd hand for $2200

it was in excellent condition and came with a matching hks split dump pipe, all braided lines and first intercooler pipe.

Tim.

[Cubes]

So what is the lag like compared to the standard unit?

[TokyoTaxi]

Joel,

On a cool / cold day on part throttle going up a hill with boost I get a rapid choofing noise and the boost gauge bounces around then the power dies off. I then have to pull it back a gear a nail it as it seems that I need revs to swallow the air that the compressor is supplying. I also get minor surging when I nail it from about 4500rpm to 6000rpm then it just pegs 1.2bar and climbs to rev cut.

[Cubes]

So it only does it on a cool or cold day then?

[KamikazeR33]

have u changed ur afm???

[TokyoTaxi]

Joel, yes, only on cool to cold temp days.

KamikazeR33, afm has been checked and seems OK although it is maxed out at the top end it doesn't cause any specific problems.

[R32 Zilla]

The Hks gt2535 has a fair amount more lag than the standard unit. In my application it is fitted to an rb20 using a front mount cooler (lots of pipe work ), matching dump pipe ect. ect.

3000rpm is 5psi

4000rpm is 15psi

and 4400 rpm is 18 psi

It has a .60 comp housing and .64 exhaust housing.

The set up has made 196 rwkw at 1.3 bar on

2 different dynos in sydney both on hot days (35+ in dyno cell). This figure does seem a little low but really only when compared to the tilbrook dyno figures for the same set up.

Tim.

[raist60]

FAT32 you blocked your standard BOV off? Or running an aftermarket?

[TokyoTaxi]

Still running standard BOV at the moment but have a blitz one to put on when I can get some time to get a recirculating pipe made up. Tried running with the blitz externally venting and it still surges.

[Ustasa]

FAT32,

We have experienced surging on a RB20DET with a T3/4 combo and it took the turbo supplier 3 goes to get the combination right. We suspect the turbine side wasn’t adequately upgraded which meant the upgraded compressor was supplied with excessive work at a certain engine operating point. This caused the compressor wheel to rotate at an excessive rpm (higher boost) for the air consumed by the engine which is what you described.

Trouble is that the RB20DET has a smaller swept volume at lower rpm and if the turbo isn’t matched correctly the compressor will operate out of it’s pressure/airflow region and all sorts of converging/diverging pressure waves will be generated in the inlet tract. Not a good thing I can assure you.

[TokyoTaxi]

Thanks much for that info.

Since my last post I've been contacted by GCG who have suggested that I have a Stg.2 turbine wheel in my setup and that I should have a Stg.1 wheel to better suit an RB20DET for that exact reason ( although they won't admit fault or prior knowledge ). Looks like it's coming off again.

Although I would love to fit a GT2530, I don't think the extra costs associated would justify the increase in power IF my turbo surging problem gets fixed by GCG. Mant thanks to those who have help out with info relating to my problem. Will post again when I try the turbo for the 3rd time.

Scott.

[Jet]

can the stock internals take 1.3bar of boost??

I heard the standard RB25 will break down if you boost it over 16psi