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Hi Borry, we have a GTST with a RB25DET that at 1.2 bar makes 240 rwkw or 320 rwhp or 300 kw or 400 bhp (whatever way you want to express it). It recently did a 12.4 at Eastern Creek with standard weight

sydneykid,what sort of mods were done to the engine to get this result?

cheers

warrick

2nd hand 2530 in very good condition, you can pick them up for under 2k, new under 3k - locally (by the way 176000yen is 2378AUD as of today, the AUD is currently low). Fitting, $600.

Sell RB25 turbo in good condtion $500-600, if it needs reco, 3-400.

Basically, you pay $2-2.5k for a recon, or 2.5 to 3k for a HKS 2530, and as pointed out, you will get a much better resale for a HKS turbo.

The above figures are conservative, because if you hunt around you can pick up a good HKS 2530 for well under 2k second hand. I have seen them for as little as $1200 in good condition.

Hunt around and see what you can get? you wont be disappointed.

As for turbo to suit an RB25, if you want close to stock lag with a good midrange, top end and will make boost quickly - get a HKS 2835 - perfect all round street turbo;) Should make around 230rwkw at 1bar based on what a 3037 and 2530 will do anyways.

HKS turbos that I have had experience with (2530 and 3037) will hit hard as f*ck, boost when it comes on is like throwing a switch so the difference in lag between 1 bar and 1.2 bar would only be a couple of hundred rpm if that. (with correctly matched turbine AR) - would that describe twin 2530s on a GTR sydneykid?

I am a big fan of HKS turbos. They are the sh#t.

I am looking at hiflowing my stock turbo at some point in the future as well, as I don't think i will be able to afford a HKS item as well as all the other modifications needed to run it. My problem is that I live in melbourne and would prefer to hiflow my turbo somewhere local, or within driving distance, rather then sending a turbo interstate. Does anyone in melbourne know of a good workshop that hiflows r33 turbos with good results? I'd be appreciative if someone could help.

You can buy the HKS 2835 with a t3 flange, or a gt25 and internal gate. If GT25, you would need adaptor plates to fit it to the stock manifold (mine for 3037 cost $80) and of course, different bolts.

You would have to do oil feed and drain lines, water feed, about $300. Also pipe to AFM and turbo to cooler - cost me $180 for both. Then there is silicone joiners, I am not sure how much, probalby $50odd. Lastly dump. I had one made from stainless and it cost me $350.

Roughly. You can get a new HKS 2835 for about $3500 new in aust, over the shelf with HKS wastegate acutator (thats t3 flange to suit skyline, not sure if you would need to do the dump, but it is always a good idea)

Great thread!

I'll be weighing up the same options in the months to come, tossing up between a HKS2530 or high-flowing, at the moment i'm leaning towards the hi-flow due to no post purchase fiddling.

Sydneykid, how far can you actually safely push a high-flowed RB25 without having to look at fuel pumps and new internals?(220rwkW?) Cause I dont want to take it past that point really. All i'm really after is more power in the low and mid range with the responsiveness of the stocky, I'm not after wopping topend speed.

Do they design the high-flow to the way you want, as I mentioned above?

Just throw on a T88 and away you go!!! :( Have a look around the forums as there are good posts on people getting great results from various turbos. No need to buy an HKS turbo if you're short on cash, a Garrett one in my opinion is almost as good and is BB based so will not be so laggy as an equivalent sized normal bearing turbo. But then it costs more, but it's worth it. You can always hi-flow the stock turbo but if you really want more power it's better to get a bigger turbo in the long run. It's not cheap to hi-flow turbos either.

Just to add my 2 cents..

All the new HKS turbos I have seen all come with the fittings necessary to bolt them up to a standard motor. The 25 series to suit RB25/20's are a bolt in solution - they fit the standard exhaust manifold, dump pipe, AFM to turbo pipe, and with the fitting kit you get a 90 degree elbow that fits after the turbo.

The rest of the mods like stainless AFM pipe/dump pipe etc. you can deal with later at your own leisure.

All those costs you added up Mr. Sydneykid are also relevant to your GCG high flow option....

ive got a gcg stage 1 turbo, and im not making anywhere near the kind of power sydney kids skylines examples. my rb25det is only pulling 204rwkws at 1.2bar, although iam still running the standard dump pipe . my question is: will adding a split 3inch dump pipe make me an additional 15-20 rwkws? apart from this midrange torque is awesome!!

Guys are making 215 at 1bar on stock turbo, unless the dyno is reading 30kw+ low (which I doubt), I think you got problems. But at the end of the day, if you are happy all is good.

BTW with 230 at the rears, I was getting wheelspin all the way through second and into 3rd with 255/40/17 revspecs, 0.5deg neg camber and pineapples.

"All those costs you added up Mr. Sydneykid are also relevant to your GCG high flow option...."

Excuse me Doughboy but that's simply not correct, we have an R32 GTST with a GCG hi flow on it and it has every standard bracket, nut, bolt, screw, pipe and washer. The only thing I changed was the clamps as they were getting a bit tired. I fabricated nothing to fit the turbo.

Hi big carl, the split dump makes a lot of difference and we find a lot of cars have cheap and nasty cat's fitted for compliance. I good hi flowing cat will help if yours is affected this way. We see 8 to 10 rwkw from the split dump and as much as 10 rwkw from the hi flow cat. So your 204 rwkw is pretty much on the money, particularly when atmospheric conditons are taken into account with different dynos and operators.

I wouldn't worry too much about 1.2 bar, we get the above result at 1.1 bar but I have seen brand new boost gauges differ by more than 0.1 bar. As long as you are happy, that's the main thing.

Sydneykid, when a RB25DET is hi-flowed, is it possible customise the way you want it, for example have it setup for more low-mid rev range torque or on the other end of the scale for top end grunt?

Or is it basically a sort of one size fits all reconditioning?

Whats the max (rwkW) a high-flowed RB25DET cold be safely pushed without having to start changing fuel pumps and internals? Cause thats as far as I'd like to take my car.

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