HKS3037S 56T Retune

[bbenny]

yeah ive read that heaps of time, that putting in a metal shim style headgasket will give you better compression to run more boost. How much boost would u be able to run with metal headgasket and std internals? or even better how much in say an RB20 ?

[Roy]

Im assuming the reason so many RB25 owners often run thicker/aftermarket headgaskets is so they can dial in a little more boost as the lower compression ratio starves off detonation.

RB20s already have a lower compression ratio of 8.5:1 (vs R33 9.0:1) meaning that it isnt as common to see RB20s running thicker head gaskets in the quest to run more boost.

Im actually considering upping my compression ration if my engine needs rebuilding.:bahaha:

[Steve]

RB20 is already 8.5:1, with the HKS 1.6mm gaget, my compression will drop to 8.6:1, hoping to be running around 20-22lbs, maybe a bit more if all goes well:D

[bbenny]

so what would you consider "safe" for the RB20 would more than 1.2 be pushing it a little?

[Roy]

It will be interesting to see what hp you get for every psi increase in boost???

Perhaps Steve you should wait until you have racked up 155,000 kms like me, then you dont have to run a 1.6mm gasket as the engine will already be decompressed:(

[Steve]

bbenny, its hard to say, just gotta get the car on a dyno and see what happens. Tuning, fuel, intercooler. plugs, etc - all make a bit contribution to how well the engine will handle boost.

On the subject of power to boost, a guy I know was getting around 230rwkw with the same turbo on an SR20 at 1.2bar.

1.3 bar was 240

1.4 bar was 250

1.5 bar was over 280,

so I am hoping for good things as the turbo gets up around the 1.5bar mark - time will tell.

[Roy]

bbenny, dont worry about dropping the compression ratio, or fitting a thicker head gasket.

My thoughts are the less boost you can run to make your required power the better.

For an RB20 i dont see 1.3-1.4bar being too much a problem on the street, as long as

- You stick to the factory rev limit (with your 2530, perhaps think about dropping it to say 6,800rpm)

- Your fuelling, engine cooling etc is keeping up.

- Proper care is paid to maintenance.

I say on the street as you are never really afforded the opportunity to sustain high engine loads for long durations.

If venturing out onto the circuit, i would wind a little boost out of it.

[Roy]

Steve, was the SR using the same A/R exhasut housing as you, did it show a similar level of boost response and lag on the SR?

[Steve]

It was running a 0.73 turbine housing, Boost hit hard about 4000 from memory, with an 8000 redline - sorry cant remeber exactly at the time I was more interested in power vs boost and how well the hks turbos went once the boost was wound in:D

[bbenny]

Steve your thing is just going to go mental at 1.5bar by the sound of it. what power are you expecting or hoping to achieve?

[Steve]

Really dont know, just going to wait and see:)

[EVOIV]

Lowering the compression will bring detonation higher in the rev range and thus you should be able to wind up the boost more without detonating in your car's rev range. But lowering the compression is also going to make off boost performance worse. So there's a tradeoff, like most things.

Steve, has the power curve been fixed up now so that power increases in a nice smooth fashion? Will be good to see the results at 1.5bar when the turbo is most efficient. When are you getting the head gasket done? You going to do cams too?

[EVOIV]

Oh another thing, does anyone know where to get heat wrap material from? I might be thinking of heat wrapping my exhaust manifold and dump pipe come summer. Because my car's engine bay gets quite hot in the 35+ degree heat!

[RS500]

EVOIV,

try Autobarn or Repco if they exist in SA.

[GTS-t VSPEC]

Steve, Well done mate, that's great power:D

[whatsisname]

EVOIV,

I got mine from Revolution Racegear on Main North Rd. I got a small discount off the price too

[EVOIV]

whatisname: How much was the heat wrap? Did you find it worthwhile in keeping your engine bay cooler?

[Steve]

EVO, I am doing cams at the same time, I have 256/8.8in and264/9.0ex so hopefully will take car of the off boost response side of things. The crazy thing is, at the moment off boost is so much stronger than with the stock turbo its amazing. I put this down to a decent set of headers (tuned lenght, ceramic coated) and I am not sure if the front facing plenum is helping too, all up it is awesome. The car is just bloody awesome to drive, just wants to go hard:)

I may have to go a larger turbine housing if it starts to choke the top end, but I am keeping my fingers crossed.

Paul, cheers mate, so how is the GT30 coming along? I have decided that you guys will need to have a bbq when you come over for the drift day. Are you driving over? Would love to check it out:)

[Steve]

EVO, sorry to answer your first quesion:

I have all the bits sitting at home feeling lonely, hopefully fitted in the next two weeks or so.

Oh, and a HKS exh cam gear:)

[GTS-t VSPEC]

Steve, It's all back from the ceramic coaters, putting it back together today, and retuned tommorow:D We're driving, but I'm not bringing my car. Either an R32 GTR or a Cefiro will be drifting:D