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On my RB25, this is my boost curve

2200rpm = 6.5psi

2600rpm = 11.6psi

3000rpm = 15.8psi

3400rpm = 17.3psi

3800rpm = 17.9psi

4200rpm = 18.7psi

4600rpm = 19.1psi

5000rpm = 18.5psi

5400rpm = 17.4psi

5800rpm = 15.8psi

6200rpm = 13.8psi

Edited by Robo's

On the dyno a Rb20DET with a gt2530 generally makes 1.1bar around 4k. On the street obviously it will be a little later, say rolling on in second gear may have the car start pulling hard from 4500rpm.

Edited by Cubes
On the dyno a Rb20DET with a gt2530 generally makes 1.1bar around 4k. On the street obviously it will be a little later, say rolling on in second gear may have the car start pulling hard from 4500rpm.

I've put in an order for a gt2530 for my rb20.

I was expecting the gt2530 would be a little more responsive than that.

What rpm does it start to build?

surely it makes SOME boost before 2800, even a couple of psi?  Its also gonna depend hugely on your tune and boost control method.  At the end of the day it is an rb20! not exactly known for their super response and early boosting!

well i have a TD06 on my rb20 and set at 1bar it starts to spool at about 3800rpm and holds till around 8700rpm

Once i get it tuned will let you know progress with it.

Cheers B

8700rpm?? And it needs a tune? Sheezus. What valve train components and cams are you using? Mine makes max power at ~6100rpm and limiter is set to 7K.

Robo's is making 6psi at around 2200rpm with an RB25 which is 25% larger in capacity than an RB20 so its gonna spool the same turbo 25% earlier so I guess 2800rpm is around the mark.

Thanks guys it seems mines fine then I may still need to get the spring checked as it seems to hesitate at .5 bar before continuing on to .7 bar I fitted up my Walbro last night it seemed to make the power come on a little more smoothly feels like it's making 170 rwkw ish it feels easily as quick as my old 180 did (which made 169 and its a heavier car I think I may need to get my cooler put on asap rather than waiting till next pay day though as Im a little worried that it feel's so quick

8700rpm?? And it needs a tune? Sheezus. What valve train components and cams are you using? Mine makes max power at ~6100rpm and limiter is set to 7K.

Robo's is making 6psi at around 2200rpm with an RB25 which is 25% larger in capacity than an RB20 so its gonna spool the same turbo 25% earlier so I guess 2800rpm is around the mark.

Well i have not yet finished with the car and the Power FC is about to go in so thats why i say i need a tune.

My ride:

1990 R32 GTS-t

RB20

Car mods as follows:

TD-06 turbo with external waste gate

550cc GTR injectors (with extra injector for high boost)

GReddy injector equaliser control (for extra injector set up)

GReddy electronic boost controller

GReddy turbo timer

upgraded fuel pump and swirl pot

adjustable fuel regulator

Z32 AFM

Hybrid FMIC

GReddy oil cooler and relocation kit

3' dump from the turbo into rear muffler which is standard at the moment, with extractors.

GTR rotors with green stuff pads.

irridium plugs

rods and pistons have been done as well as bearings (is what i was told) and a set of HKS cams

set of race springs with stock shockies (soon to be replaced)

Apexi air intake with modded CAI /Heat shielding (thanks to SAU thread)

button racing clutch and locked diff (thing of changing diff)

Mods to come:

front and rear strut brace (looking for a Cusco BT front)

new seats (as the BRIDE drivers seat is a carbon race seat with not much room)

new steering wheel (again for some extra room)

new gear knob (as the old one is pretty crummy and slips)

and maybe work on a new suspesion set up. (want coil overs)

Other than that its pretty much a stocker in the looks department ;)

So ~4000rpm for what ever boost you dial in to it sounds about right then. It kicks hard you look down and notice the tacho on 4500rpm swinging towards 7000rpm. :D

Yeah i know that feeling well ;)

  • 3 weeks later...

hmm well i've DEFINITELY got a problem... :P

got a hks 2530 - fmic/zorst/pump/ standard comp with hks fcd... it max'd power at 225rwkw 'conservatively' on 14psi...which is good right...YES.

BUT

...now that i drive it, its not making f*k all boost and LAGGGGGGGY as all the way until around 5000rpm... can say i'm very disappointed and hope its a fixable problem...

possible probs i thought of was - collapsing intake pipe to turbo / faulty boost controller (turbosmart dual stage fairly old) / maybe its not even standard computer...

just spewing coz its got absolutely NO midrange... heaps spewing...

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