Hks Gt-rs Turbo Analysis For Rb-25 Engine

["EN4CER"]

There are different types of A/R for some of these turbos are they all the same? eg: 0.68 or 0.87

[paulr33]

300 RWKW using the GT-RS

I think the one you are thinking of is 'thizzle' he was one of the first guys in AU to get the GT-RS

it was setup at BD4's from memory and it made a touch over 300rwkw with cams and other junk

since then no one else has come close to that mark - im not saying its bullshit or not, but average GT-RS is around 260-270rwkw

there's a few other "high scorers" some that come to mind;

grepin's 2835 setup

thizzles GT-RS setup

again - it doesnt mean the figures are bogus, they are probably legit

but i suspect there some info from the puzzle missing, theres always a reason a car makes more power etc.

you dont make extra power from magic dust or magic tricks.

[paulr33]

there's a few other "high scorers" some that come to mind;

grepin's 2835 setup

http://www.skylinesaustralia.com/forums/30...es-t151839.html

thizzles GT-RS setup

[R338OY]

Interesting discussion guys. I agree with SK that boost isn't what determines horsepower. The formulas are good indications of likely power with standard aftermarket mods, though each car's setup can have so many variables the formulas can't be taken as any more than a guideline.

Certain mods (like cams) will shift an engine's powerband around depending on the setup the owner wants, so this can throw off the calculations as the maximum power at a certain boost pressure will be higher/lower than the same turbo on stock cams. Setups like these would obviously be classified as outliers in graphing power vs boost, so that will automatically distort the formula depending on whether you keep the outliers/disregard them.

There are too many variables to generalise RB25 power levels IMO. But the formulas come very close, closer than an estimate at any extent.

[ENM13]

I think your right on the money, i got my 34 dynoed today and i got 240.6kw atw on 15psi. Unfortunately i ran out of fuel as im still waiting on my injectors to come. Ahh well, the gt-rs is a sick turbo, i get full boost at 3200!!!

Hi guys,

I conducted a regression analysis using the output figures and boost ran from the dyno thread relevant to the RB-25 engine with a HKS GT-RS Turbo.

Basically, a regression analysis is a form of statistical modelling that attempts to evaluate the relationship between one variable (Boost - PSI) and another (Power output - RWKW).

This data will help you 'predict' what sort of power you would get if you have an R33 GTS-T (RB-25 engine) with a HKS GT-RS turbo and other supporting mods of course (ie. Front Mount I/C, Full exhaust, Fuel pump etc etc) running the boost of your choice.

Basically, select the amount of boost you wish to run, and look at the corresponding output figure next to it for an estimate of how much power you would be making.

This analysis is ONLY a rough guide, please do no use it as a definite determinant since all cars are individual and differ to one another.

This post should eliminate those repetitive questions such as; 'How much power will I make if I run XX amount of boost with a GT-RS turbo on my R33?'

Cheers!

[ztuned]

lol i got bored. using the least squares method from your data, assuming it is linear outside the range of data u gave

RWKW = ( 6.9 * PSI ) + 135.8

Edited April 14, 2008 by ztuned

[PM-R33]

My cams go into her in roughly 2 weeks time with a bit more boost, cant wait!! The GTRS is a great little turbo

[Marco-R34GTT]

I heard you can also get a .72 housing for both the GT-RS and the 2835...

IIIRC I think it was bubba that had one or was selling one...

[PM-R33]

Pretty sure on the RB25 you can only go the .64 exhaust housing and on the SR you can pick. Might be wrong though.

[sl33py]

BTW, my GTRS was just installed/tuned. Got 256rwkw on 16.5 PSI. Graph in turbo thread soon. Stock airbox too!

Edited April 22, 2008 by sl33py

[Turbz RB-25]

BTW, my GTRS was just installed/tuned. Got 256rwkw on 16.5 PSI. Graph in turbo thread soon. Stock airbox too!

My GT2835 Pro S was installed, 273rwkw on 17 PSI

Cheerin'!

[sl33py]

Told ya the 2835 should make more at same or less boost Looking at the graphs, the only difference is a lil extra lag for you, and bit more top end... as expected.

[roy33]

sorry to go off subject but iam running the gtrs on the stock computer until i can afford to get my apexi tuned, what boost would it be safe to run at?

[STATUS]

Nice turbo, just finished tuning a customers car silver SII r33 277rwkw @ 1.1bar which is bit of a suprise as it was bought from the auctions as an unknown.... turns out to be a stolen and recovered jobbie with full whiteline and bilstein handling kit, 555cc injectors, PFC (i had one laying around) and hybrid cooler... and of course a HKS GT-RS

it is almost identical in response to a 8cm T67 kit i did for a customer awhile back but is a little short on top end.

[PM-R33]

Wow at only 1.1bar? That's pretty impressive. Why didn't u run a bit more boost through it, surely it would have still made a bit more power at around 1.3bar...

[joeyjoejoejuniorshabadoo]

interesting topic...

i just got my car back today with a 2835 pro s (.68) and its making 265 @ 19psi ... click for more detail

bombtrack has a neo gtt with EXACTLY the same mods as me but with tomei cams and will be getting his done soon on the same dyno / tuner

will post results when it happens

[STATUS]

Wow at only 1.1bar? That's pretty impressive. Why didn't u run a bit more boost through it, surely it would have still made a bit more power at around 1.3bar...

Yeah, the customer asked for the best result i could get a 1.1bar so i did what i could, it definately would run bigger numbers easily but he's happy

[PM-R33]

Well thats the main thing then. Im very impressed at that figure at only 1.1bar. I want that kind of power at 1.1bar!! Whats ur secret?

Edited July 3, 2008 by PM-R33

[NickR33]

there's a few other "high scorers" some that come to mind;

grepin's 2835 setup

http://www.skylinesaustralia.com/forums/30...es-t151839.html

thizzles GT-RS setup

I just looked at the dyno chart in that Grepin thread... 322rwkw with sub 10:9 air fuel ratios!?! something not quite right there

would love to get 300rwkw out of the 2835... pointless on the street but would be heaps of fun on the track... I don't think it would quite get there tho

[Equinox]

1.25 bar all the way. Knocked this up for a friend who was trying to decide on a turbo for his RB25. The blue dot is peak torque on stock RB25 cams.

Edited July 4, 2008 by Equinox