Some advise about GT30

[gtst25]

Hi there,

Sorry for another turbo thread!

Having read a lot of threads about HKS and garret turbos on here, and taken my car to the limit of the standard turbo I am in the market for a bigger one.

What I am looking at is a GT30 from horsepower in a box.

A summary of what they say is:

It's the smallest t3 style turbo from garret.

Normally comes with .82 external wastegated exhaust housing.

Has as standard .70 comp cover and garret dual ball bearing internals.

* Unit can be supplied with a nissan RB .63 internally gated housing as a special offer making a great bolt on package.

After emailing them and asking about getting the standard heat shields to fit they said it can be supplied with a smaller comp cover.

They have also said it is a good responsive performer good for 280-300rwkw.

My goal is around the 280 - 300 rwkw mark - the reason why I am leaning towards the GT30 is I don't want to go too small, especially since I will very likely be using a rb30 bottom end in the near future.

I was looking at a hks 2850 pro s but they are a bit pricey at the moment.

I think the GCG and GTRS will be too small if I'm looking at a 30 bottom end, but if anyone has a differing opinion please post away.

I'd like to keep the stock exhaust manifold and internal gate as I want it to look as standard as possible, and it will bolt up to my nice split dump.

I understand that a few people here have fitted gt30's - what specs were they?

Any other recommendations?

My car has got all the usual for a stock rb25:

Bigger cooler

PFC + PFC boost control kit

044

ADJ Press reg

Will have bigger injectors + AFM

Magic cat on the way + has 3'' exhaust.

I am keen to order soon so please send some advise if you have any - I really don't want to spend my hard earned on the wrong turbo. I understand the GCG is capable of 265rwkw, but that was with different cams, ported head, inlet manifold, exhaust manifold etc.

Thanks in advance. :uh-huh:

[R31Nismoid]

Whats the inteneded use of the car?

circuit racing or whatever?

[Abo Bob]

I asked about that turbo (the one with the nissan exhaust housing) and everyone seemed to think it would come on like a light switch and run out of puff up top.

I reckon a HKS2835ProS might be the trick.

[grigor]

PM stu

[gtst25]

I asked about that turbo (the one with the nissan exhaust housing) and everyone seemed to think it would come on like a light switch and run out of puff up top.

I reckon a HKS2835ProS might be the trick.

You ended up going the GCG hi flow didn't you?

Yeah I definately like the 2835 pro s - bugger they're so expensive.

Cheers

[gtst25]

Whats the inteneded use of the car?

circuit racing or whatever?

It's a street car that I like to take to track days etc.

Ie Willowbank circuit and drag

[Abo Bob]

You ended up going the GCG hi flow didn't you?

Yeah I definately like the 2835 pro s - bugger they're so expensive.

Cheers

yup.

[R31Nismoid]

If you intend to do circuit i suggest you'd be limiting power to around 250rwkw and aim for a turbo that will support that.

Around a track belting out 280-300 a stock RB25 wont last long at extended RPM.

But as abo bob said, a smaller than .82 housing and personally it think they are too twitchy.

Mine with the .82 rear end is so nice and progressive and it doesnt jump onto boost crazy or anything

[BH_SLO32]

I'll be chasing similar power levels from my RB25 (in R32) and given down the track I'll probably build an RB30DET, I opted for a Garrett GT35R with .82 rear housing (will upgrade rear housing with the RB30). I have seen members quote up to 280kW @ wheels with the GT30 using at least .82 rear housing. Ben Ellis achieved 290kw at 20psi from memory and he had a .82 or 1.06 rear housing.

With the smaller skyline housing (.63), the motor will come onto boost quickly but will run out of puff at higher rpm. I would suggest a GT30 with .82 would be a good alround choice.

Hope this helps.

Cheers

[R31Nismoid]

you can make over 300 with a GT30

[180bfj20det]

you can make over 300 with a GT30  

Yep.

Also I got a GT30 0.82 on my standard FJ20 which is 2L in capacity. Its quite laggy but makes full bost at 4K so suppose not that laggy but compared to lets say a GT25...Anways, for your engine, youll have a car thatll spin the wheels coming onto boost and make it hard to control. Go the 0.82 and you will avoid a large portion of this....mine still spins like crazy coming onto boost but thats what you get in a 1100kg car with 230rwkW!

[gtst25]

r31 nismoid and 180 fj20det - you are both running custom exhaust manifolds and external wastegates aren't you?

Not really what I want to do as I want to keep the engine looking as stock as possible.

Do you know if it's possible to go the 0.82 with an internal wastegate?

I see on Nengun the HKS 2850pro s can come with .87AR - this has internal wastegate....

I think I'll send another email to horsepower in a box.

[gtst25]

you can make over 300 with a GT30  

Out of interest what power does your car make, and what mods do you have?

Cheers

[180bfj20det]

Yeah I got a custom manifold. But I think you can fit the GT30 on your manifold with a spacer at worst.

The GT30 easily makes 300rwkW:

http://www.skylinesaustralia.com/forums/sh...ead.php?t=55845 #reply 16

[R31Nismoid]

my turbo is slightly mis-match, as in i need the next size up exhaust wheel as the 600HP version doesnt seem to work like the 500-550 so im getting detonation problems on PULP.

so we stuck some decent fuel in there, wound up 24psi and on the mainline dyno it span up 369rwkw.

On a DD it was 330rwkw

Normally pumping around the street its 270rwkw on around 17psi or there abouts gve or take as you do.

But ive found contrary to popular belief, that the Garrett turbo really doesnt wake up until you get over 20psi. 17psi feels very lazy. Its still fast. Just lacks a bit of poke.

Being that they are almost identical to a HKS turbo as it is... they love the boost just th same. At least mine does.

Next year if i have money ill sort some ignition and give it something over 24psi

As for mods, rebuilt bottom end --> Forgies/GTR Rods

Stock RB25 head... GTS-R manifold, Turbosmart 45mm Pro-Gate, 740cc Nismo injectors.

Surge tanks etc etc.

Everything one needs to support it all well and reliably