Gt 30r On Rb20

[RAZOR32]

I've got a GT30R To go on a RB20 and I am abit worred it is going to be to big and laggy???.

Specs are .7 front cover 58mm wheel and rear housing 0.63 56mm wheel.

Dont know why i was sold such a big front cover? and it is internerly gated,

Any one got any idear when it would come on boost and what have other people got on there RB20's, what kind of power will it make-230rwkw or so on 1 bar?

It would be great if any one could help me out, Thanks

[discopotato03]

If its what I think it is the boost threshold will be high and transient response only Ok . Have a look at the numbers on the tag rivited to the bearing housing , would one of them be 700177-12 or -15 ? The 7 blade compressors are not GT wheels .

To get these in a proper GT30R use turbo no 700382-12 , though probably still pretty big for an RB20 . The GT3071R (CHRA 700177-23) in small .63 housing form would be the most responsive GT30 based turbo .

Even the larger capacity GT28 based turbos can be lagy on RB20's , what sort of power curve are you looking for ?

Cheers A .

[paulr33]

lag city, id say 4500rpm

[ebola]

yeah, it does sound like lag city, but its what makes you happy that counts.

and speaking of couting, consensus seems to ge that the stock injectors cant count past 200kW at the wheels (well, 220 is possible, but with other supporting mods - such as a fuel pressure regulator)

Don't try for more without upgrading the injectors (and fuel pump).

I don't think the gearbox likes much more, either.

what sort of power curve are you looking for ?

Good luck mate. I'm envious. I'd try (even if I took it off next month).

[ebola]

Arrh!! Whats with the server!?! Why cant I delete this post?!? Why am I here?!? Hey - Why are you here? GET OUT!!!

Edited October 21, 2005 by ebola

[R31Nismoid]

try searching, this question gets asked every 3 weeks or so.

Same response - too laggy

get a smaller GT25

[Roy]

But what is wrong with lag anyway?

Not saying its great and we should all hope to get it one day. But whilst turbo technology has improved out of sight in the past 15 years...if you want more power then std and dont want to crack open the engine...there is always going to be a compromise.

To me i dont think of it as lag. I consider that i am moving the power band of th engine. Leaves me with a nice quiet tractable engine for potting around at and around 3,500rpm. But stick my foot thru the firewall and im making 130rwkws more then std...remembering the thing only made 110rwkws when new.

If you want to drive like aluntic on the street and want a quick road car...then its your sworn enemy as it doesnt allow the flexibility to get out of slow corners etc. But if you are up it and having a red hot go, as long as you are 500rpm above where you make full boost when changing from 2nd to 3rd etc then i dont see a problem with a jekyl and hide power delivery.

Also what i see technically as lag can be a good thing. If you are cruising at 70km/h in 4th and shift back to 2nd gear, then you will be at about 5,000rpm. With your foor off the accelerator and at 5,000rpm trample the accelerator and see how long it takes to make the boost you are running. That delay is what is really lag. The rpm where it makes your designated boost is the boost thresh hold, not lag.

So based on those definitions lag can assist with traction as when you crack the throttle you dont get a whip of boost, it softens the response and cen make getting power to the ground that little bit easier.

[Shaun]

I had an GT30 (0.86 turbine housing) on my RB20 with an external gate plumbed into the standard modified manifold. I got full boost by 4200 and, while the boost threshold was high, fu*ck it sounded good while on boost! I had it on for about ayear or so and then went on to something else. 0.63 housing will be more responsive tho.

Shaun.

[R31Nismoid]

4200rpm?

dont tell all the people with GT30/.82's that are running them on thier RB25's when they are coming on around 4000/4200rpm...

They might get jealous a smaller motor is doing the same as thier bigger one...

[Roy]

Be ineteresting to see how much of a difference going from a 0.84 to 0.63 housing would make. I went from 10cm^2 housing to an 8cm^2 housing and the boost thresh hold wasnt overly different. Perhaps there was 300rpm in it. But the thing is it made so mush more power ramping onto boost as the transient response was much improved. From memory it just about doubled the power it made at 4,000rpm:)

[Roy]

4200rpm?

dont tell all the people with GT30/.82's that are running them on thier RB25's when they are coming on around 4000/4200rpm...

They might get jealous a smaller motor is doing the same as thier bigger one...

<{POST_SNAPBACK}>

LOL..yeh but so many different places will sell you a GT30. Put them side by side and they are different animals.

[carl h]

indeed.

a real gt30r has a 4" inlet with the 'fluted' compressor housing, if it doesnt have that then its not a real gt30r.

[RAZOR32]

Thanks for the help guys. Will the .7 front cover be to big... should i change it to a .5 or .6 and what will that change? top end?

and i also dont think the .7 front cover will fit as a low mount...

Edited October 23, 2005 by RAZOR32

[discopotato03]

If its not going to fit take it back and ask for what most people consider the most suitable "GT30R" . Yes it will have the .60 ARR T04E port shrouded compressor cover and the propper or GT series compressor wheel . The turbo part no to ask for is 700382-12 which uses cartridge (CHRA) no 700177-7 . This is the better version Garrett retails .

HKS (rebadged Garrett) sells a version of the GT30R (they call theirs GT3037) with the same GT series of compressor but in 52 or 56 trim and with a .50 rather than .60 ARR compressor cover on the 52 trim version . This version is supposed to come on boost 500 rpm lower than the 56 trim version on an SR20 so better but at what cost . Its cartridge no is 700177-6 , may be out there somewhere 2nd hand .

Garretts GT3071R (CHRA 700177-23) is supposed to do a similar job but I don't think anyone's tried it with a .63 GT30 exhaust housing on an RB20 . It uses the same compressor cover as the 52 trim HKS GT3037 and is about as compact as they come .

Cheers A .

[RAZOR32]

so can i change to the Garrett .60 T04E port shrouded compressor cover with out changing the front wheel??? sorry i dont really under stand

[discopotato03]

Look into the compressor inlet , if you see seven blades (seven full and seven splitter blades) its not a GT series compressor and won't perform like one no matter what housing is put on it .

I'd be asking the retailer to swap it or pay the difference in price for the real one .

Garrett specifically calls it the GT30R so if they won't play ball demand you're money back and go elswhere , you did not ask for a GT30/T04S so why did they sell you one .

This problem keeps coming up because any turbo wearing a GT30 turbine and ball bearings gets called a GT30R , I can think of 14 different cartridges that do and probably 6 of them are good on petrol engines .

Cheers A .

[gt-t_r34]

whats the hks gt-rs like on rb20? is it the same as the gt28rs or a little different as HKS says?

[RAZOR32]

Look into the compressor inlet , if you see seven blades (seven full and seven splitter blades) its not a GT series compressor and won't perform like one no matter what housing is put on it .

I'd be asking the retailer to swap it or pay the difference in price for the real one .

Garrett specifically calls it the GT30R so if they won't play ball demand you're money back and go elswhere , you did not ask for a GT30/T04S so why did they sell you one . 

This problem keeps coming up because any turbo wearing a GT30 turbine and ball bearings gets called a GT30R , I can think of 14 different cartridges that do and probably 6 of them are good on petrol engines .

Cheers  A .

<{POST_SNAPBACK}>

Yeah, well I thought I had brought a GT30R but it’s got 7 blades, so its not then?

I was sold its as a GT30R LS for $1950 from a place could Buzz engines, they are up in QLD and I am down in Hobart and I got it in February this year and only just getting around to putting it on. I don’t really now what LS means?

So it looks like I have been done over a bit then and because I got it 8-9 months ago there is properly not much I can do? Is there. And so how many blades does a real GT30R turbo have. Thanks heaps for your help discopotato03

Cheers Raymond

Edited October 24, 2005 by RAZOR32

[BHDave]

Just to add fuel to the fire...

I am running an HKST300s on an rb25 which is basically the same turbo as what you have (T04s comp wheel, .7 a/r comp and .63 a/r exhaust). It makes 17psi by 3100rpm and it's only a plain bearing turbo.

My previous GCG highflow would make 14psi on the rb25 by about the same revs (3100), i also ran the highflow on my old rb20 and it made 14psi by about 4300, so we're talking about a 1200rpm difference. This was on the same car with all the same supporting mods.

So based on my own experience i can't see why your turbo wouldn't be making decent boost by 4200-4300 in all honesty. It will need more than 1 bar to make that sort of power though, probably closer to 1.3 or so.

As for low mount, are you using the stock side mount manifold? it might fit. It would definately fit an r33 but i don't know how the engine bay width compares. They will fit low mount on an HKS cast manifold but it's a bit of work to massage the engine mount to clear the comp cover.