Gt 30/40 on rb20 help

[BiZzReVhEad]

Hi guys , im currently lookin to upgrade from standard T28 to the GT model turbos .

I have spoken to a friend who used to work at a performance place and said that this turbo would be better then runnin a smaller turbo like the GT 25/30 , saying because puttin the engine under to much stress from boosting it up to much with a smaller turbo . (The cars done 140,000kms) . Saying that the boost would come on earlier and still create alot of good power (on standard internals still) , im inclined to think of more wat most ppl have tried already , maybe i havent done enough searchin on this forum for the answer but can someone PLZ help me with, ANY experience with RB20 and GT30/40 setups .

He also said if it lags we can install anti-lag thing on it (like da rally cars have) .. What would u guys do if u were me ...

Im not lookin to crack my lil RB20 to bits , but i know i am lookin to go at least 200rwkw .. Any Turbo selection advice for this would be great THANK! .

Oh and he said its pretty much the same as a to4 . So should i just stick with the smaller turbo like 25/30 ? can it do all that i want without stuffin my engine

[doridori32]

Get yourself a a big compressor cover with a big wheel , and leave the rear standard it will be a good upgrade for 200rwkw on low boost

[cameron]

doridori32: :uhh: ???

Bizz,

You could try putting a standard RB25 turbo on as these can get upto 200rwkw's, other wise stay away from the 30/40 if you'r only after 200kw's as its too big and too laggy, I'd surgest standard RB25 turbo or HKS 2530. make sure you have all the other components to able you to get that figure: Fuel pump, inj's, aftermarket ecu, afm's, exhaust, metal head gasket etc.

Anti-lag = NOS - You wont need nos if you'r running a GT2530

It's all possible with out dammaging you'r engine but you'll need to have a propper look at the internal's other wise as soon as you crank some boost through it the piston's will be rat sh!t being, 140,000k's old. - This also depends on how the car was driven previously.

Jun

[BiZzReVhEad]

Thank u all (only 2) for ur comments i appreciate it. I was thinkin Exactly that , the GT30/40 would be a lil big for rb20 , however i been reading on http://www.horsepowerinabox.com/HPIAB2/cat...ategory12_1.htm that the 30/40 IS suited for a RB20 , but wat cost? I guess wat u are telling me is that GO THE GT 25/30? or GT25/35 even better? Will it put to much load on the car ? or am i being realistic about this turbo (gt25/30) being rated AT 320HP which is fine , but he was sayin why stop there if u would be movin UP in future in power get it NOW instead of buy it later and be stuck wif a smaller turbo ..

Would it just make more sence to get a GT28 or just keep my original one and HIGH FLO it ?

I will get the engine looked @ when i get the head ripped off and stuff. Thanks for ur info guys . Im more inclined to beleive ppl here that have TRYED and PAID for their conversions then beleive a SALES man trying to SELL me a big ass turbo for a lil ass 2.0L .

I just want to get it right NOW. and not wish i chose something BIGGER or BETTER

Get yourself a a big compressor cover with a big wheel , and leave the rear standard  it will be a good upgrade for 200rwkw on low boost

So ur saying Keep standard Turbo ? and change the internals ? ive herd ppl have some issues with that . But i have at least 2G to spend on a turbo alone cheers .. Oh ANY1 Selling one gimme a PM

[Morgs]

Pick a power figure before you go picking turbos.

Also consider, your engine, and support systems will need to be upgraded according to the desired power level.

My opinion, a GT3040 is way too big for a RB20 unless it has had considerable investment in terms of engine modifications.

[BiZzReVhEad]

im wanting 200kw rw . . would a GT 25/30 handle that or should i go for another unit ?

is the figure x1.74 of the KW pwr = HP ?

[doridori32]

If you ONLY want 200rwkw.. get yourself a GARRET GT25 with the " big Spec" option from them.

Do not buy HKS parts, waste of money on such a setup. Garret offer options , build your own " HKS SPEC " turbo.

[BiZzReVhEad]

Build ur own ? how da f .... i think u talkin bout da GT 25/35 ya ? i think thats a goer ... does any 1 have a link to prices and once again thanks heaps ... I want to get my hands on a Apexi PFC , are they hard to get ? they bout 1500 ya

[Morgs]

GT2530 is fine. Garett. HKS if fine but you'll need 2nd hand for your budget. T3 flange remember.

PowerFC for a RB20 with hand controller, budget $1650. Its a special edition AP package.

Find someone to retune the ROM.

[doridori32]

GT2530 is fine. Garett. HKS if fine but you'll need 2nd hand for your budget. T3 flange remember.

PowerFC for a RB20 with hand controller, budget $1650. Its a special edition AP package.

Find someone to retune the ROM.

Get a Brand new Garret GT25..... run 1k boost, and get her tuned!

bang 200rwkw you have.

[BiZzReVhEad]

re tune the new one ill get ? (apexi ? ) or current one ? sorry its late and im not all here

[BiZzReVhEad]

cool. its done . ill order one on monday . Then get it all installed and dynod up and ill let u all know how i went Thanks heaps for ur comments ... I knew the 30/40 was to big , i aint lookin for a full drag car . Just a nice street car that can be taken out if i wanted and boost it up for some action ... Cheers all and safe driving

[Morgs]

Im pissed off my nut

You can retune your current ECU, although I'm not sure in Sydney who can do it for you.. ask around and you will find !!

Its better than paying $1650 for a PowerFC/HC plus tune !

[BiZzReVhEad]

hmmmz ... well i got da extra $$ and if i dont do it now and im sure it will be one day ... Wat are the benifits wif retuning the standard ECU ? wat besides visual readouts do u get from a New ECU . i dont mind either one but i still would prefer to save the money as i aint totally dumb. If any1 got retuned ECU lemme know wat u gettin out at rear

hehe oh and go hard Morgs

[Sydneykid]

Here is a post I made several times, most of it is applicable. If you want to know more, do a search, all the info you will need is there.

1. We use a ball bearing hi flowed RB25DET turbo on our old RB20DET for 220 rwkw (295 rwhp or 370 bhp) at 1.3 bar. This turbo holds more than 1.1 bar of boost from 4,000 rpm to 8,000 rpm, so it is never off boost on gear changes. We have found this is the most airflow (max power) we can get and keep the rpm range useable. We have a few more mods than you have listed, split dump, 3.5 inch exhaust, no cat (it's a race car), GTR cams, adjustable pulleys, Power FC with boost controller, POD filter, heat shield and a substantial ambient air feed. The exhaust manifold was a copy of the R31 GTRS Group A manifold which has the turbo mounted low and rear for better weight distribution. As usual GCG did this hi flow. Oh and the engine was standard internally, never even had the head off.

The other alternative is to go the Garrett route as you said, but I would suggest a GT25R with this spec;

0.86 A/R Turbine Housing

0.70 A/R Compressor Housing

Watercooled Core

48 Trim Compressor Wheel

76 Trim Turbine Wheel

Internal Wastegate

This turbo will flow 48 lbs/min max, which is easily enough for 420 bhp. But it ain't gunna make much boost at 4,000 rpm, more like 5,000 rpm. And it's gunna need cams, pulleys and a good split dump/exhaust system to make even that. So you are gunna have to rev it to 8,000 rpm before you upchange, otherwise it's gunna drop off the power band severely. You will need at least 1.6 bar and maybe as much as 1.9 bar to make your power target. Add these together (1.9 bar + 8,000 rpm) and you have a short life for your internally standard RB20DET that already has 100,000 k's on it.

End of that post, but there are plenty more around if you do a search:cheers:

PS; Did I mention doing a search?

[RS500]

Here is a post I made several times, most of it is applicable.  If you want to know more, do a search, all the info you will need is there.

The other alternative is to go the Garrett route as you said, but I would suggest a GT25R with this spec;

0.86 A/R Turbine Housing

0.70 A/R Compressor Housing  

Watercooled Core  

48 Trim Compressor Wheel  

76 Trim Turbine Wheel  

Internal Wastegate

This turbo will flow 48 lbs/min max, which is easily enough for 420 bhp.  But it ain't gunna make much boost at 4,000 rpm, more like 5,000 rpm.  And it's gunna need cams, pulleys and a good split dump/exhaust system to make even that.   So you are gunna have to rev it to 8,000 rpm before you upchange, otherwise it's gunna drop off the power band severely.  You will need at least 1.6 bar and maybe as much as 1.9 bar to make your power target.  Add these together (1.9 bar + 8,000 rpm) and you have a short life for your internally standard RB20DET that already has 100,000 k's on it.

End of that post, but there are plenty more around if you do a search:cheers:

PS; Did I mention doing a search?

SK,

the Garrett GT25R u mention above is a mismatched turbo that requires high boost as to provide the required air-flow to make ~400hp, with the addition of plenty of lag given the larger (dinosaur age technology) 48 trim T04S compressor wheel which is more suited with the 84 trim GT30 turbine wheel as to work more efficiently.

Our friend would would be much better off with a turbo which houses a smaller compressor wheel with the same turbine wheel to provide a better balance b/w boost build up and air-flow.

given this and the requirements of the car, i recommend the 350 or 400hp GT25 (446179-0031 or 446179-0032) which use the GT35 compressor wheels.

these are much more efficient turbos which can provide the required ~200rwkw or more at 1.3 bar.

for a real life example, a friend used the larger of thes turbos (56 trim compressor wheel and A/R .64 turbine housing) and managed to produce 222rwkw on 1.3bar from an internally standard RB20DET with a larger FMIC, Unichip, Bosch 040 fuel pump, K&N air filter and malpassi fuel reg.

the car was quite responsive and nice to drive also.

[Angry]

interesting discussion

what does the compressor map look like on one of them "GT25 (446179-0031 or 446179-0032) which use the GT35 compressor wheels."

sounds bout what i'm aiming for..

Matt

[BiZzReVhEad]

Our friend would would be much better off with a turbo which houses a smaller compressor wheel with the same turbine wheel to provide a better balance b/w boost build up and air-flow.

given this and the requirements of the car, i recommend the 350 or 400hp GT25 (446179-0031 or 446179-0032) which use the GT35 compressor wheels.

So ? get a GT25/30 or GT25/35? then change the compressor wheel and turbine wheel on that ? ... me gettin confused now ... Im sure the GT25/30 will be fine ( remember i am doin everything BUT injectors )

[RS500]

interesting discussion

what does the compressor map look like on one of them "GT25 (446179-0031 or 446179-0032) which use the GT35 compressor wheels."

sounds bout what i'm aiming for..

Matt

this is what i was able to find;

http://www.atpturbo.com/root/maps/gt3071r.htm

[MerlinTheHapyPig]

well, hks gt-2530 (GT25) is a fairly common replacement for an RB20DET, that's what i'd go (daym, there was a turbo & piping kit for an rb20det on sale on yahoo japan a while ago that sold pretty cheap)

it would probably be best to avoid ceramic turbo's altogether, they tend to crap themselves over about 1.0 bar. Don't know about a high-flowed one.