[steiner]

Curious to see if anybody has put this kind of setup on a 2.5L and what kind of gains were made.

[steiner]

So which big turbo kit are you guys going with...16g, 20g, GT30?

[impreziv]

i dont think anyone is running this turbo on an STi. its basically a faster spooling/lower output GT30R. Garrett claims it is capable of flowing 450hp at the crank, on the average 4cyl.

this turbo would require a custom uppipe and downpipe, and custom intake piping, and charge pipes. there are many stock mount turbos, that use the stock plumbing, that are more than capable of that kind of power.

a good comparible turbo to this would be a FPGreen, or a Deadbolt SZ49. they can bolt onto the stock location, and use stock hookups. although upgrading the intake tube, and downpipe is recommended.

[impreziv]

Originally Posted by steiner

So which big turbo kit are you guys going with...16g, 20g, GT30?

16g and 20g are kinda considered small turbo upgrades (cant speak for everyone on this). a big turbo upgrade for an STi is like a GT35R.

[Nachos Libres]

Originally Posted by impreziv

16g and 20g are kinda considered small turbo upgrades (cant speak for everyone on this). a big turbo upgrade for an STi is like a GT35R.

16g is almost like staying stock.

[steiner]

Agreed...although I can't see how a 16g capable of 25psi would be comparable to the stock setup. Also, would a GT35 swap require fortifications to the stock block beforehand?

[Nachos Libres]

Originally Posted by steiner

Agreed...although I can't see how a 16g capable of 25psi would be comparable to the stock setup. Also, would a GT35 swap require fortifications to the stock block beforehand?

Depends on how much boost you want to run, but I believe several people have done the GT35 without upgrading the stock block.

[steiner]

LMAO! And now we've come full circle. Running a GT35 at only 25psi is a crime against humanity. That was the whole reason I started this thread. I figured the smaller 3071, 3076 or 3037 would be popular with STi tuners since swapping a GT35 into an STi would involve some expensive strengthening of the stock block in order to make the turbo swap cost effective. I'm looking into a 3071 for my Evo but my tuner has never installed and/or tuned one for either an Evo or STi. I'm really curious to hear what guys running a 3071 on their little 4 bangers have to say.

[impreziv]

the amount of power you make out of a turbo isnt just dependant on the amount of PSI the turbo makes. there are many other variables in play, like CFM output by the compressor wheel. which is a direct correlation of the CFM emmited by the engine, into your turbo. ie: a 2.0L DOHC S2000 engine might be able to spool a GT30R to 25ish psi... but a 2.0L 8v VW Jetta engine, might only spool it to 19psi. simply because the S2000 would output waay more CFM than the 8v.

i almost ran a GT3071 in my other car.. the GT3071 is an attractive turbo to use. i mean it spools like mad, and is fairly capable. it also is availible with a simple 4-bolt 3" turbine outlet, which makes downpipe fabrication really easy, and exhaust flow really good.

hopefully someone who knows what theyre talking about pipes up here...

if you want to know more about what im trying to explain, read Maximum Boost by Corky Bell (owner of Bell Enterprises). best read ever if you are doing anything with turbos, or turbo engines.

im not a turbo expert by any means, but having read the book i felt i knew enough to custom fab the turbo system i wanted for my VW. and now moving on to an OEM turbo system (STi), i am confident i can handle the goals i have for this engine.

/my-ghetto-turbo-knowledge

[steiner]

Thanks for the info dude. I'm downloading that e-book as I type this. Which of the aftermarket turbo companies (ATP, Z1, RnR, AMS, etc) have stepped up to bat with the best packages for the STi so far in your opinion?

[impreziv]

ATP is currently making an STi turbo kit... although subarus are new for them, they are a terrific company.

popular garrett-GT-series kits for the STi seem to be

- Ultimate Racing
- Kingpin Performance
- Forced Air Technologies (they have a twin turbo kit, and a twin turbo/supercharger kit)
- Crawford Performance

i know im missing some here... my brain is in safe-mode

Ultimate Racing is a place that works on Evos and STis... they have a GT35R kit for the Evo VIII.

if a shop was able to impliment a GT35R, a 3071 should be easy... they have similar fittings, T3 turbine inlet, 3" turbine outlet... 4" compressor inlet. except the 3071 has a 2" compressor outlet, where the GT35R has a 2.5".

although, when choosing a turbo, your choice is best made using the old rule: right tool for the right job. dont choose a huge turbo if you are going to ***** out on the tune and psi. and dont overstress a small turbo to do something it cant do for too long.

ie: Forced Air Technologies makes a GT30R kit for the 2.5RS, its set at 5psi. why? i dont know. my prediction: their customers runs it at 5psi until they can afford internals (2yrs?).. then when they turn up the boost... bam, broken GT30R (or a disgusting amount of shaft-play).

[double helix]

I've seen that ATP test mule at Infineon last summer. The thing runs low 12s, looks and sounds stock. They are going for the fastest STI on mostly stock components. Stock TMIC, manifold, catback, amazing.

[impreziv]

i just went to ATPs site, and read up on their progress.

they have 4 turbo options
- GT28RS (350HP)
- GT2871R (400HP)
- GT3071R (450HP)
- GT3076R (500HP)

i wonder how many people are going to do the GT28RS. i mean, its a damn expensive turbo for only flowing 350hp.

looks like they ARE doing a 3071.. and they have a dyno of the 3071 too



i really wonder how the turbo is fit in there... i want to know if it uses the same intake pipe and such. im also curious if aftermarket TMICs can be used, and if the downpipe tapers to 2.5".

[steiner]

The extra .5 liter of displacement that the EJ25 has over the 4G63 really shines through in those numbers. However those numbers are not on pump gas. Here in CA we get the 91 octane pee-pee, so I'm guessing somebody on the wesy coast would lose atleast 50whp/50wtq across the board.

[MZM Performance]

FYI APS SR55 uses GT3076R CHRA which is common amongst Subaru enthusiast; so you may want to look at their results. Though I'm not sure how much that would help with your research as you asking specifically about GT3071R and planning to use it on your 4G63 equipped DSM. We are on the verge of releasing our own hybrid turbo for the 4G63 platform which has an awesome combination of 1/4 mile performance, stock like spool, and pricing. If you still in the market for a turbo within the next few months feel free to check with us on the release of this turbo to the market. Best of luck.
MZM hybrid vs. Stock 16G

MZM hybrid