M20 2.7i turbo. Need advice... a lot of it.

[timmyr77]

Haha well the location is exactly why I can afford to do this. And remember. I'm 18 and this build will take more than a few years. So I will have a lot if time to save up.

[einstein57]

I'd say save the money from a fully built head and invest in a nice clutch. They can get pretty pricey. A cam and stiffer valve springs should be plenty fine for your power goals unless money truly is no object. Then your budget should realistically be $5-6 assuming you do all the labor yourself.

[Nutzy]

I recommended the Subaru turbos. a lot earlier peak boost than the holsets.

but much more costly.

Wow....do NOT use dinky little turbo's like that. You are looking for minimum 60mm turbine exducer, unless you like detonation and back pressure.

I use an S256 317222, 11psi at 2800rpm and has a 65mm exducer!

[TheTacoMan]

Few people on here running subaru turbos and getting boost way before 2800.

[einstein57]

Few people on here running subaru turbos and getting boost way before 2800.

How many in the 350-400whp range?

[squidmaster]

Wow....do NOT use dinky little turbo's like that. You are looking for minimum 60mm turbine exducer, unless you like detonation and back pressure.

I use an S256 317222, 11psi at 2800rpm and has a 65mm exducer!

not everyone wants over 400hp. each turbo has its own application and advantages, no reason to think that your setup is the only correct one and everyone else is an idiot.... that's not how this works.

Few people on here running subaru turbos and getting boost way before 2800.

:ohsnap:

How many in the 350-400whp range?

vf39 is good for nearly 400whp on a 4 cylinder. trust me, I've tuned them before.

[einstein57]

So zero on a 2.7L engine? A ko3 is good for 240whp on a VW but i would not put one on an m20.

[squidmaster]

on an m20b25 you'd need a turbo flowing at 400CFM at ~15psi to reach 350chp.
A VF39 flows at:
425-450CFM at 18psi
410-420 at 14psi

[einstein57]

map?

[squidmaster]

http://www.ihi-turbo.com/turbo_RHE-RHF.htm

[Nutzy]

not everyone wants over 400hp. each turbo has its own application and advantages, no reason to think that your setup is the only correct one and everyone else is an idiot.... that's not how this works.

Yeah, it does work that way. Against all advice not to, I used a -0032 GT2871 on this motor and battled detonation. I had to run about 8 degrees less than others were running with HX35's etc. Back pressure and heat are killers. 9psi and more timing with the S256 was making more power than 14psi and less timing with the GT.

vf39 is good for nearly 400whp on a 4 cylinder. trust me, I've tuned them before.

Yeah, when guys llike iXer and Gunni give you the right advice about turbo choice, you listen. They've tuned more BMW's than you've had hot dinners.

And if you don't want 400hp, turn the boost down. But if you do want around 600HP, this turbo will do it too.

The small turbos are also a right c**t to try and modulate. The GT was either on or off which makes smooth exits from corners very difficult when on the limit of lateral adhesion.

Edit: Wow, holy shit. The VF39 has a smaller exducer even than the dinky GT2871 at only 47.9mm!

[Nutzy]

Few people on here running subaru turbos and getting boost way before 2800.

I'm also running the largest A/R turbine housing I could buy.....

[TheTacoMan]

How many in the 350-400whp range?

I know kamotors has one, and also HF doom is getting one.

[kamotors]

there is no stock subaru turbo that will get you even close to being worth the effort, they would all be horribly undersized. a 20g turbo which is pretty large for a subaru is what I would consider a low rpm turbo on an E30.

my td06 20g w/10cm housing spools at 2100rpms and hits extremely hard. Hard enough to break traction just rolling around 45mph and has instaspool.

a 20g on a wrx since its AWD hits hard enough to shear the teeth off of the gears in 1st and second gear and is really laggy.

Keep in mind just because my turbo is a 20g and is sized internally similar to a popular subaru turbo does not make it a subaru turbo.

My turbo is a t3 with a 3" inlet 2.5" charge outlet and 2.9" exhaust outlet. NONE of the turbo is compatible with a subaru.

and a subaru turbo has such manufacturer specific flanges it wouldnt even be worth installing on an E30. Plus the good ones cost around $500used.

here is how a subaru turbo flange looks.


and downpipe flange.

[squidmaster]

Look, I never said anything about it being the most efficient turbo, or getting the most power gains. Just was a cheap option that people have done.

As far as flanges, they can be had for under $50 for both. No different than needing to buy flanges for a t3 to fab your own stuff anyway. It does hinder your manifold options to custom fab only.

A 20g would be a better option than a VF39 though. For sure.