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M20b25 turbo ?

Posted: Sat Dec 12, 2015 6:24 pm
by Blackacerim
Hi guys, (I know you guys are probably sick of this newbie question BUT)

I basically have a spare m20b25 engine complete just sitting in my garage which I wanna have fun and make use off

So I'm thinking to turbo it, look for a clean or near clean e30 and do engine swap, brakes, suspension etc.

I think I have watched everything on you tube to get an idea of what I want

And I'd like to achieve a reliable late 375 to 400 Bhp usable monster.

QUESTIONS

1) Are there any guru's on hear I should be boring with detailed questions lol

2) maybe there are some good sites maybe someone could show me what would help me do even more research.

4) is there a guide somewhere and a m20b25 turbo conversion parts list that you guys recomended so I can price it all up?

3) from what I understand:

Standard internals can handle upto 400bhp ??????
( all I would need is Apr head bolts and upgraded head gasket)

Which turbo would give me a nice wide torque band, (I heard a g20 turbo maybe)??????

Engine management ( I'd like it to be custom to my engine because I'm thinking it the best way forward ???),

what would I need to invest in and would I have to teach myself how to tune before I turn the key for first time (which I'm ok with)

Do I need to upgrade anything like the fuel pump, guessing injectors, the diff, if so any idea what too.

Please help

Thank you in advance

Re: M20b25 turbo ?

Posted: Sun Dec 13, 2015 12:40 am
by chu346
Biggest question is how are you going to make or buy a manifold? The rest is easy from there :D

Re: M20b25 turbo ?

Posted: Sun Dec 13, 2015 1:56 am
by jimmyspeed
There Loads of info on this site if you search you will find start to finish builds - don't discount other engines as you can just pick and choose the good parts from others peoples projects

When I looked into my ongoing project I used to google image m20 turbo ect to find interesting blogs- e30tech and bimmerforum also have good info the tech one has a run through guide.

Its worth getting a good tuning book and reading through it'll explain how to size everything up and give you a better understanding off what's involved I got the forced induction tuning one by graham bell

The borgwarner/holset turbos seem popular for bigger power engines. If you specifically want torque you'll go smaller to stop the lag. It's possible to calculate your desired turbo after you know your engine spec and ensure it won't surge. All info in the book am sure it's online as well

I'd say you Definetly need a standalone - you can run a map sensor which is great for boost as well as control boost pressure an a host of other sensors to help tune

As for other upgrades/parts. clutch, injectors, fuel pump,, brakes, medium diff or torsen, intercooler, larger rad if it's pre facelift, turbo oil feed, external wastegate, improved ignition, steering rack faster, Camber tabs , charge pipes, new exhaust system the bigger the better, turbo manifold. And a descent engine an she'll to stick it too

Re: M20b25 turbo ?

Posted: Sun Dec 13, 2015 10:39 am
by chu346

Re: M20b25 turbo ?

Posted: Sun Dec 13, 2015 1:22 pm
by ross_jsy
Standard internals won't hold 400hp. Ross should be able to help if he sees this thread as he had a well built turbo m20 with similar power

Re: M20b25 turbo ?

Posted: Sun Dec 13, 2015 1:28 pm
by ross_jsy
And to answer a few questions, e30tech and bimmerforums have some great boosted sub forums. e30tech has a complete and useful guide here:

http://www.e30tech.com/forum/showthread.php?t=74816

Parts list depends on your power goals. At 400 I would recommend forged low comp pistons, forged rods, a complete rebuild goes without saying, a decent clutch, i/c etc etc, the full list is massive, get reading.

You are going to need standalone. VEMS and megasquirt are reasonably priced. You can get cheaper systems if you want to build it yourself and more expensive if you want extra features. The best thing is find out what a decent local mapper knows how to use and go from there. I wouldn't recommend learning to map your own car.

You are going to need larger injectors and a fuel pump as a minimum. Also the ignition will need adapting with coil packs so you can adjust ignition timing. There are several ways to do this.

Re: M20b25 turbo ?

Posted: Sun Dec 13, 2015 7:10 pm
by Blackacerim
Ok. Thanks guys for the feed back. Looks like I got a lot of research to do.

Re: M20b25 turbo ?

Posted: Tue Dec 15, 2015 2:33 am
by motormanmick
A must read when you are turbo/supercharging, a little old but nothing has really changed, we just have more modern electronics, explains everything, cheers.

http://www.fusca.net/wp-content/uploads ... _boost.pdf