e34 525i turbo charger questions

MR 535i · #1 (**permalink**) 02-23-2009, 05:25 AM

Hi all, I have a 1990 535i that i have had for the past year. Three years ago the automatic gear box got a rebuild (standard) and i have had the head rebuilt my self. So saying that here is what I have read about turbo charging...

I have looked around on a lot of different BMW forums and I have come to the conclusion that the 535i is one of the best stock BMW N/A engines to turbo charge.

I have only found a write up about a 199? 525i and I'm lead to believe that you can run 7 - 8 psi of boost with a completely stock engine (internals etc, obviously you need a turbo etc). Can any body give me any feed back on the information i have gathered.

Also I'm lead to believe that if you change the head gasket to a 0.14" size gasket you can boost it to 12 - 14...! Can any one confirm this...?

I'm also thinking that the 535i would be able to handle the same power as the 525i.

Every ones help will be appreciated

Thanks in advance
Jonno

Ps I do apologize if people are sick of questions like these.

Xear0 · #2 (**permalink**) 02-24-2009, 06:31 AM

7 - 8 pounds sounds about right, mayb a bit high. Thats assuming your engine is in over all good condition.

MR 535i · #3 (**permalink**) 02-24-2009, 11:35 PM

thanks for your comment im assuming that it should be fine

CRZYBM · #4 (**permalink**) 03-05-2009, 07:10 PM

you shouldn't have to change the headgasket. the m30 motor has a relatively low compression to start off with. unless your car has done a headgasket before and needed to get machined then the compression would be higher of course.

itsabimmerthing · #5 (**permalink**) 03-29-2009, 08:08 AM

7-8psi is a cakewalk. As I always preach, your turbo setup is only as good as the weakest link. Don't start off with a honkin turbo because at 7-8psi its not going to be efficent. Also a big turbo at lower boost obviously means more power than a smaller turbo at high boost. But a big bimmer motor needs a decent snail it won't max out.
I would get a wideband 02 setup, upgrade the fuel pump and put an adj regulator on, because these are growing steps anyhow. I would reccoment a mitsu 16g or garret t28 depending on which flange you wanna run.
I run a 2000 vw new beetle 1.8t, I went from k03 at 16psi to a gt28rs at 14, it is an INSANE change.
Keep an eye on air fuel ratios and make sure to upgrade your exhaust so the turbo can breathe.
Have fun boostin that bimmer. Any questions shoot me a pm and I will be more than happy to help you out.