Educate me about turbo [Archive] - Bimmerfest - BMW Forums

: Educate me about turbo

10-22-2007, 05:35 PM
Just have a couple of question about force induction (turbo) so I have some basic idea about setting a system up for my 1991 318is.

I have seen several photos of other set up. One question is. Is the MAF gets eliminated? If so how is the air flow gets metered?

Do I need to change the ECU for better management?

The stock throttle body. Will it work with turbo application?

For the most part I can manufacture the exhaust manifold to meet my need to put together a system.

Which turbo is best to run with? T3 or T4.

What size tubing is best for the application?

How about EVO turbo?

There are several pictures of other members turbo. Most of them show the tubing being hooked up directly to the throttle body without the MAF in play or I did not see it in the photo. Thank you for any inputs. If I missed any other critical parts I need to consider please share them.

I consider myself “old school” meaning big piston, high lift cam and big carbs for power. Now this days “turbo” is a house hold name now so I thought I would give it a shoot in putting together one.

Has anyone used the intake manifold from”666fabrication”? Does it come with it’s throttle body?

10-23-2007, 07:47 AM
The MAF meter and air filter usually get relocated and attached directly to the turbo air inlet (before the compressor does its magic) and the air is metered at that point which is why you don't see before it goes to the throttle body. You can't meter compressed air all that well. Go with a smaller turbo and an intercooler as most BMW's have a higher compression ratio. Also, make sure you use the proper wastegate and an ignition boost retard to help pull back timing as boost increases. Stock throttle body will work, but when you start going with forced induction, things that normally produce small to no HP gains (throttle body, intake, MAF etc) on a natural aspirated car, make huge power gains on a blown application. So the answer is yes to stock throttle body, but upgrading it will give you a big boost in HP.

If you can afford it, rebuild the bottom end with quality forged parts and lower compression pistons, then you can crank up the boost to your hearts content. With stock compression, just be careful. And as always, and with any power adder, add more fuel to the mix or else say good bye to head gaskets, or worse!