my turbo set up

[bmwconnect]

Originally Posted by Bullet Ride

Makes sense. Not ideal but that should work relatively well. I'm guessing Alpina did something similar with their old turbo motors.

ya it works better then most would think

[jamison67]

alright guys i ran a 1in line of the valve cover to open air and drilled out the restricter and now shes up and running ,no oil leaks from the turbo and she runns pretty good.....the wideband is still jumpin all over the place on idle like 14 to 15 to 16 back to14,,,but under boost shes at a steady number ,,,,i just have to ghetto tune it to hopfully run some decent a/f ratios

thanks for the help guys

[MarkD]

Originally Posted by Bullet Ride

Makes sense. Not ideal but that should work relatively well. I'm guessing Alpina did something similar with their old turbo motors.

Which Alpina motor are you referring to? The Alpina B10 bi-turbo (E34) uses the same MAF and DME as the E34 M5, plus a MAP sensor which allows ignition retard and different fueling when in boost.

[Bullet Ride]

Originally Posted by MarkD

Which Alpina motor are you referring to? The Alpina B10 bi-turbo (E34) uses the same MAF and DME as the E34 M5, plus a MAP sensor which allows ignition retard and different fueling when in boost.

If they had a MAP sensor why did they keep the MAF? All they would have needed was IAT

I'm pretty sure the B7 turbos still used the AFM, did they have a MAP sensor as well?

[MarkD]

Originally Posted by Bullet Ride

If they had a MAP sensor why did they keep the MAF? All they would have needed was IAT

I'm pretty sure the B7 turbos still used the AFM, did they have a MAP sensor as well?

I am sure that the B7 had an AFM. I doubt there is a MAP sensor on that one.

By using a MAF and MAP on the B10, the software could easily use the MAF when not in boost and the MAP just to retard timing and increase fuelling when in boost. This would be the easiest way to adapt the software from the M5 to run the B10 motor without a complete re-write and all the associated testing. Remember, they didn't produce enough of these cars that they would want to develop completely new code with a different control strategy that had not even been used in a Bosch DME before.
The 944 Turbo also uses a similar setup, with a DME for spark and fuel and a KLR to sense knock and boost, and send a signal to the DME to retard timing.

[NOTORIOUS VR]

VW/Audi/Porsche, etc all still to this day use MAF + MAP as load inputs on boosted engines.

MAP only works well, but MAF's work very well when tuned properly, and I guess you can guess where MAP + MAF gets you.

[MarkD]

Originally Posted by NOTORIOUS VR

VW/Audi/Porsche, etc all still to this day use MAF + MAP as load inputs on boosted engines.

MAP only works well, but MAF's work very well when tuned properly, and I guess you can guess where MAP + MAF gets you.

That's correct. There is more resolution when using a MAF as you are measuring the exact air mass instead inferring it from MAP, which does not always correlate with the air mass entering the motor. Personally I'd always try to go the MAF + MAP route on a boosted motor.

[bmwconnect]

No matter what setup the stock ecu runs, Afm only, maf only, maf+map.... At the end of the day they are all tune-able for high boost & high hp and in most cases daily driveable without any issues...