Turbo or not

[Whacko]

The car in mind is the Z3 MCoupe. Seeing that BMW reasoned that our fuel in SA is crappy enough to warrant a full 0.8 bar lowering of the compression from the Euro spec of 11.3:1 to 10.5:1, what is the dangers of retrofitting a turbo on this car and limiting the boost to 0.5 bar?
Just pondering on this.

 

[applehero]

The car in mind is the Z3 MCoupe. Seeing that BMW reasoned that our fuel in SA is crappy enough to warrant a full 0.8 bar lowering of the compression from the Euro spec of 11.3:1 to 10.5:1, what is the dangers of retrofitting a turbo on this car and limiting the boost to 0.5 bar?
Just pondering on this.

Hey Whacko

I'm not sure one can link compression ratio directly to the pressure a turbo gives. As compression ratio relates the maximum volume of a cylinder to the minimum volume of that same cylinder. Where the pressure a turbo gives, is the increase in pressure than if the turbo wasn't there.

What you guys think?

 

[Whacko]

The car in mind is the Z3 MCoupe. Seeing that BMW reasoned that our fuel in SA is crappy enough to warrant a full 0.8 bar lowering of the compression from the Euro spec of 11.3:1 to 10.5:1, what is the dangers of retrofitting a turbo on this car and limiting the boost to 0.5 bar?
Just pondering on this.

Hey Whacko

I'm not sure one can link compression ratio directly to the pressure a turbo gives. As compression ratio relates the maximum volume of a cylinder to the minimum volume of that same cylinder. Where the pressure a turbo gives, is the increase in pressure than if the turbo wasn't there.

What you guys think?

Yes, I am aware of that, the inlet pressure is raised by 0.5 bar, or 0.5 atmosphere. But consider a car boosted to 1 bar, with a compression ratio of 8.5:1 with no problem. I think keeping the boost to 0.5 max should work, but I stand to be corrected. My boet is into turbo modding, and he has a chipping setup, he does that as part of his business, so he suggested I go this way, but I wouldn't like to blow the motor. The car is reasonably strong as is.

 

[Major]

Which engine is in your M Coupe? Wikipedia says 99-00 models had an S50 and after that had the S54.

 

[Whacko]

Which engine is in your M Coupe? Wikipedia says 99-00 models had an S50 and after that had the S54.

It's the S50B32 motor. The S54 has more power but needs attention to the conrods if modded.

 

[james]

Ye whom does not attempt, shall not succeed.