I was wondering if it would be wise to change the compression ratio on the N54 engine and if it was safe. I dunno much about it, but I've seen other cars that have increased it and heard from their owners it makes a world of a difference. I do understand how it works, and especially on a turbo engine the effects seem to be exponential.

So I was wondering how smart would it be to do it? Are BMWs equipped with something that would hinder the performance? Searching the forum as well as Googling it didn't yield a whole lot of results for E60s.

 

how would one do this? change the head gasket? wouldnt that involve a lot of work and wouldnt just increase the boost pressure be easier?

anyway, wouldnt mind finding out more myself if you have more info.

 

Yeah, a friend just suggested that increasing the boost pressure would be easier. He also asked if the JB3 did anything to the compression ratio. Or at least alter the amount of fuel put in?

 

Changing the head gasget is the only way to do that with reasonable cost but that won't gain you more than a 1/10 or so I'd bet. Plus you'd risk issues down the road with too thin a gasket. The only other ways are very expensive and would require a well engineered kit, such as the Dinan stroker.

In the 80's, it might have been a reasonable upgrade with a small block Chevy or Mustang or the turbo cars of the era but in general, most modern BMWs are designed with as high a compression ratio already as can be safe and usable on the street. And with the turbo, increasing the boost is faaaar easier and more cost effective.

 

Is 10.2 considered low for a turbo'd car? I thought I remember hearing people running 14+:1

 

The n52 is 12:1. In the old days, I think most na engines have 10:1 and tc engines usually lower.

 

So the N52 has a higher compression than the N54?

 

more detail on cr for you:

http://en.wikipedia.org/wiki/Compression_ratio

happy reading