M3 cams in 2.8 - Page 4

E30 Stu · 10-17-2003, 12:20 PM

Pat--

Yes sorry I did forget to mention the bumped compression. I PM'd you about dyno information.

JazzM · 10-17-2003, 01:01 PM

Usually when you increase compression on a NA motor you'll get more hp... what compression is that one running? On street gas, then probably something lower than 11.5:1

Best Regards...

E30 Stu · 10-18-2003, 03:31 AM

We run 10.8 or so compression on street motors, 93oct. Keep in mind over time the compression raises, as carbon builds up on the piston tops, so after mileage that 10.8 moves to about 11:1.

JazzM · 10-18-2003, 12:48 PM

That's the same as the bekker's heads...

So you're saying that 11:1 compression with everything else stock = 250 hp?

97 Z3 2.8 · 10-20-2003, 06:22 PM

That's pretty good. You certainly don't want to go much higher compression. These engines are built like freight trains, but avoiding predetonation is probably best.

E30 Stu · 10-20-2003, 08:26 PM

I'm not saying that if anyone builds a motor like this with 11:1 that it will make 250whp. Ours did, with little to no tuning at all. My father has been building engines since before he could drive a car, so he has a bit of experience.

11:1 is pretty high for a street motor, 10.8-10.9 is how you want to build them.