hey everybody,

for a while I was thinking a turboed M20 or M30 was the way to go...

my friend drives a 1972 datsun 240z. he has a 280zx turbo engine that that he is thinking of "buiding" (i.e. remove turbo, stroke, ported, high compression, etc.). He says for his car, it would be cheaper, more practical, and more reliable than the turbo.

My question is, can the M20 or M30 be built like that? is there an aftermarket? is it indeed cheaper than the turbo route? how much power can be made?

Thanks

www.metricmechanic.com Great work- they sell 3.9L M30 strokers with hot cams ported heads, higher CR, the works.

A built (bored, stroked, camed, 11.0:1 CR, P&P, headers, the works) M30 produces less than 300hp. A built M20 will produce even less. Your friend was dead wrong about a built motor being more reliable, by the by. A built NA motor is, by its nature, high strung and requires very tight tolerances, and thuly will not last long and have very tight upkeep requirments.

Turbo is the only way to go for more than 300rwhp. The main limitation of the M30 NA is that it is SOHC. This limits your volumetric efficiency, especially at high revs, meaning low power. There is a reason why the max power in a M30 is at 5k when the redline is at 7k.

well, he wasn't trying to get more than 200hp at the wheels in his situation. he says it's less headache (college student, no engine management headaches, etc). I don't think I'd need more than 300 hp for my daily driver...

well, he wasn't trying to get more than 200hp at the wheels in his situation. he says it's less headache (college student, no engine management headaches, etc). I don't think I'd need more than 300 hp for my daily driver...

It doesn't get 300hp. It gets more like 280hp, and that is after about 15-20k. The Metric Mechanic motor is 12k after all is said and done. I looked into this extensively when I was making a plan for my e9 build.

It doesn't get 300hp. It gets more like 280hp, and that is after about 15-20k. The Metric Mechanic motor is 12k after all is said and done. I looked into this extensively when I was making a plan for my e9 build.

I see...so basically, the all-around best way to make power in a bimmer is forced induction?

Most likely. Google TCD.

I see...so basically, the all-around best way to make power in a bimmer is forced induction?

For the most part. BMW has historically been very good about making their NA motors excellent by not cutting corners like american or japanese engines do. That's why headers on a US or Japanese car give such a huge gain, ditto for CAIs and exhausts. The OEM stuff is cheap to make and crimps the power significantly, while the BMW stuff is usually very good already, thusly bolt-ons give minor advantages.