m20 or m42?

[ApexGoblin]

ok so i have a 91 318is with the 1.8l 4cyl m42 motor in it, i also have a m20b25 motor and trans that i bought. my goals for the car are around 300hp when its all said and done. this said i have read both m20's and m42's can achieve this hp range (if i was turboing a m20 i would do a Frankenstein with build with 2.7 lower and 'i' head). so with that in mind that I have both engine options, its really just which one should i invest the money into?

considering:
-money needed to achieve desired result
-power to weight ratio
-reliability (as it will be on the street with occasional canyon running and track days)
-etc.

any opinions would greatly help!

[acolella76]

The 318is is already a bit lighter and has better weight distribution due to the smaller motor. It would also be better do not do the 2.7i thing, it really doesn't make that much of a difference I don't think. Just boost the engine you already have rather than have the headache of swapping motors

[Dozyproductions]

sr20det swap?

[ApexGoblin]

sr20det swap?

lol nahh im too much of a bmw lover to do that... maybe if i had multiple e30's :P but i was thinking more rb26det though

[mr2peak]

m20 will take less boost to reach that goal, less boost usually equals better reliability.

[Dj Buttchug]

m42 is also more expensive to boost.

[jaye30]

The 318is is already a bit lighter and has better weight distribution due to the smaller motor. It would also be better do not do the 2.7i thing, it really doesn't make that much of a difference I don't think. Just boost the engine you already have rather than have the headache of swapping motors

you dont know what your talking about. clearly you have not ridden in a stroked m20

[mikeedler]

The 318is is already a bit lighter and has better weight distribution due to the smaller motor. It would also be better do not do the 2.7i thing, it really doesn't make that much of a difference I don't think. Just boost the engine you already have rather than have the headache of swapping motors

there is a 50hp difference right from the beginning before you would even turbo the motor. of course you will get more power out of a 2.7l displacement. the sound of the M20 alone is reason enough to swap to it!

[gearheadE30]

More displacement will almost always be easier to make more power from. You'd have to seriously build the M42 to get in that range. That said, I'm a proponent of the M42 and have a turbo one myself.

[Dozyproductions]

ok so i have a 91 318is with the 1.8l 4cyl m42 motor in it, i also have a m20b25 motor and trans that i bought. my goals for the car are around 300hp when its all said and done. this said i have read both m20's and m42's can achieve this hp range (if i was turboing a m20 i would do a Frankenstein with build with 2.7 lower and 'i' head). so with that in mind that I have both engine options, its really just which one should i invest the money into?

considering:
-money needed to achieve desired result
-power to weight ratio
-reliability (as it will be on the street with occasional canyon running and track days)
-etc.

any opinions would greatly help!

dude, do you know camacho? I'm the one that got him in his e30 that he drives :D

[blueapplesoda]

DO the m42. More HP per PSI (in essence, i understand PSI =/= HP in many cases) if you know what you are doing. DOHC flows better than SOHC.

I love the simplicity of turbo m20s, but m42 are fantastic alternatives if you know how to build/tune your engine for boost.

[AndrewBird]

I'd say the M20 purely on the fact that you can build it while still driving the car. Spread the spending out so it isn't such a big dent to the checkbook, then just drop it in on a weekend when it is ready.

[acolella76]

you dont know what your talking about. clearly you have not ridden in a stroked m20

Oh, not only have I ridden in a car with a stroked m20, i own one!

there is a 50hp difference right from the beginning before you would even turbo the motor. of course you will get more power out of a 2.7l displacement. the sound of the M20 alone is reason enough to swap to it!

What I meant was the difference in hp between boosted 2.7i and boosted m20b25 is not going to be that much to justify spending the extra money on a new bottom end.

[BMC227]

M42 is gay, go M20 because parts are much cheaper.

[Pantless Spency]

just get a boosted m42 or an m20.

anddddd sr engines< rb engines :)