m20 or m42?

[e30Rooster]

IIRC the m42 has a timing chain, and its comes from the factory with foraged internals.
I'm not sure where I read it but, why don't you just practice tuning, and installing a turbo on the m42 and see what it can do. get a new head gasket and some good head studs and go to town.

Worst case the m42 takes a shit, then you have an m20 and some experience so you have a good idea of what your doing, and you will know what you want and how to do it.

[iamsam]

I hear the M20 loves boost, but I know that M42 turbos are much much more badass.

[nando]

I'd say M20; every aspect of boosting an M20 is going to be simpler/cheaper and a 300whp turbo M20 is going to be far more tractable and less stressed than a similar M42 build.

I do like the idea of a turbo M42, but the extra expense doesn't add up for me.

[amcp]

M42 can be built for boost but make sure you're Johny on the spot in regarding to maintenance. Tiiming chain tensioners go out... new valves and pistons.

[slammin.e28]

Just say fuck M20, fuck M42. Get an M30, boost it, and roll on with life.

[Dj Buttchug]

listen betch stop being a pussaay and turbo a m42

[MikeDE]

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

Have to disagree, Boost likes displacement. Picture an M42 with a JRSC running 6-8 psi. Whadda ya gain, like 50hp max. Now picture a C5/6 Vette with a 5.7 running 8psi, what does he gain?? Probably 2x that. Granted these are two different animals, but the displacement takes the boost further.

[nando]

it's true; an M42 might be 10% more efficient, but the M20 is ~40% larger. you can make the same amount of power, it will just cost more, and require *more* boost.

[bmwguy325is]

I say build the M42 so it will spin 10K and boost it just like the old 320s did. They got 600hp out of an M12.

[nando]

yeah, a home built 10,000rpm 600hp M42 is totally realistic. :p

[BMC227]

Just say fuck M20, fuck M42. Get an M30, boost it, and roll on with life.

word.

[immajackuup]

listen betch stop being a pussaay and turbo a m42

amen!!!!!!

[Dj Buttchug]

if your going for fun factor m42 would be the way to go. its all about usable fun power than can be used daily on the street. granted m20 with boost falls into this area as well, its not really a choice of engine its a choice of build direction.

What does the OP want. maybe 10-12 psi m42 which would give 240-260 hp spooling at 2500 somthing?
orrr turbo m20 which gives maybe 40 more hp and is spooling at 3k or so? provided the builds are somewhat proportional and similar...

OP do what you think will be the most fun. Just dont not do anything and be gay. my 2 cents

[Ryann]

They got 1300hp out of an M12.

Fixed for you.:)

[slammin.e28]

Fixed for you.:)

IIRC those were USED blocks too, that had sat around a while.