stroking a m42?

[el_4ever]

Where in Tampa are you located? Coming to the AutoX in Brooksville this Sunday?

i'm near ray j...didn't even know about it but my girl's from brooksville. where? what time? you going?

[BimmerToad]

Why, The increase of stoke would make more Tq and not gain that much lbs.

Increase in torque from a stroked M42 ~20-30ft lbs, from a fully sorted touring car-style rebuild. (max torque peak at probably 7k) The S42 touring car engines IIRC only made ~180ft lbs.

Increase in torque from swapping a lowly 2.5L M50 ~at least 30ft-lbs gain, with more from mods.

Despite the fact that you've 'stroked' the engine, you are still down when it comes to the displacement game.

Fun street engines have gobs of torque.

If you want torque from a M42, blow it, or spend gobs of money increasing the redline of the engine, and bolt up at least a 4.5:1 ratio differential.

Don't get me wrong, the M42 is a good design. And I'm sure it would be a killer set up with a 9k redline..... in a car that weighs less than a E30 (i.e. Lotus 7 replica)

[Rob]

I dont remember where I said 'dont do it!DFOJNSDOGJN", I simply made arguments against it. *shrug*

[SchnellerVert]

Why, The increase of stoke would make more Tq and not gain that much lbs.

If some one is willing to do it then so be it let them. Maybe they don't want to upset the balance of the 318iS.

[DrMcDave]

well that may be, but it would be a cool project. The 318is so nimble that for some it isn't worth the hp to throw off the weight distribution, that being said. If was to mod my 318 i would swap an s50. Unless for some reason i had unlimited funds to play with.

[Rob]

I think getting 160 to the wheels out of an M42 is a unicorn, you might hear tons about it, but no one has ever seen it...160 crank maybe, but wheels, hrmm...

having an m42 built would cost what, in comparison to a 2.5L m50 swap (which would probably have a lot more torque...)?

[screamingbmwe30]

some of us don't have to worry about smogging. gray market smog exempt. my euro 320i is smog exempt. dont ask me how, but even on the title it says non-catalyst. no cat from the factory and passed inspection like that! plus the county i live in requires no exhaust gas check. digitalway, with m44 crank it is closer to 11.02:1 or something. gotta call peteMC up again.

[DrMcDave]

what about some cams and a Multi throttle body intake, and maybe MS. you could probably put down atleast 160+ i would think. I am beginning to like driving my 318is. I wouldn't mind a bit more go though.

[BimmerToad]

What is the compression with E36 M3 pistons?

Static compression ratio of 10.5:1 (stock M42 = 10.1)

The M42 essentially has the same head (minus vanos) as the M/S50, including valve sizes/stems. E30 M42 has the same valve stem size as a NV M50 (7mm), while the E36 M42 has the same valve stem size as the M5x (6mm).

The main problem of building up a M42 is that to get power out of it (NA), you're going to have to get some serious cams, lifters, headwork, and standalone. Try smogging that....

Still though, someone needs to do it and document it. It would be a pretty involved and costly build...

[Digitalwave]

What is the compression with E36 M3 pistons?

[screamingbmwe30]

you have 2 options

stock crank not sure which rods and e36 m3 pistons = 2.0l around 170-180 hp +/- with good tuning cams are good for some more power not sure how much though

m44 crank (not as high quality as m42's but bigger stroke) +e36 m3 pistons =2.1L 180-190

spend 3k on the top end to get it to 8500rpm and who knows what it would make.


(m44 crank (not as high quality as m42's but bigger stroke) +e36 m3 pistons =2.1L 180-190 currently pieceing together right now)

^

[AdamF 88iS]

s42? didnt that have something like 380hp? i dont remember exactly but on the website i found you could purchase all the parts.

And it would last about 6 months before needing a rebuild.

The head is decent on M42s, the problem is finding a good crank and cams for it.

[gazellebeigem3]

s42? didnt that have something like 380hp? i dont remember exactly but on the website i found you could purchase all the parts.

[Bavarian3]

Where in Tampa are you located? Coming to the AutoX in Brooksville this Sunday?

[Rob]

A cheaper, easier and imho better solution would be to add a ltw flywheel, and do a MAF conversion with some dyno time.