casting differences

[Freedy]

Are the m42 and m44 blocks the same casting? I am doing preliminary research on a bored out turbo project.

[318.g25]

the extra .1 litre of displacement and the electronics

[Jeff Spooner]

the M44 uses a crank sensor that sits on the left side about 3/4 way back. the M42 reads off the front balancer. the M42 has a boss in the same area but it is not drilled. Not sure if the castings are the same though.

[KIRASIR]

This has nothing to do with your block question but M42 has forged crankshaft, while M44 doesn't, which in my opinion is more important than the extra .1 liters.

SL

Originally Posted by Freedy

Are the m42 and m44 blocks the same casting? I am doing preliminary research on a bored out turbo project.

[318.g25]

I Agree

[GDB]

Would the crank from an M42 work in a M44? I have wondered about this and believe that I asked it on here but never got a response.

[ClubSport]

I think the cranks are interchangeable, but you would lose that .1L of displacement. There may also be issues with rod length causing compression changes.

[RAiMA]

Originally Posted by KIRASIR

This has nothing to do with your block question but M42 has forged crankshaft, while M44 doesn't, which in my opinion is more important than the extra .1 liters.

SL

Although a forged crankshaft is always better than one that isn't, most M44 owners won't find the limits of the M44 crankshaft. We ran 258rwhp with 19.1PSI @ 7200rpms with the stock M44 crankshaft. It's running fine and strong.

With the M44 crankshaft being so strong, the exta 100 cc is more beneficial than a forged crankshaft would be.

[J!m]

Originally Posted by ClubSport

I think the cranks are interchangeable, but you would lose that .1L of displacement. There may also be issues with rod length causing compression changes.

I am reasonably certain the stroke is identical, and the bore was increased. I do not believe the stroke was changed.

[RAiMA]

Originally Posted by J!m

I am reasonably certain the stroke is identical, and the bore was increased. I do not believe the stroke was changed.

The bore and stroke are both different

84 x 81 (M42) vs 85 x 83.5 (M44)

[Freedy]

OK, from m42 to m44...

bore increase gives an extra 43cc, and stroke increase gives an extra 56.8cc...total difference of 99.8cc (0.0998 Liters).

Next question, whats the maximum BMW recommended bore?? Anyone ever go bigger with cryo-treating the block? If the cranks are interchangeable then they are most likely the same casting. FYI, I would be looking for ~350 rwhp...boost only. I plan to heavily port and polish the head, add cams, fabricate all air/water plumbing including both manifolds, and run a standalone. Seems like the m42 is my best bet for high revving and big boost because it can do solid lifters, and has a forged crank. Any opinions?

EDIT: Forgot to mention this will be a daily driver.

[RAiMA]

Know of anyone that's hit 350rwhp from an M42 or M44? I'm interested to hear about the specs.

[Freedy]

Not particularly, although I do know that porting and polishing can do wonders when combined with larger valves and hotter cams. Add a turbocharger pushing 25 lbs of boost through lower compression pistons with a decent intercooler, nice plumbing(including manifolds), and standalone and 350 rwhp should be attainable with halfway decent spool characteristics(~2500-3000 RPM positive manifold pressure and ~3500-4000 RPM full boost). I know better spool can be attained with those new active turbos...but havent seen much data about them.

For an alternate example, the mitsubishi 4g63 engine (140 flywheel hp N/A) can do upwards of 500 wheel hp when turboed and massaged in a similar manner. Thats the engine in eclipse, talon, and laser DSM cars, FYI. I figured 350 rwhp was actually a conservative estimate for a bored out m42 or m44. I would prefer over 400 because I want 11-second-time-slip type thrust.

[RAiMA]

I know a guy running a turbo on M44 with 20 PSI. He's producing 230rwhp with most of the stuff mentioned above. We helped him refine his car and improved drivability with the engine management system. He now produces more power than the inital install done by another shop, has less problems and drives well. His maps are based on the RT318ti. The only thing he hasn't done is the port and polish and larger valves.

I've only heard someone produce simular to the 350rwhp, but it was an E30 318. I'm not sure if it was the M10 or M42 engine, but he's running about 35PSI and NOS to produce those numbers. Apparently he's done the full hog and has broken a number of diffs.

Other than him, as far as we're aware, we're the next closest thing for a 318 in terms of power output.

I hope this helps Good luck with your project and keep us up to date

[GDB]

Although the 4G63 starts out producing similar horsepower in stock trim, it is also one of the more robust engines out there, and it responds incredibly well to BPU. If you did get 350 hp from a M44 or M42 then it would probably be a car that was a pure dyno queen and not especially fast.