Building an M42

[I8UR911]

Anyone have experience with VAC's "hot" cams and the Miller AFM to MAF conversion with WAR chip? Looks like this is where I will start.

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[broach328]

Not sure about the cams, but the MAF is supposed to be a really nice upgrade. Possibly look into regrinding the cams to save some doh?

[I8UR911]

Just scored a M42 engine, trans, driveshaft, engine harness and ecu for $150. Also found a M44 crank for $50. Picking everything up tomorrow.

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[I8UR911]

Miller doesn't make a WAR chip for M42

:(

MS2 anyone?

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[bmwman91]

If you do cams and any sort of porting or mods to the bottom, make sure to spend time on a dyno for a custom tune. Trying to run off of a chip that wasn't tuned for those mods is going to rob you of power.

A MAF conversion is not going to gain you any power on a mostly-stock M42. I spent years developing a plug and play conversion and dyno testing showed no gains on a stock M42. Throttle response does improve a bit, but it is not worth $hundreds. Now, on my 2.1L Metric Mechanic Rally M42 a MAF can gain me a little power since the engine flows a lot more air at high RPM, but I still need to tweak a few things before running to the dyno.

Basically, the only things worth your while are chips and a lighter flywheel

[wazzu70]

On the M42club there are guys running the VAC 269/269 combo with good results, over 140whp.

An M42 car with cams and a good tune is a really fun track car. The reduced weight over the front end is very noticable.

I believe someone here has MS PnP which would be a nice option. I am running VEMS on my M42 if you want to look into another option.

The tune makes the biggest difference. A chip with cams wont yield nearly the same results! Also both MS and VEMS allow you to ditch the AFM/MAF for much better throttle response.

[broach328]

Just scored a M42 engine, trans, driveshaft, engine harness and ecu for $150. Also found a M44 crank for $50. Picking everything up tomorrow.

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Wait, I could be wrong but I'm somewhat sure that the m44 crank is actually cast, not forged like the m42 crank. You mentioned at one point I believe that you wanted high rpm capability?

edit: I must have read the higher rpm bit in another thread. but regardless, isnt the m42 a stronger crank?

[decay]

On the M42club there are guys running the VAC 269/269 combo with good results, over 140whp.

you've just reminded me i found these a while back:

http://catcams.co.uk/acatalog/BMW_318iS_E30_136hp____E36_140hp_.html

since their "fast road" grind is also 269/269, i wonder if VAC is reselling Cat?

could be worth going around the middleman if that's the case (unless cross-pacific shipping means it would make no difference).

[evandael]

edit: I must have read the higher rpm bit in another thread. but regardless, isnt the m42 a stronger crank?

i'd think that the rod bolts, oil pump, and valvetrain are more of a concern for high revs.

the m20 cranks are cast as well. people rev those past 7500, and the 6 has more harmonic issues than the 4.


also, VAC is CatCams USA (they say so on their website), so it's very possible that they are the same camshaft.

[Ryann]

Upgrade the 180 degree thrust bearing to the m50 360.

[decay]

also, VAC is CatCams USA (they say so on their website), so it's very possible that they are the same camshaft.

Ah, hadn't seen that, thanks. Not that $750 is a bad deal for two billets in the first place. Probably will just go through VAC when I'm ready.

[wazzu70]

Yeah, VACs specs match Catcams directly....so its probably catcams rebranded. Thats not an issue really since its a great product and decent price.

The crankshaft material doesn't really come into play on this build. The metallurgy matters much more than cast vs forged. Not all castings and forgings are created equal!

[carnurd]

On the M42club there are guys running the VAC 269/269 combo with good results, over 140whp.

An M42 car with cams and a good tune is a really fun track car. The reduced weight over the front end is very noticable.

I believe someone here has MS PnP which would be a nice option. I am running VEMS on my M42 if you want to look into another option.

The tune makes the biggest difference. A chip with cams wont yield nearly the same results! Also both MS and VEMS allow you to ditch the AFM/MAF for much better throttle response.

That was me, however I'm running the 279/274's. They are basically the biggest you can go whilst retaining hydraulic lifters. I did however replace all lifters with new OEM's also put in VAC dual valve springs, hardened retainers, and SuperTech SS +1 valves. Also this I feel is a very low estimate of what those cams can actually do. In the next year or two I'm planning on higher compression and ITB's with possibility of solid lifter conversion.

[joolz635]

I will let you know my dyno results next week. I basicly have the same big cams, solid lifters, duel springs, m44 valves, big port job, itb's, motec ecu, bosch blue top injectors, light 11.5:1 pistons, light forged rods, crank scraper, and an m20 lightened flywheel. Fingers crossed for about 180rwhp.

[I8UR911]

Joolz I definitely want to hear how your car dynos

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