My First M42 (dyno inside)

[Dricebrug]

Posted twice!

[deansweet]

another empty thread?!

[Warsteiner]

I know....I was getting excited that people would start posting some dyno charts of their chipped, stand alone or stroker motors!!

So why don't we fill this thread with all those??

Cheers,
~Ralph

[Dricebrug]

Hmmm.... Not sure why the original post is gone :confused:

Recently I purchased a 91' 318i with 150k. The previous owner was very upfront and said he believed the head gasket was bad.

After getting the head off, I quickly realized that the head was infact cracked. Luckily however, I had a spare M42 head.

Taking both heads to the machine shop, here is the list of what was done:

- The valves where used off the E36 M42 head vs. the E30 M42 head's 7mm valve stems. (Thats 12g PER VALVE of weight savings)

-Even with the lighter valves, I used the dual spring setup off of the E30 M42 head. (even tested against the conical s52 springs, they were stiffer!)

- .020" was shaved off of the head for a little better compression.

- I had some minor port work done. (Mostly bowl blending and smoothing everything out)

- Lastly, once I had it up and running again, I threw in a Mark D. tune.

Here is the car as it sits today:



Here is one of the intake ports after port work:



And finally, here is the dyno graph from today (~40 degrees out)




I am happy with the power, considering its a stock motor with minor touches. Having that been said, I have full access to a dyno and would love to move some power up top.

I am open to all suggestions, and I will dyno test them!

[Dricebrug]

Showing up for me now!

[e3091318is]

That is pretty good that you are getting factory power from that!  I have a used engine I bought from a wrecking yard.  M42 off a 1995 318i.  About 140k miles.

[Dricebrug]

That is pretty good that you are getting factory power from that!  I have a used engine I bought from a wrecking yard.  M42 off a 1995 318i.  About 140k miles.

I'm not sure if the M42 is under/over rated, but with a claimed 134hp and 127ft/lbs stock, if you use 18% drivetrain loss, that puts my little M42 at 162hp and 150ft/lbs at the flywheel. Not too too bad.

[carnurd]

My M42 with +1 SS valves and cams made 142rwhp @ 2600ft elevation 90deg ambient temp, same torque though of 128.  But looks good I wish I had a lot of head work and i know that number would be way higher.  The main issue I run into is that I'm severely choked down by the intake manifold, my car loves to breathe at RPM and so from 5800rpm-7.5k it just hits a wall, shows up on the dyno graphs.

[Dricebrug]

My M42 with +1 SS valves and cams made 142rwhp @ 2600ft elevation 90deg ambient temp, same torque though of 128.  But looks good I wish I had a lot of head work and i know that number would be way higher.  The main issue I run into is that I'm severely choked down by the intake manifold, my car loves to breathe at RPM and so from 5800rpm-7.5k it just hits a wall, shows up on the dyno graphs.

From what I can see, there is absolutely a flow restriction causing the top end to fall on its face.

Oh well, it makes decent power for what it is. I may mess with cam timing a bit, but you can only do so much with limited air flow.