M20 dyno results

[digger]

What's up with the massive power drop off tho?

Also weird to see HP and Tq cross at almost 6k

Probably the rev limiter or lifting off the throttle.....the units and the scale need to be the same/consistent otherwise they don't cross at 5252 rpm

[digger]

that makes sense. would be interesting to see what ign. timing and type of fuel he runs

ok so got some info from him

98 RON fuel which is 93/94 PON 22-24 degrees timing WOT
234 whp was best run with with mild port job BMW 885 head casting, down to 205 whp with mild ported AMC (AMC needs massive amount of porting to equal even a stock BMW 885 casting) and now back to BMW 885 mild port and same basic power as original

this is consistent with your results.

[nando]

Here is stock 3L n52 dyno from 2011 128i.

I think for the good old M20 to be there ain't bad at all, considering e30 is 500lbs lighter. This M20 has 7 less hp that peaks 400rpm earlier than N52 but has 12lbs more torque that peaks 700 rpm later than N52. Not a screamer like N52 but definably pulls like a donkey everywhere.

not gonna argue about whether it's still worth running an M20, because of course it is (I still have my original build from 2007 - I still love it). But... that's the detuned/neutered version of the N52. here's my stock N52B30 - in a 330i, back in 2014, the M20 can't even come close



Anyway, I agree with digger, the head probably isn't ideal, and maybe cam timing could be adjusted. However, when I first looked at your graph, I thought it looked pretty good for the M20. it's better than mine from 2007 at least! I don't think I ever got over 180whp, on the other hand, I haven't touched it in 14 years and it still starts up every time, so that's a plus side for the M20. FWIW I have the same cam as you too.

edit: oh, it's worse. My best on my M20 was ~165whp - granted, that's in a 325ix, so I lose extra to drivetrain losses. but man, I'm not really seeing what the complaint is with 196whp in an M20. I used to collect dyno charts of every M20 I could find, even 150whp was remarkable (stockish)

[zaq123]

not gonna argue about whether it's still worth running an M20, because of course it is (I still have my original build from 2007 - I still love it). But... that's the detuned/neutered version of the N52. here's my stock N52B30 - in a 330i, back in 2014, the M20 can't even come close



Anyway, I agree with digger, the head probably isn't ideal, and maybe cam timing could be adjusted. However, when I first looked at your graph, I thought it looked pretty good for the M20. it's better than mine from 2007 at least! I don't think I ever got over 180whp, on the other hand, I haven't touched it in 14 years and it still starts up every time, so that's a plus side for the M20. FWIW I have the same cam as you too.

edit: oh, it's worse. My best on my M20 was ~165whp - granted, that's in a 325ix, so I lose extra to drivetrain losses. but man, I'm not really seeing what the complaint is with 196whp in an M20. I used to collect dyno charts of every M20 I could find, even 150whp was remarkable (stockish)

Oh no, there are zero complaints, this M20 is awesome minus this annoying valve cover oil sweating. I knew/was warned by digger that unmodified AMC head is gonna be a limiting factor going in but really just got tired of this long ass project when discovered 885 was cracked. Needed to get the car up and running to just appreciate what I did with it over the years and its very fun car to drive with the current setup/power. I do have new (used) 885 head sitting and ready for some work. Possibly gonna be this winter project.
At least we all know now what are limits of stock AMC head now is. If one is building/has M20 with anything under 180-190whp, bone stock AMC should do the trick I guess.