200whp with stock N/A rotating assy?

[LJ851]

Not many m20 enthusiasts are willing to pay $1 plus for proper headers. I have been sitting on my "180 degree" headers for 2yrs plus due to price.

On an inline 6 i can't see a way to get 180 degree headers?


Thanks for this build, really looking forward to seeing what gets accomplished.

[trujillo937]

sub'd interesting to see the fight for the m20
currently working on an m20b27i low funds kill the fun...

[ForcedFirebird]

This was your OEM performance tune, very surprised the AFR's were so behavioral. Client put 19's in and been driving it, and was surprised it had adapted that much - still the common BMW lean conditions.

Idles and drives like junk though, just like everyone else who puts bigger injectors on without a matching chip. Didn't want to waste time dyno tuning this motor, already showed low power.

Best to date on an all stock motor was 157whp header and exhaust only car. It has the Racing Dynamics headers, true merge collector in reverse to a Vibrant 2.5" resonator, back to true merge into a Billy Boat rear section, OEM induction, cam, rebuilt head, dyno tuned.

Everyone loves pic, right?

[squidmaster]

My tunes actually have changed values for fueling and ignition all the way to 7k RPM, instead of stopping at 6200 like stock.

In terms of that tune, I think john said it was for the 19lbhr injectors? I've added a little more fueling to it in the past few months so that should bring the AFR down a bit more. I am for high 12's and low-mid 13's throughout when tuning, so this does look a bit lean.
All-in-all, not bad for such an old and beaten engine! I'm surprised it did dyno that high to begin with. I was expecting lower 140's.

[ForcedFirebird]

power and torque curves have all the right shapes and like many seem to be running a little leaner than ideal at the topend

That happens because the ECU stops reading higher RPM's before the rev limiter and the last block in the maps are carried through for fuel/spark. That can be changed, but since this was a Spec e30, it had an unopened ECU.

[digger]

power and torque curves have all the right shapes and like many seem to be running a little leaner than ideal at the topend

[ForcedFirebird]

Dyno day. Run 1, pulled on dyno as it sat. Run 2 cut the P/S belt. Run 5 is Sssquid's file. Pretty sure this engine has never been opened, if it did, it was eons ago as the head is pretty filthy inside.

[Wanganstyle]

I'd do some stahl or bav auto style. I seem to remember jlevie saying he gets somewhere around 160ish on his and that's stock tune.

Norcal Spec e30 dyno (MCE tuning)

m20b25 1987
Stock 200K + bottom end with over 80 hours of lemons racing
fresh built stock head with all stock ports, stock cam and rocker arms

some chip I think turner

154rwhp on pump 91 right after a 14 hour race.


to gain 46rwhp without removing the block from the car....... that would be pretty impressive.

[ForcedFirebird]

Not many m20 enthusiasts are willing to pay $1 plus for proper headers. I have been sitting on my "180 degree" headers for 2yrs plus due to price.

[ForcedFirebird]

I'd do some stahl or bav auto style. I seem to remember jlevie saying he gets somewhere around 160ish on his and that's stock tune.

Still made in China and have lots of copies. These headers are similar to what you are talking about. 24-30" primaries.

[tinkerputzer]

I'd do some stahl or bav auto style. I seem to remember jlevie saying he gets somewhere around 160ish on his and that's stock tune.

[ForcedFirebird]

Any ideas on what a stock rebuilt m20b25 with only headers and a tune (with afm) can do?

Tune can be significant pending what's wrong/right with your hardware. 100% healthy m20 is going to be 150-ish whp. Through dyno testing typical ebay headers are lucky to see 5wtq, no peak HP change with single 2.5"

[tinkerputzer]

Any ideas on what a stock rebuilt m20b25 with only headers and a tune (with afm) can do?

[digger]

Sounds like fun! Keep me posted

Iirc his specs were bh 274 cam, 10.5:1, pnp, new stuff. I could be wrong. I know he has a build thread somewhere here

found mentioned its a 2.8L bimmerheads head and cam combo.....thought it was a 2.5L. nice well specced engine by looks of it

[ForcedFirebird]

Sounds like fun! Keep me posted

Iirc his specs were bh 274 cam, 10.5:1, pnp, new stuff. I could be wrong. I know he has a build thread somewhere here

YES! Will keep you posted. We are in this thing together. Without all this development behind the scenes, and helping each other out, this community would be dead. Let's keep the m20 alive! 24v swaps For The Loss.