Saturday, April 7, 2012

To the dyno!

It's all been fun and games until now, finally had a chance to see what it does at the dyno.

Two e36 M3's ran before me and set the bar at about 225 whp and 210 torque.  My best with the OBD1 ECU last year was 217whp, but the delivery wasn't smooth at all.  Lots of peaks and valleys.

227 SAE Hp, 226TQ  and a flat torque curve
Plot showing the increase going from my old OBD1 ECU to Megasquirt.
Here is the M54 with an S50b30 and S52b32. Same day, same dyno.  DISA really works!

I forgot to remove fuel cut at 6000.  whoops!  My power peaks at 6200 so I would have seen around 230whp. 
The mods on the motor at this point are ZHP cams, headers and a hot-air intake.  The exhaust is a "Y" into single 2.5".  Borla center muffler and Magnaflow rear muffler.  I pulled the rear muffler on the dyno last year and gained 3hp.  Does having a short intake tract overcome sucking hot air???

Hot air intake.  Air filter is attached where the MAF used to be. ABS pump is in the way of better routing.  Hot air is the secret for big power!  Not..
I needed to add a little timing near peak torque and pull timing above 5000.  This reflects those changes.

Auto-tune got me close, but I needed about 8% more fuel across the board at full load and then another 10% near peak torque at 3500.

Intake timing has a much stronger effect than exhaust timing.

  Megasquirt is weird on the exhaust side and you need to read it as 40 minus X to find the retard amount.  This shows 12 degrees of exhaust retard at 3000 at 100kPa.  Exhaust retard is very sensitive to your exhaust configuration, without headers use much less retard.
My exhaut, if anyone is curious. 

Thursday, April 5, 2012

EGO Correction

I haven't used EGO Correction until now because, theoretically, it's not needed.  If all of the tables are set correctly Megasquirt can run the motor in open-loop and always inject the perfect amount of fuel to achieve the AFR target.

I've gotten close, but now I'm getting lazy and enabling EGO Correction is easier than trying to get all of the tables and corrections perfect.  It works particularly well in cruise conditions and keeps the AFR on the lean side at low loads to help save gas.  I'm not using it at idle because I find it induces oscillations and it's better to just to tune the idle VE table.