My J2 dynoed at 132whp 131ftlb



Then I added a mildly p&p'ed Beta 2 head, shaved 40 thousandths. And installed 1.8 pistons.



Today It made 136whp and 135ftlb... Massive 3% gain... Was I wrong to be expecting more than 4whp?

 

Without tuning? Yes.

 

running my cams 6 degrees advanced in my beta 2 head which moved the powerband nicely in to play. Even at 3 degrees advanced the power was still rising when it ran out of revs

 

Oh boy...

I was expecting a lot more!? Hopefully your tune is really bad and when you do it right the gains will show up

 

The car ran 12.2-12.8 afr 4,000-6750 rpm. So it should be a better tune than the first dyno.

Ignition timing is between 25-28 at wot. Although I don't have a way to adjust that.



What makes this even worse is all dyno runs were done on a Dynojet in 3rd gear.

 

Did you enlarge the ports or just de-burr and clean up?

 

AFR is not the most important thing if you ask me. Ignition timing is the real deal ! When I hit the dyno later this month I will show you the difference

P.S how do you know that the ignition timing is 25-28 at WOT ?

 

@Rob40 mostly just cleaned them up.



@Blitz I monitor timing using the Torque app via the obd2 plug. Yes I realize timing makes a huge difference. Even with stock ignition timing I thought I would get more of a gain. I figured the ~12:1 compression alone would get me +3% Whp.

 

I've had almost 20% variation in the same car with same mods on different dynos in the GK. I've had around 10% variations from day to day on the same dyno. If everything else seems pretty good the dyno gods might not have smiled on you.

 

I cannot be the only one interested in seeing the before/after dyno graphs.