As you know our new AMS CNC head is working awesome. We have a few cars we built here that just putting down in the mid 500's on pump gas at 23-24psi on a safe tune, up considerably from our previous setups.
Now we had a chance to finally run the head on our drag car and got great results!
Previously our drag evo had a Cosworth head which has powered us to an 8.42 pass and a best MPH of 171 mph.
We put the car on the dyno and got baseline #'s at different boost levels with the Cosworth head. Next step was to put our CNC head on and again run the car at the same boost levels.
With the AEM in speed density mode anytime you make a change to the engine that improves or hurts the power it will change the fueling requirements. For example, a better flowing head will require more fueling so it won't run lean. In anticipation of the improved VE (volumetric Efficiency) I added a considerable amount of fuel in the high RPM range of the fuel map, and good thing I did! The first pull and I saw right away it needed the extra fuel, it still ran almost half a point leaner than it should have!
I dialed in the fuel a little closer and did another pull.
Here are the results at 46psi! The initial spike was 1psi higher and then dropped 1psi lower (i was still working on the boost feedback control) that's why the CNC head graph jumps up a bit and then dips back down. The gains where substantial everywhere. At 9000 RPM the AMS CNC head is making 140 whp more than the Cosworth CNC head!
All the work playing with valve jobs, porting, flow benches, and dyno testing has paid off.
Next boost level was 56psi dropping to 53psi. I really had to adjust the wastegate duty cycles to maintain the boost levels on our CNC head. The more air an engine can flow, the harder the turbo has to work to reach the same boost level. While we can run 35psi with a GT35 on a 4G63, put that same turbo on a big v8 and it would struggle to make 20psi. So here is the comparison of our CNC head and the Cosworth CNC head with the turbo being about maxed out (76mm compressor wheel).
Although not quite as big a difference as it was on the lower boost levels it's still making 60whp more at redline.
For everyone reference here are RPM points to the MPH points.
90mph = 7000 RPM
100mph = 7800 RPM
110mph = 8400 RPM
120mph = 9100 RPM
124mph = 9400 RPM
I'm really happy with the results and it once again prove what a great engine Mitsubishi gave us to work with.
-Martin Musial
presidentAMS Performance
