Guys,
I need the help of the experienced tuners here...
What the car has :
- ARH long tube headers
-MSD Intake manifold
-Katech ported TB
- AFE Cold air intake
- VVT3 Camshaft / PRC dual springs/C5R timing chain/Phase lockout/Chromoly pushrods/Trunion upgrade kit etc
Dyno : Mustang dynamometer
Final numbers :
508 WHP at 6750 rpm
424 WFT/Lbs at 5200 rpm
So this is a Mustang dyno, we could fairly assume a dynojet would have read significantly higher (530-540WHP and at least 450-460 WLbs)
Power is not really the issue. Mid range is.
See the dyno results compared to FBO 455WHP/420 ZFt/Lbs on exactly the same dyno. Basically I loose a lot below 4600 rpm and only start to make more above 5200 rpm. Then the difference is big no question. But this is far from satisfying me.
Dyno comp2.jpg
This weakness down low concerns me. You can see the difference of torque already at 3300 rpm, but then the torque drops even lower at 3800 rpm !!
I see my cylinder airmass decreasing in this area FYI I'm at 0.72g at 3300 rpm and it drops at 0.69g at 3800 rpm (2700Ft elevation where the dyno is). This does not make sense as the with more rpm my airmass should increase (the MAF value increase) . Also no torque management intervention on the logs, no throttle blade closing...
I tried adding or removing timing... Adding timing does not change a lot past 25 deg. Removing 10 deg makes me lose a ton more.
I tried SOI 10 then 15 deg before no change. I tried 10 deg after no change. Always this damn weakness and this drop.
I'm lost. Dynos I see for this cam don't show that. I think all of the one I saw were on Dynojets, but even if they read higher, they don't show this drop and as much torque difference between min and max.
I really need your help, this afternoon cost me $490 in dyno rental and I did not make a lot of progress...
Here are my tune and log also
Tuning TSP timing SOI 15 3500 +2 timing.hpt
dyno pull 10.hpl
Thanks
Alex