[pgfpro]

After going over some data logs I'm thinking I need more back pressure at light load freeway? Right now I'm at 1psi intake with .5psi exhaust back pressure. It did increase exhaust pressure with my new turbo compound system but not enough IMO.

I want to try 1psi intake with around 3psi back pressure. My thoughts are to increase the blow-down efficiency. After talking with some of the guys on the F1 Technical forum I think I could increase combustion efficiency by running a little more back pressure. Being my engine is a port injection and not direct injection I don't have the luxury of controlling the injecting timing event. So when my intake valve opens and comes off its seat the fuel is already there and I will lose some of it during cam overlap. I can adjust the cam gears with my adjustable cam gears and decrease the overlap but it will have to be set back when I want to make decent power.

Right now my Over Lap is 8 degrees @ .0394" which is pretty tight being a turbo engine. After reading some technical papers it looks like you can achieve around 8% blow-down recovery with a little back pressure or a negative engine delta p?

So my new plans are to start figuring out where my boost exhaust valve cut out will go??? This will reduce exhaust noise by running through a small muffler and at the same time increase back pressure at light load only. At WOT the e-cut out will open and by pass the muffler. This should give me around 3psi to play with.