Don,
You mention that you have over 240 @ .050 lift. I would not consider this high duration and sounds in line with what I have. When I say "high duration", I'm refering to high 250+ @ .050. with tigh lobe seperations in the 104-108 range at these durations. Again, this is all relative info.
Allan G.
I have run 252 @ .050" on a 108 lobe seperation angle, and I was very happy with it. It all depends on how the cam is matched to every other specification of the engine. Every specification. Not just intake manifold volumes.
With that particular engine, I ran 9.10s on 22 psi boost. Destroked, same small heads.
edit: Exhaust was 260 @ .050".
My statements don't need correcting....
Allan G.
You're right. You didn't say it was impossible. You said, 'With a turbo cam, you simply can't have this', referring to overlap.
If you don't need correcting, just how do you explain my experience?
BTW, using the same method for measuring exhaust back pressure, I measured 1.5-1.6:1 when I was running the T76 turbo. Same cam, and the engine was still a monster.
Bison. My BSFC is not out of line for the hp I calculate I'm making. It all has to do with the total combination.
Pulse tunning has its place. I think that ultimate goal and efforts with pulse tunning would be faster spool-up with large turbine turbo's such as your BW 91. The ultimate goal with this pulse tunning is not going to be cylinder scavanging IMO.
Like I already stated, you need to talk to Steve Kinsler of Kinsler Fuel Injection. He even tested a Helmholtz resonator on that Buick V6 I was referring to.
FWIW, the sim I used was Performance Trends EAP.
For me to make the real world results match the sim, I had to pump up the head flow numbers to just about Stage II numbers. You still think pulse tuning doesn't happen on a turbo engine?
My valve sizes are 1.835 int, 1.5 exh.
What are your valve sizes?
This video shows the street characteristics of the cam I am presently using. Very streetable.
DRW / Buick V6 Alky v3.2 20L video test - YouTube
Realize that in the above video I was running a 2400 rpm stall torque converter. It worked perfectly with the T76, but when I switched to the 91mm, which was on the car in this video, the new combination needed more stall speed. I switched to a 3000-3200 rpm stall torque converter, and with the ALS I developed, it's worked out great. The ALS is capable of pushing the stall of the new 3000 stall TC to over 6200 rpm, if I allowed it.