Quote:
Originally Posted by Stan Weiss
Isn't that Air Fuel Ratio kind of lean?
Stan
|
I didn't have A/F ratio on my charts, but his bsfc numbers are in the exact neighborhood the tech guys at Reher-Morrison Racing targeted for best power when we dynoed mine. The air valve on my Q-Jet was not opening smoothly and the engine was running anywhere from .545 to .565 during the initial pulls. We were getting almost 400 lb ft of torque at 4000 RPM but only 330-340 HP around 5200 RPM.
With some tweaking on the carb, we got the bsfc down to .513 and the torque went to 442 lb ft at 4400 RPM and 388 HP at 5200 RPM. Then they determined they weren't getting a clean signal off the MSD distributer causing almost a 500 RPM delay in readings. Their manual calculations with the same torque number yielded 453 HP at 5600 RPM. You can see the extreme lag in the numbers in the video:
https://www.youtube.com/watch?v=cfso2r9udv8
We were running the engine out to an indicated 6000 RPM and it always seemed to be pulling harder at the very end of the run, so we did the last pull out to an indicated 6250 and that's really when the bsfc numbers started coming down.
Not sure what the RPM limit is on the Johnson Hyd rollers Butler supplied for the build, but I didn't want to push it any further without accurate tach readings. I'm thinking it should be good to 6500 though.
350 Block bored 60 over with Eagle cast 4.25" crank
Eagle forged H beam rods and Ross forged pistons
6X-4 heads, all valve spring seats machined to correct height
Torker-I intake, port matched
800 CFM Quadrajet from 1971 Buick GS455 Stage-I, modified to Stage-II
Comp 1.5 roller rockers, Comp springs
Comp XR276HR cam (this one has 110 degree LSA)
Johnson Hydraulic Roller Lifters
Threaded Mode