Hi guys. Interesting thread.
Lynn, (and Jim C) you're right about the MAP. I have a vacuum pipe running from each of the 4 twin throat throttle bodies to a plenum chamber in the valley. The IAC is also connected to this plenum, and closed loop idle works great (butterflies are fully closed). Vacuum hoses from this plenum also connect to the fuel pressure regulators for their reference (nominal 44 psi).
I ran in TPS mode before, and MAP provides much more consistent and cleaner running. I can't say I notice any improvement in throttle response at the higher rev ranges, but the slow 'putz around town' and idle performance is noticeably better.
A question: how much improvement (percentage) would there be from going to a MAF system? Would it be worth a)the trouble sealing the rear deck and b) how good would it look with whatever boxes/plexiglass sealing would require?
Sandy, there was a thread some time back that got into power (especially high RPM power for track purposes) with Ron Earp. Seems the concensus then was that there would definitely be a big HP gain, and no RPM limitations (obviously within engine specs) with a single plane manifold and a good carb. The limitation of an individual runner/8 stack set-up, as I understand it, is the single stack/throat. That's all there is, vs. the plenum and 4 barrels (or 8?) of a carb. At any one instant, a cylinder has access to the entire plenum. So, 8 stacks look great, are great for mid range, but start to run out of steam at higher RPM. I believe somebody said you could get up to the 7's with 8 stacks, whereas you can push 8-9000 rpm with a good carb set up...but I'm getting out of my league here. Somebody help me out
