Quote:
Originally Posted by garyd1961
Why would you run an open spacer on a duel plane intake.
Make sure you have fresh 93 octane gas in it. You should have tons of low end torque with your setup. Probably something simple like a vacuum leak.
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Because it allows the individual cylinder to draw from both sides of the carb.
It evens out afr, and smooths out the carburetor signal.
Plus can reduce the needed size of a carb in many engines.
Provides extra plenum volume some combos really need with out a manifold change. A 1" spacer on a Super Victor manifold is not the same thing on a Performer dual plane manifold. Where the concept really shines by comparison.
Does it work on a dead stock low compression smogger 350. I have tried it, and got no where. This was a last tuning trick on a already well tuned engine.
This is a worse case scenario, but I have done it on a built 350 that I had for a sleeper build I was fascinated in. It had Dart iron eagle heads with about 190cc runners, and 64cc chambers. Followed up with 9.5-1 compression, and pretty wicked circle track mechanical flat tappet cam. I ported a cast iron intake to get as much advantage out of as possible. When I got it running I had the Q-jet on the manifold as normal, and it was pretty wicked. After hours of needle, and other changes.
Well a few weeks later I made a 1.5" spacer out of resin coated wood because of a article I read, and the truck was on the road fully as a back up vehicle. Plus I recovered financially, and emotionally from the project. So I had time to play again. Drivibility went up considerably, and felt power was across the board.
Its hard to say in words, but the cam/carb combo was not ideal. Just when driving the truck when the engine was up to temp it had a bunch of flat spots in part throttle. The spacer smoothed out idle, and removed all but one of the flat spots. That flat spot was at just under 2750rpm under full throttle. Plus I had to lean the carb out again due to more even air flow. So mpg would go up. It got crap mpg anyways so it would be hard to confirm, but memory says it went from 11mpg to 12 mpg. Under the more idealistic conditions, but not really noticeable bombing around town. That engine drank gas.
As for power before it could easily bark the tires hard in second. After it could continue the burn out into 2nd gear.
HotRod, and Carcraft have a bunch of articles on how they work. Plus they hopefully can explain it better then I could.