Been contemplating a 2v conversion but concerned that the throttle blades dump directly at center ports. This would make distribution worse than a blade opening for and aft.. Anyone experimented with a deflector to stop this ? Here is an example.
All Small Six Fuel distribution
- Thread starter comet6
- Start date
This relates to all small sixes
aussie7mains
Famous Member
Snake oil IMO.
Oem do it on dry throttle body to help homonegize egr dilution. Those gaskets pictured are presumably oem replacements. Cleveland use a similar tounge on exhaust port to prevent reversion. However without 6 wideband o2 sensors it would be totally speculative trying to design something. I'm just surprised no-one has attempted it, especially with discussion on intake shortcomings. I think the problem would be a non linear effect as flow increased.
PSIG
Well-known member
The OEMs used flow tabs in the carb to 'bend' flow towards lean areas, similar to sticking your finger tip into a stream of faucet water to alter flow direction. Apparently it works to some degree, as they all used it. I knew a Super Stock racer that used small sections of tubing bends (like the first photo but more extreme) to both direct flow and to keep fuel off the floor, and claimed it solved the majority of lean cylinder issues with the massive wet fueling. That was a Chevy I6 that did low 10s, and I still remember the radical cam making a steam locomotive beat at idle... chug, chug, chug. He said fuel distribution was his greatest single limiter.
Fuel distribution is a fact of life with long heads and single-point wet fueling, but whatever you can do to improve it is a good thing. Limiting over-carbing to maintain flow velocity is a first step. I've seen this done with progressive linkage and throttle limiters, so they only open enough for max power required flow and no more. Wet flow can be a tough hurdle.
Speaking of measuring cylinders, exhaust gas temperature (EGT) is inexpensive to use today, so if your application can benefit from cylinder balancing data, it's much more accessible. The specific readings are less important than comparative values for purposes of balancing.
Fuel distribution is a fact of life with long heads and single-point wet fueling, but whatever you can do to improve it is a good thing. Limiting over-carbing to maintain flow velocity is a first step. I've seen this done with progressive linkage and throttle limiters, so they only open enough for max power required flow and no more. Wet flow can be a tough hurdle.
Speaking of measuring cylinders, exhaust gas temperature (EGT) is inexpensive to use today, so if your application can benefit from cylinder balancing data, it's much more accessible. The specific readings are less important than comparative values for purposes of balancing.
a box plenum on the Comet 250 fed the three ports of the Offenhauser 3X1 adapter. The big 4412 (2300 series) Holley did make tuning simpler with idle to power with a more consistent response over time and different conditions. Multi-port setup built into the Log Manifold could enable equal intake runners for the seriously concerned.
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The Offy' linkage allows for the progressive 3X1 carbs to convert to synchronous with two simple linkage screw adjustments. Throttle response while carbs synchronous, was degraded but made for assured WOT launches. 'Was working on plenum toward a forced induction setup on the Comet 250 but it never reached fruition. The box plenum with big 500CFM Holley was much better at consistent idle and had as good or better throttle response as the three carb setup but wasn't any faster ...
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have fun
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The Offy' linkage allows for the progressive 3X1 carbs to convert to synchronous with two simple linkage screw adjustments. Throttle response while carbs synchronous, was degraded but made for assured WOT launches. 'Was working on plenum toward a forced induction setup on the Comet 250 but it never reached fruition. The box plenum with big 500CFM Holley was much better at consistent idle and had as good or better throttle response as the three carb setup but wasn't any faster ...
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have fun
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