Correct the air bleeds do not work like jets, they flow air.....open them up equals leaner, go smaller to make richer
Yes, I totally agree. This is why I went with leaner bleeds at cruise, so I could get my Afr from 12:1 to 13.2-13.5:1 However, I may have to go with smaller bleeds on the secondary high speed side, to increase my full throttle richness
Just food for thought, is there not a member close to John with this kind of expertise that could help him out? Two sets of eyes better than one? Maybe he's missing something that a seasoned guy would pick up on?? Just some thoughts.
Could the headers be sucking in air? One pipe goes around the frame and is removable...I should also tighten my header collector gaskets to make sure there’s no leaks there either. But a leak there wouldn’t cause a lean condition...it would seem like it would push more pressure out under full throttle
So in light of probably not trusting the AFR gauge, I have 82 jets in it. Should I just jump to 84/94 with a blocked power valve in the rear? Trust science, not the results?
Just checked the rotor. A lot of condensation and buildup on all the contacts in the distributor. Cleaned everything off
As I said earlier, exhaust leaks can cause air to sucked in after the exhaust pulse passes by......thus is why header vac systems work. This unburbt air nit mixed with gas would cause a lean reading on the gauge.......
Yes I have exactly that, and the AFR gauge is mounted downstream of that connection to the header vac system
I'm with Bens99gtp, I think we may be on to something here. The more airflow through the carb (WOT), the more crankcase air is drawn into the header collector, thus increasing O2 at the sensor (false lean at high throttle opening!). Devon
Funnily enough, when I got my richest WOT mixture of 14.5:1, I had the two tubes to the header vac plugged, cause I thought they would impact the ratios. I guess I’ll go block the driver side one where the bung is and then let the passenger side flow freely, since it pushed out oil last time I left them both unplugged
Some quick searching seems to confirm this. General consensus is that the O2 sensor MUST be upstream of the evac/collector connection. This prevents false readings and sensor contamination from engine oil vapor coming out of the crankcase. Devon
Well damn, there’s almost no room to put it further up. For example, look at the picture of the header vac system you sent, no place to add a bung. Same on my headers
