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How much will going from 90 degree summer to 50 degree fall affect A/F?

Started by XH29N0G, September 15, 2014, 06:15:58 AM

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XH29N0G

Continuing with the quest to set the accelerator pump up right yesterday (our first day in the 50's - all others were done in 90 degree summer weather), I found that even after warming up the car, I had a lean spot with the A/F right when I depress the accelerator.  What had been a small quarter second spike from idle to about A/F = 15 before the pump shot appears, was A/F = 17 or so.  All else looks similar. 

My suspicion is that the manifold might be just that much hotter when it is 90 to vaporize/atomize the gas better.  Does this make sense or is it something else?
Who in their right mind would say

"The science should not stand in the way of this."? 

Science is just observation and hypothesis.  Policy stands in the way.........

Or maybe it protects us. 

I suppose it depends on the specific case.....

Challenger340

Took mine for a drive the other day on a 45-50* cold morning... similar accelerator pump "bog" that was pretty pronounced in the cold air, even after well warmed up.
Seems I just don't have enough "squirt" to cover the colder denser air ?
Although,
Mine works great at anywhere between 75-95* so I am thinking the Colder Air makes a BIG difference !
Factory Carter VS #4618S, original carb.

I am not going to try and tune the cold air bog out out of mine... simply because it works so well(no Bog) in warmer air when I do 99% of my driving.
Only wimps wear Bowties !

firefighter3931

The colder air does make a big difference.  :yesnod:

Try jetting up 2 sizes and have a look at the AFR's  ;)


Ron
68 Charger R/T "Black Pig" Street/Strip bruiser, 70 Charger R/T 440-6bbl Cruiser. Firecore ignition  authorized dealer ; contact me with your needs

XH29N0G

Ron and Challenger340,

I'll need to do a few more tests, but I think WOT A/F is also high and this would make a difference and I'll do the switch.  Thanks I continue to learn about the car.  
Who in their right mind would say

"The science should not stand in the way of this."? 

Science is just observation and hypothesis.  Policy stands in the way.........

Or maybe it protects us. 

I suppose it depends on the specific case.....