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Air filter and AFR

Sonny

It’s all fun til the rabbit gets the gun.
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I’ve been tuning my new Holley carb using a 14” x 2” dropped air cleaner. Had it dialed in and then I put my Mopar oval air cleaner on it, hit the highway and man went lean quick. Way lean! From 13 afr to 16 and higher! Car was lean surging like crazy at 70 mph. Pulled over twice and then put the drop cleaner back on and was back to normal. I guess the oval cleaner is super restrictive?
 
A higher number would be less restrictive.
Likely the base more than the filter element.
 
Think square inches of filter and cubic inches of air. If its pumping in more air it can not be running rich.
 
View attachment 915293 View attachment 915296 I’ve been tuning my new Holley carb using a 14” x 2” dropped air cleaner. Had it dialed in and then I put my Mopar oval air cleaner on it, hit the highway and man went lean quick. Way lean! From 13 afr to 16 and higher! Car was lean surging like crazy at 70 mph. Pulled over twice and then put the drop cleaner back on and was back to normal. I guess the oval cleaner is super restrictive?
Sonny yes you are restricting airflow with that 2" drop base setup. The oval one flows more air and you saw the evidence! Common to re-tune a little when switching to a good flowing piece. I use a 14x3 k&n with their open-element lid, and the afr doesn't change but maybe a tenth with it on or off.
I actually have a parts-store 'Specter' brand element on there now, much cheaper and flows freely like the k&n did. Still using the k&n x-stream lid, but I had the element on the garage floor, with the car mostly out of the garage door. I'll be damned I hopped in to pull forward some and forgot it was over there, and drove right over it ...maybe that should go in KernDog's 'embarrassing moments' thread!
:rofl:
 
Think square inches of filter and cubic inches of air. If its pumping in more air it can not be running rich.
Got it. So a K&N on the oval is going to make it even leaner correct?
 
Got it. So a K&N on the oval is going to make it even leaner correct?
That would be the proper assumption. I think K&N has an air cleaner size calculator on their website to match the size air cleaner to engine requirements.
 
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