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Carb settings with pod airfilters and cut exhaust....

Started by Goodhew11, June 06, 2016, 03:34:54 AM

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FJ_Hooligan

Quote from: fj1289 on June 13, 2016, 03:00:30 PM
But, back to the original topic, just because CV carbs were "designed" to work with an airbox does not automatically mean they can't/won't work well without the airbox if appropriate supporting modifications are made.  I'm sure any set of carbs can be made to perform poorly under any set of situations -- that doesn't mean that it becomes a universal truth that this or that carb with or without that is bad.  Usually the opposite -- put them in the hands of someone that knows and understands them from a point of experience vice theory and they can make them sing most any tune you want...

Excellent points here.  If I may add some clarity;  The FJ CV carbs were "tuned" to work with an airbox.  They can be "re-tuned" to work just as well with a set of pod filters.  Everyone keeps talking about changing jets when the most important effect of pod filters is leaning out the needle circuit.  When removing the restriction of a stock filter and airbox, the needle needs to be shimmed up to compensate for the reduced intake air velocity that causes the needle to seek a lower (leaner) position.  Other than this, nothing else is gained or lost with pod filters.  Pods "can" flow more air, but you only see that at WOT.  At all other throttle positions, the throttle plate is controlling airflow.
DavidR.

ribbert

Quote from: FJ_Hooligan on June 13, 2016, 04:58:29 PM
Quote from: fj1289 on June 13, 2016, 03:00:30 PM
But, back to the original topic, just because CV carbs were "designed" to work with an airbox does not automatically mean they can't/won't work well without the airbox if appropriate supporting modifications are made.  I'm sure any set of carbs can be made to perform poorly under any set of situations -- that doesn't mean that it becomes a universal truth that this or that carb with or without that is bad.  Usually the opposite -- put them in the hands of someone that knows and understands them from a point of experience vice theory and they can make them sing most any tune you want...

Excellent points here.  If I may add some clarity;  The FJ CV carbs were "tuned" to work with an airbox.  They can be "re-tuned" to work just as well with a set of pod filters.  Everyone keeps talking about changing jets when the most important effect of pod filters is leaning out the needle circuit.  When removing the restriction of a stock filter and airbox, the needle needs to be shimmed up to compensate for the reduced intake air velocity that causes the needle to seek a lower (leaner) position.  Other than this, nothing else is gained or lost with pod filters.  Pods "can" flow more air, but you only see that at WOT.  At all other throttle positions, the throttle plate is controlling airflow.

Yes and yes.

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

Pat Conlon

Quote from: ribbert on June 13, 2016, 07:03:58 PM
Yes and yes.
Noel

Noel is correct.

That's why I saved this explanation in the Carb Files: http://www.fjowners.com/index.php?topic=4714.0
Lots of good stuff in the Files, now, if only folks would read them.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3