propane ?

extremetownie · Dec 3, 2009

im trying to find the correct answer to a propane question. when adjusting the mixer, i have been told the idle adjustment does everything except wot. the big adjuster does only wot. is this correct? i just installed a air ratio meter to try to dial it in. as it sets it is showing rich. all through my rpm range, even at wot. just want to do it right the first time.
thanks

HotRodpayton · Dec 3, 2009

Call the guy at Precision Sales and Services. I think I gave you his #. I think it is Birmingham AL if you google it. :dblthumb:

draggbody · Dec 4, 2009

the little screw is for no throttle at all, simply put, an idle mixture.... the big screw is for everything else, so basically if you are touching the pedal, the big screw adjusts that...

extremetownie · Dec 4, 2009

draggbody said:
the little screw is for no throttle at all, simply put, an idle mixture.... the big screw is for everything else, so basically if you are touching the pedal, the big screw adjusts that...

that makes more sense, but it is just the opposite of what have been told. thanks jimmy. i got another question. i have read that a impco 425 will only flow 450 cfm. i know my truck should flow way more than that, and a 454 should flow even more. how are you getting by with one mixer? the reason for all these questions is my truck is great off idle and lower rpms, but in a load i cant even get up to 6000 rpms. i prefer to wheel at more 6000 rpms.

J.A.B · Dec 4, 2009

extremetownie said:
that makes more sense, but it is just the opposite of what have been told. thanks jimmy. i got another question. i have read that a impco 425 will only flow 450 cfm. i know my truck should flow way more than that, and a 454 should flow even more. how are you getting by with one mixer? the reason for all these questions is my truck is great off idle and lower rpms, but in a load i cant even get up to 6000 rpms. i prefer to wheel at more 6000 rpms.

EFI

zukiscott · Dec 4, 2009

PROPANE RULES.........PERIOD

draggbody · Dec 4, 2009

roger there is a formula for calculating cfm on an engine... basically your engine can only displace so much air... i think these numbers are conservative, as i was turning 5500rpm's this weekend on primos... the math says it just wont do it, but it did... are you sure its not freezing somewheres... at the SETTC i ran both tanks open at the same time because my valve on the tank will freeze after long durations of throttle, with both valves open it was never a problem.... here is the formula... the CFM on a 425 is 460cfm's...

CFM=CIDxRPM/1728/2x.85

this is mine
614=454x5500/1728/2x.85
so obviously this should not be enough, but it is... and remember, cfm has nothing to do w/ fuel or air/fuel mixture...