Re: HypoJets and O-tubes on the way
Posted: Sun Sep 02, 2012 6:08 pm
simonknee wrote:If you tune for anything greater than 12.5 on webers then you will get lots of unwanted lean crap.
Thought you might like it if I explain myself here. 12.5 is the (power) ideal and it is the value I am aiming to acheive with all the tweaking. However in the above quote I am talking about the idle mixture. As I mentioned before this is the only thing you have absolute(ish) control over.
Having the AFR meter means I can see what the difference is between different idle mixture settings. At static idle (i.e. stationary) I can adjust the screws evenly to move the idle mixture (normally doing this somewhere in the region of 900rpm). For me there is no discernible difference in idling whether I end up at 12 afr or 14 afr. The difference happens when you drive the car. This idle mix setting has a big influence on the mix under all sorts of part and closed throttle driving. When the idle is 13 and above you get many driving situations where it heads lean up to 16 and beyond! Get the idle to 12.5 and it generally stays under 14-15 whilst driving.
This best idlejets I found for my engine were 45f9, Keith's H223 hypojets have improved control of afr further. However with any idlejet I can confirm (for my SE anyway) that Keith's recommendation to tune the idle to 12.5 is correct. So every time I fiddled with the idlejets or hypojets I try and adjust for 12.5 (it bounces around this value of course).
Simon