Team Camaro Tech - View Single Post - Timing & Vacuum Advance 101
View Single Post
post #28 of (permalink) Old May 22nd, 11, 01:59 PM
Steptoe
Senior Tech
Steps
 
Join Date: Dec 2005
Location: New Zealand
Posts: 13,316
Re: Timing & Vacuum Advance 101

Quote:
Air Fuel ratios at idle = 13.8:1 AF, 14.8:1 at cruise and 13.8:1 WOT....all on regular gas.... lovin it!
For petrol you are looking at around 14.6 /14.7
The idle can be leaned out a little... within reason, lean mixtures require more advance. At least 115.1 to about 15.3....big economy savings to be made while sitting at interections.
Cruise again can be leaned out further...that is the basic concept of the VA add a few degs of advance for the leaner cruise mixture....u are only looking at 10 to 15 hp requirement to cruise...so around 15.1 to 15.3

Under power WOT dont even risk leaning..hi temps /kill engines
And more power is made with a far more richer mixture...getting down into the 11.5 to 12.5 AFR range....the richer the mixture...withing reason gives more power.

If messing around with data loggers /AFRs get the timing in ball park, re jet/powervalves etc the carb.....fine tune the timing curves and VA....MAY have to re set the catb again.. but generally once at this stage mixtures are pretty spot on... or close enough for a good street machine....influences like ambiant temps altitude will have more influnence from this point.

My Spelling is not incorrect...it is creative

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Steptoe is offline  
 
 
For the best viewing experience please update your browser to Google Chrome