View Full Version : tune for hot weather?
13-01-03, 04:28 PM
Hey all, well melbourne is getting hot, and my cars gettin slower!
Is there a tune for hot weather...
Richer, leaner, more advance????
I thought more advance but then though pinging would be a problem...but then why do dizzys have vacuum advance that comes on when cars overheating???
when the air is hotter it is less dense so a leaner mixture to keep air/fuel ratios in check.. never seen a car that has vacuum advance come on with overheating.. what do you mean by that?
13-01-03, 07:55 PM
Retarded timing can lead to engine overheating or running hot. Not exactly sure why but I know for sure that it does.
It drastically heats up the exhaust gasses as well.
Me an a mate were fiddling with the timing on my 12AT one night and after retarding it as far as adjustment allowed (to see what would happen) gave it a thrash down the road and back (two full throttle runs 0-100) then popped the hood and the whole exhaust housing was glowing bright orange. I have driven it hard before an then looked at the exhaust hosing and there was a slight dull red glow but nothing like above.
Whoops close my mouth before more crap falls out!
14-01-03, 04:02 PM
gmh265 - Most 80's carby cars have some sort of Vacuum vlave that will open when overheating is detected and send vacuum to vacuum advance of dizzy...
RotaryRocket.... retarding the timing causes the air/fuel mixture to be ignited later, and if it is retarded too much it is ignited during the 'power' stroke, so basically it becomes half a power stroke & the unburnt fuel/air escapes and finishes burning inside the headers/exhaust. Hence the increased heat.
I thought the vacuume advance was to change the timing when under heavy load..
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