tune for hot weather?

[karl_2ltGC]

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???


Cheers Karl

[gmh265]

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?

[RotaryRocket]

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!

Cheers

[karl_2ltGC]

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...

[Lonx]

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.

[hornet]

I thought the vacuume advance was to change the timing when under heavy load..