Cold start AFR..

[Guest |229|]

Hi all.

What AFR should i aim for when engine is cold? (about 0 degrees.)

[Guest Dave-Kriedeman]

0 degrees Celcius, damn thats cold.

I normally aim for approx. 12.5 : 1 and add a few degrees timing, until up to running temp.

I find this ratio a good general setting.

However on some engines i have done with very large camshafts i find 12 : 1 is a better target.

I normally aim to be at approx 13.5 : 1 by 60 degrees C.

These values are only what i have found work for me in my climate, coldest temp in winter approx 12 - 14 degrees.

Best to experiment and find what A/F that the engine you are tuning is most happy at.

Note:

I always use CDI Ignition systems with every install i do, so these values are what work for me on my installs.

Prolonged post start enrichment values can cause sparkplug fouling when used with weak ignition setups.

[rayhall]

On first start at 0 degrees the AFR would be in the high 10's and then in the low 11's a few seconds later.

Ray.

[Guest |229|]

Thanks for replys.

Rayhall:

If thats the case, then my AFR are spot on. Thanks for clearing it up. Now its only the fine tuning i need then for my cold start.

Dave:

0 degrees isnt bad... It can get much colder here. ;-) We had minus 19 the other day... But we should be moving towards summer now.

It starts fine, but feels a little as its a bit too rich when touching the throttle. When warm no probs. I will try and move the AFR around a little and see if it gets better.

[Guest Dave-Kriedeman]

Minus 19,

I wouldnt even get out of bed, infact i think my body would go into shock and shut down.

[Guest |229|]

hahaha.. It only in the night i gets that cold. ;-) In the day its minus 3 -5 now...

But my car is in garage so the car only has about 0 degrees cold. :-p

Should the AFR be much lower (read previous post) if temp gets much under 0 degrees?

[Guest Marcel B]

LOL , in the tropics COLD is 23 degrees C

[Guest |229|]

I am movind to spain next week, so finally a little more hot. ;-) hehe