MK5 Golf GTI

All Things Mk5 => Modifications & Technical Area => Technical Workshop => Topic started by: E30Dom on August 12, 2012, 09:28:34 pm

Title: Air Fuel Ratios
Post by: E30Dom on August 12, 2012, 09:28:34 pm

OK, can someone explain these to me?

I've done a little research, and always been told that ideal is just over 12... My AFR graph shows my AFR running just above 12 gradually dropping below 12 into the 11's...

Is this getting richer as it's going through the rev range? Or leaner?

This might explaine the soot deposits I've been getting...

Cheers you knowledgeable lot!  :signLOL:

Dom

Title: Re: Air Fuel Ratios
Post by: Hedge on August 12, 2012, 09:39:17 pm

Richer.

Title: Re: Air Fuel Ratios
Post by: GrayMK5GTI on August 12, 2012, 09:40:40 pm

Richer in the higher revs is good  :happy2:

Component protection and reduced EGT's  :smiley:

Title: Re: Air Fuel Ratios
Post by: E30Dom on August 12, 2012, 10:49:35 pm

If I was to drop from F7 to F8 and this made it run a steadier line just over 12, would this not be better?

Title: Re: Air Fuel Ratios
Post by: PDT on August 13, 2012, 12:51:01 pm

AFR's are not as simple as you might think, theres lots more at play than just rich/lean.

The higher a number the leaner the AFR mixture (air : fuel ratio)

For most direct injection engines an AFR of 12 is 'normal' and is beneficial to dip into the 11's under higher RPM to keep things safer. For older turbo engines 10.5-0.8 is normal, for N/A engines 12.5-12.8 is normal.

Title: Re: Air Fuel Ratios
Post by: E30Dom on August 13, 2012, 02:09:03 pm

Thanks Dave... And how much difference does a revo F setting usually make?

Dom