greenking

Hi all,
I was wondering if anyone can explain how you know if you are running rich or lean??
I have been told that it is best to run slightly lean, but how slight??
What damage will it do to your engine if you are running too lean or too rich??
This is because of the mods I have on the car and the waiting list of 2 months for a 4 wheel rolling road session.
Regards
G.

teknopete

G,

Check 4 soot in the exhaust, will have if running rich. If you cant get on a RR set the car up by gas values. The figures below are as quoted by a well known scoob rally team.

Max economy @ light load (on a scoob ) no boost AFR 14.7:1

Best emissions AFR 14.7:1

Max power @ high boost whilst protecting the engine 12.5:1

WARNING: Leaning the mix increases temperatures, therefore check with professional wideband oxygen sensors. Theres not much margin between power gains
and an engine rebuild.

Ive been using their guide figures for the past 18 months without probs.

Pete

Pete Croney

Greenking

You are running rich. Your exhaust will be sooty.

This is not a fault, its a design feature of turbo engines, to protect against predetonation.



[This message has been edited by Pete Croney (edited 17 February 2001).]

David Lock

Yes but also note that generally an exhaust on an engine with a 'cat will be blacker than on a non-cat car because there are no white lead oxides emitted which turn the black into a greyish deposit. DL