Supercharged Air Fuel Ratios

[Cobber]

I am running a Harrop TVS 1900 on a std un opened 1uz through a ported Richwood manifold with an Adaptronic ecu. I am running around 11psi boost. Below are the air fuel ratios I am running on Premium 98 fuel.

These were some generic AF ratios I put in to get me going but now I want to fine tune the beast.

Question is do I need to play with them a bit or is this close to the money.

 

[cribbj]

I think you could go leaner at low load if you wanted to be more fuel efficient. With my 2JZ setup, my cruising (high vacuum conditions) AFR's are in the 15-17 range, and under deceleration conditions (engine braking) they go even higher because the AEM can actually cut power to the injectors under decel conditions.

I think your AFR's at high load are good, but some might argue that you could nudge them up a bit, as with our supercharged setups some believe we don't require as much piston & valve cooling as turbo motors with their high exhaust backpressures.

Having said that, if you do decide to lean it out, you'll have to watch your ignition map very closely and keep your octane up to stay out of det territory.

FWIW, with my setup, Mitch aimed at keeping the high load AFR's at 12.

 

[Cobber]

Thanks John, I did set up a lean cruise 16.5:1 when it was NA and it did seem to work quite well (I used less fuel with no noticeable power difference). I also cut fuel on decel.

Not worried about saving fuel though in this instance I just want to make sure I have a good AF ratio at the business end.