So here what’s up….. I’ve already done my dyno tuning on a dynojet and I’ve got the a/f ratio adjusted with my fpr(50psi at idle) and vafc (its at about 13.5/1) …. The fuel curve is almost completely flat and I can’t complain with the power at WOT..

The problem is that the guy that tuned my car said that on a dynojet, you can’t really tune at part throttle (is this true) so for low throttle position and below 4500 rpm +10% was just added to the whole fuel curve…..it runs good but I’m burning at ton of fuel (went from 29 to 22 mpg). That much loss in fuel economy adds up when you drive it daily..

So my question is, how do you tune for low or part throttle and what the best a/f ratio below 4500 rpm……

 

OBD-1 or OBD-2?

 

get on a dynopack, or mustang dyno

loading dynos

 

just tune it so it drives good... normally i leave the narrow throttle correction at 0 on vafc's

 

Not sure what engine management you are running but if you're na, make sure the closed loop feature is enabled to help your gas mileage during cruise and part throttle.

Also, the newest dynojets have the inertia roller option that will allow tuners to tune partial throttle as well. If you can't find one around your area, dynapacks are probably the next best thing...

There is also road tuning as well if you know anyone with a portable wideband setup w/datalogging capabilities...

 

Forgot to ask what size injectors you're using.

 

Wow quick responses, thanks guys...

(IN VTEC)... I've got OBD-1, stock 240cc injectors, B17/CTR .25 over pistons, I/H/E, had to retard the timing to 12degrees.....

(n1div)...... I've got the Low throttle at 20% and Wide Throttle at 70%..... should I go higher or lower on that?