really? so why do you have to set the timing then?

 

The only timing that really has to be set is the base timing when the ECU control is bypassed [so that the computer knows where the timing is SUPPOSED to be, which it will still adjust], and the valve timing.

 

You think I'd get any performance out of the V-AFC? I wouldn't be tuning it myself, I'm not that good.

I was thinking maybe I could lean out the 7000+ A/F ratio for a little something, any truth to that?

The thought of dropping my VTEC point comes to mind, but I think I remember reading I'd need better airflow first. So maybe after the intake or header or something?

 

Exactly, so advancing the base timing will in effect advance all the timing maps.

I.E. Test 1
Set your base timing @ 0* TDC
Under acceleration lets say that the computers timing map advances timing 12* at 3000 RPM @ 40% throttle position for a total of (0* base + 12* computer advance=) 12*.

Test 2
Now advance your base timing 3*.
Again, under acceleration the computers timing map advances timing 12* at 3000 RPM @ 40% throttle position for a total of (3* advanced from base + 12* computer advance=) 15*.

 

Some dyno time will definitely yield a nice power increase. You're right to want to lean it out a little up top, since most NA Hondas run a bit rich in the upper RPM range. As for your VTEC engagement point, you'll need to play around with it on the dyno and see what setting gives you the smoothest power curve.

 

Sweet, thanks. My friend has one in his SI, maybe I can talk him out of it.

 

That's exactly what will happen on an OBD-1 car.

However.

The OBD-2 ECUs have a learning capability. It will eventually figure out that the timing has been advanced and make corrections in the signal sent to the ICM to make sure that the actual timing map is what gets carried out. The way to get around this is to cut power to the ECU every time the car is turned off. There are a couple of ways to work it out, but it's not really worth it just to advance the base timing maps a little bit.

 

Could one leave the service jumper connected? Would that disallow the computer's control of timing? I know on m mustang, the to set timing you pull the spout connecter which in essence removes all computer control of the timing, then put it back in after the timing is set. would this be the same thing as the service jumper?

just for my info....

 

If you left the service connector jumped, your car probably wouldn't drive all that well. Among other things, jumping the service connector keeps the radiator fan from coming on(which is good when you're trying to maintain a constant idle while setting ignition timing, or trying to set idle speed). I would wager that jumping the service connector probably disables some other things as well, like VTEC perhaps.