Hondata

Just a quick (possibly stupid) question...when I'm launching my car, my A/F ratios get to about 29-30 while it's bouncing off the limiter (mine is sitting at 3500 due to all season tires). I don't forsee any way to correct this. Any chance this is harming the engine?

I'm only launching it a couple times a month, but next spring I'll be tearing up the track multiple times every weekend. Just want to make sure I'm not harming my little four banger...

Also, I did have my VTEC set to about 4200RPMs for awhile (4750 now), and during that time it would go on/off VTEC while launching...how hard is that on the engine/solenoid?

Edit: Move to US forum if possible, didn't realize what section I was in...

The a/f ratios read as such because the launch limiter is a fuel cut, you're rapidly bouncing in and out of fuel cut. Your engine will be fine as long as you don't make a habit of riding a really high limiter with no load on the engine (really high being 6k+).

As for your VTEC question, I wasn't aware we could crossover with the car stationary. I'm pretty sure you have to be moving for VTEC to crossover.

Are you sure it is a fuel cut? I thought the computer was just opening and closing the throttle plate. If it was a fuel cut, I would expect it to be more like the regular rev limitter (very quick response). Either way, I don't see any reason why it would hurt the engine.

Yes, it is a fuel cut. And it does have a quick response, but remember, you're in neutral free revving the car, so it tends to rev a lot faster.

I have a datalog of one of my track runs. TPlate % is constant, no opening or closing. Ignition is constant. A/F is all over the place... fuel cut.

And also note that I was not crossing over into VTEC (3800 rpm vtec, 4200 rpm launch) because my launch technique does not involve pegging the throttle to the floor and riding the launch limiter. I give it just enough throttle (about 15% tpedal) to ride the launch limiter gently and go from there. A 13.9 @ 100mph with a 2.13 60ft on all season street tires with DC RH, Injen CAI, Vibrant Exhaust, & TBS/IMG gaskets must mean I'm doing something right ;) .

I can post this datalog if anyone's curious.

Thanks for the info!