[Frank Lee]

I'm into this mod more than most of the others!

If the modder is happy with what is likely to be <25% fe gain, then I say GO FOR IT! Just be forwarned that the compromises in power and driveability are great... they may even seem disproportionally great vs the fe gain.

I'm opposing this notion that just killing a few injectors leads to anything constructive, because 1. it's been tried, tried, tried, and tried again 2. it's failed, failed, failed, and failed again. 3. the theory behind it isn't any good either. How do I know? Because I've read about all the failures over the years, as well as many tech articles on DoD (BTW there are many of them online). And I went out and failed myself, by doing the injector disable, and by doing the injector disable plus the valves disable. For just injector disable you don't have to install a thing. Pop the hood and pull the wires off a few injectors. Start it, go for a drive. It practically takes less time to do that then it does to sit here at the puter and dream about it. If you leave it that way long enough to get an fe reading, get back to us. I'm quite sure the O2 sensor compensating for the extra exhaust fresh air is only part of the reason fe didn't go up... it is the fact that the remaining working cylinders are having to do extra work in uselessly pumping all that air. Remember, engines are basically air pumps. Find a recoil start engine and pull on the rope. It does take substantial work, even with various ports left open.

To try yet again to disable while pumping air: perhaps an EFIE-type device could spoof a "normal" O2 sensor signal for this test/mod? Just take the sensor out of the equation for a while? Or, perhaps another sensor bung could be added to a runner off a working cylinder prior to the collector without too much effort. I don't know if O2 sensors have to be a certain distance away from the cylinder... wouldn't think so.

ALL the DoD systems close BOTH valves. They HAVE TO. Otherwise it DOESN'T WORK.

Speaking of air pumps... we are talking about small amounts of hp, like 6 hp for aero and 2 for r.r. or something like that... and think about air pumps- air compressors, in order to move any amount of air, require quite a bit of power; most of the decent ones need 220v. So without touching any "real" calculations on it, to me it appears that if one is trying to DoD with the dead cyls still pumping, even if the pumping uses only, say, another 4 hp vs shutting the valves down, that 4 hp might be the difference between a 20% fe bump and a 0% "bump".

It appears an engine swap has the best chances of returning real gains/per unit of effort and expense. Motorcycle engines, though, are generally not all that efficient, as they tend to be biased more towards high rpm hp output than BMFE.