Disabling intake and exhaust valves (going to 8 valves in a 16-v head)

[Potenza]

Okay, finally went through with the mod tonight. Haven't done a lot of driving yet, but from what I feel so far I'm disappointed.

- Certainly no gain in low-end torque; all I feel is a loss in power, still staying at my usual <3000RPM.

- Valvetrain seems to be much noisier than before, despite adjusting the valves as part of the process.

- Not enough data for fuel economy, but my two short trips both showed a decrease from the norm, based on the ScanGauge. I'll try to get at least half a tank for comparison's sake - if I can stand it that long.

There seems to be some pinging noises now when under load, like going up steep hills. Is this just a timing issue perhaps, or is this mod just a dud in my case?

[Gasoline Fumes]

Are you sure you adjusted the valves correctly? Don't forget that on a "backwards" Honda, the #1 cylinder is on the timing belt end of the engine! I have to keep reminding myself when adjusting my valves.

[ultimx]

I believe web cams has ground many cams for mpg in mind fwiw.

[nbleak21]

I never ended up reporting back after doing my testing... it appeared that disabling Vtech improved cruising MPG in the higher rpm range 2500-3k rpms when in gears 1-4 (up to 60mph), but when cruising at highway speeds (65-75mph) the engine was very much lacking in power, and required extra fuel dumping to maintain speed.

On a side note; In the past couple weeks I've opened up the exhaust system (full 4-2-1 header, high flow cat, flow through exhaust) and have noted a larger improvement in FE when vtec engages, but I've also lost some low end power, so I will be installing a flowmaster 60 series muffler to hopefully alleviate that and the sound a little bit, while still improving flow.

[Potenza]

Pretty sure I got them right. I have the service manual and wrote it out, cylinders 4, 3, 2, 1 from left to right (standing in front of the car). I adjusted them all to the tighter end of the clearance specs. But if I got the cylinders mixed up there would be a lot worse consequence than loud tapping though, right?

Anyway as a reminder this is the 1 intake, 2 exhaust setup. Of course it was always going to be just an experiment - obviously the cam was not engineered for this, so that may be part of the issue. Or maybe the stock intake manifold is not the right compliment for this setup. (It's the "downdraft" economy throttle body manifold. D16Y7.)

Again I will try to leave it go for a bit to get some definitive fuel economy results, but I just hope I'm not harming the engine. I put 93 grade gas in to hopefully help with the pinging. I noticed the coolant temp hit 202 on the ScanGauge just before I parked it, when it never goes over 197 usually. Hmm.

But just as much as fuel economy, a main goal was to get some added torque down low, and that certainly has not happened.

[Gasoline Fumes]

My D15B2 engine has a downdraft DPFI (TBI). And my cam wasn't engineered for this either. I find it hard to believe the 2 exhaust valves can make such a difference compared to my setup. I've had a lot less pinging after my valve delete. You might want to recheck your clearances or at least do a compression check. I was told by "experts" that I couldn't do this. Maybe your ECU doesn't like it?

Did you recheck the clearances after tightening the locknuts?

[ps2fixer]

Just an idea, if you didn't reset your ECU, try that. Most of the time you can just unhook your battery for 10 mins and it will reset. The ECU will go back into factory mode/settings and will have to "relearn" the engine. Something like 10-15 mins @ 55mph.

[slownugly]

potenza, one thing to keep in mind is the difference is fuel injection systems. gasoline fumes performed his on a obd0 system i believe. yours is ob2 so maybe the way that ecu works might have somthing to do with it. i have no in depth experience with honda obd2 ecus so i wouldnt know for sure.

fuel maps are probably important for it to run ok. but honda didnt make an 8 valve head after 95 so you couldnt really swap ecus to find out. if it were obd1 you could swap a cx ecu (p05) that engine came 8 valve. or obviously the hf ecu if it were obd0.

[ultimx]

Obd2 runs way more sensors, u would need a jumper harness and the corresponding ecu which is close to what u have.

[Christ]

Don't really need a jumper harness unless you plan to change it back at some point. You can easily just depin and repin connectors to fit the ECM you want in there and mate it to the harness. IIRC there are cases wherein you have to change some sensors for them to owrk properly when changing ECU as well, but that's a more in-depth and model/donor specific thing.