TSX / K24a2 Engine: Help!
 

Here's the situation:

My wife has been driving efficiently in the TSX all week by using constant throttle on hills, and using the instant feedback display to keep the FE above 30-35, despite the hit in speed. She managed to get 32.0 mpg on the last tank, which is darn good.

So, we hop in the car last night and run some errands. I'm using my usual Integra techniques, keeping the revs between 2k-3k on accel, CODFISH, ICE-on coasting, shutting down at long lights. Long story short, I killed the FE by 0.2! Boy did I get an earful, "I've worked hard all week to get up to 32, which is my personal best, and you come in here and ruin it!" I did, indeed, and was frankly disappointed. We had to take it out on the highway and really work some magic to get the number back up to 32.0 before fill-up. She says that every time she starts up the car, she loses 0.1 on the FE avg.

So, engine-off coasting might not be the best option for this car...

This LEV-2 system is something else. No EGR because of the variable Cam Timing, throttle by wire, etc. What do we do here? It does have the auto-stick transmission, but the ECU probably works agains me -- argh!

The only mod is tire overinflation. Coasting with ICE-on-Neutral has been found to be beneficial. The car already has partial under pans, airflow tabs in front of each wheel, and an awesome emissions system.

We'll talkin' "New School" tech. Any K-Series gurus out there? How do you hypermile this puppy...

RH77

Data
 

Anyways, were taking it on a trip downtown tonight. The outbound leg will have the ScanGauge hooked up to monitor what the TPS is doing -- now we'll have to see if that's the pedal-position sensor, or the actual throttle (guessing throttle). MPG, timing, and Load for the other variables.

Return leg:
Speed, Timing, Fuel Trim, Pre-Cat 02 sensor feedback, and throttle position.

Hopefully some secrets will be revealed on what this drivetrain wants.

RH77

The thing that sucks about the SG is that instant readouts on oft-changing variables are pretty useless. You really need a laptop OBD2 system (or perhaps the coming SG2 USB data export feature, though I don't know how that will work yet) - something that will plot the values over time. Much more useful for comparison.

On another note, I noticed my TPS values as reported by the SG1 range from 13 at idle, to 76 at full throttle (pedal jammed against the stop).

I used the CarChip to log
 

I used the CarChip E/X on the way back to log data in a graphical format. The SG shows around 10-92 TPS, so I use a percentage of that as throttle input. I'm pouring over the data now to see what's up. I noticed that at no throttle and idle, the ignition timing goes down to 8, and if you're above 45 mph and decelerating with no throttle, the timing is -10! I had never seen a negative number on the SG. It's the whole VCT minimizing valve overlap for emissions, and adjusting the timing is interesting. I need to crunch some numbers...

RH77

i find sometimes my TPS doesn't update at all... would advantages TPS offers over MAP? since my MAP works perfectly fine and is pretty accuate to where my throttle position is at.

Well, 1/2 tank, and I got it up to 32.9 today (highest so far). From a standing start, the trick seems to be to use the auto-stick to get it into the highest gear at no more than 60% throttle, lift, and modulate the instant FE meter to 40 and do quite a bit of bleeding on light downhills, and Neutral-ICE-On for the bigger ones (also, constant hill-throttle). The car uses 0.3 GPH at idle, so that definitely helps, and doesn't require ICE-off -- as it uses quite a bit of fuel to get things started again.

I hear that Honda is coming out with "Advanced" VTEC (A-VTEC), utilizing the Variable Cam Timing, and a variable ratio valve lift/timing from the existing setup. The i-VTEC is often confused as having an "infinite" variable valve lift, but it actually hits at one preset RPM like before, but with VCT and soon. The valve variability is coming soon. It's getting more complicated under that hood. Just like any other engine, I'm sure that a PCV Catch could help cut gunk build-up, and definitely an EBH (working on that). But, there's 40% life left on the break-in oil, so after that, a slicker blend should help. As far as mods, regulating intake air temps in the Winter may be needed -- but we'll see. With some work, we hopefully can get it up to 35+ combined.

RH77