should i be disappointed with my vtec-e 43 MPG?

[jdmVtec-E]

ok i have a 94 civic hatchback, has the jdm vtec-e d15b(same as VX engine) car has an EX TRANSMISSION, does 3k rpm at 70 mph in 5th (probably why i didnt nail 50+)

went on a trip to the beach, 250 miles, did 43mpg, car loaded with crap, no cruise control, tires at 45 psi, windows open 3in, the night before i left had 15 miles of city driving somewhat spiritedly with a couple WOT pulls. averaged 63 mph ish at 2500-2800 rpm.

bad news is, i do have a custom tune that has it running lean burn at cruising speed, and optimal power fuel and timing when in the gas. i really didnt try to hypermile that much, but im still slightly disappointed. i want 50 mpg. with 51 psi in the tires, no junk in the car, windows up, and no spirited driving do the trick?

[euromodder]

Welcome to ecomodder.

The higher your MPG get, or want to get, the worse some spirited driving will affect a tank.

While the MPG scale may seem linear, it's not.
Sure, 25mpg burns 2 times the fuel than 50mpg,
But every extra mile you squeeze out of a gallon is harder to achieve than the previous one.

With a 63mph average, your speed is too high to get the high MPG numbers.
Even lean burn will burn less at lower speed.

You'll likely be able to get 50mpg.
Maximise the time you're in lean burn.
Try to keep WOT @ 75-80% of throttle

Go slower - except over long distance drives it won't take much longer, if at all.

Extra weight mostly affects city driving.
Once on the highway and up to speed, it doesn't have that much effect.

Try coasting to slow down, even with the engine on, if you aren't doing that already.

Go over the 100+ Hypermiling / ecodriving tips & tactics for better mpg - EcoModder.com and see what else you can do to help your mpg up.

[slownugly]

Well the ex trans would kill it if you were running a p07 but since youre running a custom tune it's hard to say what it's capable of. Running wot is def not good for mileage. What afrs are you running in lean burn? And can you engage into lean burn at your 3k cruise speed? If no I'd say find your sweet spot cruising speed when lean burn kicks in and shoot for that. Might be slower but at least you could hit your target.

[jdmVtec-E]

basically I'm running 19-20 at cruise at any speed but Highway lean burn is set at 20-21. I also have vtec set at 3100 rpm so it's in 12 valve mode on the highway. the tune will get better when I go back for a follow up, I really want to be around 22 afr (where the p07 puts it) at 43-45deg timing. runs amazing currently at 20-21 and it didn't start breaking up until 23.5-24, so there's definitely a little more room for improvement in the tune. I have it set up to make the most hp around town and as much fuel economy as possible on the highway, so I think that spirited driving really hurt me this time around.

[jdmVtec-E]

I honestly love having the ex transmission, it's way more fun to drive lol

[slownugly]

Definitely. Always remember when you burn that fuel in wot or more aggressive driving it's so much harder to make up for it when you are Eco driving. You have to average a much higher number to compensate for it.

I'm running an innovate afr gauge and its limit is 21.9 and the highest I've seen it go in lean burn is 21.8. So you are spot on with the 22(I'm running a p07) another thing you could try is pick a speed you travel the most on the highway, say mine is 65, record your rpms at that exact speed and have vtec engage at that rpm along with lean burns highest reading. Then as load increases take your afrs down safer and safer. I'm guessing you run a p28 or equivelant. I have no experience tuning but I am somewhat familiar with it. Not sure of what I said can be done. You would be better at telling me. I'd love to get into tuning like this.

Would be awesome to see you pull off some 50+ tanks without the vx trans and egr.

[jdmVtec-E]

yeah I'm running an innovate gauge that reads like 34 when the engine is off lol... you are correct iI'm running a chipped p06. and yes at any push of the throttle I have the tune adding fuel so it runs the best. as far as vtec goes, I may have misunderstood you, but you DON'T want vtec (all 16 valves, basically a regular non vtec engine at this point) if you want to best mpg. the tune is way more capable of a safe lean burn with the swirl effect that happens when only running 1 intake valve per cylinder (12 valve mode)

[slownugly]

Yea I meant the 12 valve mode.

Mine only goes to 21.9 yours must be a different model.

I say shoot for low rpm shift points and stay in lean burn as long as you can. Keep me posted what this thing can do. I like to hear what different combinations are capable of