Please Help Civic VX MPG

[Ryland]

Originally Posted by Quasimoto

Putting premium gas in anything but a high compression engine is just a waste of gas and money. I does absolutely no good, since it needs the higher compression to ignite the higher octane fuel. Stick to regular gas and save your money.

It's not about the higher octane, it's the lack of alcohol as alcohol burning engines have different needs then gasoline burning engines, yes it will "work" but it will also work to dump a small amount of diesel in to a gasoline engine, not the best idea but it will work, veggie oil would almost be a better idea then alcohol.

[tim3058]

You've got a lot of factors working against you Robertsvx, the fact you are getting 55mpg is impressive. How long have you been driving it? More than just those 3 tanks right? Look at any of our mpg charts and it took a long time to crank out the big mpgs, mine actually improved quite a bit as I learned to DWL. Don't just keep the vac. over 6", hold it at a constant spot (9, 8, whatever it takes to hold your preferred -average- speed). Yeah you'll slow down on the hills but if you speed up going down the other side it all evens out. My DX w/VX motor is lowered 2", has a 3/4 grill block, no mudflaps, .030 shaved head, VX 13s, vac gauge and MPGuino, and my best ever is 63.8mpg, so you are doing great for no mods. My tires are at 48psi (shhh) and its pretty flat around here, mostly 60mph commute. I noticed a small boost running a block heater on a timer back in the spring, although I haven't used it since it got warm out. Speeding hurts mpg, and you won't really get there faster if you are in city/traffic lights anyways. Timing the green lights will help (watch the X-walk flashers for side road, or when the side road traffic stops). As others have said coast in gear with no gas pedal as much as possible. Where you can try to do a lazy "pulse & glide", get up to say 50 or so and DFCO down to 45, then accelerate at around 6" vac til you are back up, coast down again. That last few mpg's you want is going to take an MPGuino and some patience. Good luck

[WD40]

tim3058
I would like to know a bit more about getting and installing a MPGuino for my 92 VX .
What can you tell me about cost, installing and setting it up in the VX .
I really appreciate any help or insight you may have .
Thanks in advance, Dennis

[robertsvx]

Good stuff tim3058!! Keep it coming people!!

[user removed]

Originally Posted by robertsvx

thank you bestclimb,metro,redline,bruce,ryland & old mechanic for responding with great tips and ideas.Sorry it took a while to get back.For fun, because is has been +90F this past week,i tried something different.with a slightly heavy foot and the A/C on full time, i went 200 miles and only got 33mpg.this proved that we hypermilers have to work for high mpg figures.
few questions for old mechanic-my idle is about 22" vacuum, my lean burn kicks in a 6" and kicks out at 3". Does this sound about right? Have you ever got above 55mpg? looks like my dfco rpm is the same as yours because with a/c off, injectors stay off below 1000rpm,and 1300rpm with a/c on.
I'm glad to hear that my vx is getting the milage it should but i still want to get better then 55mpg.i am little disappointed they rated this car 55mpg from the fctory and have yet to get better then 55. one problem is i carry about 150lb of tools around with me because im a mobile mechanic.Also where i live is in the mountains so its hard if not impossible to stay in lean burn up hills(the car really slows down).

few other things,my speedo is right on,tires are correct 165/70/13 summitomos @45psi,gas is mainly enmark 87octane sometimes i put premium,currently i have no aero mods,oil is 5w30,timing 16 degreesbtc @ 600rpm.

thank you all for resonding.please keep it coming.are there any other tricks for this car in particular? one idea i might add is a hobbs vac switch to turn on and off a/c above so many inches.

lets get more ideas and tips up for the honda civic vx.thanks

The alcohol in your fuel is a major disadvantage, in trying to match the original EPA figures.

My best tank ever was in the spring of 08 on a 300 miles trip from Williamsburg to Chantilly and back, exactly 300 miles on 4.627 gallons of regular for 68 MPG.

The problem was that was on the original, made in March, 1993 tires!

I would not use premium unless you have it set up where you have to. I run the cheapest regular I can buy in mine, and tried premium with not benefit.

Idle speed should be as low as you can get it. I have no instrumentation above OE, but the idle on mine is very low, almost to low. Lowest idle speed car I ever owned was a 37 Ford flat head at 350 RPM/ My VX is probably around 500, but I have never checked it.

At 58k miles mine still has the original brake pads, still over 50% left, the ORIGINAL fan belts, that are yet to show and cracking. I am taking the same 300 mile trip today, but I will probably not try to get the same mileage I did 2 years ago, going 64 in the right lane of I95 with 3 stripes separation between me and a big rig in the same lane.

The VX has always been a difficult car to get much over original EPA mileage.
It proves the point that when the manufacturers really pay attention to high mileage in their designs, it will really require drastic driving techniques to significantly improve mileage over estimates.

And I am not talking about averaging 22 MPH, more like 64 MPH.

regards
Mech

[tim3058]

Another thing Robert, is the original EPA mpg was way overestimated - the corrected new values for that car are 39/50, avg of 43- your 55 is well over EPA in that case. The old values were pretty unrealistic for any vehicle as we all know.

[robertsvx]

thats very interesting to have a high mpg machine that does not do much better with hypermile techniques.I am very happy with it even though 55mpg is the best i can get this summer. I will continue with a light foot,coasting and watching the vacuum gauge to save gas.this car has a super low idle too.with fan and lights off idle is around 300rpm.with fan or lights on,rpm goes to about 500,a/c on goes to about 900.i am not putting anymore premium in the tank since i havent notice any advantage either.also the only 100% gas station near me is about 45 minutes away(according to internt).I have put 8k on this car since i purchased it.

[Joe1234]

Why would you coast with the clutch engaged? Makes more sense to disengage the clutch so the engine can drop to idle RPMs.

[tim3058]

Originally Posted by Joe1234

Why would you coast with the clutch engaged? Makes more sense to disengage the clutch so the engine can drop to idle RPMs.

When coasting with the clutch engaged the car's momentum is pushing the motor to continue turning. The Civic computer senses this and cuts all fuel to the injectors, creating a "dead" engine until you touch the gas or put the clutch in, idle rpm or not (called deceleration fuel cut-off, or DFCO). Not all stick shift cars cut the fuel on decel, but Civics do. If you were to put the car in neutral or push the clutch in the computer would continue to pump fuel to keep the engine at idle. DFCO can really bump up your mpgs going down a long hill or where you can decel slowly without ticking off other drivers.

[Joe1234]

Originally Posted by tim3058

When coasting with the clutch engaged the car's momentum is pushing the motor to continue turning. The Civic computer senses this and cuts all fuel to the injectors, creating a "dead" engine until you touch the gas or put the clutch in, idle rpm or not (called deceleration fuel cut-off, or DFCO). Not all stick shift cars cut the fuel on decel, but Civics do. If you were to put the car in neutral or push the clutch in the computer would continue to pump fuel to keep the engine at idle. DFCO can really bump up your mpgs going down a long hill or where you can decel slowly without ticking off other drivers.

Got it. I didn't know it cut the fuel.