1992 Honda Civic VX--57.7 mpg!
 

After reading this
https://www.edmunds.com/insideline/do...rticleId=68272

('92-95 civic VX gets 48-55 mpg) some time ago, been looking for one. Picked up a '92 Civic VX about a couple months ago. Had approx 153k mi on it. Been running FP60 in gas-- initially 2 oz per 5 gal briefly & now 1 oz per 5 gal.
https://www.lubecontrol.com/fuel.htm

Added Auto-RX to oil & changed oil filter.
https://auto-rx.com/index.html

Changed Transaxle oil to Amsoil synthetic 10W-40 (Honda recommended viscosity). Currently in first of two clean/rinse phases with Auto-RX. Initially getting 40-41 mpg. Did partial tune-up (checked/gapped plugs, replaced distributor cap/rotor, replaced spark plug wires, replaced air filter & fuel filter). Still got 40-41 mpg. Due to exhaust system rusted through in various places, replaced cat-back exhaust system with stainless steel LT warranty Magnaflow cat-back. Engine was stumbling upon acceleration & skipping. Checked ignition timing--was substantially off. Set properly. Installed Michelin tires (seems they have low rolling resistance for better mpg). Filled up with 87 octane Shell. Checked mpg 296.5 miles later. Took 5.141 gal to fill up == 57.68 mpg. More mpg checks needed to confirm. This was apprx 60/40 highway/city miles, operating in economy mode, around 2k RPM's max. I expect to pick up a little mpg (maybe a couple) after Auto-RX cleaning done & swithcing to synthetic motor oil. It's looking like it'll be close to 60 mpg combined & over 60 mpg highway. For years I've dreamed of having a car that gets 60 mpg. Looks like I've found it. I'm impressed!!!

Your car is capable of 70 MPG with 60/40 driving with a good driving technique. You don't need any additives. See my garage, The VX. https://www.gassavers.org/garage/view/104

on the highway is where that thing will realy impress you! like krousdb said you should be near 70 then! :)

I thought 55 mpg was great. 70 mpg is amazing for a regular gas engine car!

I haven't been able to get much above EPA numbers on my VX with mixed, all city, or all highway driving yet.

I too endorse Auto-RX. GREAT product. I have used it in 4 cars now. All had positive results. Smoother idle and acceleration. Albeit small, but measurable results with MPG. An great way to prep for syn.
I also dig Amsoil. So much that I can sell it. If anyone needs anything, let me know.
Otherwise, that is really the extent of my sales pitch.;)

I like what you're doing. Sometimes people get caught up in skipping over small things because they don't make a big impact. Regardless if you have 1, five dollar bill or 5 one dollar bills, they all add up to 5, right? :thumbup:

Re: 1992 Honda Civic VX--57.7 mpg!
 

So which adjustment increased your MPGs?
It seems like either it was ignition timing or replacement of exhaust? Anyone?
I'm getting 40's so i'm not really impressed as i wanted to hit 50's
I shift at 1500rpm and never go above 2000 rpms. I go threw entire gearbox before 40mph. My driving technique is good but i'm stuck in 40's MPG on highway.

Re: 1992 Honda Civic VX--57.7 mpg!
 

Timing, mostly, as I recall. I'd like to know how you end up solving your issue as my wife has same problem with a 1994 VX. It gets 41 mpg. I haven't figured out why yet. Hers had well over 200k miles on it when purchased. I wonder if it has a JBM engine & if that makes a difference---newer EPA regulations, etc.? I also wonder about the brain box--is it possible for previous owner to have modified the original or have obtained a modified one? One day, maybe I'll have time to figure it out.

Re: 1992 Honda Civic VX--57.7 mpg!
 

Brain box as in...ecu? You can check the ECU p/n easily enough, right?

Anyway, timing seems to be a worthy check to me(also, what brand fuel filter did you use for your 92? Thanks)...

Had the belt servicing done about 20k miles ago. Best trip MPG I had gotten was right at 50, and perhaps has suffered. Had the valve adjustment done since, might need to recheck that.

Re: 1992 Honda Civic VX--57.7 mpg!
 

Yes, ECU, brain box, whatever it's called. I didn't recall the formal name. The part # should be simple check, but I still wonder if it's possible to have been reflashed/reprogrammed.
I was using Wix fuel filters til local NAPA closed. Currently using Puralator. Been using Wix or OEM air filters.

Don't know how much difference it could make but the valve clearance on my wifes 94 VX probably should be checked.