The story of my 1995 Honda civic EX coupe
 

Nearly six years ago I became fed up with the oil companies and so I decided to buy a lot less of their products.I purchased a 1995 Honda Civic EX coupe that was a salvage vehicle for 2800 dollars with 134,000 miles on it.When I got it, it only got 34mpg Highway.
I increased the tire pressure to the maximum cold pressure.I switched to Mobil 1 5w30 and the mobile 1 filter.I installed new plug wires,rotor and cap.
I installed NGK Iridium standard heat range plugs.I replaced the oil in the transmission with synthetic Mobile 1.
Then I drove it.Over the first year the hwy mpg slowly floated above 40mpg.
I then added a Tanabe Super Racing Medallion exhaust system.That instantly netted 2mpg hwy....and considerably better high RPM HP.The mileage has stopped increasing and has now stabilized at 40 to 46mpg combined.I have gotten over 50mpg (53.4mpg absolute record)5 times....pure hwy,59mph.
The car has higher than stock compression...I estimate roughly 10 to 1.It is supposed to be 9.2 to one.I am not certain, which is a shame.

I have toyed with the idea of lighter wheels....but the lighter ones are not aerodynamic enough.What would help some is a set of moon wheel covers...but I can't find any.
My last tank was 45.983mpg.And it was a mix with plenty of city!
Current odometer is 266xxx!

I love my car!

First generation honda insight wheels and tires are going to be smooth wheels and the tires are light weight low rolling resistance tires.

I have looked at those...too skinny and pricey.I carry a substantial load in my car for work...so I have to have a bigger tire.I currently run Pirrelli P4 sized 185/65-14 which does well in the rain.I live in the mountains of Western North Carolina, so that is as small as I want to run.Moon covers would rock.

How do you figure your compression is higher than stock?

You can run 185/65-14 on the Insight wheels.

Have you calculated your mileage adjusting for the larger tire? Your stock size is 185/60-14, so if you're not compensating for your larger tires, you're actually doing better on fuel economy than you think you are.

The block was decked and the head milled.How much, I don't know.But it is much stronger than the identical car I got my wife.More torque down low and throughout the range.It has also closed a few sparkplugs...which I guess was caused by carbon pieces.But the wife's car has never done this.
The difference is not subtle.

Also, regarding tire size, apparently EX could come with either size.The speedometer is more accurate with the 65 series.I ran 60 series before.If the insight wheels clear my brakes, and if I could get them very cheaply, They would be nice if my current tires fit.Forgive my somewhat scattered replies...I am enjoying a raging tooth abscess and equally unpleasant antibiotic.And the pain meds made me hallucinate...so no pain relief.
I have to research offset on that wheel too.As the cars age, maybe I can find used wheels cheap...but based on my searching so far, I doubt it.

Hmm... you must have a LOT of carbon buildup to get a compression increase that noticeable- especially if you're closing your spark plug gaps. Honestly, I'd get that looked into. If you have that much buildup, something's wrong.

Totally understand the tooth pain. The 92-95 EX came from the factory with 185/60-14 tires; the 96-00 EX came with 185/65-14. Honda did always calibrate their speedometers conservatively though- the 5th gen Civics would show 60mph when the car was moving at 57mph. Your taller 185/65 would defnitely make the speedometer read more accurately, but it's not the size that came on the car.

Your stock wheels are +45mm offset. The Insight wheels should be the same.

carbon
 

It's fine now.The previous owner used regular oil, and changed it seldom.I used a borescope to check it and it is clean now.I use techron every other tank most of the time.And no plugs have closed in a long time now.It first happened on a long descent using engine braking.I figure the thermal shock popped off a chunk.
I found some sites that sell disks that fit 14 inch wheels.I will have to get some.I swear I couldn't find any before...I guess my google-fu was off.

Ouch. I've mostly just burned tips off of cheap spark plugs while running really high compression setups- but never closed any gaps before.

Definitely try to find 1st gen Insight wheels (or Civic Hybrid wheels) online- they're out there. You might have to wait for a set, but they'll give you the pizza pan advantage without having to worry about stuff falling off.

Air Intake
 

This is the first thread I've ever joined because its been really informative. I just bought a 1995 Civic Ex Coupe with a 1.6L Vtec engine and 141,xxx miles and I'm looking into how to get better mpg. I haven't done a very accurate reading yet but it looks like I got about 31mpg on my last tank that was probably 90% city driving.

I was wondering if you have added an after market cold air intake system. I was thinking about getting one like the K&N intake system. I heard that it can help. Nonetheless, thanks for this thread! It's awesome!