anybody with 88-91 civic with supermid what did you find out
 

what driving techniques helped and didn't help. I know all cars are somewhat different, but curious in general what was noticed on this particular year civic.

well I don't have a supermid but by changing my driving habits I have increased my mpg significantly. My rule of thumb is 5 mph less than posted speed limit. This way I don't piss too many people off yet I can still keep the drag down somewhat. The best tank I had ever gotten before I changed my habits was 39. Now my best is 48. A side note, I did add VX rims since then.

39 highway, city or mixed? the best I've got was about 35 mixed. but that's still relative, cause it's never 50/50 mixed. on the freeway I easily get 45+ and that's at 70, only on flat though. hilly highway changes it.

it would be nice to see what gears my car likes in different situations, speeds, vacuum, etc.

My best before at 39mpg was a mix of driving.

There are easier, cheaper ways to make that particular decision than a SuperMID or ScanGauge. The link in my sig about a DIY fuel rate monitor can help for under $40 and a mere few minutes of work (and there's links there to other ideas that could be cheaper).

Here's some things

The injectors stay off when DFCO above 2k rpms with the A/C on but only if you push the a/c button above 2K rpms. So suppose you want to save some brakes and cool the car a little going down a hill wait until the are above 2k before pushing the button. They will come on again when the rpms go below 2k. Think of this as an extra downhill gear. On a big hill if you drive in 2nd at 3500 rpm and it slows too slow, and if you go 2500 in 3rd it goes too fast and you need to brake. Put it in 3rd with the A/C on. Also I assume the extra rpms must cause a little more wear on the engine

It is better to get the car to speed a little quicker than accelerating slowly on a decent 1/2 mile or more stretch. If it's a 35 mph stretch i'll take it all the way there in second gear and shift straight to 4th. It gets about 15 mpg accelerating slowly from a stop and not that much worse quickly. So get it in 4th for the 50MPG

If you need to accelerate from one speed limit to another you should downshift. You are cruising at 45 and need to speed up to 55. If you were in 4th and just accelerated up to 55 and shifted to 5th would be worse than going 45 in fifth and shifting to third accelerate to 55 and then put it in fifth. If it will accelerate well from cruising speed, you are cruising in too low of gear.

When the fuel injectors come back on after dfco you can feel the car lurch forward a little. When this happens downshift two gears to get them off again

A CRX hf takes about .2 Gal per hour warm to idle .35 cold. and about .4 idling warm with the A/C on.

It barely slows the car down with DFCO at moderate speeds in fifth. So if you are 1/2 mile from a light you are sure you are not going make you might as well save some brakes rather than EOC.

Warm, the injectors shut off about 1.2K on decel and stay off until 800

a vacuum gauge would kinda do the same thing, as the injector duty cycle is lower the higher the vacuum is. but there's weird spots in the map where's it higher in some random spots and not completely linear. well in the honda maps that I've seen and use as stock maps for my car. that run the car perfectly fine.

this of course is direct access to the output of the injectors and is more accurate. it would be sick to have both, as I already have a vacuum gauge.

Despite all of this, you can't beat a SuperMID when really going to ridiculously high mileage. I went from 32-42mpg over a few months, then got a SuperMID, then went to 60MPG on the first tank :) Due to changes in pulse/glide style and so on.