91 civic LX sedan - 5 speed

[Ecky]

The engine bay for the CRX will be similar, but the rest of the car will have a lot of differences.

Cutting the belt should get rid of the rattling if your compressor is shot, and will not be irreversible. Simple fix the compressor and get a new belt.

There are measurablegains from an alternator delete. You can realistically expect 10% minimum.

I have 2 Michelin Defenders on my Insight (in the rear). They're one of the best tires available for it.

[CivicMPG]

That's all good to hear. I appreciate your assistance! I'll send you a PM with my email address. I think that Manual would be helpful.

[California98Civic]

Originally Posted by CivicMPG

Is there much difference between whats in the manual and my 91 civic?

You could cut the A/C belt to experiment, or remove it intact so as to save cash later (assuming the belt is not already dried out and worn).

I don't think the belts are likely to be different between a CRX and your trim. The D-series engines were famously interchangable. And according to http://ecomodder.com/forum/showthrea...tml#post378478 your LX and the non-Si, non-HF, CRXs had the same engine, anyhow. I think that image likely has your exact pulley layout. Only way to be really sure is check the driver side of the engine block. It should all be there. Power steering was often just an option in those days, so don't be surprised if there ain't none.

[elhigh]

Low rolling resistance tires, taller tires and topped up tire pressures will all make a significant difference to your results. Pumping tires to a higher pressure is free and pays immediate dividends.

NOTE: taller tires will throw off your odometer reading, so you may need to rely on phone GPS recording to know what mileage you're actually getting.

[Gasoline Fumes]

Originally Posted by CivicMPG

I think I may start out with an auto-meter vacuum gauge and then look at a MPGuino

I'm pretty sure your LX has DPFI (Dual Point Fuel Injection). You won't get accurate numbers with an MPGuino. I've done OK with no fuel economy instrumentation in my Civic Wagon.

[Gasoline Fumes]

Originally Posted by elhigh

Being a sedan, your aero at the back isn't great and difficult to change without limiting access to the trunk. You may want to spend most of your time making the rest of the car as slippery as possible before you get into a partial or full kammback that will work with your trunk lid.

Instrumentation is your friend, except it may not be your friend. A 91 Civic will have an OBD 1 port, and all the aftermarket instrumentation devices use OBDII, which has been the standard since '96 in the US. There are adapters available to convert an OBD1 port to use an OBDII scanner, but I don't know whether that will permit the instrumentation devices to talk to your system. If it does, I strongly recommend you go for it - more information makes you a better driver.

I'm seeing adapters on Amazon for $20 and less, and the OBDII-to-phone transmitter I got was about $25 or less. Torque Pro is about $5 and opens up a RAFT of instant readings, average readings etc. Again, I don't know how well Torque Pro, which is geared toward OBDII, will function with OBD1. As they say, your mileage may vary.

The sedan's Cd is actually worse than the Wagon! 0.38 vs 0.35. But the taller Wagon has more frontal area.

I don't think these old Civics have any diagnostic port. Trouble codes are read by counting blinks of an LED on the ECU.

[California98Civic]

Originally Posted by Gasoline Fumes

I'm pretty sure your LX has DPFI (Dual Point Fuel Injection). You won't get accurate numbers with an MPGuino. I've done OK with no fuel economy instrumentation in my Civic Wagon.

Have you ever thought of a vacuum gauge? You and the OP could both use it to find optimal engine loading during "pulses."

[Gasoline Fumes]

Originally Posted by California98Civic

Have you ever thought of a vacuum gauge? You and the OP could both use it to find optimal engine loading during "pulses."

I had a vacuum gauge in the car for a short time. With my really tall gearing and low-RPM driving, the gauge pretty much went to zero with any acceleration. I wasn't sure how to use that information, so I took the gauge out.

[elhigh]

I have a vacuum gauge in my truck. Its calibration goes completely wonky - over time the needle creeps up to the point where, with the engine off, I'm showing 10" of vacuum. Obviously that's wrong and I fixed it once, but it did it again and now I don't care. It's most useful at showing me small changes from moment to moment, so the actual values aren't what matters to me, just the direction the needle is moving.

I learned how the pedal felt when the resistance increased just a teeny bit from the second carburetor barrel opening, and that makes a BIG difference on the vacuum gauge. Keeping it out of the second barrel seems to be the sweet spot for modest acceleration without slurping the fuel too fast. I have 3.73 gears in the rear end so it doesn't take a lot of push to get speed changes, even going uphill - kind of the opposite situation from Br'er Fumes. I just have to live with the rapidly churning engine even in top gear.

[CivicMPG]

I plan on getting a vacuum gauge to try it out. I did my first fill up after 137 miles, was at 3/4 of a tank, but didn't know if the way I was driving was working or not so I filled up to get a MPG calculation. 34 mpg. So I was glad, but at the same time with all that I was doing I figured I would have gotten a little bit more. Not sure if the way I was accelerating is negating what I was gaining from all the coasting in neutral that I was doing, which was a lot, have have several good opportunities on my route to take it easy. So I definitely need something to give me instant gauge to get a better understanding of what I am doing is good and what is bad. But to get a better understanding of what my car does normally, this tank I am just going to drive "normal" without being conscious of trying to save gas and increase mpg, and see what it would get "normally", and then I can get a better idea of how my personal driving is improving upon it and go from there.

On a side note from that, the car did die on my going down the road again yesterday after work. I rolled to a stop and it started right back up. it doesn't run rough or have any hicups, it just died. Anyone have any ideas?