91 civic LX sedan - 5 speed

[CivicMPG]

I am new to this world, I currently own a 09 Honda Accord EX-L V6. Life is changing, will be going back to school and will need to get out of car payments and also find something better on gas mileage, as I will be looking at a 120 mi a day commute everyday in the near future. So I picked me up a 91 Honda Civic LX sedan with 176k miles on it for $500. (need to sell the Accord still) But couldn't pass up the Civic. Looks to be a well kept, clean little civic, so far it is running pretty good, and am on my first fill up. The A/C does not work, which I am ok with at the moment. Next summer driving in the Texas heat I may think otherwise.

I have been trying to apply Hypermiling techniques as best I can on my 30 mile to work and back trip, 5 days a week, I got the car last Thursday, so I have only been driving it a few days. Hoping to see good results. But my 120 round trip commute may start in January, and want to look at what would work best as far as mods and techniques that I could do in preparation for that time. mainly all Hwy driving/traffic from south of ft worth to north part of dallas. I would love to see 50+mpg, is that even possible with my car? I don't have much of a budget for it.

The only 2 known issues with the car from the previous owners, are

1. the A/C does not work. Can I cut the A/C belt off and be fine till I decide what I want to do with the A/C next summer? will this affect my power steering? or is it completely separate belt?
and

2. it would stall on them sometimes, now it did stall on me when I was driving it home, and since checking, have replaces spark plugs, spark plug wires, and distributor cap- wires looked like some rats or mice had chewed to bare wires in several places. so since doing that i have not noticed any issues. Not sure if that solved it , but haven't had it stall anymore since.

[Gasoline Fumes]

Originally Posted by CivicMPG

I would love to see 50+mpg, is that even possible with my car? I don't have much of a budget for it.

50+ MPG in a '91 Civic on a budget? Can't be done!

[Ecky]

1) I'm fairly certain your Civic's crank pulley has separate belts for each accessory, so cutting the A/C belt would be fine.

2) A tune-up of that sort is always a good idea on an old and probably neglected car.

My #1 technique for raising my economy has been to slow down. I try to never drive about 55mph, as this is what happens to economy as speed goes up:

(stolen from a fellow member here on Ecomodder)

[elhigh]

That's the last year of the square-edge style. I really like those.

As I recall that's a very lightweight car. You could do some experimentation with disconnecting your power steering. To start, you would disconnect hoses from the pump to the rack, and loop the rack hoses from its input to its output. It will feel heavier than normal but it's such a lightweight car it's not a big deal. If it's okay with you, you can remove the belt from the power steering and not have made any changes that can't be changed back in an afternoon. If you're committed, you can remove the pump and get a few pounds out of the car - never a bad thing.

Being a manual opens up all manner of EOC opportunities. All the aero work you do will simply make your engine-off glides that much longer. The biggest bang for the buck is with a deeper air dam at the front and grille blocking. How much grille you block is up to you. Monitor your running temps so you don't go too far - some guys have been able to pretty much close off the entire rad.

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.

[CivicMPG]

I haven't been able to get a good look at the belts just yet, I am hoping that is the case. I'll have to probably wait till this weekend when I have a little bit more spare time and figure it out.

I've been trying that technique, accelerating slowly and trying to stay under 2,500 rpm when shifting, but getting up to 55-60mph my RPM's are running around 2,700-2,900, so I definitely have been trying to take slower roads and take my time. I am anxious to fill up again to see what my mpg is like. I've got 120 miles so far and needle is showing between 3/4 and a full tank. just hoping it doesn't start to fall over faster. haha.

[CivicMPG]

Originally Posted by Gasoline Fumes

50+ MPG in a '91 Civic on a budget? Can't be done!

[CivicMPG]

Originally Posted by elhigh

That's the last year of the square-edge style. I really like those.

As I recall that's a very lightweight car. You could do some experimentation with disconnecting your power steering. I'll try and check this weekend if the belts are connected or are all separate. I'd really like to keep the power steering, and not opposed to getting rid of it. un-attaching the hoses would be a good test.

Being a manual opens up all manner of EOC opportunities. All the aero work you do will simply make your engine-off glides that much longer. The biggest bang for the buck is with a deeper air dam at the front and grille blocking. How much grille you block is up to you. Monitor your running temps so you don't go too far - some guys have been able to pretty much close off the entire rad. I just took my mud flaps off last night, and I plan on looking into doing some sort of air dam in the front and grille block, just not sure when yet.

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.This is an idea I have been thinking about , but your right, The next things i'll probably do is the side mirror delete on the passenger, have to keep the driver side, and maybe the passenger side wiper. Radio isn't that great, so will do an antenae delete as well, and figure something else out for radio. With that long cummute Im going to need to figure out best way to spend my time as far as school goes. listen to recorded lectures etc.

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 have looked into some instrumentation, I think I may start out with an auto-meter vacuum gauge and then look at a MPGuino

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.

[Ecky]

MPGuino's are wonderful instruments. Their accuracy is usually better than OBD-based instrumentation, but you need to calibrate them, and installation is more complicated than simply plugging something into a port.

[California98Civic]

I have the 1988-1990 CRX Honda factory manual. Here is a screenshot of the pulley belts. Like the 5th Gen and the 6th Gen, the belts appear to be separate:



I run without my power steering. My 1998 civic is a little heavier than yours. You can do it, easy. I would however experiment by first removing the belt only. You'll get all the MPG gains and still have the whole system if you want to reverse the mod.

If your AC compressor has an electromagnetic switch on the pulley, like the 6th Gen does, then all you really need to do to get virtually all the MPG savings from an AC delete is avoid turning the AC on. The pulley will be freewheeling. The question is whether you have a compressor with the electromagnetic pulley.

Then the alternator. You can pick up a few MPG here. Get a big deep cycle 12 volt battery from Walmart or somewhere... get at least 40 ahr. Then install a switch to turn off your alternator on demand. Charge the battery by plugging in over night and in emergencies by turning on the alternator.

Those reduced loads will cut your fuel use and give you a few (maybe more than a few) MPG.

Change tires with Low Rolling Resistance Micelin Defenders. They cost more but they last twice as long as lots of tires and they will get better FE. Make those tires taller and thinner than stock for the gearing benefits on your freeway commute.

(BTW, if you want this 1990 CRX manual, PM me an email address and I will try to send it to you. It is a big file.)

[CivicMPG]

Originally Posted by California98Civic

I have the 1988-1990 CRX Honda factory manual. Here is a screenshot of the pulley belts. Like the 5th Gen and the 6th Gen, the belts appear to be separate:

If this holds true to my engine, that would be great! So my issue was this as far as the A/C. They previous owner just said it doesn't work. so I was picking up some bulbs for blinking and brake lights and decided what the heck, i'll pick up a small can of Freon, while filling it up made my engine jump a bit and started a sound like a rattling pulley, now it still has the sound, when I turn the A/C on it gets really loud and shakes the car. Still no cold air though. If I turn the A/C off it quiets down but is still there. so figuring my A/C pump and/or condenser are bad. Wondering if I just cut the A/C belt if it will quit making the rattling noise altogether, and worry about fixing it next summer if I need it with the heat. thoughts? I'm not the most mechanically inclined, but willing to get my hands dirty. The engine still runs fine so I am pretty sure the noise is from the a/c just not sure why.



I run without my power steering. My 1998 civic is a little heavier than yours. You can do it, easy. I would however experiment by first removing the belt only. You'll get all the MPG gains and still have the whole system if you want to reverse the mod.

If your AC compressor has an electromagnetic switch on the pulley, like the 6th Gen does, then all you really need to do to get virtually all the MPG savings from an AC delete is avoid turning the AC on. The pulley will be freewheeling. The question is whether you have a compressor with the electromagnetic pulley.

Then the alternator. You can pick up a few MPG here. Get a big deep cycle 12 volt battery from Walmart or somewhere... get at least 40 ahr. Then install a switch to turn off your alternator on demand. Charge the battery by plugging in over night and in emergencies by turning on the alternator.

This is an interesting idea, is there significant MPG gains from it?

Those reduced loads will cut your fuel use and give you a few (maybe more than a few) MPG.

Change tires with Low Rolling Resistance Micelin Defenders. They cost more but they last twice as long as lots of tires and they will get better FE. Make those tires taller and thinner than stock for the gearing benefits on your freeway commute.

I had to change out the front tires when i picked up the car and the only ones i could find were from Discount Tire, and they were the Michelin Defenders 175/70R13, so I guess I lucked out with those for now, when I can get some more saved up i'll replace the backs with them as well, they are old, mix matched and worn.

(BTW, if you want this 1990 CRX manual, PM me an email address and I will try to send it to you. It is a big file.)

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