new to board - seeking update/mod advice
 

alright, so i've been saving gas for a while by simply driving a FE car or the past 15 or so years and adapting to economy driving. That was over a span of 3 cars - 88 civic 4dr dx, 88 crx si, 91 crx. each of those cars at least got over 30 mpg, the si would get 40+ city/hghwy. and i made my first real deletion on the 91 crx with taking out the ac system. i just recently bought a 97 civic hatch dx. i haven't had the car long enough to test the mpg but i've gotten 120 miles hghwy on less than 1/4 of an 11.9 gal tank. it's going to take me a few refills to really get a good mpg reading. so i wanted to start modding, but don't really know where to start. i've seen a lot of the aero mods and i'm really not interested in that. i 'd like to just replace certain things listed below as well as slightly "modify" existing parts, i.e., i've heard that drilling holes in your air filter gets better FE and removing the exterior mirrors and such) but nothing major like removing the alternator. however, I've never been much of a tech, but i did just order a chilton's repair manual, so i'm somewhat banking on the fact that that will help with my mechanical inclination. oh and one more thing, i'm willing to get a scangauge if it will really help, but it's just to better monitor your usage right? I've always thought that i was doing okay with zeroing the trip meter upon fill up and watching it that way, apparently a scangauge is better for this? Below are the mods i'd be looking to make. i don't really want to drastically mod anything other than replacing parts and slightly modifiying appearence. Does anyone out there in gas saver land have any suggestions for the follwing?


spark plugs/wires/cap - what are the best ones for FE?

fuel injection control chip - what about these chip mods i've read about, do they really get you better mpg and more hp without repercussions?

ignition - I've heard a hotter ignition will get better MPG - any one know how do achieve this?

tires/wheels - i'd obviously be seeking lrr tires, but i wanted to get alloys instead of the steelys on it now. i know the alloys are lighter, but i don't want to get too much thinner than stock at wheel witdh. i've noticed a lot of honda people seek out the civic vx rims but they're a little too skinny for my taste, i'd be looking for a honda alloy like older si or prelude 13's.

exaust/catalytic converter - ok this one is tough for me. i'd really like to get an exaust that gets better MPG and is either aluminum or stainless so i only have to buy it once. i haven't seen any cats out there other than universal and oem. do FE cats even exist?

air filter - i was leaning towards just the knn highflow replacement. i read that the knn's weren't even worth it. i liked the idea of just simply replacing the filter itself rather than replacing the entire assembly with cold or warm air intakes, but i would do it if it meant significant FE. i 've also read on this board that warm air intakes can cause problems, not sure if would for my 97 htchbck.

oil/oil filter/fluids - i've also read that using synthetic oils/trannyfluids are better than dino. is this a matter of opinion? and can i just switch from dino to synthetic without any problems? i also heard that using synthetic will cause oil leaks. is this true?

octane - i use regular, would a higher octane get better MPG? would the difference in price even be worth the trade off?

and anything else i may have missed, like fuel pump/injectors

thanks

MPGmonger

Higher fuel octane isn't likely to do anything for you if your car is supposed to run on regular.

Some people prefer synthetic oil over dino, but I've been using dino in my '88 Escort ever since I've had it and I'm averaging between 44-45 MPG on it and it has 483,000+ miles and still running. It uses about a quart of oil every 1000-1200 miles. I've normally changed the oil in it every 3,000-4,000 miles. As far as synthetic causing leaks I think that's usually in older high mileage engines and it starts leaking around the seals and gaskets.

As for the K&N air filter, I have one on my '97 Escort. I think it improved FE on it by about 1-2 MPG. Some people say it did and some say didn't help their FE so this is your call.

Narrower tires and LRR tires should help your FE and lots of people claim lighter wheels help.

I use platinum plugs (usually Bosch) in my cars and have had good luck with them and I like having a 100,000+ mile change interval on them. I've ran several sets over 100,000 miles and they were still firing good and getting good FE when I changed them.

There are high flow catalytic converters available, and they claim to help FE and HP, but I've never used one so I can't offer any suggestions.

A scan gauge will give you instant feedback so you can see what works best in your particular car for improving FE. I bought one back in the summer and really like it. It's not only good for the feedback, but will also check the computer for codes and reset the check engine light.

Don't forget that the 1/4 mark may not represent 1/4 of the tank's capacity. I've never had a Honda, only GM, Ford, and VW, but the top 1/4 of the gauge always represented a whole lot more volume than any other 1/4.

Drilling holes in the air filter sounds like an awful idea, and won't help (for reasons I'll describe below). Removing exterior mirrors is an aero mod. Removing the alternator would seem to be a large undertaking indeed.

Using your trip meter is the most accurate way to get your MPG average. The SG will have to be calibrated based on that, in fact. The SG is good for a million other things instead. It gives you instant MPG, multiple resettable average MPG readings, and all the OBDII data you can eat, all of which helps you test mods/techniques and learn.

It's technically possible, but I have some doubts that there's any pre-fab chips on the market that will increase FE for a hypermiler. The occasional reports I see claiming improvement from reprogramming tend not to be credible, and I've never seen any from the point of view of someone who drives for FE.

There are definitely people who know how to do it, but I'm not one of them. I'm not sure if it would help or not.

Changing your wheels probably won't help anything. Changing your tires will, but it may not be necessary to go narrower. It's difficult to find useful RR data for tires, unfortunately. There's some links about tires in my sig containing far more reading than you'll ever want to do on the subject.

If you drive even vaguely economically, making your intake and exhaust more free-flowing is unlikely to help. If the exhaust or intake was restricting airflow at low RPM and/or low throttle, it's never going to make more power when you open it up and rev it up high. OTOH, if it can flow well enough to make lots of power at WOT+high RPM, it can't reasonably be restricting flow at a hypermiler's RPM/throttle combinations.

I can think of engineering compromises that could produce intake or exhaust pipes or a catalytic converter that restricts flow (though for the reasons I describe above they don't engineer it that way)...but I can't imagine a reason why they would specify a paper filter that can't flow well enough for high power, let alone for fuel economy. A larger paper filter doesn't cost anymore to include on the car than a smaller one.

People have produced results going all synth, though I have some doubts as to the conditions...it's hard to argue with results.

No. If there's 200,000 miles on the engine and it's all beat up and you've been running "High mileage" dinosaur oil in it for a long time, going straight to common synth could certainly not work out so well for you. Synthetic is often attributed powers of loosening buildup and stirring up old trouble, and not swelling seals. Switching carefully ought to do the job, and maybe using a "high mileage" version if there is one.

Personally, I'd recommend sticking with whichever type you've already been using, and just changing weight/brand/variety.

In most cars, higher octane than recommended will have zero effect or (according to a recent thread) could even lower your FE. Higher octane changes the compression ratio and spark timing you can use, but if your engine isn't designed for it it's not going to take advantage of it.

It is said that the best nut to adjust is the one behind the wheel. New members often ask about modifications but there's not many that really work AND are cost-effective. Most that could possibly work will never be able to pay for themselves. If you're not doing it for the money, then lots of modifications could be worthwhile. If you need to save money then modifications are limited.

Driving techniques, OTOH, can be continuously refined and improved, and the most you'll spend on them is if you buy a ScanGauge to help make it easier. What kind of techniques do you practice?

ok, there's some good stuff here, thanks for replying

"Driving techniques, OTOH, can be continuously refined and improved, and the most you'll spend on them is if you buy a ScanGauge to help make it easier. What kind of techniques do you practice?"

Not sure what you mean by OTOH. the techniques are driving sensibly, no speeding, keeping it under 60mph, filling up in early morning, coasting, no jack rabbit starts, drive a manual shift small 4 cylander car, no warm up time, no idling time, parking on hills and rolling as much as i can. timing traffic lights,i try to use as little brake as possible. staying up on maint. (tune ups alignments and such)., little to no AC use. basically I try to use every little bit of acceleration decay as possible. i try to keep the windows shut I try not to travel with uneccesary weight, but don't remove parts of the interior. that's pretty much it.

it seems that you're saying the mods i seek wouldn't really help much. i'm not really bent on mods, just need to know about it to see if it's worth while.

what mods if any, might you have?

OTOH = On The Other Hand

thanks

Your techniques are good, but there's more you can do. You have the right fundamental understanding.

Are you aware of DFCO (Deceleration Fuel Cut Off)? If your engine is on and you need to slow/stop, it's often worthwhile to stay in gear or even downshift, since under certain conditions when your foot is entirely off the throttle the computer will shut off all fuel delivery. The programming differs greatly from one car to the next, but a '97 Honda with a manual transmission is bound to be pretty good about it. Others with similar cars report that it generally works any time they're above 1000rpm, except if A/C or lots of electrical accessories are on, at which point the floor raises to 1250rpm.

Do you coast with the engine idling, or with the engine off? I don't usually jump to suggesting that with a new member but you do a lot of the basic stuff already.

The ScanGauge, or any other real-time fuel usage device (such as the less expensive but less capable hack linked in my sig), can help you improve your existing techniques.

Interior parts weigh surprisingly little. Weight loss seems to have no effect on most cars, but some with cars like yours report credible success. See the links in my sig meta thread, such as this link:
https://www.gassavers.org/showthread.php?t=8361

1. Tire inflation (another link in my sig).
2. Wiring for my fuel rate meter.
3. FM antenna removed -- the aero effect is minor and probably not measurable, but it also helps with reception when using an FM transmitter, and I don't listen to normal FM radio.
4. I'm experimenting with grille blocking and radiator blocking. Grille blocking is common and often produces good results but it can be difficult to make it look nice. I haven't heard of anyone else doing radiator blocking but I did it just to see if I could get away with complete grille blocking before I put in the effort to do it. I can (it doesn't cause overheating on either of my vehicles), and it seems to have produced good results, but it's too early to tell.

WAI (Warm Air Intake) produces results for many people, and for some it doesn't work at all. I want to do it but I'm just too lazy...