building my lil honda for mpgs!

[Wicked72]

I have 90 honda civic hatchback I am building for mega mpgs. I drive 140miles round trip and I get about 40mpg running an average of 70-80mph. not to shabby. obviously I could slow down..duh. however getting run down on the highway in my gocart wont end well. its a 1.5l with dual point injection , i just pick up another motor and some other goodies. I am rebuilding the new motor and converting to multi port for starters which could help big time. on top of that a nice little header and to get it flowing better and the conversion to mpi i got a new intake that will flow so much better. the came choice I havent firgured out till i get a good tuner to help me make that choice. a big add to the mpgs will be the trans choice which will help drop my rpms by close to 700 in od. btw my current exhaust is about 1inch so thats gotta go and I am working on an exhaust design that will flow better (2") yet be silent cuz I cant stand the import buzz. After its all in and running well (before the tune) its on to areo, the car is going to be lowered but ive getta find a good combo that will lower the car some and still drive comfortable. I am planning on using a different bumper thats after market but looks similar to stock yet will provide a more controlled air movement. I plan on boxing in the radiator on the top, bottom and sides to help create a high pressure area in the front of the car to help the air roll off. also in japan their version of this car has an extended wing which should help the air roll and defuse in the back to help reduce suction. since its a hatch back that actually hurts the mpgs due the high amount of suction produced. my goal is 60 mpgs so ill see what happens!!! a good tune will good a very long way.

[Charger-Bodie]

My guess is that you could have bought a lot of fuel for what all that stuff cost.

[bakerhillpins]

My guess is that you could have bought a lot of fuel for what all that stuff cost.

Yea, I'm with Brian. the Few MPG you are likely to save will require lots of miles to recover. I got a 37mpg Corolla and avoided the Prius (44mpg?) because it would take 144k miles to simply recover the sticker difference.  That would take me 4+ yrs and I have a 90mi round trip commute for work every day.

[Wicked72]

lol lets see what ive got into it. one complete running engine with 130k miles + new ecu for mpi conversion+ mpi intake + heman header+ transmission = $200    yeah not much money, just becuase its an import doesnt meant it costs alot. so far ive got $400 into the complete rebuild of the engine plus machine work and another transmission which is the one im going to use for the build. if this was a performance build I could get 1500hp out of my charger with the money before i could get 300 out of a honda but in the case of keeping things stock the import world they just about throw away anything thats stock and pay a retarded amount on crappy china parts. so i have a major advantage to what im doing. Ill probably have $1500 into make it into a new car. and yes id rather put that into my charger. I just thought ppl would be interested. maybe I was wrong

[Wicked72]

im rebuilding the motor bc i want a fresh motor and it was only said 130k miles could be 230k by the way it looks.

[greenpigs]

I think it is worth while trying, for the $1500 your putting in it that's not going to get a better replacement. That is a healthy amount of gasoline but WTH will it hurt?

[RallyeMike]

Hey Wicked... that sounds like an interesting project. Is 60mpg a number out of the air, or is there some research behind it? Sounds like an extremely lofty goal to me, which is why I ask. I'd like to eventually hear what you get out of it.

Boxing the radiator is great idea. Excess air passing through the engine compartment and boiling around the fenders and such creates mucho drag. A front air dam with rubber to almost the ground will eliminate most of the under body drag which you also need to get rid of. Also having the ability to adjust the size of the opening based on air temp will limit even more drag. You are going to need to go 100% to hit 60mpg.

[bull]

You need to beat the 67 mpg US record set in a Jetta TDI driven by Helen and John Taylor of Melbourne, Australia. Or maybe their world record for diesel fuel economy set driving around the coast of Australia in a diesel-powered Peugeot 308 HDi 110 in 25 days, posting the American equivalent of 75.6 mpg. Good luck.

[bakerhillpins]

I just thought ppl would be interested. maybe I was wrong

Sorry, didn't mean to take a dump in your Wheaties but when I read your post it sounded like cost was one of the main driving factors in your push for MPG with this car. So ROI didn't seem like a invalid consideration. 

It's all good man, and I am interested in hearing how it goes. 

[HPP]

My CRX was getting close to 45 when newer. Now that its older with more miles on it, it has slipped down to 35ish.

The biggest bang for the buck in mileage is as much compression as you can get away with. I'd even skip other mods you're contemplating to push more compression and use a methanol injection system to keep detonation under control. Compression is all about using the power in the consumed gaoline at it highest levels. The more you squeeze it, the more power you get from it. The more power you're making, the more efficient it is working and the less throttle angle you need to run at your desired speed. The less throttle angle, the less gas required. My first hand experience with this is in my 1 ton truck I use for hauling on teh highway. I lost around 5 mpg moving from a 10.5:1 engine to a 9:1 engine.

Don't miss other basics such as optimizing spark and timing and smoothing airflow into the engine. Also will need tall skinny tires with high inflation pressures. Synthetic lubricants whereever possible.  Install a vacuum gauge to assist you with understanding where your driving habits can be improved. Engines are most efficient when producing the most vacuum.

If you just playing around for the fun of it, sure, why not. Like others have said, the payback may actually take some time, and the more you spend on it, the longer that period will take. On your trip of 140 miles, moving from 40 mpg to 60 mpg means you use 1.2 gallons less every day. Actually getting 60 may be a stretch, but what the heck, go for it. Anyway. using 1.2 gallons less, means you save $4.20 daily, based on gas being approximately $3.50. That will take 357 days to pay back the $1500 you're into the project now. Assuming you work five days a week, that means it will take 71 weeks before you pay off the modifications, if you can complete this all with the $1500 you've spent now. Not discouraging you, just pointing out the payback period.

If you still want to pursure it, google hypermilers. There are websites out there with others pursuing the same objective that you may be able to garner some ides from.

[Troy]

Congrats on actually picking a good starting point. So many people try to defy physics and start out with a big, heavy gas hog. On the other hand, getting 13 mpg out of a truck that normally gets 8 is a 62% improvement and will save you a lot more money than getting 60 mpg from a 40 mpg car (you'll spend a ton to "save" that though). I think just having everything "new" with a few minor improvements is the way to go - basically optimize the heck out of it. The factory engineers are pretty smart so there's no need to ignore all their efforts.

Hypermilers get a lot of their improvements by driving at ridiculously low speeds - typically the bare legal minimum on the highway (usually 45 mph). In my opinion, saving a few bucks (or just having bragging rights) isn't worth getting killed or spending that much more of my life in the car. Some other things have a lot of merit - improving aerodynamics and lubrication, shutting the engine off instead of idling, slower acceleration, carrying momentum/less braking (ie having to hit the brakes hard to come to a stop means you were carrying too much speed which cost you fuel to produce).

Troy

[Todd Wilson]

if its a comuter car only  what about applying some racer technics and lighten up the car backseat,passenger seat and stuff like that.


Todd

[bull]

My brother used to own an 86 Jetta diesel non-turbo that got really good mpg. It was a major turd without that turbo but he consistently got into the mid 40s. That is until an attendant at the station put gas in the tank instead of diesel. It quit after about a half a mile but once they got the gas drained out and got it running again the mpg jumped to 49... until the engine got dirty again.

[Wicked72]

I was working with a guy building a turbo motor from mpgs and he actually was getting 70.22mpg! how ever that lean of a tune ended up burning up the pistons lol I told him it would but he didnt care. I will be looking for a different head that will up my compression but for now I have this complete engine. the head and block have to be decked so that will give me a hair more comp. the head machine work is done, Im having him just build the head. once the pistons come in i have to send him one for bore specs.....the motor had water in the one cyl and he couldnt hone it out enough so Im doing a .30 over bore... not really what I wanted to do but ill still have a fresh motor but im worried how it will effect the project. and the 60 is just a high set goal based off what ive learned from the first engine. Im also trying to keep it reliable so a super lean tune will not be part of it. I was thinking a porting the intake to get out all the cast boogers and maybe port match? would that help in my case?

Another reason why Im taking on this project bc I figure of that pay back cost. I was considering buying a new car but I missed my old hatch back and found another and decided to make one thats worth driving so really at $200-$300 a month for a new car or throw $1500 into an old honda all at once I figure ill have more money later for my money pit charger lol! thanks for the positive feedback   Id love any input that may help me reach a high mpg goal for sure!

[grdprx]

That's cool!!  I hope it works well for you.  I jumped on the MPG bad wagon last spring.  I was getting 15 mpg in my truck, was killing me!  Found an 87 Civic sedan 5psd for $800.  Ran good, just needed some TLC.  I've gotten 38 mpg consistently out of it.  I'm into it for $1,500 and spending half as much on gas, plus going an extra 80 miles per tank!  I figure in another 8-10 months, it's a free car. 

I too didn't see the point in spending $10k on a newer car, to save $50 a month in gas.

I'll be interested in watching your progress, I might be persuaded to try some of the areo stuff.   

[HPP]

I agree tinkering with a car on hand is a huge finacial savings over buying a brand new one. That is why, IMO, spending $10k to rebuild my old crew cab was money well spent compared to the $40k it would have taken to buy a new version. And guess what, along the way I was able to produce more power than a new truck while obtain gas mileage comparable to a new truck.

I'm still sold on cylinder pressure increases for gaining efficiency, especially on a small aluminum engine. You shouldn't need to modify cams from stock. Most aftermarket hot rod cams are designed for additional power at higher rpms anyway. You might be able to play around with cam timing a bit to increase cylinder pressure, but you want to build an engine to maximize torque in the rpm range you will be doing most your driving in. That will net you the biggest increases in mpg. If you think about it, one reasons diesels get such good mileage is because of the extreme compression ratios they use to extract as much power as possible from the fuel, and the massive torque they produce in a street friendly, useable rpm range.

Might also consider eavesdropping on some Honda sites for info or cheap parts sources. One good thing about starting with a Honda is that there are plenty of enthusiasts out there. They are the small block chevy of the under 30 crowd.

Aero mods will net minor benefits compared to the above, but are still worth considering. Smoothing the air flow under the car is an often overlooked area that can great reduce turbulance and drag.

[Wicked72]

just sourced just about all the other parts I needed to convert to mpi for $50 ! just need a distributor which wont be much at all. I was thinking of upgrading to an msd ignition help with that crappy spark a little and its cheap!

[Todd Wilson]

Might also consider eavesdropping on some Honda sites for info or cheap parts sources. One good thing about starting with a Honda is that there are plenty of enthusiasts out there. They are the small block chevy of the under 30 crowd.

If he finds a good Honda site I would be interested.  The last honda site I found had absolutely no info on fixing or repairing anything. It was all about buying crap to add on to the car. If you wanted to put a wing on it and some fancy blue headlights it was the site. Ask anyone about a mechanical problem and no one had a clue.

I have a 1986 Honda Prelude that turned into a beater over the years. Runs great but is falling apart inside and out.


Todd

[Wicked72]

I know a alot about hondas, ive worked on them for a long time with a friend who owned a shop. I needed the money, dnt judge me lol. if you need help let me know, if i dont have the answer I can get it in a heart beat. the problem with the honda sites is they are a bunch of douche bag kids that act like your retarded for any questions you ask because its been asked before 10 years ago and you can do a google search for 3 hours to find and answer and you didnt. those little trolls wouldnt know what to do on a forum like this where ppl actually respect one another. (insert shameless pull here) hahaha. I love the mopar community 

[Todd Wilson]

I know a alot about hondas, ive worked on them for a long time with a friend who owned a shop. I needed the money, dnt judge me lol. if you need help let me know, if i dont have the answer I can get it in a heart beat. the problem with the honda sites is they are a bunch of douche bag kids that act like your retarded for any questions you ask because its been asked before 10 years ago and you can do a google search for 3 hours to find and answer and you didnt. those little trolls wouldnt know what to do on a forum like this where ppl actually respect one another. (insert shameless pull here) hahaha. I love the mopar community 

I've learned a lot from my 86.   I got ahold of the service manuals and its helped a lot. Theres still some oddball things about the car I have solved over the years.  The most odd thing was my speedometer would stop working. Hit the dash and it would start to work again. It has a speedo cable that turns a box under the dash that created a signal to the actual gauge. It was probably losing a ground somewhere but for the life of me I could not find it. My solution was to rig the wire.switch on my E brake (which is between the seats) to always show the E Brake was applied creating the E Brake light on the dash to stay on all the time. After doing this the speedo gauge works like a  champ! Has for many many years! HAHA!


Todd

[grdprx]

Any update on your project?   

[1974dodgecharger]

you just need to learn to hypermile it......

[Supercharged Riot]

I got a 94 civic with a 1.5 liter also
I just do simple cheap things that will improve my mpg
I remove unwanted interior lol

Great car to have for the mpg, cheap cost of parts and maintenence
Especially with current gas prices

[odcics2]

Always being a 100% MoPar guy I have never owned a Ford or GM, let alone an import of any type.
When I wanted a car for better MPGs, I got a 2000 5 speed Neon.   Paid 3,500 for it 4 years ago with 15K on it. (got 75K on it now)
Back and forth to work nets me 37 - 38 to the gallon.  The ride is about 3/4 highway, 1/4 city. 

Strictly highway gets about 42-43.   I have added no "tricks" to get better mileage.   Keep in mind everything is a trade off!!
Higher PSI in your tires will stress out the ball joints and they will fail sooner.  Sealing off all the air getting into the front end can cook your battery and age any rubber parts under the hood.   A K&N will keep out small animals, but for MPGs, it's useless.  The scoring of the cylinder walls over time due to poorer filtering will cost you plenty!

The bottom line is to think about what you're doing to see if it will give you problems down the road.  You are not saving money if you have to replace parts prematurely.