You know how everyone is fixing up their cars to to be weekend warriors and what not? Well I drive a stock HF, and i was wondering if it would be worth rebuilding an HF engine to achieve maximum fuel efficiency.

Now hear me out. Gas is hella expensive and while most people put thousands of dollars in their cars, with good performance results, the oil tycoons make you pull out a home equity loan just to keep your wheels on the road.

MPG Happiness.
Now, i have been getting about 44-48 mpg with my Betsie, so i guess i shouldn't complain, except for the fact that i have a slightly smaller tank than the rest of you so every 300 miles or so, i have to refuel (have to drive around alot). I really feel that i can get more out of this car, especially since the Insight has a i3 engine (but with vtec) and electronic assist that gives it about 90 hp, versus my 62hp. (correct me if i am wrong). And yes i know that the Insight has an aluminum body but, it is just a benchmark for what i would like to have.

Reliability.
Also, i know that everything in the HF engine is puny so i would like to have a better piece of mind knowing that my weak, puny parts are reinforced (connecting rods and all that sort).I'm pushing 163k on the chassis, and engine and stuff is starting to die finally(right now the alternator). Everything besides the battery on this car was stock except for the normal tune up stuff and wheels (plugs wires battery etc, brakes). So far i have replaced the Starter motor (which later found out was fine), ignition switch, struts for the hatch, and intake (i have a CAI). Soon i will do a rear disc conversion.

Performance.
Most of you who are concerned with performance and power, tell me if you think this is a good idea? I mentioned an article in import tuner or Honda tuner mag (can't find the mag right now) about 2 years ago where they installed a garret turbo from a stock eclipse to push the '90 HF to about 160HP with about 6 or 7 psi. They did this reliably and actually were able to push the stock rex up to about 200hp with about 192 or 196 ft-lb of toque, but because of drive ability and fear of breaking something, the dropped the psi to about 6 or 7. So if your concern is about performance, then this could be an option with alil bit of fab work. But notice how i said option.

or...

Another "Bad Idea".
If you guys think that this is a bad idea (just like my CRX with a Rotary engine idea), How about a diesel CRX. Now i bring this one up because i am a fan of diesel engines and Honda has recently make a diesel CR-V in the land of 'pan; i bring this up because i have heard of people doing CR-vtec swaps (i know nothing about these particular swaps)!? Was just wondering if this would work, because i have yet to see a diesel crx. I know it would be a heavier engine (its diesel) but it would most likely take better to turbo or supercharging because of the nature of such engines. This little section is in fact for the weekend warrior rex.

In conclusion.
These are just my thoughts. i would like to see what people think, or if you have any suggestions on the topic. An please no smart ass remarks, I'm just trying to think different and encourage others.

 

guess either no one cares or, now one can speak with out a smart remark quid quid. Can a mod please remove this post as to not waste anyone's time!?

 

I think the fast Hondas are neat, but I too am trying to get high fuel economy. I'm going to start a 120 mile a day roundtrip and I just got an 85 Civic 1300 with a 5 speed (it was originally a 4 speed, but it was converted to a 5) from a friend. I plan on buying low rolling resistance tires (Consumer Reports includes rolling resistance in their rating) and keeping the tire pressure up. Also, I'll do a complete tuneup on it. I may go as far as taking the back seat out to save some weight.

 

For one, anything you add to the car will increase weight, that means more throttle must be added to acheive the same speed. also, a turbo will not only increase weight, but it will also increase the ammount of FUEL added to the engine. so you will loose out either way. The best thing you could do, is completely strip the car of things you dont need, keep the stock drum brakes (even though they may suck pitifully due to the alluminum drums) they are lighter than Discs, and get the drivetrain perfect, meaning rebuilding the 1.5 engine putting in new iridim sparkplugs with new wires and rotor. getting a six angle valve grind with new valves and an adjustable cam gear. The HF computer is the leanest computer of all the PMF serries computers. Bottom end, Dont use chrome rings unless you are willing to trade off cylinder wear for longer ring life, there also abit harder to seat. Getting the bottom end perfect also, new bearings with a special anti friction coating on them, along with getting the crank micropolished. then running on the best sythetic oil you can find.Then you move to the tranny, replacing everything inside of it bearings,synchros, seals, you name it, and filling it with MTL redline fluid, it really does make a diffrence. Then getting the CV-joints perfect as well, and then finally the wheel bearings perfect so as they offer allmost no rolling resistance. Then you either use the old stock rims or you buy lighter alloy rims the same size and the stock tire size, the lighter the wheel the better mileage you will get overall. i cant think of anything else lol. good luck.

 

i appreciated the post. You gave me some ideas that i hadn't thought of (cv-joints, bearings)

 

hey man, if you want more milege per gallon out of ur crx, there are 3 basic things you can do without getting into a lot of science.

One is of course weight reduction. Since ur car is already only 2000 pounds, i dunno if going any further will benefit because it will be dangerous to be driving such a light car going that slow. This might not be a problem if you only drive 65 on the highways (which i'm guessing you drive that slow because your getting such good milege already). So if thats not a problem, shedding some extra weight WILL help you even tho it is not very noticable. you can shed a lot of weight with a CF hood and lightweight rims.

2. aerodynamics. areodynamics believe it or not actually help a lot. it is not only for top speed. even tho you might go so damn slow on the highways to get good milege, it still is a crap load of drag. maybe you can find areodynamic front and rear bumpers. getting just those two parts will help on highway milege. oh and. if you happen to have big ass dents and random holes where air can leak into ur car, those will affect areodynamics.

3. efficiency. comparing the energy going into ur engine and comming out, the energy comming out is ONLY around 20% of the total energy going in (ie, gas, spark, etc.). you can remove AC, improve engine parts to lessen friction and also improve them so they will not steal as much energy. remember the engine and the whole drivetrain is the problem here. at every point along the drivetrain energy is lost due to sound, vibrations, heat, etc.

now about FI. since i'm not too sure about this topic, this is all i can tell you. if you go FI, yes you use more gas. but using that extra gas means more torque/hp at a certain rpm which means you can rev lower on the highway. now does that extra gas equal out the lower rev ? i dunno. theres the question for you. (this is assuming your turbo is small and it spools low) if you have a big turbo that isn't really spinning the right way when ur on the highway, then it just adds that little restriction to ur intake cause its spinnign backwards or not moving.

 

Weight reduction and engine efficiency are the most reasonable suggestions.

-Keep your car empty of dead weight. If you have some type of towing plan with your insurance (like AAA or something) you could eliminate your spare tire and jack.

-There are lots of routes to go on efficiency, depending on your budget. Rebuilding the motor and doing things to eliminate friction from the rotating assembly is a great start. Getting more expensive means doing things like head porting, thermal coating and upgraded internals.

Just look at your budget, and do what will give you positive results within that budget. It doesn't make sense to spend thousands of $ to net you an extra few miles per gallon.

On the MTL, just go with Genuine Honda MTL. I had Redline put into my tranny after it was rebuilt and went back to Honda MTL. The Redline seemed to behave like it was too thick and made my tranny seem noisy. I'm happy with the Honda MTL.

Speaking of gas results...I went to Sacramento over the weekend and my '89 Si made it there and back on less than a tank. I calculated my miles per gallon when I filled up this morning and I got around 34mpg. Not bad for a motor with 211k miles on it. My best so far was 37mpg going to the Pismo meet.

 

wow pacificdude thats pretty terrible i got 36 in my RX7 and 45 on my 93 civic after a tune up.. my point being that the best way to improve gas mileage is to keep your foot out of it if you accelerate slowly and drive like a sane person (witch it sounds like you do) youll get better gas milage than keeping your tire pressures up... just my 2 cents

 

shit i turboed my hf motor with 180k on it and pushed 5 psi it was fun and still got good mileage i just used a little more pressur when needed. i even have pics on my comp somwhere from when i did it. i still got about 45-48 mpg even in it. thats me a i pulled it out and went way futher so my 10 minutes are spent.

 

Yeah, it's not in the best shape, but I still think thats reasonable gas mileage for an Si, and for the wear and tear I put on it. It leaks some oil, and the head gasket needs replacing. I'm sure it will do better when I swap the new head on + new gasket. I do have a heavy foot tho h: