OK, so now that I have my shiny (well, not so shiny..) new (well....) '88 CRX, DX, auto in my posession, and have confirmed via a 4th of july road trip out of the state that it is indeed safe and reliable on the highway, I'm interested in boosting the fuel economy as much as possible. I honestly don't give a damn about performance this time out. For a change, I'm building a fuel sipping commuter instead of a toy.

I'm already planning to do a manual trans swap as soon as I find one, but I wanted to see what other people have done to boost fuel economy? I'm pretty competitive, so I really want to be able to sneer at the people buying brand new prius's and the like and point out that I get the same or better fuel economy out of a 20+ year old $800 beater.

Aside from the manual trans, I'm considering adding (don't laugh now...) a low buck DIY turbo. Apples to apples, turbo cars usually get 1-2 mpg better than the same normally aspirated car, and I know that I've seen a magazine article in years past about adding a DIY turbo for around $300. I figure it might be worth a try (and I won't begrudge a few extra hp even if it isn't my goal)...

So what else have people done to squeeze a few extra mpg out of their crx? If there are any tricks or things to look at, I'd love to hear about them....

 

proper full tune-up (new plugs gapped right, new wires, cap,rotor,pcv),clean air filter,proper tire pressure, low viscosity synthetic motor oil (low viscosity oil means dont beat the car!!), and don't flog it are a good start. all these things will make a nice difference. most of them will make sure its what it should be and the others will improve it a bit.

 

That's a good start all right. I've already done the full tune up minus plugs and wires due to lack of time. But I have the parts on the shelf and waiting to go in. Due to the mileage on the car (180K) I bypassed the low viscosity oil. I think that to reach my goals, I'm going to have to do some lightening up of the car (dunno where... maybe interior and wheels/brakes), as well as find some creative tricks.

I KNOW that there are other CRX owners who are focusing on gas mileage out there. What all are the other penny pinchers doing?

FWIW, I got 46 mpg on the road trip, which is a bit higher than I expected since the EPA fuel economy for this car is only in the low-mid 30 mpg range. I just want to be up in the mid 50's instead of the mid 40's.

 

http://www.gassavers.org

http://www.gassavers.org

http://www.gassavers.org

You will find quite a few people on there with 1 and 2G CRX's. And most of the advice is top notch!!!!

The magical 50MPG threshold is going to be tough. Especially if most of your driving is in the city. Check out the website though - some of those guys are hardcore!

 

i got 52 mpg on hwy in my 91 crx si with the stock d16 and 89 hf tranny (way longer gears) .. if u rock the hf tranny you are gauranteed 5 mpg or more.. 70 mph is like 1700 rpms in 5th gear.. and those trannys are a real quik swap

 

Aerodynamics!
Tape the seams in the body panels?!
Some sort of ridiculous body kit? Drive with the windows closed? Small mirrors? No antenna?

 

i pulled off 55mpg in my 88 crx dx with a sohc zc swap and mpfi swap. I had a dx transmission and just went real easy on it for the whole trip.

 

i would suggest the hf tranny too.

in my dx sdn, i killed the compression in one cylinder, drove it home (40miles to tow is expensive) and i still got 28mpg hitting about 4000rpm at 70 on the highways the entire time

 

There are numerous threads here and on gassavers.org where people have swapped in HF and VX transmissions (and not their respective engines) and not bested their previous FE numbers.

The HF transmission, if not paired with an HF engine, is likely NOT going to increase your FE. I can't remember who tried it, but one of the more respected EF forum members already tried it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jonathan_ED3 &raquo;</TD></TR><TR><TD CLASS="quote">There are numerous threads here and on gassavers.org where people have swapped in HF and VX transmissions (and not their respective engines) and not bested their previous FE numbers.

The HF transmission, if not paired with an HF engine, is likely NOT going to increase your FE. I can't remember who tried it, but one of the more respected EF forum members already tried it. </TD></TR></TABLE>

That's been a concern of mine. The HF engine just about has to have the torque curve biased more to the low end of the rpm range than the DX engine. Does anybody know specifically where the peak torque for either the HF or DX engine is? That would make it easier to tell how much of a difference the HF trans would make if mated to a DX engine.

What about that MPFI swap? I've heard it mentioned a few times in a few places now. Is it really worth the time and investment? And just how hard is it to pull off?

 

you need the mpfi especially if you plan to turbo, but that probably will not increase mileage. the mpfi swap will increase mileage. also a hot air intake will increase milage. just route some pipe from above your manifold to the stock airbox

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Crx Jimmy &raquo;</TD></TR><TR><TD CLASS="quote">you need the mpfi especially if you plan to turbo, but that probably will not increase mileage. the mpfi swap will increase mileage. also a hot air intake will increase milage. just route some pipe from above your manifold to the stock airbox</TD></TR></TABLE>

I'm really not trying to be rude about this, but it's been pretty well proven that turbos do improve fuel economy at cruise. The challenge is that you have to keep your foot off the throttle and not use the extra power available. The increase is minor... maybe 1-2 mpg at most, but it's a good excuse and if I can find that damn article I know I can do it on the cheap.

Also, a hot air intake? Maybe if I lived in Montana where the engine stayed in warmup mode for a while that would make sense. Living here in AZ keeping as much heat as possible out of the engine is usually the goal.

So back to the MPFI swap.... What's involved in terms of parts and labor, and how difficult is it? Again, if it's akin to major heart surgery then it's probably out of the question at least for the time being in my case. Also, what kind of fuel economy advantage should I expect? 1-2 mpg, 5 mpg, what?

 

the hotter the air the less dense it is, therefor the less fuel you need. its a very proven method.

 

Right, but that also means that you produce less power for a given throttle setting. To cruise at a given speed you'll need to open the throttle more. Ditto for a given rate of acceleration.... It just sounds like a zero sum equation to me. Although it might make a difference at idle.....

Besides, out here in the summer, heating the intake air temp is just about guaranteed to lead to knocking and detonation. I live in Northern AZ, but spend a lot of time in the Valley where summertime temps routinely top 120F, and overnight low temps stay in the three digit range (yuck!).

So what about the details of that mpfi swap?




Modified by Hal9000 at 9:41 PM 7/8/2008

 

i heard that the pulstar spark plugs adds hp and improves gas millage. anyone tried it before?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jonathan_ED3 &raquo;</TD></TR><TR><TD CLASS="quote">There are numerous threads here and on gassavers.org where people have swapped in HF and VX transmissions (and not their respective engines) and not bested their previous FE numbers.

The HF transmission, if not paired with an HF engine, is likely NOT going to increase your FE. I can't remember who tried it, but one of the more respected EF forum members already tried it. </TD></TR></TABLE>well my stock crx si d16 motor got around 40 or so mpg with si tranny and with the hf tranny i got 52.(do the math im not lying) the hf tranny pairs to a 8 valve d15.