00 Civic Ex vs 00 Civic Hx MPG?
 

Hey guys, I am new here and new to trying to get the best MPG I can. I drive a 95 Civic Ex fully loaded coupe with d16z6 vtec, intake, header, exhaust and a little suspension work. I used to want to make my civic faster, but now I really dont care too much about hp, and am more concerned with MPG.

I'd really like to upgrade from my 95 to a 99-00 civic coupe. I am considering either a 99-00 Civic EX coupe automatic, or a 99-00 Civic HX coupe automatic (CVT). I have tried looking for MPG info regarding the Ex coupe and Hx coupe but cant find any concrete info.

I am considering the Ex coupe because it has all the options I like. d16y8 vtec, a/t, large 4 wheel disc's/abs, ac, ps, pw, pl, moonfroof etc....
I am considering the Hx coupe becuase of the MPG, d16y5 vtec-e, cvt and the fact it has more options than a Dx coupe, pw, pl, tach etc...

Now my question. What are the average mpg of a 99-00 civic ex coupe automatic and the average mpg of a 99-00 civic hx coupe automatic cvt?

If there is only like a 5 mpg differance I may just go with the Ex since I would likely swap alot of Ex stuff onto the Hx. If there is more than a 5 mpg differance I may go with the Hx, and slowly start swapping Ex parts onto the Hx. i.e. brakes, ac, ps, door panels with tweeters and maybe factory power sunroof.

What is the average MPG of the EX auto, and HX CVT?

I love these 6th-gen Civics, but the HX CVT is the one I would stay away from. That's a weak transmission. HX with manual is the best mileage of the batch, but the CVT loses some of that as well as being less reliable.

If you're set on automatic, EX is fine.

If you're willing to go with a manual, HX is great. Consider the LX before the EX, since the EX manual has shorter gears = higher rpm and therefore lower highway mpg.

Ive also read that the automatic cvt Hx's did not come equipped 5 wire o2 sensor or the ability to lean burn like the manual trans Hx. Is this true? What would be the point of an Hx with vtec-e if it could not lean burn due to not having the 5 wire o2?

If I were looking for a manual trans DD I would skip the hx and ex all together and get the Si coupe, or a Gsr coupe, but I am looking for primarily an auto trans civic for my DD. I have only driven a Honda CVT once and I liked it. Im not too concerned with the transmission being weak as Im not looking to put alot of power through the cvt, and I wouldnt mind swapping out the trans every 100k miles or so.

But is what I read about the CVT HX not being a true vtec-e/lean burn engine true due to the 4 wire vs 5 wire o2?

anyone?

Yes, the Civic HX with the CVT has a 4 wire o2 sensor instead of the wide band 5 wire o2 sensor, so it doesn't have lean burn with the CVT either, so what separates the HX's engine from the EX's engine? on the HX the cam shaft is less aggressive and the valve timing is not the same, the HX has a smaller exhaust with the o2 sensor right next to the head and the catalytic converter right after, while the EX has the o2 sensor farther down stream.
They are different enough engines that they don't even share the same intake manifold, fuel rail or a handful of other parts.

Personally, I'd say if you like the EX enough that you would want to swap over EX parts to an HX, then get an EX, otherwise you will be bogging down a nice light weight civic HX, but if you are starting with an EX then anything you will do will improve it's mileage and you'll have a proper working sun roof, power options and all your frills, things that a lot of us buy Civic HX's to avoid.

1999 Civics at fueleconomy.gov
HX manual: 30/38 mpg
HX CVT: 29/35
DX/LX man: 25/32
DX/LX auto: 24/32
EX man and auto: 24/31
Si man: 22/29
Integra gsr: 22/28

My .02c on the EK series of civics. I had a 98ex four door manual that was turbocharged and never got worse than 28mpg combined. Freeway driving would yield closer to 40mpg. The lx and hx models are only slightly more efficient and far less entertaining to drive. Hope you find what you want!

My vote would be EX

IF there is in fact NO lean-burn on the cvt hx's, buying the hx seems a little pointless.

Which style intake should help mpg on a d16 civic? An AEM short ram intake, and AEM long tube cold air intake, or like a Comptech Icebox?

That would seem to be the case, but a lot depends on how you drive. The other engineering differences Ryland points out above will all make a difference in terms of MPG too. But the real reason to avoid the CVT HX is the CVT itself on the sixth gen. Nobody speaks highly of it. Everybody seems to complain about it's reliability. I would never consider one, and I also simply love my 98 Civic (DX), which I have driven daily since 2001.

Also, Palemelanesian posted EPA MPG ratings above, and I would recommend you rely on those more than anecdotal reports of unusually high numbers. You can learn to get better numbers from any car, but a better MPG platform increases your potential for MPG improvements under a wider variety of conditions with greater choices as to how you drive for those MPG improvements. For instance, I wish I had a 1998 Civic HX manual coupe instead of my DX. My numbers would be even better.

Good luck. Remember to love what you pick.

Yeah, according the the MPG above, the HX doesnt really get all that much better mileage than the EX, and then I wouldnt have to swap all the stuff I like from the EX onto the HX. And apparently no lean burn on the cvt hx either which is pointless.

Which intake style would be best for mpg? short ram intake, cold air intake, or icebox intake?

Maybe if the y8 takes a dump I will do the y5 + hx manual swap.

If you are running at near red line on a race track then any of those should work fine, if you are not racing and are keeping your RPM's more reasonable then non of those are going to do much good, the lower the RPM's the longer you want your intake.

I'm not asking which intake would make the most hp at high rpms or w/e, which style intake generally produces the best mpg if the car is driven for economy. I used to want to make my civic fast, and would floor it everywhere just to hear the engine and exhaust, but lately I've been driving like an old lady, hardly ever passing 2500 rpm.

If I drive slow, and stay below 3000 rpm, which style intake should help with my mpg? My long tube Aem cai, a short tube sri (either cut mine shorter or buy a "whale penis"), or something like the Comptech Icebox?

Theoretically, the longer intakes are better for low rpm and shorter is better for high rpm. In the real world, though, I get by just fine with OEM.

As I said, you will most likely not see an improvement in gas mileage with any of those air intakes that are designed for engines that are running at higher RPM's, the same math based theories that say larger around and shorter intakes are good for higher RPM's say that smaller around and longer intakes are better for low RPM's, it's the same math that is used.
And if you look at the cars on here that are getting the highest mileage, they are often running a warm air intake.

Wouldnt a warm air intake pretty much just be a short ram intake where the filter is still in the engine bay as opposed to the front bumper like a cold air intake?

A well designed warm air intake is sized for the engine and cruising RPM and then it takes air that has been heated by the exhaust, there is enough air flow in the engine compartment that it's not much warmer then what you see from a "cold" air intake, but if you duct 100 degree air from near the exhaust, you see an improvement.

What Ryland said, and my experience in my car to add to his: my 1998 Civic's WAI is black plumbing pipe, running from the airbox forward over the junction of the Distributor and then curving toward the exhaust manifold heat shield. It is just the tube, no filter on the end. Filter is still in the stock airbox. Last summer I saw intake air temps over 145*F at times. Commonly mid 120s to 130s. Without it and without my grill blocking, the temps would be closer to 80s, 90s, or maybe 100. I tested the results ABA and saw a modest 2% improvement (results posted on this site, search for it). The best explanations I have heard for this is that (1) the warmer or even hot air allows better atomization of fuel and maybe more plausibly (2) that the ECU adjusts to the lesser air density by reducing fuel and that leads to a gain in fuel economy because I then have to open the throttle wider to get the same power and therefore I reduce pumping/throttle losses in the engine because the throttle opening is wider than it would be, making the intake strokes less of a loss to overall engine efficiency.

A CAUTION: before you make a WAI, take a look at SENTRA-SE-R's testing here at EM. His car is newer than mine and he has the MAP sensor that mine has plus a MAF sensor. It seems the MAF cars might not see a benefit, though I don't understand why. If an 00 Civic has a MAF, my test results might not apply to your car.

james

None of them will help AT ALL! The best you can get is the one honda put on at the factory. The only exception would be if you were to add pipe to pull even warmer air from near the exhaust manifold to the stock air box. The complete opposite of what racers want from the products you listed.

Ok thanks guys. I guess if I ever sell my obd1 civic for a 96-00 civic I will just get the Ex and leave it stock, and if/when the engine and or trans fails I will swap in the HX y5 and manual trans, instead of buying the Hx and adding all the stuff I want from the Ex...