imzjustplayin

I was looking at the fuel economy numbers for the civic HX and I managed to compare the 1996 HX, 1998 HX and 2000 HX and saw that the fuel economy progressively got worse over time. Is this true? Or did fuel economy.gov screw up? Cause if you look at the old EPA numbers for the newer HXs, you'll see that the #s are actually worse. I mean we can all speculate that the emissions standards got more strict but seems a bit much. If I wanted to get a replacement ECU for the HX, how could I make sure that I wasn't getting a newer ECU that would cause the car to have worse mileage?

x0!

obd2a would be 96-98 obd2b would be 99-00.

i use to own a 99 civic hx a couple years back. it got AMAZING gas mileage.

bmoua

Any D-series at the moment should be able to get 30+ mpg. If you want more mpg, a change in driving style would def. improve your mpg. Maintence is also a key factor but driving style plays a big part in getting a better mpg.

imzjustplayin

Driving style won't matter for me, which is why I want to get a car that gets the best mileage possible.
Well if the '98 is still OBD-IIa, why does it have a lower MPG rating than the '96? Also why does the '97 have a lower MPG rating than the '96 as well?

BlackDeuceCoupe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imzjustplayin &raquo;</TD></TR><TR><TD CLASS="quote">I was looking at the fuel economy numbers for the civic HX and I... saw that the fuel economy progressively got worse over time. Is this true? </TD></TR></TABLE>


Quick answer: No!


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bmoua &raquo;</TD></TR><TR><TD CLASS="quote">Any D-series at the moment should be able to get 30+ mpg. If you want more mpg, a change in driving style would def. improve your mpg. Maintenance is also a key factor but driving style plays a big part in getting a better mpg. </TD></TR></TABLE>


Exactly! Thank you...


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imzjustplayin &raquo;</TD></TR><TR><TD CLASS="quote">Driving style won't matter for me, which is why I want to get a car that gets the best mileage possible.</TD></TR></TABLE>


This WILL shock a lot of ppl but believe me on this...

I owned a 2000 EJ7 (HX) with a D16Y5 (OEM) - drove it for 8 years - 178,000 miles.

Last tank, I got 61 MPG - which was admittedly a fluke - lifetime average was 45 MPG - never got less than 38 MPG.

Now I'm driving a 1998 EJ7 (HX) with a B16A2 (Si) swap.

Last tank, I got 41 MPG - never got less than 37 MPG!

Here's what I'm telling you... and you can take it to the bank:

If you buy a 6Gen Si and drive it like a HX - you will get HX mileage!

Conversely...

If you buy a 6Gen HX and drive it like a Si - you will get Si mileage!

Soooo... bmoua IS right and the official gov figures are wrong!

Bottom line: If you aren't willing to change YOUR driving habits, you might as well buy a Si...

yoej8

One reason it may have changed over time is because they base the rating on 65 mph now instead of the old 55 mph.
I just don't know exactly when that started.

Relic1

HX = OBD2a, always. It did not make the OBD2b switch in 99-00.

as far as why the mpg figures changed. I have no idea.
It may have been honda messing with the lean burn mode, it may have been the gov messing with how the mpg figures are calculated (they do that from time to time), it may even be something with which car they chose to do the testing on (more options, more weight = less mpg)


one thing to note, honda did keep changing the ECU for the HX. Not sure what that means...

37820-P2N-*

A21 - 96 5spd
A22 - 97 5spd
A31 - 98 5spd
A32/A33 - 99-00 5spd
A61 - 98 cvt
L21 - 96 5spd(cali)
L22 - 97 5spd(cali)
L31 - 98 5spd(cali)
L32/L33 - 99-00 5spd(cali)
L61 - 98 cvt(cali)


Modified by Relic1 at 1:22 PM 6/3/2008

NOFX

I was going to list out the HX ECus, but it looks like Relic already got to that.

I do have this though. This is the information on gas mileage of each US trim 6th gen Civic. I've sorted it by year so it's easier to see how the gas mileage really changed. I also included the old EPA standard ratings.

BlackDeuceCoupe

Nice chart, NOFX, but...

I filled up my B16A2 (1999 Si) - EJ7 (1998 HX) today:

409.4 miles / 9.876 gallons = 41.45 MPG (Chevron Regular Unleaded)

That includes a couple of 100 MPH 'excursions'!

Hey! Nobody's perfect all the time...

Last tank was:

383.8 miles / 9.337 gallons = 41.105 (Valero Premium Unleaded)

Not only does that beat the 'official' Gov figures for a Si - it also beats the 'New Standard' HX numbers!

Don't pay any attention to their figures - your driving habits are the key to great gas mileage...

NOFX

Granted your HX still doesn't have the same weight and such as the Si would have. So the numbers would be bound to be off anyway. These are just rough figures for stock cars too.

preludexl

why'd you sell it for a dx, Blackdeuce?

BlackDeuceCoupe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NOFX &raquo;</TD></TR><TR><TD CLASS="quote">Granted your HX still doesn't have the same weight and such as the Si would have...</TD></TR></TABLE>


True!

An EM1 swap (engine, tranny, front end, tails, et cetera) adds about 85-100 pounds to a EJ7...

Even so, my HX is still 200+ pounds lighter than a Si!

BlackDeuceCoupe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by preludexl &raquo;</TD></TR><TR><TD CLASS="quote">why'd you sell it for a dx, Blackdeuce?</TD></TR></TABLE>


Huh?

Does not compute!


I had a 2000 HX with a D16Y5 - now I own a 1998 HX with a B16A2 - that's all...

krazyhmongboi

when i was still driving around stock with my y5 i got 420mpg average..mostly highway miles

compared to what i get now thats HELLA!

japspecb7

if you wanna save as much gas as possible here my .02, ride the [freak]ing bus.

imzjustplayin

That's bullshit. An Si won't go into 12 valve mode under 2500RPM, which is where I'm always driving at. Driving style is important but so is utilizing the fuel you have more efficiently. Does the Si even have lean-burn?

BlackDeuceCoupe

Let me rephrase that...

If you drive a B16A2 Si motor as gently as a D16Y5 HX, trying to eek out as much gas mileage as possible, you will get HX-like gas mileage out of a B16A2.

If you drive a D16Y5 HX motor as hard as a Si, trying to get B16A2 performance out of it, you will get Si-like gas mileage.

Does that make more sense?

imzjustplayin

No it does not. An HX should nearly always get better mileage than an SI motor except during hard driving. Maybe saying that driving an SI as gently as possible while driving an HX normally (how most people drive opposed to hypermilers) you'll get the same mileage. An HX should be getting better mileage in most circumstances over an SI. I can see the mileages overlapping each other, but if on the extreme of fuel saving of both vehicles, the HX should get better mileage for a variety of reasons.

41MPG != 45MPG


You may be getting close in mileage, but overall you should be getting better mileage with the HX. Maybe your driving habits are different with the HX and or the HX with the SI swap has a newer engine than the original HX engine. The Si is the difference between 16 valves "fuel saving" and 16 valves HIGH PERFORMANCE (deeper, longer?) opposed to the HX's engine of 12 valves (2 exhaust) and 16 valves for "performance" which is really just the equivalent of "fuel saving" for the Si motor.

The HX overall should be using less fuel than the Si, the question is, how are you using that fuel and or is the old HX engine simply not tuned like it should have been. (Valve clearances for instance)

Relic1

let me throw out an example.
I have an ITR swap in my 92 VX.

I've had long trips where I pulled 37mpg, I've also had track events where I went through almost an entire tank of fuel in 60 miles. (~7mpg with the smaller VX tank)
Car is tuned via Crome via dyno & street, plus I run a wideband and EGT in place all the time to verify everything stays happy.

I can tell you even with the stock VX setup I had tanks where things were "rushed" so to speak and I saw as low as 15mpg, but I also saw 60+mpg on occasions.

Now driven the same, of course the HX/VX setup is going to get better mpg figures than a setup that runs at 5k @ 65mph. They are very different setups, and designed for very different use.
Honda was not expecting someone someone with a SI to try to squeeze out every mile they can for every gallon of fuel, and didn't expect someone with a HX to expect the car to pull or rev like the SI can.

Now all this has very little to do with the original question. As to why the MPG figures dropped in the HX over the few years it was produced.
There are WAY to many factors involved for someone without first hand experience to even guess.

Always remember, anyone's MPG figures are to be used only as a rough estimate, much like dyno numbers...
"results may vary"

BlackDeuceCoupe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">Now all this has very little to do with the original question. As to why the MPG figures dropped in the HX over the few years it was produced.

There are WAY too many factors involved for someone without first hand experience to even guess.</TD></TR></TABLE>


True!

As NOFX pointed out in another thread -- my B16A2-HX is considerably lighter than a Si -- 200+ pounds curb weight, even with all the drivetrain and 'sheet metal' changes-- so, that may account for some of my HX-like gas mileage.

Still, my driving habits account for the brunt of the savings!

Having said that, there WERE a lot of changes between a '96-'98 HX and a '99-'00 HX, even though they were both considered 6Gens...

Perhaps they gained some extra weight between those years and THAT was factored into the Gov mileage figures, yes?