I am a college student that is interested in modifying my car so that it performs better. In reality, swapping to a b-series would be nice, however it costs more money than i want to spend right now.

so this leaves another fun engineering personal project. modifying my 94 cx hatch so that i can get an upwards 60mpg.

now i currently have integra 15inch alloys with 205/50/15s along with GSR disc brakes on all four corners. If possible, I would like to keep my brake and wheel configuration. I have a d15b8 motor with a b7 16valve head on there along with a 96 cx hatchback transmission.

Now this leaves me with a few motor options:
doing a headswap to either a d15z1 (92-95 VTEC-E head)
getting a d16y5 (96-00 VTEC-E motor)
if possible, 3-stage vtec ultra rare JDM d15b

now there are other options as far as acquring better gas mileage, as far as i know, these include (but are not limited to)
intake/header/exhaust
as well as putting sheetmetal under the rear bumper so that it does not act as a parachute creating drag on the interestate.

now don't get me wrong, just because i am interested in getting good gas mileage, does not mean that i am against horsepower. It just so happens that I/H/E yield more horsepower as well as better gas mileage. Now it's a given that the d16y8 intake manifold is the "type R" of d-series intake manifolds. However because this would yield a higher hp number, would this also yield better gas mileage?

I am curious to what you guys think about this project. As well as appreciate anyones insight.

 

You're not going to touch 60 mpg. Sorry, but it's just not going to happen. You already have the best transmission for gas mileage (the super long CX with a very long fifth gear and final drive so that your crusing RPM on the highway is low). Possibly swapping to the VTEC-E head would help, as well as the rear diffuser (what you're talking about under the rear bumper). Honestly, other than those, a K&N drop in filter would be about as far as I'd be willing to go on any of those motors, even for the few extra MPG you may get in return. The cost/return won't be worth it in the long run.

 

8 valves sounds so sexy at 3.00+ a gallon

 

so which would yiled more MPG switching to the vtec-e head or getting a d16y5 and converting it to obd1

somehow, the d16y5 is rated at 115 hp with the VTEC-E

 

if you go with your "options," you'll wind up spending more than you'll save in fuel costs

 

outting a vtec-e head ont ehre is gonna cost you the head, AND intake manifold and extra wiring and ecu in order to get the egr system working.

so doing a plain head swap wont probably net you any gains in economy without doing the rest with it.

 

how about this, and its sooo much easier and more reliable. STOP ******* with swapping **** out and just get a Toyota Prius. and he shoots...... he SCORES

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bmw626 &raquo;</TD></TR><TR><TD CLASS="quote">how about this, and its sooo much easier and more reliable. STOP ******* with swapping **** out and just get a Toyota Prius. and he shoots...... he SCORES</TD></TR></TABLE>

It's going to cost him MORE in the long run. Lets do some math here. If he gets 10 more MPG (which is right about 50mpg, which is right about what a Prius gets on the highway).

Cost of car + cost of gas / MPG = cost per mile

For the Civic
0 (car is paid for) + 3 dollars for 87 octane /40= .075 per mile

For the Prius
10,000 (a VERY low estimate on what the Prius is going to run you) + 3 dollars for 87 octane /50 =200.06

You'd have to drive a helluva lot of miles to make the Prius even come close to being financially responsible, which is esentially what this guy is trying to do.

You do not shoot, you do not score.

 

Definatly stick with the car you have, if you were to upgrade the stock exhaust or maybe even just the muffler you should see a few mpg gain. If you were to add a intake I think you would see a loss in mpg. Just make sure you have a clean filter. When my dad needed a new muffler for his toyota camry he went with a more aftermarket dual tip muffler and he said he knoticed a 5 mpg increase.

Myself personally im thinking of putting my stock airbox back on to see if I can gain some mpg. With my LS swap I am seeing about 27 mph.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bmw626 &raquo;</TD></TR><TR><TD CLASS="quote">how about this, and its sooo much easier and more reliable. STOP ******* with swapping **** out and just get a Toyota Prius. and he shoots...... he SCORES</TD></TR></TABLE>

shut up

here's the thing though, ever since i switched from the 8valve head to the 16valve head i started to get 40 extra miles per tank, however i started to burn half a quart of oil about every 250 miles. I do not know what the cause of this is. at this point i get an average of 32 mpg with a canadian cx, with no AC or PS. The only thing that I can think of that would cause me to get this bad of gas mileage is my wheels and my brakes. My friend has a 95 dx hatch that's an automatic and he gets 40 mpg with his AC running.

granted, this may not be the MOST economical route, cause it would take me a long time to brake even with paying the gas. However, it still is a fun project and it economically makes a hell of a lot more sense than going the b-series route

Modified by bense at 5:21 PM 9/6/2005


Modified by bense at 5:21 PM 9/6/2005

 

If you're a college student just ride a damn bicycle and start playing frolf instead of cruising. This will get you ultimate mpg.

 

bro u better go hybrid

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by v4lu3s &raquo;</TD></TR><TR><TD CLASS="quote">outting a vtec-e head ont ehre is gonna cost you the head, AND intake manifold and extra wiring and ecu in order to get the egr system working.

so doing a plain head swap wont probably net you any gains in economy without doing the rest with it.</TD></TR></TABLE>

i have already taken that into consideration, i still do have the d15b8 (8valve) intake manifold with throttle body, which is the same as the d15z1. My car used to have a fully built and boosted b18c1, however it got stolen. I know that my car is already wired for vtec (harness that goes from passenger shock tower to inside of car) i was thinking that i could reverse the steps in the instructions that are already clearly drawn out about wiring a 92-95 civic vx to have a b18c.

and besides, it's not like its going to cost me an arm and a leg to acquire d15 parts. it's not like anyone else in honda tuning actually desires their non-vtec d15

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ej8dude &raquo;</TD></TR><TR><TD CLASS="quote">bro u better go hybrid</TD></TR></TABLE>

come one guys, edmunds lists the vx as being able to get 56mpg on the highway. granted the stock vx has the 3.25 final drive where as i have the 3.722. it's not like the d15z1 exhaust manifold flows extremely well, and everyone always says that they got more mpg with their i/h/e upgrades

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bense &raquo;</TD></TR><TR><TD CLASS="quote">i have already taken that into consideration, i still do have the d15b8 (8valve) intake manifold with throttle body, which is the same as the d15z1. My car used to have a fully built and boosted b18c1, however it got stolen. I know that my car is already wired for vtec (harness that goes from passenger shock tower to inside of car) i was thinking that i could reverse the steps in the instructions that are already clearly drawn out about wiring a 92-95 civic vx to have a b18c.

and besides, it's not like its going to cost me an arm and a leg to acquire d15 parts. it's not like anyone else in honda tuning actually desires their non-vtec d15</TD></TR></TABLE>

actually the cx manifold is NOT the same as the vx since it lacks the EGR system ports. also you will have to wire in the 5 wire o2 sensor as well to make the p07 ecu happy.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by v4lu3s &raquo;</TD></TR><TR><TD CLASS="quote">actually the cx manifold is NOT the same as the vx since it lacks the EGR system ports. also you will have to wire in the 5 wire o2 sensor as well to make the p07 ecu happy. </TD></TR></TABLE>

yeah, i figured i was going to have to get a different wiring harness. and i guess it looks like i'm going to have to get the d15z1 intake manifold as well.

 

you will either need the engine AND chassis harness, or you will need to custom wire the egr solenoid, egr lift valve and 5 wire o2 sensor, and then run vacuum lines to the egr valve, egr solenoid and cvcc valve as well. on a vx the solenoid and cvcc can be found on the firewall in a black plastic box.

honestly if i was in your shoes i would jstu stick with running the cx manifold and 16 valve head and drive like a little old lady, cause i suspect that the cost in time and money wont be worth it in the end trying to conver to vx spec...unless you got a lot of time and all the parts are free.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LShatchie &raquo;</TD></TR><TR><TD CLASS="quote">Definatly stick with the car you have, if you were to upgrade the stock exhaust or maybe even just the muffler you should see a few mpg gain. If you were to add a intake I think you would see a loss in mpg. Just make sure you have a clean filter. When my dad needed a new muffler for his toyota camry he went with a more aftermarket dual tip muffler and he said he knoticed a 5 mpg increase.

Myself personally im thinking of putting my stock airbox back on to see if I can gain some mpg. With my LS swap I am seeing about 27 mph. </TD></TR></TABLE>

FALSE!!!

Only way i see just getting a muffler as an improvent is if the old one was in really bad condtion. 5mpg seems very modest. LS Swap sees 27 mph?? Wow!!!

Anything that allows the engine to run with less restriction will yield more power. Just dont stay in high rpms for too long and you'll be okay. It could be worse you could be driving a fat *** GTI that drinks 91 octane at $3.15 a gallon for about 25 MPG

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by v4lu3s &raquo;</TD></TR><TR><TD CLASS="quote">you will either need the engine AND chassis harness, or you will need to custom wire the egr solenoid, egr lift valve and 5 wire o2 sensor, and then run vacuum lines to the egr valve, egr solenoid and cvcc valve as well. on a vx the solenoid and cvcc can be found on the firewall in a black plastic box.

honestly if i was in your shoes i would jstu stick with running the cx manifold and 16 valve head and drive like a little old lady, cause i suspect that the cost in time and money wont be worth it in the end trying to conver to vx spec...unless you got a lot of time and all the parts are free.</TD></TR></TABLE>

to be honest, i have no clue what the egr is as well as the cvcc

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bense &raquo;</TD></TR><TR><TD CLASS="quote">to be honest, i have no clue what the egr is as well as the cvcc</TD></TR></TABLE>

teh cvcc valve is a part of the egr system, exhaust gas recirculation. it allows for a very lean burn which usually leads to very high emissions of NOx but the egr helps reduce the combustion chamber temperatures making for better efficiency and safety/durability.
if you are not comfortable hooking those up you should probably not mess with "making" a vx civic, and jsut buy one.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by v4lu3s &raquo;</TD></TR><TR><TD CLASS="quote">teh cvcc valve is a part of the egr system, exhaust gas recirculation. it allows for a very lean burn which usually leads to very high emissions of NOx but the egr helps reduce the combustion chamber temperatures making for better efficiency and safety/durability.
if you are not comfortable hooking those up you should probably not mess with "making" a vx civic, and jsut buy one.</TD></TR></TABLE>

ah, now i know what you're talking about. I just didn't know what it was called.

 

Changing heads, manifolds, etc. will help you get better fuel milage, but ultimately the best way to improve your fuel milage is to improve your driving habits.

*The slower you drive, the less fuel you burn.
*Keep your RPMs as low as possible without bogging from going too low.
*Acceleration burns a lot of fuel. Hard acceleration burns more fuel than anything else you do while driving. Avoid Accelerating as much as possible and the little you should have to do should be slow and steady.
*When driving, drive a steady speed and avoid repeatedly slowing down and speeding up.
*Look ahead while driving. If you see the light is red or about to change coast to the intersection instead of driving right up to it and going hard on the breaks. Who knows, by the time you get near the light it might turn green and you won't have to stop thus saving fuel.

I get 700 km (~450 miles) to a tank of gas in my EG with a SOHC ZC swap. So thats about 45 MPG. I think thats pretty good.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by joe_bocc &raquo;</TD></TR><TR><TD CLASS="quote">*Acceleration burns a lot of fuel. Hard acceleration burns more fuel than anything else you do while driving. Avoid Accelerating as much as possible and the little you should have to do should be slow and steady.
*When driving, drive a steady speed and avoid repeatedly slowing down and speeding up.</TD></TR></TABLE>
I gained roughly 8mpg by accelerating at or under half throttle, shifting @ under 4K, and when I get up to speed I set the cruise control, then use the CC controls to accelerate/slow.

Once you start driving with cruise all the time, you start wishing everyone else was using it. Some people vary their speed constantly... if you're unlucky enough to get stuck behind one of those sods, your gas mileage is guaranteed to drop.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LShatchie &raquo;</TD></TR><TR><TD CLASS="quote">Definatly stick with the car you have, if you were to upgrade the stock exhaust or maybe even just the muffler you should see a few mpg gain. If you were to add a intake I think you would see a loss in mpg. Just make sure you have a clean filter. When my dad needed a new muffler for his toyota camry he went with a more aftermarket dual tip muffler and he said he knoticed a 5 mpg increase.

Myself personally im thinking of putting my stock airbox back on to see if I can gain some mpg. With my LS swap I am seeing about 27 mph. </TD></TR></TABLE>

really???? i put in a cais off of ebay on my car and am now getting factory specs for gas mileage 34mpg city or somethign like that for my 94 civic dx. i think i was only getting about 30mpg b4 with the stock airbox

 

what i would do in this situation is buy a hondata, 120 to 200, one time fee. go to your closest import tuner. couple bucks of gas. detune your ecu so on the freeway you are using the least amount of gas. cost your 50 bucks. saving some good money on gas = priceless.