mikefxu: 96 CX hatch w/ EX trans 30mpg. [ Archive] - GasSavers.org - Helping You Save at the Pump

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Now that I have a ScanGauge1 I have a better idea of my gas mileage. I have been getting 35-37+ MPG to and from my trip to work. This is at 55-60 MPH unless I draft a semi then I keep constant speed up to 70 MPH and get the same or better MPG. I haven't done a tank average yet but it will be lower since I deliver pizza in the evenings for some extra cash. While I am delivering I usually get 33 MPG and only have about a 4 mile max each way trip for each delivery. I forgot to mention before 96-00 CX Civics have manual steering and I have my A/C system removed to the firewall. I cannot drive with windows up since I live in Florida and its already too hot with both windows down. Before the summer ends I am putting in a new clutch, flywheel (possibly lightened), motor mounts. My clutch slips if I give it WOT, my flywheel has 400k on it and I think that its causing the clutch to lose grip prematurely (clutch replace with engine), and my motor mounts are completely shot and they cause my tranny to pop out of gear if I let of gas too quick in 3rd and 5th.

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I travel 30miles each way on the interstate Mon thru Fri here in Florida. My 1996 Midori Green hatch has over 400k on the odometer. I bought the car blew the engine and replaced it. I changed out my trans a month ago since it was about dead but used a EX since that is what I wanted when I bought it a year ago. I now regret going to EX trans 3000RPM 70MPH does horrible for gas mileage. I have driven like grandma all week keeping it from 60 - 65MPH on the interstate but still just get a tad over 30MPG. I have decided its not worth it driving slow in my car if I can't get significant gains. I had planned on buying a Integra at the end of the year but have changed my mind and want to get a VX, if one can be found unmolested or just buy a 1992-2000 Civic and swap a 92-95 CX/VX transmission into it. Thats about it besides my car has a header with no cat and a shortram intake. I think if I drove like grandma when I had the CX trans I would have gotten really good mpg but I pushed the car hard.

You guys have a awesome forum here.

Welcome Mike.

I'm certain you can find a good civic VX down in Florida. Take your time when searching for one.

Tell us more about yourself. What motivates you to increase your fuel economy? Has it always been a goal, or is it a recent development?

short ram intake will kill your mileage. All it does is let more air inside the engine and the engine compensates with more fuel.

I lost a wager to Matt when I said my car could get 40mpg. I had my short ram intake on and it sucked fuel and I only got 31.4mpg

I put the stock intake back on and now I'm in the high 30's

Thats about it besides my car has a header with no cat and a shortram intake. I think if I drove like grandma when I had the CX trans I would have gotten really good mpg but I pushed the car hard.

Do you have place for the O2 sensor in that header? No O2 sensor = low MPG.

Thats about it besides my car has a header with no cat and a shortram intake. I think if I drove like grandma when I had the CX trans I would have gotten really good mpg but I pushed the car hard.

Do you have place for the O2 sensor in that header? No O2 sensor = low MPG.

Even if he does the second 02 sensor has to be after the cat now because most headers eliminate the pre cat.

Wouldnt do much good after the cat.

Tell us more about yourself. What motivates you to increase your fuel economy? Has it always been a goal, or is it a recent development?
No really when I had the CX trans I hated the gearing and drove the car pretty hard. I had plans to turbocharge the car. I am a long time member at http://www.homemadeturbo.com/forum . I had started collecting parts to turbocharge my car but then I got a girlfriend and moved out on my own so I sold the parts, cause money was better spent else where. I bought the EX trans about a year ago because at the time I had plans to turbocharge the car. The CX trans started sounding like a bucket of marbles so I had to change it out to the EX. I think in the long run I still want to turbocharge the car and get a VX for a daily driver. My motivation is some monatary and some the enjoyment of DIY. I am 23 and have replaced replace the engine in my former 89 Accord LXi, replaced the engine in my 96 Civic CX, replaced the trans in my former 91 CRX, and replaced the trans in my 96 Civic CX. I enjoy working on my vehicles and get satisfaction from fixing and impoving my own vehicles. So I would say the MPG increase is a recent development.

short ram intake will kill your mileage. All it does is let more air inside the engine and the engine compensates with more fuel.

I lost a wager to Matt when I said my car could get 40mpg. I had my short ram intake on and it sucked fuel and I only got 31.4mpg

I put the stock intake back on and now I'm in the high 30's
Well I use to have a cold air intake but almost hydrolocked my engine. I was a ebay CAI and hung to low. I went through a puddle and my engine stumbled when the filter became saturated with water. I hop out of the car in the rain and used a dime to undo the clamp and turned it into a WAI on the spot and have left it like that. I don't have the stock intake so I cannot test your claims. I don't think I would repurchase the stock intake until my current filter becomes dirty.

Do you have place for the O2 sensor in that header? No O2 sensor = low MPG.
Yes there is a spot for the primary but since I no longer have a cat I have the secondary in open air which keeps from setting of the check engine light. My gas mileage was going down hill and replaced the primary O2 and regained what I lost.

Well, I would say to get some y8 exhaust and stick a cat on there, it's easily done and the benefits I would say are quite great.

I think this is our first HMT user around, hmm. I'd go pick up a d16y5 if I were you.

Well, I would say to get some y8 exhaust and stick a cat on there, it's easily done and the benefits I would say are quite great.

I think this is our first HMT user around, hmm. I'd go pick up a d16y5 if I were you.
I don't see how a cat will benefit me besides more exhaust restriction. I would like an HX Civic but they are hard to come by and people want good money for them hence my wanting a VX. Plus I already own a EK civic and have never owned a EG civic and would like to.

for fuel economy you want more restriction. A header even with a stock intake will suck more air. Put the cat in, you'll lose 8-10hp but you'll gain some fuel economy.

Eliminating the cat on a ~110 hp honda isn't even worth a full hp. Even on turbo'd hondas people only say it's worth 2-3hp and definately not worth eliminating.

on my car it's worth 10hp

It's been demonstrated that nissan doesn't do the best job designing there cars. Everything can be changed for 5 bajillion horsepower because nothing was built too well to begin with. And it's not like they get good gas mileage so you can't even argue that.

I did not remove cat for performance. The 96-00 Civic DX/CX/LX had a integrated cat it was part of the exhaust manifold and was one piece unlike the CRX HF exhaust manifold so to replace the entire exhaust manifold and cat is a geniune honda part affair and cost too much. Like I said the car has 400k and it was the orginal cat and was clogged. I have looked over this site and have not seen reliable claims on how free flowing exhaust or intake affect MPG on a Honda. MetroMPG showed no significant difference between a WAI and a CAI. I think someone is lining up a exhaust test and I would love to see those results. I think its easier to accelerate anytime you have more power and with less delay. I have been driving like grandma all week and ripped on it yesterday it felt so much faster after not accelerating for a week. Thing that sucks is my clutch is slipping over 6000RPM and I just changed the tranny and bought a clutch kit just to get the throwout bearing since the one on the old trans was busted. Now I have 8 hours to look forward to pulling the trans again to install the rest of the clutch kit. Clutch was changed when I swapped the engine but I guess I beat on it too much and its wore out. Clutch would not slip with CX trans but does with EX trans. I guess due to more torque applied to the clutch now.

It's been demonstrated that nissan doesn't do the best job designing there cars. Everything can be changed for 5 bajillion horsepower because nothing was built too well to begin with. And it's not like they get good gas mileage so you can't even argue that.

that's true, everything on the car sucks.

I'm the one doing the exhaust test, still waiting on my digital fuel economy gauge though. You should be able to find the y8 exhaust stuff pretty cheap. I picked up a full exhaust for the cx for free, though the y8 bottom stuff might actually cost money.

Can't wait to see you test. Man I miss my CRX but I just cannot drive on the interstate every day in such a little wedge.

I'm on the interstate pretty regularly, doing 55, :p, it's pretty tame around me though. You got any exhaust manifolds you want tested? So far I have stock, stock modified, d15b8, d16z6, and mehbe some random aftermarket header.

I'm on the interstate pretty regularly, doing 55, :p, it's pretty tame around me though. You got any exhaust manifolds you want tested? So far I have stock, stock modified, d15b8, d16z6, and mehbe some random aftermarket header.

you should be some kind of a salesman or even a police negotiator, you persuade people too easy.

Ebay headers (http://search.ebay.com/civic-header_W0QQcatrefZC6QQcoactionZcompareQQcoentrypag eZsearchQQcopagenumZ1QQfromZR10QQfrtsZ0QQfsooZ1QQf sopZ3QQftrtZ1QQftrvZ1QQmppfqyZcivicQ20headerQQsaca tZQ2d1QQsascsZ2)
Ebay headers have gotten so cheap you can buy them for less than $50. Are you just testing headers or the exhaust system also?

Right now I'm testing headers. If I can find someone with a crx will to let me borrow their exhaust for a few hours I would be very willing to test other exhausts also, but I don't have the money to purchase my own right now. I am assuming that a good starting point will be to find the best header and base the exhaust dimensions/flow characteristics off how the header functions, but hell if I know for real.

Update at orginal post above.