Bigrege943

I just picked up a 98 EX 5 speed for real cheap to drive back and forth to work, more the 100 miles round trip. I was looking into improving the fuel economy. I know its pretty good already, but I work about every day, so at a lil more then 700 miles a week, a 5 MPG increase would add up pretty quickly. The car has 130K, so aside from a tune up, tire pressure. I was considering swapping some parts from the Y5. I don't know a whole lot about the Y5, from what I've read it works similar to the Y8, correct me if I'm wrong. It normally runs using both exhaust and one intake valves until 2 or 3k RPMs (I couldn't find a definite answer). At this point ECU opens solenoid valve allowing oil pressure to lock or engage rockers for the other intake valves, Now running using all 16 valves. So can I use the cam and rockers from the Y5, I think I read the manifold is different as well. Also I know the ecus are different, does anybody know if there are any differences aside from the the RPM value to open that valve. I have a RPM activated switch laying around and was thinking of using that, unless the y5 tune is different. I know the gearing is different as well, I don't really want change transmissions. Does anybody have any experience with this? Any clue as to the increase in mileage using the Y5 valve train, manifold and ECU(if necessary) with the EX tranny? Thanks

HondaPartsHero

The HX model also uses an EGR valve and a wide band 5 wire O2 also the transmission has a different gear ratio. Have you checked out some ecomodder sites? They'll have tons of tips on how to increase mileage from aero mods, driving habits, weight reduction, and other tips and trips. Honestly I wouldn't even attempt the HX model.

jbpnoman

The biggest thing you can do, short of regular maintenance and upkeep, is change your driving habits. I'm assuming most of these miles are highway? First step is to let yourself get passed. It's ok. Go 5 under the speed limit. Second step is to not worry about maintaining speed uphill, and coast downhill. The less you're on the gas, the better. From there, keep your foot pressure balanced. Don't suddenly accelerate, don't suddenly brake.

Before you go swapping the head, I'd sit down and figure out how much it'll cost you vs. how much money in gas you'll save. I've heard people get excited over a $300 exhaust because it gives them 1 more MPG. I don't think I need to tell you how silly that is.

Former User

What is your current gas mileage?

motegicivic

Don't go swapping stuff from a y5, you just wasting money. The car is engineered to run they way it is built.

Do the basics tune up, fuel filter, check timing and accept the car for what it is.

Now if you have really terrible gas mileage that is a different story, then you would need to troubleshoot a problem

czum09

Agreed. I came from an is300 and it got terrible gas mileage. I had to change my habits big time. Shed extra weight in the car, regular maintenance. It takes about 2 weeks for people to develop new habits especially driving. I have heard of people putting acetone in their fuel tanks but I personally would not because of seals and filters. I would do all the little things before replacing the head.

grumblemarc

iTrader: (4)

It's called hypermilling.
http://www.hypermiling.com/

czum09

^^ Haha I didn't know there was an actual term. Sweet. Good info.

kyden

instead of swapping the motor, get it tuned. afr's in the 15s at low throttle can help tremendously with gas mileage. this of course would not make you obd2 compliant though.

Bigrege943

I wasn't planning on swapping the motor, I put a motor in a HX for a guy and have a Y5 with a spun bearing I was about to scrap. I was curious if I could use the valve train and manifold with the Y8 head. I don't know what the mileage is yet on this EX, I have to transfer the title this weekend so I haven't been driving it. I've had a couple Y8s in the past, if I remember correctly I was averaging low 30s but then again none of them were stock, nor did I care much about fuel mileage. I don't really want to go the OBD1 with a flash route, I did that before with a turbo set up, and getting my yearly PA emmisions sticker was a pain. Yes most of my commute is highway, all but 7 of 52 miles, and the 7 are country roads. I'm going to get it tuned up and see what the mileage is. I have a p0171 I've gotta get straightened out first. It's been sitting awhile, the vacuum lines don't look so healthy, and the fuel filter looks to be original.