Lean and Mean - 1998 Honda Civic HX Project Log
 

Introduction
From now on this thread will be used to document the ecomodding journey of my 1998 Honda Civic HX. I've owned the car since 2010 and it has served me well so far. The journey started about in 2011 when I got a new job 50 miles away. I went searching for ways to improve my fuel economy and found this forum. The goal for this car is to keep a low-profile appearance (no crazy aero mods) yet achieve good fuel economy without diving too deep into advanced hypermiling techniques.

Overview: 1998 Honda Civic HX
1998 Honda Civic HX. 220,000 miles and counting. I bought the car with 125,000 miles. The car is mostly stock besides aftermarket wheels that were on the car when I bought it. I had to replace the engine due to low compression at the 163,000 mile mark. Since then I've completed some major repairs like a faulty headgasket, snapped timing belt, and some other general maintenance tasks. It's been quite a journey, but I've learned so much about the car in the process.

Click here for full vehicle specs & more pictures!

http://ecomodder.com/forum/emgarage-...dd3786d737.jpg

The Goal
As I already mentioned in the introduction I want this car to appear stock but achieve fuel mileage well in excess of the EPA rating.

1. 50 MPG - Goal Achieved 4/11/2014 50.53 MPG
2. 60 MPG - In progress

Current Modifications
Tires at max sidewall pressure +3 MPG
ScanGauge II
Power steering delete
VX/CX transmission swap
Upper Grill Block

Planned Modifications
Alternator delete/externally charged battery (Cancelled)
Lower grill block
OEM spoiler removal
OEM antenna removal
Restore wheels to factory HX with LRR tires

Fuel Log
http://ecomodder.com/forum/fe-graphs/graph5944.gif

Alternator Delete Project
 

Alternator Delete Project

As many of you have found out, deleting parasitic accessories reduces the load on the engine, which can increase fuel economy. The alternator is another one of those parasitic systems that can be replaced with an alternative power system.

With the guidance of California98Civic and his DIY thread, I wanted to be able to switch off the alternator when I didn't need it and on when I needed a charge.

I decided to replace my starting battery with a marine deep cycle battery. This would allow the car to run without alternator assistance. Doing the same with a car starting battery would kill it very quickly. Marine deep cycles are meant to cycle many times, and a group 24 can provide about 100 Ah. Due to the size of these batteries I had to relocate the battery to the trunk. I'll need to see what kind of distance I can get out of a full charge to see if one battery will be sufficient. I'm hoping to only use 50% capacity in 100 miles of driving. If I can do that, I only need to charge the battery overnight at home.

Charging the battery will occur overnight with a battery charger. I haven't decided to permanently install it in the car or not. For now I will just use my regular battery charger on the lowest setting that will allow it to fully charge in about 9 hours.

Parts and Accessories Used
- Marine Battery Box (fits group 24-31) - $8 @ Menards
- 15' 2-gauge welding cable - $30 @ eBay
- Inline fuse holder - $7 @ eBay
- Misc. connectors and parts - $10
- Fuses - $14 @ Best Buy
- Group 27 marine deep cycle battery - $70 @ Wal Mart

Inline fuse holder with 150 A anl fuse. 2 gauge welding cable is routed through the passenger compartment up through the firewall to the distribution box.
https://lh4.googleusercontent.com/-o...810_162804.jpg


Ground is connected to the mounting bolt on the shock tower. 4 gauge ground cable.
https://lh6.googleusercontent.com/-l...810_194448.jpg


*Updated* Instead of previous distribution block, I simply bolted together the positive leads for the starter, fuse box, and battery together with copper lugs and a bolt. The bolt is connected to a plastic mounting tab, which is secured with double sided tape to the fuse box.


I don't actually have the deep cycle battery yet. I'm waiting on this 7 year old car battery to finally die!!! But it still fits nicely with the included spacer.
https://lh4.googleusercontent.com/-9...811_120905.jpg


This thing takes up quite a bit of room...
https://lh5.googleusercontent.com/-i...810_163138.jpg


Here is my alternator switch. Just a simple toggle switch that I mounted in a spare pop-out plug on the left side of the dash. Labels were made with a label maker.
https://lh5.googleusercontent.com/-m...810_163614.jpg


So far I have tested the switch and it works. You can't turn the alternator off while the car is running. The switch does nothing. I have to turn the motor off and then I can switch the alternator off. However I can turn the alternator on while the car is running.

Just waiting for the new battery. This mod would not make financial sense unless you needed a new battery anyway (like I do). I figure that despite the cost of relocating the battery, my cost is still going to come out at about the price of a nice quality battery. I'm not sure what to expect to gain in fuel economy. Some have reported as much as 10%, another 2%. I'm hoping for at least 7% but only time and gas will tell. Stay tuned.

Well I think it might be finally time for the new battery. After I got the battery relocation project finished I made sure everything worked by starting the car. It ran fine, no fires, battery was charging, etc. So I called it a night. I woke up and went out to get coffee. It started right up and we made it to Dunkin Donuts. When we go to leave I try to start the car and... Nothing! Just a loud click and everything dies. No scangauge, nothing. I hop out to make sure I hadn't blow my fuses. All fuses were good, all connections good. I come back inside to see the scangauge is now back online and I at least have power to the car. Me and my girlfriend proceed to push the car so I can push start it. Starts right up and runs fine on the way home. I get home and it try to start it again. Same thing. Everything dies when I try to start it. No voltage to the scangauge or anything for awhile after I start it.

At this point I am suspecting the battery is finally toast. I had to drive my truck to work today and didn't have time to tinker anymore. When I get home tonight I'm going to jump the battery to make sure it's a voltage/battery problem and not the starter or my wiring.

What I assume is happening is that the starter drains the battery so low when I try to start it, that there isn't enough voltage to run the scangauge or any other accessories. After awhile the voltage climbs back up enough to turn the car accessories on and bump start the engine.

Just my luck!

You might as well do a spare tire delete too:)

I actually like to keep a spare tire in there just in case. You won't need it until you need it, but I would rather be able to limp to the nearest tire place than call a tow truck or leave the car to go repair the tire.

After some more research it looks like my battery is not the problem. I might be facing a bad starter or simply some corrosion issues. I'll know for sure after tonight. I'm also replacing the distribution box. I don't like the one I have because it has fuses and is too big. Instead I am just going to bolt 3 copper lugs together and mount then on a plastic tab somewhere in the engine bay.

it could also be a bad battery ground....my old del sol had a similar problem...tried to start the car, loud pop noise...all fuses good...get out, get back in...everything works again.

A seven year old Walmart starter battery being used like a deep cycle... Have you had the battery tested?

Some of the honda starters are rebuildable. Usually just the contacts on the solenoid.

Impressive set up. I hope the troubles get cleared soon and easily.

That's exactly how mine works in my 1998 Civic DX.

I have that emergency flat-tire-filler-spray-stuff-in-a-can. Lighter and smaller than the tire.

-james

Where is your battery grounded?? pic?

Battery is grounded to the rear shock tower. It's directly behind the carpet in this picture. It's bolted on one of the shock bolts.
https://lh3.googleusercontent.com/-r...810_194448.jpg

I've got a few tests to do when I get home. First thing I am going to do is clean off the battery ground with a wire brush, on the battery post and the cable connectors. I'll do the same with the positive battery post. I'll see if that is the issue. If not I'm checking the starter solenoid signal wire and the starter power wire for voltage to make sure the starter is getting power and start signal.

If the starter is getting power and signal, and the grounds are good, the only thing left is the battery or wiring. The thing that baffled me was that after I tried to start it, voltage to the whole car would go away for awhile. The fuses didn't blow, and I never really figured out what I did to restore power each time. This is leading me to believe it is a ground issue.

The culprit was a poor ground connection. After I cleaned off the battery posts, and sanded the area on the shock tower, the car starts fine now. I also swapped out the distribution box with just a bolt connecting all the positive leads together. It's mounted on a plastic tab, connected to the fuse box with industrial doubled sided tape.

Sorry for the blurry picture, but it shows the basic idea
https://lh3.googleusercontent.com/-W...813_102056.jpg

I called it!:thumbup:

:thumbup:

I run into this alot at work when the battery has been relocated. Glad you got it sorted out. They make Lugs to connect small gauge wire,Battery Lugs & Crimp Tools, for jobs like this.

I'm not running without the alternator yet. The battery relocation could be completed using the old battery so I decided to go ahead and do that while it's still warm outside. I'll be getting a deep cycle battery within a couple months regardless of whether the current battery dies or not. It's just a matter of spending the money.

The picture is really blurry but I do have 4 gauge copper lugs and a 2 gauge copper lug bolted together onto a plastic tab.

I've got some exciting news... I've found a nice used 1995 Civic CX transmission locally that I may be picking up this weekend. The 92-95 Civic CX transmission is the same as the 92-95 Civic VX. That means going from my current 3.722 final drive to a 3.250 final drive. :)

Are you sure that isn't a flux capacitor?? :D


Looks good! Why did you make the change from the Distribution box?

The distribution box worked fine, but I was experiencing some grounding issues and the car wouldn't start. In order to eliminate the possibility of that dist. box being defective, I decided to simplify the system for troubleshooting. Plus, the box that I bought held 2 ANL fuses. I didn't want to worry about 2 more fuses that are not necessary. Another reason is that I didn't like where I had to mount it. The size and orientation of the cables meant the only place I could mount it was the old battery tray.

Another option I thought about was to take off the fuse box and somehow mount everything to the bottom of it, so that all positive wires were hidden. It might be too close to metal though.

You'll have lean burn and VX gearing and the car starts to become a legend at freeway cruise.

Still working out the details on the transmission. I'm hoping to pick it up Sunday for $50. In this case, the guy swapped his engine/transmission in favor of a higher performance setup, and the stock stuff is considered junk. One mans junk is another mans treasure!

On another weird note, it seems I am having some issues with the EGR system. Ever since I replaced my engine (Feb 2012) I have been getting EGR CEL's. I tried cleaning the passages but only recently did I realize I wasn't cleaning out the ports that connect to the individual intake manifold runners. They were completely clogged, and this was the reason I was getting the CEL. I ordered a new EGR gasket and installed it about the same time I completed the remote battery installation.

So for the last couple days I have had the EGR electrical connector hooked back up (I disconnected it since Feb 2012 so my car wouldn't try to go into lean burn). No more EGR code and it seems the EGR is working again. Still no lean burn (I thought it might fix the issue, but it seems I need a new O2 sensor) but it seems with the EGR functioning I get way worse MPG.

On the first trip to work with the EGR connected I got 42 mpg, scangauge indicated. My normal is 45. It was about 80 degrees with A/C. On the return trip only 41.5 mpg, no A/C. Yesterday on the way to work I tried really hard and got 43.3 mpg, no A/C. Fed up with my poor results, I disconnected the EGR connector for the drive home. 47.3 mpg scangauge indicated without EGR. What the heck?

I plan on running a full tank with EGR connected to verify the mpg numbers on the scangauge. Maybe since the engine is using the exhaust gases again, the scangauge is indicating low? Not only did I notice less mpg, I noticed I had to drive at higher loads than with the EGR disconnected. All I can think is that maybe the extra fuel being cycled back into combustion is causing the scangauge to read incorrectly. I will find out in another week or so after another tank.

Best tank ever! 46.86 MPG! I am still following my 60 mph speed limit on the highway. I am getting better at selecting loads to climb hills so that I use less fuel. I never allow my speed to fall below 55 mph though.

Picked up a CX/VX transmission this morning for $50! Needs to be cleaned. I'm going to purchase a new flywheel and install it within the next couple weeks.

https://lh6.googleusercontent.com/-l...818_105953.jpg

Experiment with a lighter flywheel? What do you think? I have seen guys on here saying in helps a lot in the lower gears and that the VX had a lighter flywheel. Maybe you saw those comments too?

I've thought about it. The racing guys do it to their motors, and a lot of the modifications for racing are about efficiency which also translates into better mpg sometimes. But in this case I don't believe a lighter flywheel will help. From the research I have done here on ecomodder, many seem to believe a lighter flywheel actually hurts because the motor cannot store as much energy. In daily driving duties that stored energy in the flywheel helps when taking off and shifting. The energy the flywheel uses is not parasitic like an alternator or power steering pump. With that in mind I can't see how a lighter rotating mass will improve fuel economy.

The racing guys lighten the flywheel so the motor will rev easier. On the downside for us, lighter means less energy stored. So you would need to apply higher load and RPM for takeoffs, and your RPM's would drop quicker while shifting. The only advantage I can think of would be for EOC. The motor would die much quicker since their is less "momentum" in the engine.

I think the reason the VX came from Honda with a lighter flywheel was because the motor had less power and torque than the standard Civic motors. Obviously a heavy V8 flywheel on a 4 cylinder would feel sluggish. Maybe with the VX's reduced power Honda figured it needed to lighten the flywheel to keep up the throttle response.

The cx and vx have the lighter flywheels of the d-series engines from what Ive read. The vx being around a half a pound lighter of the two.

There are a number of aftermarket companies that make even lighter flywheels for this car.

No matter what you go with, atleast get the old one you have machined to ensure its durability.

Not only that, but when you are rebuilding parts of the car with the EOC in mind you know that you'll be cutting the engine anyway. That stored energy routinely gets "wasted" because we know the energy stored in the car as a whole is better maximized with the engine off. So flywheel weight matters less for us than it seems it would (for a "normal" driver). But then there is also how lots of us get to speed: I do P&G techniques most of the time--nearly all of the time on some routes. That means I'm at 75-80% load and acclerating virtually the whole time I am burning gasoline. I'm often accelerating from stop or low speed, in low gears that spin a lot per mile. Under conditions like that, a lighter flywheel makes sense, right? And at cruise, out on the freeway, I would think a lighter flywheel is less rotating mass for the engine to keep spinning. Seems like a win all around if you do P&G and EOC a lot.

I wish I could go back and do the swap, but someday by 207,000 mile clutch must wear out and then I'll be going back in, maybe with a lighter flywheel ready to go.

james

I think you are correct for P&G driving. This article explains it better than I could:

Flywheel lightening & performance gains from lighter flywheels

I'll probably look into getting a stock VX flywheel or whatever I can find cheapest. I don't see any harm in trying a VX flywheel. I doubt I'll go any lighter due to the cost of aftermarket, and I haven't seen any results indicating I could benefit with my driving style (steady speed highway).

Do we know what the weight of a flywheel on these cars is, exactly? I have heard that my DX probably has a 20 lb flywheel, but I don't know. How heavy is the VX or HX flywheel? Exedy lists flywheels for the sixth gen Si that run as light as 9.5 lbs and claims each pound is like take 50 lbs off the car (I don't believe it).

Id bet that 50lb rule pertains to racing.

And from what Ive read, the vx flywheel is 15lbs 9oz.

The DX and HX of the 6th gen Civic share the same part # flywheel, which is about 20 lbs.

The VX flywheel, I noticed, is about double the price of a regular flywheel (from Honda). If you search parts places like AutoZone or AdvanceAuto, they don't have a direct replacement for the VX. Instead they give you the same flywheel all the other Civics use.

I keep finding more disadvantages to lighter flywheels than I do advantages. Check out this thread (was searching for stock flywheel weight): Flywheel weight? - D-series.org

It seems the 7lbs region is very extreme, and shouldn't be used for street cars. Most of these "racers" prefer around 10lbs. If the VX is around 16lbs, that should be nice balance between the stock 20lbs and the more performance oriented weight. Again, we can only assume at this point if the decreased weight was for fuel economy, or because the VX motor had less power than standard Civic motors.

And I don't buy the claim that lightened flywheels increase HP by that much. They might free up some power because the motor doesn't have to build up speed in a heavier flywheel, but once you are at a steady speed the effects are minimal. Going back to California98Civic's point, a mildly light flywheel (12-16 lbs) could actually benefit P&G driving without effecting driving.

Update to EGR Situation

I just filled up and this tank was 44.21 MPG. It appears my theory was correct, the ScanGauge was reading wrong with the EGR system connected. It was previously calibrated with the EGR system disconnected and not working. Even though 44 MPG is lower than my earlier 47 MPG tank, I blame it on about 100 miles of faster highway driving (65-70 mph) due to me being in a hurry. So I'm convinced everything is normal.

The only issue is that my aftermarket O2 sensor is not performing well. The EGR system is a crucial part of the lean burn system on the HX motor. With it disconnected the car won't try to engage lean burn. With it connected again, it tries to enter lean burn. My low quality aftermarket O2 sensor cannot handle lean burn A/F ratio's, so the car stalls out and stumbles every time lean burn engages. I have to keep the EGR disconnected until I get a new OEM O2 sensor.

Bye bye $360 :(

What o2 is in there now?

Rockauto has an ntk brand sensor (from the makers of ngk) for $240. The bosch is $360. Honestly never liked them for plugs or sensors.

It was the cheapest sensor RockAuto had, I think I paid $170. I get CELs for the front O2 sensor "slow response" and "poor performance". No doubt the car does not like the sensor when its time for lean burn.

But at this point its not a top priority. I can achieve 46 mpg tanks without lean burn, and I hope that increases with my planned projects.

Finally, finally, FINALLY found a decent set of OEM HX wheels for my car. I've been looking off and on for years, trying to find a set with a decent price and no damage. Luckily a guy responded to a wanted ad with these:

https://lh4.googleusercontent.com/-T...o/IMG_6707.jpg

I'm not a fan of the black, but they look to be in good condition. I plan to paint them the original silver color, and get new tires since the ones on there are shot. He's asking $150 which is a decent deal.

Because im cheap, and it wouldn't make economical sense to get rid of my current good tires (that wont fit the HX rims due to being 15 in and not 14 in) I'm going to wait to install them until I need new tires. I've got another 50,000 miles left! With my driving that is about a year. Another long term project added to the list.

Nice find on the wheels! I've been keeping my eyes open for a set as well, but only if I can find them in that price range. I'm due for new tires soon and one of my factory steel wheels has a bent lip, but seems to be holding air.

My car develops in glacial time too. ;)

Nice wheels.

A little update...

I've got the VX transmission ready to install in the car. I opened up the transmission and resealed the casings together with RTV. I could tell that it was leaking fluid from how dirty and oily it was in a certain area. I also installed new axle seals, and cleaned up the transmission a lot.

I've also been underestimating my fuel economy in the logs, by a pretty large amount. I've got tires that are about 1 inch larger diameter than the stock configuration. This setup made my speedometer read dead on, GPS verified. I know most cars actually read slower anyway from the factory, so I figured the larger diameter tires corrected that. Well tonight I measured out my 50 mile commute home, accounting for elevation changes. It came out to 49.9 miles. My ODO read 47.5 miles. 2.4 miles difference is 5%! If you look at my current highest tank of about 46 MPG and apply the correct miles traveled, it brings it up past 48 MPG!!!

I'm going to calibrate the ScanGauge with the correction, and use SG data for calculations from now on. I've got a GPS unit I could try too, just another way to make sure my calculations are accurate.

Go back and correct your log for the different tire diameter, if you haven't already. I did on my Ranger, now I multiply the recorded mileage by 1.026 to reflect the larger diameter tires and I corrected it back to the point when I had the tires installed.

regards
Mech

You might go back and correct your earlier entries like Old Mech says. I did not, because I only became aware of the under count my tires were producing after I swapped the transmission. But ever since the swap I have applied a 1.055 multiplier to the stock odometer reading. That's 5.5%, which I confirmed repeatedly using a GPS and ridewithgps.com ... when I get new tires this fall and switch my front wheels to my 13" VX wheels (like the back ones currently are) I will re-calibrate.