worn out civic hx
 

so i started to try to employ some of the driving techniques from the sight in my worn out 98 civic hx with over 300k on it and super low compression befor i put in my new build im doing and i have seen a good return. i went from a avg of 29mps to 36 avg!

How were you driving before?

like a kid lol

your new build will be replacing the stock engine? or something else?

replacing the stock engine. the compression numbers are way under oem honda speck. i had around 120psi on each cylinder and min is 135psi.i came buy a good d16y5 head at pull a part and got it for a good price.so i decided to build something with economy in mind. and this is what i came up with. im still on the fence about the transmission but may go with a honda vx or even the stock hx trans. im shooting for avg 40mpg with mixed driving and would like to see the old epa numbers of 38 city 45 hwy. i have read that the vx trans will net 1800rpm at 60 mph and net around 60 mpg hwy. ?

im going back to a factory exhaust also this weekend if i have time. the exhaust thats on the car is not what it needs. rightnow it has a 4-1 header with a cat and 2.25 with a 09 civic muffler. it sounds good but has taken away alot of low end torque!

I wouldn't go replacing the head without making sure it's the valves and not the Rings that's the problem. If it's just worn valves, I would recommend a good valve job. It will probably cost more but you will have a basically brand new head and not one with miles already on it.

im not just replacing the head sorry if that what i made you think. i rebuilt the engine top to down. :thumbup:
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Looks great! The only two things I would have done that you didn't was wrap the exhaust with heat wrap (makes the catalytic converter warm up faster) and painted the crank pulley black or blue to match the valve cover.

How long has the clear cam pulley and timing belt cover been on the car? Looks new. I am curious about clouding over time.

the clear cam cover is new and i have not put the engine in the car yet but it is made of lexan so it shuld not turn fingers crossed. some specs on the build. rebuilt d16y5 head. a d16y8 block that was bored .50 over. .50 over bore d16y8 pistions and d16z6 oem rods. a d16y5 crank and oem honda bearings. the head was shaved .006 to straten it. the head gasket is a bismoto single layer gasket thats .009 thick.all this is going to put me at 10.49 to 1 compression.

In my opinion you should put a GT15 turbo on it as well, and run 6psi boost, the extra torque would really help you getting up to speed and will allow you to have 'fun'.

Curious, I am surprised Balto did not recommend against using a VX transmission, he says he did that, and hated it! I believe he said fifth gear was so low he could not use lean burn.

Absolutely do not use the VX transmission. It SUCKS and lowered my highway mpg by 3-4 due to not being able to get into lean burn in 5th.

Yeah, if I remember right, you had difficulty reducing weight and aero load enough to sustain LB at speeds that still made sense for FE, or was that someone else? Was that the scenario?

Yup, exactly my scenario. In hindsight, it may have been my tires that were hindering my efforts, or my somewhat low compression on one cylinder (was ~12% off over the other three) but in the end, I wish I had stuck with the HX transmission. It was still 'peppy' but also cruised at a nice RPM at 70 (about 2700).

I'm probably going to be buying another HX soon (~ 6 months) but I'll be going for more performance orientation over FE. The engine/transmission will be stock, but I plan on putting a GT15 turbo, upgraded suspension/decent sounding exhaust, etc etc.

You and your turbos! :) Why do you discriminate against superchargers? :)

Mmwwhahahha! You have some serious CARB mojo, hey. (Sorry if I hijacked the thread a little.)

I have a guy that will smog any car for me, regardless of how modified it is, illegal, etc etc. As for superchargers, I PREFER superchargers over turbos, but Superchargers are much, much more expensive...

that went way off in to left field lol. thanks for the info on the vx trans that would have sucked.

98hxman, I drove a '97 HX for about 5 years. Had a lot of fun with it.

I never cleaned out the egr manifold on it and wish I had. When it's even partly clogged it makes it really hard to hold car in lean burn. If you didn't already clean it, be sure you do that while you have things apart. It's on the back side of the engine. On the HX I'm told its below the injectors so you have to pull them to get to the egr manifold. You can count on it being mucked up, unless you cleaned it yourself. Good to clean the egr valve too of course.

i have cleand the egr system and plan to when i swop the manifold to the new engine

Have you noticed any difference after cleaning the EGR?

the check engine light went out. other than that not really its to far gone to see any gane the car will not even hold lean burn at this point :(

My red hx is worn out as well. It's getting 32mpg city, I've never gotten that low in an HX ever. My black car will get 38mpg without sleenizing but it's a low mileage car

I'm not even going to bother with compression testing my red car, probably going to be low too. one thing I am going to change however is the catalytic converter. I'm not getting a check engine light however it has a gas stench out of the tail pipe.

I mention that because I can tell you re used the old factory 300k mile catalytic converter. New cats are 2 pieces compared to the factory one piece

Cheers

http://i758.photobucket.com/albums/x...psrbdvxes2.jpg

The clear cam cover holds up pretty well over time. It gets a little dirty after a while but no yellowing or anything


http://i758.photobucket.com/albums/x...ps0svwif0l.jpg


My red car is at 242k miles and has a very noticeable lack of power compared to my 159k mile black hx, which should not be the case since I have tons of new parts on my red car. Which leads me back to the poor performance of the red car.

Red is actually a California spec ecu, black is federal. Putting in a federal ecu did not increase lean burn in red, or gain any gas mileage, and the car still can't maintain lean burn.

The most likely causes for reds problems:
Clogged egr port on cylinder head disrupting egr flow, or filthy intake manifold
Poor catalyst effeciency disrupting primary oxygen sensor readings

http://i758.photobucket.com/albums/x...psjin3vpye.jpg

You might try wet and dry compression tests on Red. Have you? The EGR and intake can be cleaned too, while you're at it.

Egr has been cleaned with no benefit other than the check engine light being gone for over 1200 miles now.

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Sorry it does not seem solved yet. How do you know LB is not engaging? That CEL going off is a benefit, I'd suggest, since it is one of the things you cannot have for the ECU to allow LB at all. You're getting closer.

Fixed my issues staying in lean burn. My ac system pressures were messed up because of a bad expansion valve, causing my compressor to surge and cut off occasionally. Now that the compressor is functioning normally the car will stay in lean burn without any effort.

How do I know it's in lean burn, I've had 4 hx's in 3 years so it's easy to tell when you need to go from 30% throttle to 50% throttle to maintain speed. If you've ever driven a properly functioning hx on the highway it feels like you're dragging a parachute because the car takes so much throttle to stay at speed.

ok so i have a update. it has been some time from the last post for me with work and the car. i have installed the new engine and trans in my car. if you guys recall this engine is a hand built d16y8 block that is the same as the d16y5 that came in the hx cars. i over bored it .50 over and bumped the compression to 9.99 to 1 from the oem 9.4 to 1. i rebuilt the head and re did almost every part of this cars engine. installed arp head studs and a block guard so i can go with a turbo in the future.im still in the set up part trying to get all the fine points set up to have it running like it shuld. best mixed mpg i have seen it 36 mpg at speeds of 60 to 70 mph with a 4.08 finle drive trans. i know it can do better lol.as of now im not doing any hypermile driving just driving day to day like i do to see what it will get as a good base line.
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4.08 gearing, so you shortened the gearing up, why? The stock HX is 3.73, BTW.

You engine bay poc shows an exhaust manifold on which the upstream O2 sensor is missing. If that is how you are actually running, how are you managing fuel trim? You cannot get lean burn that way. Also, Balto's question above. Your gearing is too short. Given all these mods, I'd say 36 mpg at 60 mph sounds increadibly good. You'll likely get much lower numbers on average. Engine bay looks great, though. Seems you ae building more of a street racer than a fuel sipper. Is that what's up?

im using a 4-2-1 oem manifold off of a 98 civic ex with the cast upper 4-2 part. it alows you to use the oem 5 wire and read all 4 cylinders right after the head ports and make the most low to mid range torque.
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as for the 4.08 final drive out of the lx civic 4 door. i used this for the build because of the toques multiplication of the shoeter gearing and the rpm range that the hx likes to use lean burn is 2200 rpm up to 3200 rpm. this gearing puts me in the ideal rpm range in 5th gear at 60 to 70 mph. 60 mph =2400rpm and 70 mph= 2900rpm. this also drops the lode on the engine and i can get lean burn in all gears but 1st.

Oh, yeah. That O2 is a bit lower. I could not see it behind the AC exchanger (I took mine out). Where did you read about that RPM band for lean burn? For example here is a guy who says 1800 to nearly 4000 (!) works: http://ecomodder.com/forum/showthrea...tml#post473444

Just wondering... there is a lot of contradictory info out there!

i have a few ways to watch lean burn in my car and im as master ase tech so i have alot of acces to oem info. the vx had a low rpm lean burn mode and the hx has been said to have it also but the the hxhas whats like a variable leanburn that will pick how lean to go baced on feed back from the sensors. i have seen low rpm leaning out in the 16.1 afr but have not seen lean burn ie 19.1 and lower till 2200 and not past 3200 rpm i have 2 defrent ecus for my car both non cali and they act the same. i have a new ngk 5 wire. have set the fuel presser to the oe speck. new bosh ev6 injectors that are the oem 185 cc and a spotless egr system so all the systems are working lol. i also watch true rpm feedback from the ecu so its dead one.

The shorter gearing really makes the car more fun to drive and increased my gas mileage because you could get into lean burn at lower speeds. I think on my black car in the sig I could get into lean burn at 52mph and it would stay in lean burn down to 47mph. It also had a replacement flywheel that was not oem so it was heavier, I could hear the idle air control valve constantly fluttering at idle to keep the car at its idle speed from the extra weight

The y5 had dished pistons and lower compression. The new higher compression car probably isn't as effecient as the lower comp one in lean burn because it's adding more fuel to less air volume. Probably runs alot better though, but no advantage to gas mileage.

To update my trolling in page 2 my red car has been getting 42mpg city after fixing a major oil pan leak and replacing the factory pcv valve

i used .50 over bore y5 pistons so the shape is the same. the higher compression is from the .009 head mill and the .030 3 layer head gasket.