worn out civic hx

[Baltothewolf]

4.08 gearing, so you shortened the gearing up, why? The stock HX is 3.73, BTW.

[California98Civic]

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?

[98hxman]

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.

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.

[California98Civic]

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!

[98hxman]

Originally Posted by California98Civic

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.

[Chrysler kid]

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

[98hxman]

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.