Thinking of Civic DX to HX Conversion (lean burn engine)

[PaleMelanesian]

Higher pressure will not wear the centers of the tires. Not since we started using steel belts. I've witnessed even wear with high pressure on three sets of my own tires.

Try adjusting the driver. It's worth a lot of mpg, especially in a 1996 Civic DX.

[Pendragon]

Originally Posted by PaleMelanesian

Higher pressure will not wear the centers of the tires. Not since we started using steel belts. I've witnessed even wear with high pressure on three sets of my own tires.

Try adjusting the driver. It's worth a lot of mpg, especially in a 1996 Civic DX.

That is interesting. I have seen some that were badly worn in the center from over inflation. I guess it may depend upon the particular tire.

Yes, indeed, the operator can make a huge difference.

Cheers

[California98Civic]

Bump. It is possible that I will need a new ECU (i.e. ECM/PCM) in order to resolve my ongoing running problems. They cost $819 from the dealer, and my dealer says the 1998 DX ECU is no longer manufactured. Therefore, if I really need a new one, here's my chance to switch-out for something else. To work properly, the HX ECU would require an HX head, different spark plugs, EGR, and a wideband O2 sensor but nothing else, correct? I guess, alternately, I could chip an OBD1 DX ECU, perhaps. Thoughts?

[PaleMelanesian]

Here's one thought. $681 is a better price and it's still OEM. You have to install, but I think you can handle that.
Honda Automotive Parts

You'll still be missing the HX gear ratios with those swaps. Or, do you already have that VX swap in place?

[California98Civic]

Originally Posted by PaleMelanesian

Here's one thought. $681 is a better price and it's still OEM. You have to install, but I think you can handle that.
Honda Automotive Parts

You'll still be missing the HX gear ratios with those swaps. Or, do you already have that VX swap in place?

Yup. That's the HX ECU (ECM/PCM). When searching for a DX one, I get everything but the ECU on the list, seemingly confirming what the local dealer told me. The HX conversion would be more work, and I would have preferred the chance to plan and learn. But maybe this is motivation! My plan re: the gears is to try this substitution of the final drive from a 1992 VX I bought for $58 shipped, with the countershaft. It should slip right into my tranny and actually give me taller gearing than the HX. Then I'll shorten the gearing a little with the VX wheels I have and be about 10% taller than a stock HX with maybe 80lbs less rotational mass and unsprung weight.

So does anyone know if I would need to swap for the full HX air intake manifold or is their a way to add EGR to the existing DX manifold? I am guessing my answer is no.

[PaleMelanesian]

I'm pretty sure you have to swap it all. Again, I'd wade into honda-tech for more details. I'm sure most of them are doing DX-EX swaps but the main difference would be part numbers.

Here's one. Pics are broken but the words are still there.
http://honda-tech.com/showthread.php?t=735196

[sk8lyfestile]

I was reading the thread and and going to clarify how andwhy vtec-e works. Basically it does not have the performance Vtec that activates after 5k. But under 3k half the intake valves don't open at all and one stays barely open. Not for the "swirl affect" but for a leaner fuel/ air ratio. Along with the harness they are a few differences with the swap. Not sure if your header has a cat. conv but that very local o2 sensor enables it to check its unburned fuel quicker than the catback cat. conv. Other than that its mostly up to the really long geared hx transmission that lets it get the higher mpgs. Personally i'm going to switch out my hx tranny for an ex as a comfort upgrade for city driving. You really have to drive it with a light foot to get the lean burn to kick in at lower mph. but after first gear you could comfortably use 2nd up to 55 mph(street racing?) and 3rd to 100mph. You could get a new head(roller rockers!), harness, tranny,ecu, and intake manifold(slightly smaller/ higher pressure), for a complete frankenstein swap. But frankly thats alot more money and work for a 45-50 mpg car. think of the long run. you will find 100k+ mile used parts and invest well over 1500 bucks for that swap and run it for another 100k if everything was done perfectly. while you can run your current engine into the ground and just get a whole new(60kish) ek ex/dx/vx(manual hopefully) swap. I get a steady 38+ rural country and city driving. with my 165k hx without aero mods on stock pos tranny with 2 12's in the back,(not as eco as many of you / my advice is run urs into 300k while saving for a used hx. they are out there, they just take an extra month or 2 to grab. If you ever find a young HX buy it up and mod the **** outa it. i'm willing to bet they can hit 90+mpg. surprised they haven't yet

[sk8lyfestile]

@rkcarguy, The warm mix of the fuel/air ratio is only so it comes up to engine temps quicker. resulting in its fuel economy. being from upstate new york my car really needs to warm up significantly before i start driving it for your stated reasons. I agree with you totally but in terms of fuel economy. its always safer if you don't have an hx to go cold air or go home. Short rams are worthless too.

[ron]

every car with a standard oxygen sensor could benefit from a wide band sensor. if you have a 2 or 3 wire sensor for about 70bucks and a search DIY on how to convert to a 4 or 5 wire wide band oxygen sensor now referred to as sensor oxygen meter,the old sensor told the ecu too lean or too rich , or the bang bang effect. the newer meters are capable of (metering fuel ) well the ecu uses the info to meter fuel. should be worth about 3 to5 % so you can figure payback mileage. note an oxygen sensor fails to properly cycle at around 70,000 mi , so you might need a new one anyway. cheaper and less hassle ,only about 2 to 4 hrs max.

[California98Civic]

Originally Posted by ron

every car with a standard oxygen sensor could benefit from a wide band sensor. if you have a 2 or 3 wire sensor for about 70bucks and a search DIY on how to convert to a 4 or 5 wire wide band oxygen sensor now referred to as sensor oxygen meter,the old sensor told the ecu too lean or too rich , or the bang bang effect. the newer meters are capable of (metering fuel ) well the ecu uses the info to meter fuel. should be worth about 3 to5 % so you can figure payback mileage. note an oxygen sensor fails to properly cycle at around 70,000 mi , so you might need a new one anyway. cheaper and less hassle ,only about 2 to 4 hrs max.

But do you think the DX ECU I have will be able to "read" and use the data for engine management?