1998 Civic LX to HX D16y5 conversion has begun!

[Chrysler kid]

Oh you just said pending my bad. Congrats on getting everything completed so quickly!

[firehawk618]

Thanks!

[figit090]

great job that was a pretty quick swap, I'm excited to see how your miles per gallon does! if I don't find an HX soon I might actually start looking for a cheap four door and an inexpensive HX drivetrain to do this.

[firehawk618]

Yes I am excited to get a few regular commuting tanks in myself.

Ignore my claimed MPG showing up in my signature. I put a log in to test and apparently deleting it didn't make it go away. Worst case scenario I will delete the car and start over.

Keep in mind, my daily commute is ~12 miles each way and not a lot of highway time. Seriously doubt if I'll see much LB on my daily commute.

[figit090]

Originally Posted by firehawk618

Yes I am excited to get a few regular commuting tanks in myself.

Ignore my claimed MPG showing up in my signature. I put a log in to test and apparently deleting it didn't make it go away. Worst case scenario I will delete the car and start over.

Keep in mind, my daily commute is ~12 miles each way and not a lot of highway time. Seriously doubt if I'll see much LB on my daily commute.

Seems fine now, hows the fuel burning going? filled 'er up yet?

[firehawk618]

To be honest I haven't had a true tank to judge from yet.

I have been doing lots of testing / tuning.

So far doing the above it's been ~40 mpg.

I am really hoping for a true 45 when I am done.

I just got the MPGuino installed and am working on dialing it in. I have the speed nailed down but will not know if the injectors are for 1.5 weeks or so. I expect dialing the injectors in to take 4 tanks or so.

I did score a VX transmission and am picking it up this Friday. I plan on installing it Sunday perhaps.

I will never really know what kind of MPG I can get from the LX gearing but can certainly say the shorter 5th gear isn't helping things after watching the MPGuino while driving.

It seems, even with LB capability that lower RPM's is going to be the key.

I have proven to myself that lower RPM's > LB by monitoring 5th gear at a steady speed that's too low for LB then dropping to 4th to raise the RPM's and kick in LB while watching the MPG's.

[figit090]

Originally Posted by firehawk618

To be honest I haven't had a true tank to judge from yet.

I have been doing lots of testing / tuning.

So far doing the above it's been ~40 mpg.

I am really hoping for a true 45 when I am done.

I just got the MPGuino installed and am working on dialing it in. I have the speed nailed down but will not know if the injectors are for 1.5 weeks or so. I expect dialing the injectors in to take 4 tanks or so.

I did score a VX transmission and am picking it up this Friday. I plan on installing it Sunday perhaps.

I will never really know what kind of MPG I can get from the LX gearing but can certainly say the shorter 5th gear isn't helping things after watching the MPGuino while driving.

It seems, even with LB capability that lower RPM's is going to be the key.

I have proven to myself that lower RPM's > LB by monitoring 5th gear at a steady speed that's too low for LB then dropping to 4th to raise the RPM's and kick in LB while watching the MPG's.

awesome, can't wait for some solid results! I'm having a HELL of a time finding an HX. One guy (one owner) said he'd reconsidered and won't sell it. Another was way too much at $4k starting price, no A/C and some previous body work.

NOW....one I had as a reserve/last resort...has BEEN STOLEN. I was going to ask about it, and noticed it was no longer parked at a nearby chevron. I searched for my want-ad on my local facebook and BAM saw the "our car was stolen" post about the same damn car I was going to inquire about.

I haven't given up yet, but honestly I am contemplating a clean-swapped HX-EX/LX setup.

If I find an engine, tranny, and harness from an HX, can it drop right into an EX or LX? I honestly feel like that might be easier, or faster.

[firehawk618]

Originally Posted by figit090

awesome, can't wait for some solid results! I'm having a HELL of a time finding an HX. One guy (one owner) said he'd reconsidered and won't sell it. Another was way too much at $4k starting price, no A/C and some previous body work.

NOW....one I had as a reserve/last resort...has BEEN STOLEN. I was going to ask about it, and noticed it was no longer parked at a nearby chevron. I searched for my want-ad on my local facebook and BAM saw the "our car was stolen" post about the same damn car I was going to inquire about.

I haven't given up yet, but honestly I am contemplating a clean-swapped HX-EX/LX setup.

If I find an engine, tranny, and harness from an HX, can it drop right into an EX or LX? I honestly feel like that might be easier, or faster.

It's really not hard if you are mechanically inclined.

I will say that the 97 HX, engine, harness and ECU was a plug and play affair into my 98 LX.

If you start with a 98 it will definitely plug right in no matter the sub model IF you start with a stick and swap in a stick.

If you do a 96 or 97 some have the fuel tank pressure sensor, others do not and if you swap the HX stuff into one that does not that will add work.

I am picking up a complete VX engine, trans, harness, ecu this weekend.

I have no use for the engine / ecu / harness.........

I consider myself lucky with the HX setup I bought. It was 100% complete from a JY for $500

When I dropped the oil pan, valve cover it was very clean inside.

Now that I have my new MPGuino installed I went and topped off my tank. It came out to 40.5 mpg. 146 miles, 3.6 gallons.

[figit090]

Originally Posted by firehawk618

It's really not hard if you are mechanically inclined.

I will say that the 97 HX, engine, harness and ECU was a plug and play affair into my 98 LX.

If you start with a 98 it will definitely plug right in no matter the sub model IF you start with a stick and swap in a stick.

If you do a 96 or 97 some have the fuel tank pressure sensor, others do not and if you swap the HX stuff into one that does not that will add work.

I am picking up a complete VX engine, trans, harness, ecu this weekend.

I have no use for the engine / ecu / harness.........

I consider myself lucky with the HX setup I bought. It was 100% complete from a JY for $500

When I dropped the oil pan, valve cover it was very clean inside.

Now that I have my new MPGuino installed I went and topped off my tank. It came out to 40.5 mpg. 146 miles, 3.6 gallons.

so we're talking 96 and 97 chassis' have a fuel tank pressure sensor, or the HX engine from those years needs one?

That's awesome MPG, did you do any technique or manage to get lean burn or is this just ordinary driving and no lean burn?

[firehawk618]

Originally Posted by figit090

so we're talking 96 and 97 chassis' have a fuel tank pressure sensor, or the HX engine from those years needs one?

That's awesome MPG, did you do any technique or manage to get lean burn or is this just ordinary driving and no lean burn?

I have stopped trying to force leanburn to happen. I have found I'm much better off to just use 5th gear even though that may put me at too low of RPM's for LB to happen.

When I do get the VX gearing installed I will basically lose any chance of LB when in 5th gear unless I'm above 70mph. I will again experiment with a lower gear to get LB vs lower RPM.

One thing I have been doing now though is killing the engine at stops when possible and EOC everywhere possible.

My commute to work is mostly uphill travels therefore my commute home is a lot of down hill travel. I have been taking advantage of this. I can coast roughly 4 miles every day!


Here's the breakdown about the sensor I was talking about, bare with me as honda made this as confusing as possible.

Fuel tank pressure sensor:

1996 EX only has it
1997 Coupes all have it IF they are EX or HX
1997 All California emissions cars have it
1998 All cars have it

If you find a 1999 or 2000 don't bother unless it's already a HX. The reason is honda went from obdiia to obdiib in 1999 and the body side of the harness is completely different. It will NOT be plug and play HOWEVER the HX stayed obdiia it's entire span from 1996 to 2000.

One work around I can think of is get an ecu from a 96 HX as it will not expect this sensor therefore you won't have to mess with it.

Confused now? lol

Honestly I would say just get whatever chassis you can as long as it's 98 or older and whatever HX swap you can and make it happen. The worst case scenario you will have to swap fuel tanks and run 2-3 wires.

I just got REALLY lucky I started with a 98 LX and stumbled upon the swap out of a 97 HX. The stars and planets aligned for the easiest possible conversion. I had to run ZERO extra wires and had to re-pin ZERO connectors. Straight up plug in and go.

I do really like the D16Y5. It has SO much more bottom end torque than my D16Y7 or D16Y7 with the Y8 head EVER did. It's really easy to putt along at 1200 rpm's and even take slight inclines without down shifting.

It seems like this engine is impossible to lug.