1997 Civic CX to HX engine/VX trans swap! 63 MPG @ 62 MPH

[hat_man]

New to this thread and not a mechanic by any stretch or even a Honda guy so please bear with me. I have read all 14 pages though and kind of get the general jist of this awesome swap.

Can you tell me (and everyone else that has made it this far) what your current set up is and why you chose the options you did? Engine/trans/ecu/tires/etc? You may have to dumb it down a bit for guys like me though.

Also,and this may get answered in the responses from above, is the HX trans the "new" VX? What is the ratio in each gear? What is your final drive ratio and are there any more options to improve on that or are you "mechanically" as good as it gets? Or at least as good as it gets for being a practical daily driver.

This has been one of the most interesting threads (for me at least) and I don't even know anything about Hondas. I wonder if this could all be put into an early CRX. 85-88 HF's seem to be really light and, not having ever put them into the template, I wonder if the CRX is better or worse than the DX in the aero arena.

I know this would be a long reply (if you even have the time) so I'll just keep checking back. I can't wait to see what your numbers can be after some aero mods. Absolutely great swap and pictures and write-up. Congrats! I'll be watching this one for a long time.

[California98Civic]

Originally Posted by hat_man

New to this thread and not a mechanic by any stretch or even a Honda guy so please bear with me. I have read all 14 pages though and kind of get the general jist of this awesome swap.

Can you tell me (and everyone else that has made it this far) what your current set up is and why you chose the options you did? Engine/trans/ecu/tires/etc? You may have to dumb it down a bit for guys like me though.

Also,and this may get answered in the responses from above, is the HX trans the "new" VX? What is the ratio in each gear? What is your final drive ratio and are there any more options to improve on that or are you "mechanically" as good as it gets? Or at least as good as it gets for being a practical daily driver.

This has been one of the most interesting threads (for me at least) and I don't even know anything about Hondas. I wonder if this could all be put into an early CRX. 85-88 HF's seem to be really light and, not having ever put them into the template, I wonder if the CRX is better or worse than the DX in the aero arena.

I know this would be a long reply (if you even have the time) so I'll just keep checking back. I can't wait to see what your numbers can be after some aero mods. Absolutely great swap and pictures and write-up. Congrats! I'll be watching this one for a long time.

I'll just answer the VX/HX question. The HX is the sixth generation successor to the fifth gen VX, and it has lean burn, vtec-e, and all the other goodies, besides also being OBD2 (the engine control computer type). But the HX had somewhat shorter gearing, a 3.75 final drive and some shorter gears, except 5 I think. Here are listings of D-series honda engine transmission gear ratios.

Also, search this site for VX engine swaps into the CRX... one or two people have done it. Though I would think a better option would be the 99-00 HX engine with a 92-95 VX or CX tranny, swapped into the CRX body. The engine would be newer, OBD2, modestly more power, and super tall gearing.

[turbovr41991]

Originally Posted by hat_man

New to this thread and not a mechanic by any stretch or even a Honda guy so please bear with me. I have read all 14 pages though and kind of get the general jist of this awesome swap.

Can you tell me (and everyone else that has made it this far) what your current set up is and why you chose the options you did? Engine/trans/ecu/tires/etc? You may have to dumb it down a bit for guys like me though.

Also,and this may get answered in the responses from above, is the HX trans the "new" VX? What is the ratio in each gear? What is your final drive ratio and are there any more options to improve on that or are you "mechanically" as good as it gets? Or at least as good as it gets for being a practical daily driver.

This has been one of the most interesting threads (for me at least) and I don't even know anything about Hondas. I wonder if this could all be put into an early CRX. 85-88 HF's seem to be really light and, not having ever put them into the template, I wonder if the CRX is better or worse than the DX in the aero arena.

I know this would be a long reply (if you even have the time) so I'll just keep checking back. I can't wait to see what your numbers can be after some aero mods. Absolutely great swap and pictures and write-up. Congrats! I'll be watching this one for a long time.

Thanks for the interest and the patience to read the entire thread.

There are several other people doing this well if not better. Most people are using the VX engine and trans setup there. I honestly was considering swapping in a VX engine into my car, but HX’s seemed to be more common. I also liked the fact that it had a little more power and could maintain speed a little better on the highway.

The current setup on the car is:
Engine: a stock D16Y5 from a 97 Civic HX
Transmission: Stock trans from 94 Civic VX
ECU: Chipped P06 with Neptune software. (Still testing this out, seeing great potential)
Tires: Michelin Defender. (Mild LRR tire but has 90k tread life.)
Others: HX wheels, upper & lower grill block, antenna relocated to inside, side mirrors relocated to inside, kill switch, etc.

This setup would work easily in a HF CRX. I believe you could even keep the stock HF trans as it should have better gearing than the VX trans.

I would have explored lighter/ sportier options for vehicles, but I needed to keep a back seat for my family. Otherwise I could have explored the options with a CRX, Del Sol, or Insight.

I guess to really answer your aero question, we need to know what year and model DX you are comparing it to. 92 DX hatchbacks has a different CD than a 96 DX hatchback. Similarly, hatchbacks vs. Coupe or sedan have different CD’s. A lot of times you can find these swaps already done in the for sale section on here. I think in the past year there have been several VX swapped Del Sols and two swapped CRXs

Thanks again for all the kind words. Really looking forward to doing some more aero on the car, but realistically, It is probably a month out before I have the time to start the project. I will be sure to post lots of pictures though.

[Jakins]

So how has the new tune been treating you? Better then stok with lean burn? What is your a/f with it? And is there any way you could send me the bin file so I can try it too?

[turbovr41991]

Originally Posted by Jakins

So how has the new tune been treating you? Better then stock with lean burn? What is your a/f with it? And is there any way you could send me the bin file so I can try it too?

I like the tune a lot. Still needs some tweaking, but overall it is a huge improvement. Currently I am running on average 17.5:1 air fuel which I think is a little more conservative than stock (Compared to stock lean burn situations.) I guess a high level summary of pros and cons would be helpful.

Pros
1) Instant lean burn when you want it. No fumbling around trying to get the right speed/throttle/rpm, resetting the ecu, waiting for it to kick in, distracting me from driving, etc. It is especially nice now as I can EOC, bump start the car, and be right back in lean burn for the pulses to get back up to speed.
2) Enhanced monitoring with a tunerview2
3) More power over 3k RPMs. (I never thought I would care about this one until I took a trip through West Virginia. Those hills were BRUTAL!)
4) Eliminates the need for an expensive 5 wire O2 sensor and EGR valve.
Cons
1) Not as aggressive lean burn. I no longer can cruise on the highway at 63 mpg at a steady speed of 60 mph(As if I set cruise control.) In testing I seem to be getting 53-54 mpg under the same conditions with the ECU. Expect this to improve with further testing.
2) Loss of OBD2. Not too important for me, but some people need the port to work to pass inspections or to utilize existing OBD2 monitoring. The setup is pretty easy to unplug and swap back to the OEM ECU if needed though.
3) Cost. Some people might not want to spend the money upfront for potential fuel savings.

Not really sure how to pull the bin file, but even if I could, I do not want to discredit the work of the tuner and the shop by giving away what they have worked on to perfect. I would suggest contacting them to see if this is something they are willing to do. They did this work as a “public service” but I think they still are hoping to get something in return for all their hard work.

[ultimx]

Originally Posted by turbovr41991

I like the tune a lot. Still needs some tweaking, but overall it is a huge improvement. Currently I am running on average 17.5:1 air fuel which I think is a little more conservative than stock (Compared to stock lean burn situations.) I guess a high level summary of pros and cons would be helpful.

Pros
1) Instant lean burn when you want it. No fumbling around trying to get the right speed/throttle/rpm, resetting the ecu, waiting for it to kick in, distracting me from driving, etc. It is especially nice now as I can EOC, bump start the car, and be right back in lean burn for the pulses to get back up to speed.
2) Enhanced monitoring with a tunerview2
3) More power over 3k RPMs. (I never thought I would care about this one until I took a trip through West Virginia. Those hills were BRUTAL!)
4) Eliminates the need for an expensive 5 wire O2 sensor and EGR valve.
Cons
1) Not as aggressive lean burn. I no longer can cruise on the highway at 63 mpg at a steady speed of 60 mph(As if I set cruise control.) In testing I seem to be getting 53-54 mpg under the same conditions with the ECU. Expect this to improve with further testing.
2) Loss of OBD2. Not too important for me, but some people need the port to work to pass inspections or to utilize existing OBD2 monitoring. The setup is pretty easy to unplug and swap back to the OEM ECU if needed though.
3) Cost. Some people might not want to spend the money upfront for potential fuel savings.

Not really sure how to pull the bin file, but even if I could, I do not want to discredit the work of the tuner and the shop by giving away what they have worked on to perfect. I would suggest contacting them to see if this is something they are willing to do. They did this work as a “public service” but I think they still are hoping to get something in return for all their hard work.

Even if u did pull the bin file its still going to be different even if the setup is the same. All engines arent the same. The bin might be close but it's not going to work exactly like urs.

[turbovr41991]

Update. with the warmer weather I have had a couple 70 mpg tanks and several in the high 60's. Making alot of progress.

About to be putting it up on jack stands to redo a few things and add a belly pan and maybe a kammback!

[MakitaDiesel]

Finally got a refreshed '95 CX tranny into my '97 HX powered Hatch, have yet to tag it but the test drive was both promising & surprising. My first project, the '89 CRX HF + D15Z1 (VX) engine is getting better mileage but not without excruciatingly annoying quirks (iffy idle, bucking/jerking in gear deceleration, etc) so it may come down to which one I can live with on a daily basis. Selling one would open me up to ECU tuning the other, lean burn maximizing from the info you've given here. We'll see...Do you still have the shop's # or website info for a tuned ECU or to ask questions? Thanks in advance,

Mak

[Jakins]

Originally Posted by MakitaDiesel

Finally got a refreshed '95 CX tranny into my '97 HX powered Hatch, have yet to tag it but the test drive was both promising & surprising. My first project, the '89 CRX HF + D15Z1 (VX) engine is getting better mileage but not without excruciatingly annoying quirks (iffy idle, bucking/jerking in gear deceleration, etc) so it may come down to which one I can live with on a daily basis. Selling one would open me up to ECU tuning the other, lean burn maximizing from the info you've given here. We'll see...Do you still have the shop's # or website info for a tuned ECU or to ask questions? Thanks in advance,

Mak

That crx will be sick man. I got all the info for these dudes but they said they arnt selling any right now. Which made me sad.

[cbaber]

I have the same question as Mak, any contact information for this shop? My front o2 sensor is not working with lean burn. It's brand new, but it's not OEM brand. When the car tries to go to lean burn it generates a CEL and quickly returns to normal mode. Rather than buying the $360 OEM sensor I believe a chipped ECU would be money better spent, especially if it gets rid of the EGR system that is also acting up on me.

Thanks!