Honda CRX/Civic Del Sol - B16a2 OBD1 to B18C6 OBD2a - DBW - Wideband - Knock (Daily Eco driver)

[shanky]

Hey All, I know it is nothing special, but I imagine plenty of people were wanting to do this to a civic of their choice and perhaps could of done with a guide - or outline of what it takes, so I will do a write up. (I am not a professional to be clear) Project is still ongoing and looking to eek more and more mpg out of the old girl. And I imagine there are better ways of doing a better job! My name is Christopher and I am from the UK I have recently purchased a Ferrari Mondial and plan on dropping a K24 in it, hopefully putting a link in that car too!

I will drop in the thread my pin outs and my adaptions on the harness converter to help anyone who needs support.

Car info -

1993 Honda Del Sol / OBD1

Car was an OBD1 B16a2 and used a an OBD1 to OBD2a adapter loom (a reverse loom I believe is what they call it https://www.speedfactoryracing.net/products/speedfactory-obd1-to-obd2a-reverse-ecu-conversion-harness?_pos=2&_sid=51c622e73&_ss=r)

I chose a B18C6 Engine which is OBD2a. Using an S80 LSD box with 4.7 FD, with a Integra LS 0.714 5th gear to eek out more mpg / lower revs at motorway speeds (has a handy shorter ratio 1/2/3rd gear too)

Items used so far -

Purchased an OBD2a HC96X unit - as this had knock sensor input vs the 92x (still need to setup) - I would argue after buying the below ethrottle and wideband module, perhaps the standalone units monsoon/open loomed etc would of been a better choice - but the plug in capability was a great appeal to me.

Link Ethrottle Module

Link Wideband Module

2x Link Expansion cables

OBD1 female to OBD2a male adapter loop

3D printed throttle body adapter (carbin fibre mixed extruded)

I chose a Bosch ethrottle / 68mm - I chose this as it calculated out at closer to the OEM throttle body volume, as the smaller, yet similar in diameter to OEM throttle body was lower in area due to the size of the butterfly's centre support. The honda throttle body had a machined down spindle for greater flow. I imagine the bosch unit is a lot sturdier due to its use in turbo aplication - https://www.bosch-motorsport.com/content/downloads/Raceparts/Resources/pdf/Data Sheet_68749835_Electronic_Throttle_Body.pdf

For APS or PPS depending from where you are from - The ePedal I chose a rather generic and widely available unit from an Audi TT  / Audi TT 8N 6 Speed Automatic Accelerator Pedal 8N2723503B. This unit had a kick down feature in the form of a sprung bump stop, so nothing flashy there.

I also used a OBD2a distributor from the Integra DC2 to ensure the correct ignition system (Honda Acura OEM Ignition Distributor Assy 30100-P73-A02(TD-87U) B16 B18 CIVIC) with a OBD1 to OBD2a 10pin Converter. This was genuine and meant for the B18C6 engine. Be aware you will need to match (I believe) the trigger arming thresholds if you use the earlier OBD1 distributor, as when I was experimented it was the difference between firing up and not!

I also converted the cars carbon canister activation / aka purge valve to a PWM Purge valve from the later b18 Integra. Not required but I wished to do so to ensure maximum fuel vapour recorvery from the tank.

Base Map usage - "Honda Civic 96-99 G4X Xtreme Plugin not tuned"

Pinout Diagram

Google Sheet of Pinout - this is my active export - so I will be changing things as I go on based on my requirements.

 

Active Discussion

Open question and discussion thread I have on going - Purchase and Questions

 

I will follow up with more detail as time goes on!

 

 

 

[shanky]

Here are the OBD1 and OBD2a pin outs

https://docs.google.com/spreadsheets/d/1nzmWjTXbOE_ahcjIUDzNgva-g7iIL0AE/edit?usp=sharing&ouid=110945455569194839967&rtpof=true&sd=true