K20 project off to a good start

DSobota

Daily Driver
Roger, Thanks I will be starting a thread and posting my progress. I thought that maybe you ran into a specific problem with tying in the rear cross member and routing the exhaust. This site is a rabbit hole for a new guy like me. Loads of information. Great stuff. Many talented people. I have chatted with and visited MWB (only 2hrs away) Matt and Brayden have been very helpful.
 

Rodger

True Classic
Roger, Thanks I will be starting a thread and posting my progress. I thought that maybe you ran into a specific problem with tying in the rear cross member and routing the exhaust. This site is a rabbit hole for a new guy like me. Loads of information. Great stuff. Many talented people. I have chatted with and visited MWB (only 2hrs away) Matt and Brayden have been very helpful.
The reason why I said there would be a problem with the cross brace piece that Darin welded in place was because I built my header starting with an eBay cheapy shorty header. The stock Acura exhaust is routed to the left side of the car, so the header outlet is aimed in that direction. When you bring that header outlet into the X exhaust bay, it pretty much goes through the center of the large opening, which is why the MWB directions say to cut out the stock panel as it is in the way. Darin's brace would also be in the way for my header, but he is building a custom header from the flange back so he can easily route his exhaust through the right side opening.
 

DSobota

Daily Driver
Thanks Roger something I will pay attention to. Just trying to avoid any pitfalls that may come with a custom job when so many others have gone before. MWB directions??? In printed form? LOL I will have to check on that for I did not receive a copy. Just the FAQ sheets.
 

Rodger

True Classic
Thanks Roger something I will pay attention to. Just trying to avoid any pitfalls that may come with a custom job when so many others have gone before. MWB directions??? In printed form? LOL I will have to check on that for I did not receive a copy. Just the FAQ sheets.
With my kit, I got a 25 page K20-Notes document with lots of photos as well as the FAQ document. I can send it to you by email, but I would think that Matt would provide it if you bought the kit from him.
 

darwoodious

Darin Nelson
With my kit, I got a 25 page K20-Notes document with lots of photos as well as the FAQ document. I can send it to you by email, but I would think that Matt would provide it if you bought the kit from him.
Matt sent it to me in electronic format (MS Word) - if you paid for the kit already I'm sure he'll just email it to you.
 

darwoodious

Darin Nelson
This should certainly add to the rigidity of that area, but I can guarantee you would have an issue with the header coming through that opening and your welded in piece being in the way. That is if you were using the shorty headers that are available like I did. I am pretty sure you were going to build a custom header, so that should allow you to bring it back through the right side opening with no issues.
This quoted part is from an older post (here)...

I saw that Hussein (@lookforjoe) liked my post. I'm with Rodger on this tho in so far as limiting the area for the exhaust outlet, so I'm modifying it. Also - and probably more important - I was thinking about how one would install a header (even a "shorty") onto the head with no access available. Thus I've decided to replace that reinforcement with a removable part that is similar. Best of both worlds: keep the rigidity but allow the header to be extracted thru the "muffler bay(?)".

I'll post more in a week when that project is complete.
 

lookforjoe

True Classic
Wiring harness progress

I have been working on creating a custom wiring harness for the car as well for connecting the engine sensors and ECU to the instrument panel and to provide power for the ECU per Hondata’s KPro instructions. A few years ago, I had bought a used wiring harness on ebay, mainly because it had a bunch of relays with it and it was cheap because it was not quite complete. It turns out that it was from a late model Bertone with the newer style fuse panel with the blade fuses. This panel was introduced on the 1985 models. At the time, I did not even know that Bertone had upgraded the fuse panel on the X as my only experience at the time was with my ’79 with the ceramic bullet type fuses. The harness had been harvested in a hurry, so several of the end connectors were missing or cut off and quite a few wires had the insulation shredded off where someone had yanked them through a pass hole without much care. Also, the whole rear harness had been chopped in half at about the seatbelt mounting, but at least both halves were there. My original plan was to upgrade my fuse panel on the ’79, but that turned out to not be very realistic unless I was going to change out the whole harness. I put it away and mostly forgot about it until I embarked on the K20 project. Since I would be adding the wiring for the K20, plus the aftermarket AC system, and all the various relay mods advocated on the Forum, it seemed like it would be a fun project to use that fuse panel and wiring harness for my ’81 restomod, but customized for my specific installation. I would take any missing wires or connectors from the original ’81 harness.

I started working on the harness, but since I was going to modify it quite a bit, I figured I should document my changes, not only for my feeble memory, but also for any future owners. Of course, that is assuming that I will finish the car someday and my wife does not bury me in it. I got a set of the Bertone wiring diagrams and started to figure out what goes where. Of course, the first thing you find out when you look at the wiring diagrams and compare them to the fuse panel is that none of the lettering for the various harness connectors on the wiring diagram match the letters molded into the bottom of the fuse panel. Also, in the wiring diagrams, all the fuses are numbered, but on the panel diagram, the fuses are lettered with no apparent relationship. Bizarre, but this is a Fiat so par for the course. So, I made labels with the letters from the wiring diagram and put them next to the correct opening on the bottom of the fuse panel and labeled the actual connectors to match.


In the wiring diagrams, all the various subsystems are on separate pages. They show the connectors, wire color, and the pin numbers that are used for that subsystem, but you have to flip back and forth through several pages to try and figure out what all the pins in a particular connector are used for since some connectors are used for multiple subsystems. The fuse panel is quite the piece of engineering as it is not just a fuse panel. It also functions as a junction box to route signals or current from a harness from one part of the car to another. For instance, all the wiring to the front of the car is contained in a harness with three connectors A, B, and M. There is a separate harness going to the instrument panel and all the dash switches and controls through connectors F, D, and H. Eight of the relays are plugged right into the top of the fuse panel so there are a lot of internal connections inside that fuse panel that go every which way.

It was hard to keep it all straight, so I took time out and created a spreadsheet for myself that lists all of the connectors, the pin numbers, wire colors, and what they connect to externally and internally. The internal connections can be to a fuse, a relay, or another pin or pins on a different connector. I made two sheets, one that shows all the connections of the wiring harness and a separate sheet that shows all the connections to all the relays, both the ones on the fuse panel and those on a separate cluster of six. I even found a couple of internal routings that are not used in the wiring harness but I have documented them. Now that I have the complete listing of connections as it come from Bertone, I can create a separate spreadsheet with all my changes for future reference. If anyone would like a copy of the factory connection spreadsheet I created, I am happy to share it. Email me, rlawtondmd*comcast.net, and I will send it to you.

Once I had that done, I worked on the front harness. I incorporated Bob Brown’s headlight relay kit into it, but modified it as I got rid of the original headlight connectors. I also added separate right and left fused supply wires. Bob’s relay kit is first class construction.



I also added the circuit for some fog lamps and utilized the wires from the stock AC system and connected that to my aftermarket trinary safety switch mounted on the AC dryer in the frunk. These wires are part of the M connector. They are routed through the fuse panel to other connectors that I will modify to connect to my AC system.



It was good to get the front wiring harness done and installed. I finished adding the front radiator hoses so that part of the car is done!



I completed the harness to connect the K20 ECU and C101 engine connector to the car. It has five pigtails plus three relay sockets. One pigtail goes to the O2 sensor. I used some Fiat connectors to provide plug ins to the wiring harness for the backup lights, the fuel pump, and for switched and constant 12V plus the start signal. I bought an 8 pin Molex plug to provide all of the signals from the ECU and engine to the dashboard gauges.


Here it is plugged into the ECU in the trunk.


I’m almost done with the rear lighting wiring harness, then will work on the wiring for the gauges and AC system.
Just in case you're monitoring posts here - I sent you an email request for the spreadsheet :D
 
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