bbaker480 Posted October 24, 2018 Report Share Posted October 24, 2018 With our last race of the season behind us winter build season is officially here. I'm putting together the shopping list for the installation of my MegaSquirt and new wiring harness. I do plan to terminate everything in a bulkhead connector or two on the firewall so I can do away with rubber grommets and plugs where it's possible. With #556 catching fire at Gingerman and the fire at Thompson the week after I really want to make sure the driver is better protected. For the wire itself I'm sticking with TXL as it's easy to work with, holds up well, and is available in enough colors to make the harness make sense to anyone helping to troubleshoot... Purple is power for the fuel pump, orange is IGN+, etc. Everything is getting laid out on paper before I order so I make sure everything has it's own color. I've got all new factory plugs for the things that are staying on the engine (TPS, coils, etc) but I'm still debating Deustch vs WeatherPak for everything else. The Deustch cost of entry is higher but I know the pins are higher quality and the plugs are physically smaller, both of which seem like a plus. I'm not completely sold on the Deustch as it's probably 2x or more the cost of WeatherPack. Is there some other option I'm not considering that would be better than either of these? Lastly, I've wired one car in plastic split loom that seems to melt if you look at it sideways, one car in mesh loom that frays at the ends but is substantially easier to work with, and one car that used both at one point as well as the fire resistant silicone jacketed fiberglass tubing. As I'm getting to start this from scratch I've been looking at what is out there and found that the Raychem DR-25 shrink tubing is pretty popular, and you can even source heat shrinkable junctions for harnesses that split off at the ends. I think that's overkill for our applications but it sure looks good when it's done. Is there a cheaper alternative to the Raychem that would work just as well? I'm not great at finding what I'm looking for at McMaster Carr but I'd assume there is a 2:1 polyoelfin that is similar? Quote Link to comment Share on other sites More sharing options...
Technical Advisory Committee Chris Huggins Posted October 24, 2018 Technical Advisory Committee Report Share Posted October 24, 2018 Hit up our local wiring guru @vtjballeng I have also used prowireusa.com out of CA Wirebarn has wire in TXL or GXL Go deutsch for what you can afford. Get the solid barrel crimps, they are worth the price premium over the open barrels. You don't need the $300 deutsch oe crimper, I got some off of amazon that work just as well for <100. TXL is good wire. Make sure you spend at least as much time documenting as you spend wiring. Seriously. Fuse box diagrams, Labels, Wiring diagrams, etc. Otherwise you will be back. DR25 is good heatshrink, but I prefer something that is 3-1 or 4-1 for connector and crimp applications. Glue lined is even better. I used alot of Raychem ATUM 4-1 in my harness. I prefer NOT to use DR25 to cover the entire harness. We don't need that level of protection in our application, esp with the good TXL or GXL wire and external abrasion protection. I encapsulated my harness in Techflex F6 (split braided loom) inside the car, and wrapped it with F4 Tape in the engine bay. The F6 is good for places you will be adding or modifying, as you can easily integrate additional wires at a later date if needed. The F4 tape was a cheap way of fully encapsulating the wiring harness, but dont expect to go back later and make any changes. Once its fused, its fused for good. DR25 would have been also possible, but some of my engine bay body harness had connectors that were older and I did not want to risk de-pinning them. I leave well enough alone with the harness if its in good shape. I have created more issues trying to modify or change than I have solved. I would only go for a full standalone harness or a major invasive change if you are 100% confident in your abilities and have a significant amount of time on your hands (and money burning a hole in your pocket). You are welcome to PM me if you have any further questions. -Chris 3 Quote Link to comment Share on other sites More sharing options...
mhr650 Posted October 24, 2018 Report Share Posted October 24, 2018 The deutsch connectors really are that much better if you can swing them. Another advantage is that you can get them in the mini version low power bits like signal or sensor connections and you can get large gauge power connectors. Another option is Sumitomo, Mazda used a ton of those on their cars and they are pretty nice. Wish I would have known that I could get a matching connector before I cut the one off of my CAS and replaced it with a weather pack which, is a big flat 4 pin that I hate. I used the nylon mesh for all of my wiring, it works well but one downside is it is difficult if you need to do updates later on, the split corrugated can just be opened up to run new wires when you need to. The thing you need with the mesh is good adhesive lined heat shrink at the ends, believe it or not the adhesive lined heat shrink kits from Harbor Freight are very good, the only downside is that you will go through the larger sizes quickly and be left with a lot of 1/8 inch that is pretty much useless. I believe you already have a Megasquirt, but on my next car I am going to use the MS3Pro Ultimate. They added a 3rd plug and have a massive amount of inputs and outputs, my plan is to not have any gauges and very few switches and run everything through the ECU and a CAN connected digital dash. By the time you are through it won’t be that much more expensive than buying a bunch of gauges and you can use simple GM temp and pressure sensors to monitor pretty much anything you would want to keep track of. In my case I will be logging a lot of turbo parameters since part of my pitch is that I can get testing hours on experimental hardware… 2 Quote Link to comment Share on other sites More sharing options...
vtjballeng Posted October 30, 2018 Report Share Posted October 30, 2018 (edited) On 10/24/2018 at 12:24 PM, bbaker480 said: With our last race of the season behind us winter build season is officially here. I'm putting together the shopping list for the installation of my MegaSquirt and new wiring harness. I do plan to terminate everything in a bulkhead connector or two on the firewall so I can do away with rubber grommets and plugs where it's possible. With #556 catching fire at Gingerman and the fire at Thompson the week after I really want to make sure the driver is better protected. For the wire itself I'm sticking with TXL as it's easy to work with, holds up well, and is available in enough colors to make the harness make sense to anyone helping to troubleshoot... Purple is power for the fuel pump, orange is IGN+, etc. Everything is getting laid out on paper before I order so I make sure everything has it's own color. I've got all new factory plugs for the things that are staying on the engine (TPS, coils, etc) but I'm still debating Deustch vs WeatherPak for everything else. The Deustch cost of entry is higher but I know the pins are higher quality and the plugs are physically smaller, both of which seem like a plus. I'm not completely sold on the Deustch as it's probably 2x or more the cost of WeatherPack. Is there some other option I'm not considering that would be better than either of these? Lastly, I've wired one car in plastic split loom that seems to melt if you look at it sideways, one car in mesh loom that frays at the ends but is substantially easier to work with, and one car that used both at one point as well as the fire resistant silicone jacketed fiberglass tubing. As I'm getting to start this from scratch I've been looking at what is out there and found that the Raychem DR-25 shrink tubing is pretty popular, and you can even source heat shrinkable junctions for harnesses that split off at the ends. I think that's overkill for our applications but it sure looks good when it's done. Is there a cheaper alternative to the Raychem that would work just as well? I'm not great at finding what I'm looking for at McMaster Carr but I'd assume there is a 2:1 polyoelfin that is similar? We carry wiring supplies here that are automotive specific:https://www.bmotorsports.com/shop/ There are a lot of competitors with similar catalogs, so you don't need to resort to McMaster on this. We also carry a lot of the stock connectors to sensors, etc. Nobody should be using Weatherpack these days. They were a 70s era design long ago obsoleted in the Delphi/Packard catalog. Since then they've had several additional design iterations which have also been obsoleted or nearly so. It's the engine equivalent of taking your modern overhead cam engine putting flat heads on it. Full Deutsch kits are available such as this: https://www.bmotorsports.com/shop/product_info.php/products_id/4119 . Though we don't have them on the site we have packages for DT & other options as well. The biggest issues I see are: A lack of planning. Mock it up, draw it out, make a spreadsheet of connections. Trying to make it go quickly (wiring is TIME CONSUMING). People think this will be an easy task and will often get frustrated with the progress. Even professionals who've done this hundreds of times can spend 30+ hours to wire a car. Terrible crimps that do not pass validation ( http://news.bmotorsports.com/faq/terminal-crimp-validation-charts/ ). A poor understanding of loads such that you end up with too small wires with high amperage loads and too large wires on sensors and other unloaded electronics. Incorrect tooling. If you want one tool that can do nearly all open barrel crimps you will encounter, this is your best bet: https://www.bmotorsports.com/shop/product_info.php/cPath/111_112_170/products_id/2268 . Poor strain relief. Most failures happen at crimps / terminations and are often caused by tight bends at the back of a connection or vibration that occurs at the termination point. Do not solder. Crimp, validate, glue lined heatshrink Here is a resource for high end work: https://www.rbracing-rsr.com/wiring_ecu.html Here is a basic course: https://www.hpacademy.com/courses/wiring-fundamentals/ Here is a practical course: https://www.hpacademy.com/courses/practical-harness-construction-club-level/ On a related note, here is a failure from our ChampCar. Headlight failure analysis. Failure expected in ballast internals. Found it was in ignitor instead. Destructive analysis of ignitor showed failed crimps in aftermarket system. Pulled copper to failure but only a couple of strands held between 3 terminals (3rd one destroyed but had no captive copper). Proper failure mode for a correct crimp is that all copper remains captive in all terminals. Relevant to you @Huggy, since y'all should have the same ignitor. Sebring ultimately caused the failure but inspection showed larger internal problems. How many other failures do you see using our validation charts? http://news.bmotorsports.com/faq/terminal-crimp-validation-charts/ Edited October 30, 2018 by vtjballeng 1 1 Quote Link to comment Share on other sites More sharing options...
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