# MoTec

Discussion in 'Mazda Rotary' started by TXFlyGuy, Oct 27, 2017.

1. Nov 2, 2017

### TXFlyGuy

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The dealer made a big emphasis on the quality of their wiring, and wiring harnesses. Yes, he used the term Mil-Spec, as if it was a big deal. This is one big reason that I want to go with Fischer Motorsports.
And their experience in aviation is impressive.

2. Nov 2, 2017

### pictsidhe

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The assembly is just as, if not more, important as the components used. Mil-spec includes the complete assembly and tools used. If they get military jobs, they should be good. If not, it could just be sales BS for wiring ranging from awful up to very good. I don't claim to do mil-spec anything as I believe you need to get certified? If you want to do a proper job, you need to use the $200 crimp tools, the cheap ones do a cheap job. if you need a few of those, a homemade harness can get very expensive... I've seen plenty of dreadful wiring. One favourite of the clueless is soldering crimp connectors. Wiring 'improved' like that has a nasty tendency to fatigue and break right where the solder stops, unless new strain relief is used. Corrosion and fatigue are the two big killers of wiring. Back to the OT. MoTec have been making well regarded ECUs for several decades. They likely have them pretty much perfected by now. 3. Nov 2, 2017 ### Winginit ### Winginit #### Well-Known Member Joined: Jun 13, 2016 Messages: 811 Likes Received: 242 Location: x pictsidhe kinda took the words right out of my mouth.....about a true Mil-Spec connection being not only the components, but the actual method of assembly. I'm going to attach a web site that explains the assembly steps so everyone can see whats truly involved in making a connection that meets Military Specfications. First, let me say this...I don't know if Motec builds thier connections according to Mil-Spec requirements or not. They seem to be a very reliable and reputable company, so my guess is that they know how to do it correctly. Originally Tex had mentioned modifying the harness once they returned home. I think that plan has changed but there seems to be a little uncertainty (unfininished decision) at this point in the build. My purpose is to help Tex and anyone else considering wiring changes, modifications, or completely building a harness to understand what it means to build to Military Specifications. Like many things we learn in life, the use of certain terms often gives us confidence in a product because the term has always been used to identify something good. Just saying "Mil-Spec" tends to give most of us confidence we are buying a good (the best available) product. I worked in the weapons industry for many years, both for the government and for a private contractor. I approved and ordered many many parts that met Mil-Specs. One thing you learn is that there are Mil-Specs for everything...even beer. Most specs are pretty thorough, but you also find out that the low bidder is able to meet the spec for an awful lot of government purchases. In most cases if something meets a Mil_Spec it will definitely be a high quality part...especially if its used on an Airplane or a Submarine. I suppose that Hummers have wiring that meets some government spec, but I doubt that it compares to what is used in aviation or weaponry. So, I'm only trying to point out that while using Military grade components may be a step in the right direction, like everything in life, it should still be approached with a little speculation. Hopefully it proves to be what the buyer/builder expected. If you read this attachment, you will learn a lot about how the connectors are attached. Its way beyond what most builders will want to deal with on their own. It requires special crimping tools unlike any most people have used. They are very expensive. Wires must be routed a certain way and allowances made for "service loops". Lots to do to make a proper connection. The connectors themselves are expensive too. Be sure to look at the beaker picture entitled "Wicked Wicking" and the explanation.Might even try this yourself. So, anyway this post is not meant to be critical, but rather explanatory. Hope everyone learns something from it. https://www.rbracing-rsr.com/wiring_ecu.html 4. Nov 2, 2017 ### pictsidhe ### pictsidhe #### Well-Known Member Joined: Jul 15, 2014 Messages: 6,872 Likes Received: 1,852 Location: North Carolina 5. Nov 2, 2017 ### TXFlyGuy ### TXFlyGuy #### Well-Known Member Joined: Apr 26, 2012 Messages: 1,493 Likes Received: 436 Location: Republic of Texas The harness, and it's wiring, is a major concern. Let's just say that the current harnesses could use some improvement. I won't say any more than that. I was told that our harness may be (maybe?) usable. With upgrades. This would be the best for us as it would save$. If a complete new harness is required, it gets real expensive.

Last edited: Nov 2, 2017
6. Nov 2, 2017

### Winginit

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When I worked in the Technical Materials Dept at a govt facility, we researched items to be purchased to make sure they met the needed requirements. Generally we (the public) never think about the many things that the govt must order, store and have immediately available for our troops. During our research we often stumbled upon Federal Stock Numbers for items that we never thought about. For some reason the fact that there were FSNs for beer stuck in my mind. Gotta have something for the troops NCO clubs. Another thing that I remember was that one of the guys found there was a Mil-Spec and stock numbers for womens hygene products. Guess the different numbers represented different sizes....:gig:

7. Nov 4, 2017

### TXFlyGuy

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I just learned that the MoTeC has multiple fuel ladders for programming. This is good, for burning 91/93 Octane and 100LL.

8. Nov 5, 2017

### TXFlyGuy

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This is one time bigger is not better.

Winginit likes this.
9. Nov 5, 2017

### TXFlyGuy

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After doing some additional reading online, one of the biggest factors supporting buying this ECU is the world class factory support. This appears to be a weak area with the Link.

MoTeC is a bit more complex, and requires an expert tuner. Note than any ECU is only as good as the person doing the tuning. Thankfully, we have an expert right here in the Dallas/Ft. Worth area.

Last edited: Nov 5, 2017
10. Nov 5, 2017

### pictsidhe

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You want an ECU that doesn't need support! Fit and forget is the order of the day here.
I'm not knocking MoTec as the do have a good reputation and have been in the game longer than most.

11. Nov 5, 2017

### TXFlyGuy

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Everything that I own needs support! From my appliances, to my automobiles. That is why we have selected a dealer with much experience in aviation applications, including racing at Reno.

This is the one area where this company is head and shoulders above the rest of the ECU crowd. Based on ECU - Auto Forum feedback.

12. Nov 14, 2017

### proppastie

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Confused, how do you have problems with a wiring harness? Is cross-talk a problem? A wire goes from here to there, whats to go wrong.

13. Nov 14, 2017

### pictsidhe

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When it doesn't go from here to there. Bad connections, or worse, a fatigued wire. If you discover a fatigued wire on a complex harness. Do yourself a favour. Remove the whole harness and insert it into the nearest trash receptacle. Other wires are usually not far behind.

14. Nov 14, 2017

### proppastie

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On an new harness? Yes I can see if the wires go to wrong place it is a problem, except he said the unit ran fine. Sure there could be a bad crimp, easy to see, easy to fix. I wounder if there is something else going on here. Perhaps this should have been in the
Supplier / Manufacturer Announcements category.

15. Nov 15, 2017

### TXFlyGuy

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It’s a connection, QC issue from what I’ve been told. May have a new harness built by a third party.

16. Nov 15, 2017

### Winginit

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What seems difficult about a harness to a first time buyer is deciding what wires you need to have.....what components need to be connected to what. Once that is determined, then making the crimped connections.....and doing it RIGHT is really pretty simple. It's pretty much repetitive crimping, but you have to use the right crimping tools for the kind of connectors being used. Have you thought about maybe having them get the wiring and letting you do the crimping? Who better to be sure the crimps are properly done than the person who will be relying on it. For the most part, the wiring should not give a problem, it's the terminations and connectors where the biggest chance of poor assembly will give a problem. If you insure the connections and terminations are properly performed then you don't have to wonder.

17. Nov 15, 2017

### pictsidhe

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Hell no, crimping is an art that few do well.

18. Nov 15, 2017

### pictsidhe

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To elaborate, people think they've done a good job, but actually, they haven't. Most people overestimate their wiring prowess. Is the malfunctioning harness a 'pro' job?
I've made two EFI harnesses. It is not something I'd ever recommend the average Joe attempt on an aircraft where one bad joint can really **** your life up. I've been playing with electronics for 40 years, I'm still learning.

19. Nov 15, 2017

### Winginit

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Exactly my point, one bad connection "can" ruin everthing, so who better to decide if all the crimps are satisfactory than the person who will be at risk. I realize it can be a daunting task to build a complete harness from scratch, but wires being routed to an incorrect connector will quickly reveal the mistake during pre flying testing. The hidden component is whether the "connections themselves" will be done properly....or improperly and loosen later.
That seems to be the point of contention to me, whether the connections themselves will be/are properly done. The process itself is pretty simple when using WeatherPack connectors which fit the sensors specific configuretions.I'm not sure why you would find this to be difficult. To me the difference is you have a Pro performing a simple task that he may have done a thousand times and does it with a second nature involvement, or you have a person performing a task for the first time and he has a serious interest in the outcome. The pro may skim over the process while the builder will concentrate and want it perfect. The Pro may be more capable overall, but the builder will watch every detail while seeking perfection. Crimping is a small but important step in building. We may disagree on the difficulty of the crimping process, but I do agree that trying to build a complete harness from scratch and get it right the first time can be very difficult. Here is a video of the crimping process for WeatherPack terminals.

20. Nov 15, 2017

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