Circular Connectors: Deutsch Autosport, Souriau 8STA, MIL-Spec - which connector is right for me?

Motorsport wiring took cues from aviation and defense applications in the mid 1980's to implement high density circular connectors into wiring packages. Originally, the connectors used were a specific series of MIL-Spec connectors which are now antiquated and quite different than those you'll find used currently and also available on our site.

In the nearly 45 years since then, Deutsch Autosport & Souriau's 8STA lines have put together an extensive offering of connectors based on some of these older MIL-Spec connectors but reengineered them to be smaller and lighter, include a conductive black zinc finish standard, increase the amount of keyways (color bands in this case), removed the need for separate accessories such as backshells which are now integrated into the connector itself, and greatly increasing the planform (layout) options available. Both manufacturers are continually adding to their value add technology, and it's extremely impressive to see how much is going into these connectors we rely on.

MIL-Spec Connectors

'MIL-Spec' is without question my least favorite word in this industry, as very little motorsport wiring advertised as 'MIL-Spec' would last a minute or even be allowed in a defense application. There are many different MIL-Spec connector series that are specific to each other, many of which that are absolutely not the right choice to integrate into a race vehicle.

In fact, the specific connectors we use and sell are available in three different series - none of which are compatible with each other! For the sake of this article, all statements are referring to the specific series we offer.

MIL-Spec connectors will typically be the most cost effective solution for mid-density circular connectors to integrate into your project. They are available in planforms ranging from (3) to (61) positions, and use three contact sizes:

• Size 20     Rated to 7.5A, accepts 20-24AWG
• Size 16     Rated to 13A, accepts 16-20AWG
• Size 12     Rated to 23A, accepts 14-12AWG

These connectors will not take a boot natively, you will need a backshell on each connector to fit a Raychem straight boot or 90-degree boot. The connectors and backshells are available in both nickel and black finishes, though in addition to these additional parts required the downside to these connectors is that they are larger than Deutsch Autosport or Souriau 8STA connectors. For comparison, a Size 24 MIL-Spec connector plug is 1.77" in diameter while a Size 24 Autosport/8STA plug is 1.75". The bigger issue? The MIL-Spec has a maximum 61-way layout where Autosport/8STA have a 128-way layout in this shell size! On the panel or bulkhead side, the MIL-Spec connectors we offer have a 4-bolt square flange while Autosport/8STA connectors have a 2-bolt oval flange.

Autosport Connectors

TE manufactures Deutsch Autosport connectors which have been somewhat of the de facto standard, especially here in the US.

Deutsch Autosport connectors offer a variety of configurations including high-density (ASDD) planforms that are both smaller and include more contact positions. They are available in planforms ranging from (1) to (128) positions, and use a number of different contact sizes:

• Size 24     Rated to 3A, accepts 24-30AWG
• Size 23     Rated to 3A, accepts 22-28AWG
• Size 22     Rated to 5A, accepts 22-26AWG
• Size 20     Rated to 7.5A, accepts 20-24AWG
  
• Size 16     Rated to 20A, accepts 16-20AWG
• Size 4       Rated to 200A, accepts 6-2AWG

Additionally, Autosport connectors are available with a handful of specialty options. PCB, coax, fiber optic, hermetic, through bulkhead flanges, fuel submersible connectors, composite shells, and more are all available through Autosport.

In addition to being smaller than MIL-Spec connectors, some of which have similar layouts, is the integration of a knurl ring at the rear of the connector which removes the need for a backshell and is designed to allow a boot to be fitted directly to the connector.

Autosport connectors are rated to 500 mating cycles and are available in seven different keyways. The keyway is identified by the color band on the connector, and eliminates the chance of mating connectors to the wrong components in situations where the same connector is used in volume in the same area. Yellow can only connect to yellow, green cannot connect to blue, etc.

Autosport's machining is second to none, though the supply chain management approach often results in lengthy lead times for both common and oddball connector configurations. It is also incredibly unlikely to find alternate keyways for larger connectors in stock, and at minimum they will often carry a 10-12 week lead time and MOQ (minimum order quantity).

Souriau 8STA

In using these connectors day in and day out for the last ~15 years, I naturally have found myself to have a preferred manufacturer and product line and that is without question Souriau's 8STA.

Reason? There's a handful...

• Wider array of planforms, many being hybrid with various contact sizes
• Superior tine design
  • The tine is the mechanism in the connector that retains the contact after it is inserted
• Manufacturing methods to ensure better availability and shorter lead times
  • For example, the popular 79-way 20-35 planform is shared between Autosport and Souriau. If you wanted anything other than the standard Red 'N' keyway from TE, you're in trouble.
    
    From Souriau, we can supply virtually any combination with little to no lead time. Need a rare Orange 'C' keyway of a 20-35? Just a few weeks out...if that.
• Connectors with support for Size 12 and Size 8 contacts

• Souriau 8STA connectors share many contact sizes with Autosport, but do have some exclusive to their catalog:

  • Size 26     Rated to 3A, accepts 24-30AWG
    
  • Size 22     Rated to 5A, accepts 22-26AWG
  • Size 20     Rated to 7.5A, accepts 20-24AWG
    
  • Size 16     Rated to 13A, accepts 16-20AWG
  • Size 12     Rated to 23A, accepts 12-14AWG
  • Size 8       Rated to 45A, accepts 8AWG
  • Size 4       Rated to 80-200A, accepts 6-2AWG
• Cross compatibility with Deutsch Autosport for the majority of planforms.
  • This one is very important, let me elaborate:

These connectors have a bit of a 'Chicken or the egg?' mindset to them, right?. The standardized planforms available from both manufacturers are directly compatible with one another!

Say you have an Autosport 18-35 planform in a flange that you cannot find a mate for. You can use the Souriau mating connector as they are direct crosses. This isn't a trick of the trade; it was by design, at some point. 

So how much of each catalog does this carry over to? Now things get complicated....

The entirety of Autosport's 'standard' Size 8 - Size 24 connectors are also offered by Souriau. Additionally, Souriau has numerous exclusive connectors in these shell sizes that are remarkable considering how versatile they can be. Let's take a look at some of our favorites:

Both Autosport and Souriau then have further exclusive connectors for each of their lineups, respectively.

• Autosport offers the ASU Size 3 shell in 3-way and 5-way layouts while Souriau does not.
• Souriau offers a Size 4 shell in 3-way, 5-way, and 6-way layouts while Autosport does not.
• Autosport offers ASHD 1 position connectors in a Size 14 shell, while Souriau does this in a Size 12 shell.
• Souriau offers a Size 1 3-way while Autosport is set to formally release their Size 1 4-way.
• Autosport's ASDD (Double Density) ranges from a Size 6 9-way and ends with a Size 18 118-way, Souriau's High Density ranges from a Size 2 5-way and ends with a Size 14 68-way. In comparison, Autosport's Size 14 double density is only a 64-way.
• Souriau offers single bolt flange connectors for maximum space savings while Autosport does not.
• Tired of reading? Overwhelmed? The variations and differences are abundant, and there are devices and components that require proprietary connectors from either manufacturer. On a top tier loom, it is extremely common to see a mix of Autosport and Souriau connectors.

Come back soon, leave a comment with any questions you may have, or take a look at our inventory for both of these products. There's a bit more to come!