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Amphenol SurLok plus connectors

EFI Wiring Fundamentals

Discussion and questions related to the course EFI Wiring Fundamentals

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These look to be a new cost effective high current option, with a few PDM's now using them.

looking for some info / peoples experiences,

i am looking specifically at the 8.0mm sizing with 35mm2 crimp connections, i am expecting to use a generic hydraulic hex crimper (

my questions mostly centre around the keyway, my under standing is there is a master keyway regardless. the final digit is the second keyway which is optional. how ever the receptacle has a with out key way option (R vs IR), what does the R vs IR mean as far as its mating plug?

thoughts on running non-sealed? (due to availability) will be mounted on the engine bay firewall.


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we will reply on the other post Regards Ross

Ross the double post was an accident is there a link to the thread you responded too?

Hi Josh,

From my experience with working with PDM/PMU devices, the majority of devices use Amphenol Radlok instead of Surlok as these have no keyway and allow 360 degrees of rotation, Therefore fitting battery cables is much easier regardless of there position of the device. The Radlok connectors also come with a lipped edge at the bottom of the connector for easy sealing of the crimped joint with a boot or heat-shrink. I have also used these on the bulkhead of our RX7 project with great success. I personally have no experience with the Surlok so I can't help you with that I'm afraid.

If you have any more questions about Radlok let me know and ill help you out. I'll leave a link below of the data sheet.


Also picked up the Radlok series for battery thru firewall on my project, Here is a picture of the ones I have which are great.

The bulkhead fitting has the rubber seal to seal against the firewall and work extremely well.

I have used the Radlok for the first time a couple weeks back and would higly recommend! Very cost effective, compact, and easy to install. They also look really professional and much better than most other solutions when it comes to through-bulkhead battery cable solutions. We do a lot of engine changes and the quick disconnect makes things even better. They will be used for pretty much all future projects now.

i have ordered some radlok through firewall plugs and pins.

whats everyone using to crimp these?

i cant find any specification on the crimps to check they are acceptable etc.


Im planning on using these.

I'm assuming it should be fine so long as I get full engagement on the copper strands.