Where to mount a power distribution box
 

I’m dangerously close to analysis paralysis on where to mount the box that’ll contain the circuit breakers and relays for my K24 build.


The car is currently cage-less, but I intend to have one put in after I get the swap running.


The goal of the car is NASA ST/TT4, maybe eventually some enduros.


The wires for all engine circuits go through the firewall at one of the holes for the A/C lines, via a bulkhead connector. The power feed comes in from the battery disconnect through the other A/C hole.


Option 1: in the center stack area, ahead of the shifter. Downsides - crappy access with the shifter in the car. There’s nothing in there that the driver can resolve while in the car (all circuit breakers are self-resetting). Extra wire length to firewall.

https://cimg4.ibsrv.net/gimg/www.mia...0b754de9d.jpeg
Option 1


Option 2: on the transmission tunnel. I don’t like this one because if/when I have a passenger, their knee is likely to connect with the box. Also, heat from the transmission tunnel is a likely issue.
https://cimg1.ibsrv.net/gimg/www.mia...360d815eb.jpeg


Option 3: on the dash bar, in front of the passenger. No good if I remove the dash bar in the future. Will require welding to mount securely. I’m not sure my skills are there yet. On the positives, access is convenient and the wiring doesn’t have to be too long.


https://cimg3.ibsrv.net/gimg/www.mia...ba971af85.jpeg


Option 4: hang from existing bolts on the bulkhead. Not great for access, but definitely a short wiring run.
https://cimg6.ibsrv.net/gimg/www.mia...68bec3c80.jpeg


Option 5: deep in the passenger footwell. I’d probably have to protect it from feet. Horrible access. Short wiring run (you can see the bulkhead connector in the upper left.)
https://cimg7.ibsrv.net/gimg/www.mia...551e8fda7.jpeg


O great MT.net hive mind, what are your thoughts and suggestions? Your input is much appreciated.

psssst, race cars don't have passenger seats.

I can't help much with it's mounting location, I can't really picture what product you're holding.

I will say, "tombstone" area is usually reserved for driver controls like cool suit/defrost/ignition/starter/lights/etc. I'm leaning towards your last option, on some sort of panel angled like the stock ECU panel, perhaps housing other electrical items, like the K-pro and what not.

I’d do 3 or 4.

The PDM is just a box, right? So mount it wherever you like, it doesn't matter but handy to the ECU and/or battery would be neat. If you mean the control panel for the PDM, that goes on the tombstone, or some other place where you can reach easily and without taking eyes off the track/road.

I'd use position #4
Away from heat and liquids.
Doesn't infringe on seating positions, gives you options.
Doesn't care about dash bar.
Leave the pigtail a bit long and access can be better, just remove it from the brackets and it will drop into passenger foot well.
The excess pigtail could be clipped to the firewall easily.
Stupid easy mounting and it will look like you made a "custom" mounting point in the car.
It looks like it is in a spot that you have no other plans for...

This is a super timely post for me. I'm in the middle of figuring all of this out for my swap too, and had four goals...out of the way of a passenger, in a place I could semi easily access, all (fuse / relays etc.) in one place, and out of the way of a future cage. (I cut out my lower half of the dash, so this is a bit more accessible for me.) I mocked up a location using a thin piece of pressed wood as a template. My location is basically your 4.5...in the middle of those two. I was just reusing some studs that were already there.

BTW...This looks like crap, but its just a mock up, I needed to have an idea of where to run all the wires. I was gonna wait and get the car running first, but I'm about to pull the trigger on an AIM system that includes a PDM...so most of the shit I have mounted here is gonna go away.

https://cimg6.ibsrv.net/gimg/www.mia...3409286fca.jpg
https://cimg7.ibsrv.net/gimg/www.mia...8924653c5e.jpg

True, but seeing as full-on race spec is at least a full year away and I have a list of people who want HPDE ride-alongs, there's going to be a passenger seat in there for a while. Plus I'd like to get a pro friend to drive the car post-swap and show me what it can do.

This is an example of how the box will look once populated, except I have only one panel. Relays and circuit breakers in a sealed enclosure. These use ISO280 relays and ATM circuit breakers. The box will have connections to the bulkhead fitting, ECU, and ABS. The relays are controlled via the MicroPDM (light blue box in left-hand panel), which is connected to the CAN bus and controlled via a keypad. I'm not expecting to have to do a lot inside this box once the system is running but if something goes wrong, it's going to be a central debugging point and access should be easy/comfortable in the paddock/garage.

https://cimg6.ibsrv.net/gimg/www.mia...48fc04392.jpeg

Yeah, it's the "wherever" with which I'm struggling. Too many options.

I think I'm leaning towards exactly this.

Nicely done. That particular location would interfere with my bulkhead connection, but I think that 4 is going to be the answer.

Have you talked to your distributor about availability? I called to order mine months ago and was basically told to watch for flying swine. I've seen exactly one in person and while the owner is a self-aggrandizing know-it-all, I do believe him when he said it took a special relationship with AIM to get it in his hands. The story is something like, they're making them, but every time someone sneezes in the factory in Italy, they go home for two weeks, so there's little to no supply. I've gone with MicroPDM instead. Much smaller investment, it was in-stock, and the guy is local and at all the events I attend.


My two favorites. I think 4 has it though.


Thank you all for your input, I really do appreciate it!

Option 4. It is the most protected from water ingress. After watching videos from a rain race, you would be amazed where significant amounts of water can get to. I have see "waves" of water splashing well up the passenger footwell.

I would gladly write off my car if it meant that we consistently got enough rain here in CA to worry about that sort of water ingress. I have been planning to close off the cabin air intake in a reasonable manner, just to be thorough.

well, maybe not gladly. But I’d do it.

@thebeerbaron FYI...Pegasus auto racing is showing AIM PDM's in stock right now.

Step carefully. Having had cause to use the AiM FB group, I have seen some chatter about problems/frustrations with the AiM PDM, I haven't taken that much notice of the detail as I am not looking at a PDM but it would be worth doing some checking before pulling that trigger. I have had a very bruising experience with the (no longer new) Solo2DL, which leads me to say that being an early adopter of AiM stuff can suck. If there are proven alternatives I would be putting my money in their direction, or at least deferring a decision as long as possible. YMMV of course.

Yeah, it's funny - I was an early(ish) adopter of the RaceCapture hardware and ended up scrapping the system as being wholly unusable. I went to a Solo 2DL because a pro friend of mine used it and considered it table stakes for data capture and analysis. It immediately fell into the "it just works" category for me. It seems that RaceCapture is getting more attention and I see the value there, but I'm done with them.

The big reason I went with the MicroPDM was that the guy who built/sells it races in my NASA region and is very helpful.

But this PDM discussion is probably best in another thread...

I made mounts for location #4 and consider this "done". The Haltech has been mounted just to the left of the power center, I just need to add a brace to the mount to give it that third dimension of stability.

Yeah, that comment was directed at RDB :o , my bad I should have quoted the post I was replying to.

The life lesson I took from that experience was to only get something that WORKS. In my case, check that the damn thing works with my ECU. After 3 years turns out some hardware mod was required to make it work, I'm guessing that was cheaper than getting the engineers involved back in Italy.

In your case I reckon that having that sort of expertise on tap would be a great confidence boost that it will work for you.

Option 4 looks good to me!