Is there a best practice I should be aware of here as I continue to plan this out?

Thanks!

In the car.















Sorry I couldn't resist

Behind the driver or passenger seat most often.
Once I clean up some wires, I want to see if I can get it to the passenger footwell. If I can't, It may go between the seats in a little custom cover.
It should always be kept dry and cool.

Ha, so extra long extension cord or someone running with it next to the car is not an option. Got it.

@mepstein - are you planning on modifying the interior backpad or, instead, passing it through and mounting it on the interior side of the backpad? Sounds like that later.

Thanks!

I put mine under the foam block on the passenger footwell. But I had to extend the DME harness to make it reach.

If I were going to do it again, I would put it in the middle of the car under the back pad.

Thanks Clay

Under the dash on the passenger side ...

I don’t think mine will reach but that would be the perfect spot.

Where? I couldn't find a spot under there.

Do you have a picture?

Don’t think mine will reach either, great spot however

I went through the “dimple” on the lower part of the firewall, behind the right seat. I did cut short the stock early backpad by about 2 inches on that side. Doesn’t show behind the seat since I left the viny and it covers the wire bundle. Eventually I will replace with a later adjustable seat and perlon.

http://www.914world.com/bbs2/index.php?s=&...st&p=883879

The PMS harness was actually long enough to mount the brain horizontally under the dash in the position where Mark is holding it vertically in the picture.
We mounted it on a custom frame using rubber isolators to counteract vibrations.

It's tucked away so nicely that you can't see it at all unless you get your head under the dash ...

@ClayPerrine @mepstein

http://www.914world.com/bbs2/index.php?s=&...st&p=893545

Mine fits perfect behind the drivers seat. I use a longer backpad screw to hold it in place. The DME relay and altitude sensor is behind the passenger seat. Did not have to modify any of the cables.

''
just another..what if thread.....rear trunk ..under seat, under glove box.. Surprise Us ....

@Steve - I noticed you don't have a sound pad in the engine compartment, how is the noise level for longer trips?

@sixnotfour - nope, not a "what if" thread, a making sure when I do it early next year I get it right having learned from the people here thread.

Tell you what - want to bet $1,000 it gets done?

I've seen a few conversions where the DME/ alt-comp + dme relay were cleanly mounted in the rear trunk. Still able to store the targa top. I like the accessibility of getting to the relay, it can be popped out on occassion...adds another level of anti-theft

http://www.914world.com/bbs2/index.php?showtopic=116617

Mine is under the driver's seat. Definitely wanted it in the interior of the car.

Any where Porsche don't put them,what were they thinking with the footwell and floor locations ,hell even the one in my 944 got drowned,Motronic ECU's are hardly cheap to replace and many now are getting old and failing without being wet.

Thanks for the ideas and pictures. I’d be inclined to think that interior of the car but off the floor would be the safest place.

Quick shout out to @MB911 for spending some time with me today on parts planning.

Some of them used a circuit board that wasn’t much more than compressed paper.
Porsche still places a lot of electronics down low.

A friend had his 996 cab (top up) windows down, parked in his garage / laundry area. While he was on holiday, a water hose entering the wash machine burst and doused the car for a weekend. Most of the water made it out the garage floor drain...except for the interior floor of the 996. Fully insured and $$$ claim fixed the moldy carpets & cables / ecu/ relays

Mine is in the rear trunk. Stock harness ,works great .

Boxster ECU issues due to wet floors are not uncommon from wha I’ve read.

Going on the inside somewhere, likely mounted vertically.

I did order a PMS harness today so will see it is reaches up front, will report back.

Thanks all!

The PMS harness connects the chassis harness to the engine harness. It doesn't connect the ECU to the car. It won't lengthen the DME harness.

I have an amplifier in the front trunk, so I just crank the stereo louder than the motor if I do not want to listen to the motor. It is on my list to install 914rubber's engine compartment firewall pad and see how much it helps. Otherwise the motor is loud. Much louder than my 2.7 with webers, but I had a stock sound pad with that motor.

My harness to the DME appears to be longer than normal and came from PMS ...

Mine is placed in the center console vertically.

Oops! Thanks for the clarification.

If you made a watershield, like a small aluminum box why not put it in the engine bay?

I had my SDS EFI system in a hollowed out D-jet box in the stock location, now my MSD box is in the same place now with just a water shield over the top.

If it needs a bigger box there's lots of room on the firewall just behind the drivers seat. the box would need to be waterproof up top but the bottom doesn't need to be. I'd wire it through the bottom and would add drain holes to the bottom even if I semi-sealed it.

It’s still a product worth buying. It makes wiring the engine to the chassis a two minute job. I wish there was a similar adaptor from the DME to the car.

My DME for the 3.2L is located vertically just off the floor, in front of the stock backpad and behind the passenger seat. Relay is next to it with a spare in the glovebox. The seat still retracts but not quite fully flush into the backpad. Works well and no moisture access.

@mepstein - true, yes, but a bit embarrassing I got my parts confused .

Anymore pictures of how you guys mounted them on the inside to the backpad? Did you weld some mounting screws on the firewall and then have them poke through the backpad?

Thanks ( and happy Saturday to everyone )

Ditto......

I wouldn’t mount the dme until you get all the wires figured out. Then you can see what you really have to work with It’s much better to put your car together and get it running before you set the interior. It’s also useful to have an old seat for testing. Can’t tell you how many times the techs at the shop would sit down on a finished interior with grease on their clothes or a tool in their back pocket.

Sage advice, thanks!