Mounting an amp to the front firewall

[politby]

I'm adding a new amp to my 03 986. I have removed the old amp and CD changer and the new amp will go where the CD changer used to be.

I first intended to use the CD changer bracket but I do not feel it is up to the task of supporting the much heavier amp.

So I am now looking at mounting it directly to the bulkhead/firewall with an MDF mounting plate in between.

Question is how to affix the mounting plate to the bulkhead. Is it safe to screw it directly to the metal, or is there anything behind the CD changer location that can be damaged? Where exactly is the gas tank?

[JFP in PA]

Originally Posted by politby

Where exactly is the gas tank?

Directly behind that bulkhead...............

[politby]

Originally Posted by JFP in PA

Directly behind that bulkhead...............

Are you kidding? Gas tank directly below the battery, right in front of the passenger (my car is RHD)???
In between the crumple zone and the cabin?

I really hope I am misunderstanding you...

[JFP in PA]

No, you are understanding me correctly, and that is exactly where the tank is……

[politby]

Oh dear. Looks like I'll have to use the changer bracket.

Or maybe the 2 bolts which held the bracket can be used.

I realize it's not the easiest to find a place for the tank in a mid engined car but still...

[JFP in PA]

Well, as the engine and trans are in the rear, it had to be behind the front bumper, on wheels being towed behind the car, or where it is.

[Christian H]

You still might be ok fixing to the bulkhead as the tank is fairly low slung



And quite a strange shape!



Measure twice cut once.

[politby]

Okay, I am looking at four screws, two at the extreme top of the bulkhead and two 200 mm further down.

From your pictures I do not believe the tank is located so high.

[Christian H]

I would have thought that Mr Porsche would have wanted to keep the centre (center) of gravity as low as possible.

[JFP in PA]

Originally Posted by politby

Okay, I am looking at four screws, two at the extreme top of the bulkhead and two 200 mm further down.

From your pictures I do not believe the tank is located so high.

The opening in the top of the fuel tank pictured is directly beneath the battery..........

[xamfed]

Use silicon or some other adhesive to mount a piece of MDF to the firewall. Then screw the amp to the MDF. No worries on whether you may or may not puncture the gas tank.

[politby]

Originally Posted by xamfed

Use silicon or some other adhesive to mount a piece of MDF to the firewall. Then screw the amp to the MDF. No worries on whether you may or may not puncture the gas tank.

That's a great suggestion, why didn't I think of that?

I have lots of 6 mm marine plywood lying around. Assuming there is space to insert a sheet between the carpet and the bulkhead I'll use the two CD changer bolts and my trusty PL400 adhesive to affix it. Voilá, invisible mounting plate.

[Homeboy981]

Using plexiglass might be easier and it would "flex" a little. The bracket doesn't have much force on it.

I managed to fit my larger amp over the existing bracket with only one "modification piece" made out of plexiglass. It tightened down nicely. Not much weight either.

[politby]

I ended up using the CD changer bracket; fastened the amp to it using strong double sided tape (the sort used to hang bathroom mirrors on tile walls) and it worked out great.

Unfortunately one of the two threaded nuts in the bulkhead fell down - impossible to retrieve or replace - so the bracket is now held by just one bolt until I figure out a solution.