So... any thoughts?

 

Just a thought - if the amp chassis acts as a heat sink, mounting it upside down may affect its ability to dissipate heat.

 

rear window heat transmission (from sunlight) to the rear deck, then to the rear deck metal, means that whatever you mount from the rear deck will have increased temperatures to deal with even more than the non-climate controlled trunk environment.

then, you have the upside-down amp thing. Most amps are made to allow heat to radiate vertically, and if you mount them upside down, it will radiate heat into the circuit board, eventually causing caps to dry out and fail prematurely, the effect is essentially, mounting the amp so that it hurts itself. A big problem is the amp isn't operating like it is supposed to, and temperature protection circuits can be calibrated to trigger or not trigger in error, which could make the transistors vulnerable to excessive heat, or the amp goes into protect too quickly...

now, if you put a little board beneath the deck about 3 inches, and allow a 1/2" of space between the amp's heatsink (mounted right-side up) and the metal of the rear deck, in an amp rack situation, you mitigate several of the negatives of the location.

heat transmission comes from 4 sources externally with amps, and you should give an amp as much help as possible.

conduction
radiation
convection

internal production through current

 

Picture a hanging tray secured by some 1/4" threaded rod, nuts and washers.

 

I did mine with standoffs. Looks like larger version of CPU motherboard standoffs. Bolted through the rear deck to give some space between the rear deck on amp for circulation.

McMaster-Carr

I've done this in 2 different cars with 2 different amps. One was an amp with an active fan and bolted straight to the bottom of the rear deck. No space. Never had issues even running the amp at 2 ohms mono. The second is passively cooled and I have the standoffs. Never had any issues with heat on this install either.

 

My previous car had two amps mounted in this fashion (100x4 and 600x1 @2ohms). Had no overheating issues but live in a cooler climate. Amps where passively cooled as well. If the amps have plenty of heatsink area I wouldn't worry.

 

Nissan maxima?

 

only thing I would suggest is, however you mount it, DONT ground the chassis. if you use standoffs like people are suggesting, use nylon washers to isolate the chassis from the vehicle.

 

If you are willing/able to get the rear deck trim off the inside. I would carpet some plywood and bolt it all the way through the deck lid. Then attach your amps to that.

I wish I could remember who had the little flip down rack in their build log. I would link it, seems like a very doable and elegant solution.

 

I wish I could remember who had the little flip down rack in their build log. I would link it, seems like a very doable and elegant solution.

One of the only ones I can remember. Though it's for crossovers not amps, same concept, albeit over the top fab work.

http://www.diymobileaudio.com/forum...m/forum/build-logs-project-install-gallery/30321-one-badassed-bmw-330-a-10.html

I'm still trying to work out the details to have a tray slide out on drawer slides, then fold down to a workable angle.

If you can find some ball bearing slides, from an old tool box, to make the tray slide out.
You could then cut apart the under deck trunk liner and reattach it to the bottom of the drawer to create a stealth slide out tray.
Cable movement/management becomes an issue, though.

That's my grand plan for my trunk.

Edit; something like these

http://www.doorcorner.com/pr16fuexb...=googlepepla&utm_medium=adwords&id=20005783933&gclid=CO-j_fibir8CFSsSMwodjQkAhA

 

My amps have been mounted under the rear deck in my past 2 vehicles with great success and no overheating. Of course, my amps have been internally fan cooled which certainly helps.

In both instances, a metal-frame rack attaches to the car and then the amp mounts on the frame. The frame spaces the amp away from the deck so there is an airspace between the amp and the car's metal. That helps the amp to ventilate and also leaves room to hide the cables.

See pics below:

You can see the airspace between the rack and the amplifier here:

Here is a closer look at the rack:

Finally, here is the trunk carpet installed hiding the frame from view:

 

Some interesting advice/thoughts.

Unfortunately, I have to figure out some other place to mount two amplifiers. As noted in my first post, I just can't visualize the installation considering my trunk bottom is not flat like several other cars; otherwise I would have an idea.

 

I would still like some help with this... about to give up. Has anyone mounted to a slanted rear deck? I just can't visualize it and don't want to start drilling without a plan of action. All the pictures I see are of flat decks.

...please read this post twice.

 

have youi considered the hanging amp rack?it sounds like a pretty sweet idea,

 

I am going to do the same thing, and SubterFUSE has the right idea. Except I have an older (and likely less sophisticated) amp, so I am going to mount it to a rick like his, but upright, to allow for cooling.

There is nothing wrong with mounting the amp flush against the deck, thus having it angled, except it might look "off".


Here are some of the best examples I could find:

Also, check out the "bimmer forums" for some of the best examples of DIY stealth installations.

 

The only thing I would mention about my setup vs. these pictures:

My amp rack has about a 1 or 2 inch gap between the rear deck and the rack. So even though my amp is upside down, there is still an airspace between the amp and the car's metal.

And..... like I said.... my amp is internally fan cooled. I am sure that helps.

 

If one mounts the amp under the rear deck, is it OK to ground it to the rear deck? If not, the ground would get pretty long to go elsewhere.

 

I just did a rack.. I didn't want to mount upside down.. Also couldn't figure it out.. Lol.. So.. After lots of research and trips to Home Depot I came up with a plan.. I didn't want to drill new holes in my deck., so I got slotted metal from homedepot Everbilt, 1-1/2 in. x 14-Gauge x 72 in. Zinc-Plated Slotted Angle, 800517 at The Home Depot - Tablet

And hung it using existing holes in the rear deck.. I used 1/4 inch bolts? Idk they r like threaded rod but with and end like a bolt.. ... I put two of these in.. About 3 inches from the deck.. Now from these I hung another set of slotted metal.. This was done to deal with issues of needing holes for the bolts.. It will also solve your angle issue.. U can just screw mdf to your shelf or u can go get drawer slides and make sliding drawers.. Lots of options..

My ground is messed up.. I have very little experience but pretty sure it's related to this.. But Gluck

 

Got inspired by the Sti build by Simplicityinsound. Ordered a rivet nut kit to hang a board with offsets below the deck and mount amps right side up below the deck decoupling amp chassis of course.

Unless I get a little crazy and mount them to a side wall possibly as there's a rather deep unused space behind the wheel wells. Or maybe up near the seat. Jury's out until I get in there and wrap my brain around it. Should work nicely.

Best part is with the rivet nut tool, any safe and solid inside metal surface is fair game.

I'll be mounting two NVX amps and a DSP (MS-8 for now).

 

We have a demo vehicle with amps mounted in the ceiling upsidedown. Then again, they have a liquid cooling system or something goofy like that but even when that's off they don't get hot.

 

I see this thread went down its own railroad tracks