Subwoofer Install for dummies (Stock Headunit)
 

Hey guys,

First off, if anyones wondering I have the 2014 GT86 [GT]
This model comes with the tweeters in the dash, woofers in the door and rear speakers which are pretty useless.

I wanted to keep the stock headunit, because i like it.. Its easy to use, has bluetooth ect.. Stock speakers go alright too. Plenty of time for upgrades in the future.

Okay, ive put the amp in the wheel well in the boot (GT has no spare) and comes with a plastic+carpet boot trim which is quite firm.

You will need a Speaker to Low Line Frequency Convertor (Turns speaker frequency into usable subwoofer frequency)

Everyone should be familiar with their boot:

http://polyfedelicio.us/imgs/images/2015/07/26/1.jpg




I got a older amp off a mate, swapped for a carton of piss. Just using MDF (think its 12mm) as a base plate. Chopped the foam T out to size and fitted the mdf+amp

http://polyfedelicio.us/imgs/images/2015/07/26/2.jpg


Power i used some 4 gauge cable i had from my old car. The power lead will have to run straight of the battery to the amp. Use the same gauge of bigger as an earth for the amp (4gauge or 2gauge ect). I earthed straight to the rear strut bolt because its close. If you want to keep the plastic + terminal cover you will need to chop it..

http://polyfedelicio.us/imgs/images/2015/07/26/3.jpg


Theres a big grommet behind the battery which easily fits a 4 gauge wire through. If you peel the plastic trim pannels off (they just clip on/off and have one or two push clips) and pull back the weather seal you can run the wire below the plastic floor cover to the boot. I went under the back seats through an opening under one of the foam trims in the boot.

http://polyfedelicio.us/imgs/images/2015/07/26/4.jpg


The Frequency Convertor runs off the rear speaker wires. Il include a diagram of which pins to splice into which i found off an 86 site. The Convertor has RCA outputs which you will need to connect to the amp. I ran the RCA's and the Remote wire down the opposite side of the car than the power cable to avoid distortion. The trims unclip the same both sides.

http://polyfedelicio.us/imgs/images/2015/07/26/5.jpg

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In the boot, all wires hooked up. I cut a square tubing to size to maintain some strength and make sure the boot doesnt have a hollow/low point.

http://polyfedelicio.us/imgs/images/2015/07/26/6.jpg


Run the speaker wires as you need to your subwoofer. I opted for a premade fibreglass box which was locally made to fit the boot. Take some time to consider ohm's, watts and cubic space while choosing a sub / amp / box combo.

I just strapped it to the boot floor, it already fit quite well in the space and doesnt move at all.

http://polyfedelicio.us/imgs/images/2015/07/26/7.jpg

http://polyfedelicio.us/imgs/images/2015/07/26/8.jpg


Sorry if i missed anything out, i did this rather rushed.

Cheers fellas!

You're begging to overheat that amp. There is absolutely no air movement the way you set that up.
There are any number of posts that explain how to tap the wiring in the trunk for the factory amp instead of running wires all the way to the H/U for the signal. That allows you to put in a crossover to take some of the low frequency load off the door speakers and clean them up at the same time. Assuming your vehicle has door speakers with a small amp in the trunk, that is.

On the plus side, I like how unobtrusive your box is.

I considered the overheating issues you mentioned, and have done tests in the past with other cars, and it never has reached hot enough to damage the amp, or to overheat it.. I'm defiantly not ruling it out though; I did want to have some sort of large 'breather' into the boot covered with mesh or something but haven't come up with any way to mount the mesh (espically since it will cop heavy vibrations..)

The AUS delivered gt86 missed out on any factory amp.. I'm not sure, maybe the GTS model has them, it would be made things a bit easier.
None the less though, it wasn't hard