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The car came to me without a headunit but with like 22 RCA cables run from the head unit to who knows where.
If this car was ever going to be wife-approved, the harmonious sound of eight cylinders working in unison to convert dinosaurs into motive force wouldn't be enough for her to agree to spend time in it, this car needed a clean install capable of pumping sick beats.
The car came to me with stock speakers up front, some garbage 6x9s in the back, and a Rockford Fosgate compact 4-channel amp mounted in the truck where the stock amp used to be.
After doing some research, I found that the RF amp is actually decent, capable of putting out 75W RMS x 4 channels at 4 ohms, so I kept it. Because it's so compact it's really popular with motorcyclists like that guy that always went roaring through my old townhome development at 5AM blasting Bon Jovi's Wanted Dead or Alive. If the amp can pump out the ultimate badass biker anthem over the sounds of his even more ultimate badass straight pipes, it should suffice for belting out my jamz.
The amp had been wired up through the stock wiring harness, so I disconnected that and instead used some 4 gauge wire left over from the my Focus stereo install for the power and ground to the amp.
After realizing that the installed 6x9s were rated for 50W RMS max and hearing how badly they performed under any type of power from the amp, I knew they had to go so I yanked them out. Fortunately, a previous owner had already installed the adapters to allow the installation of 6x9s in an E36. I decided to fill the blank space with some Polk DB691 6x9s. Rated at 125W RMS with a 93dB sensitivity and response down to 35Hz, they were a good choice for a car that wasn't going to get a subwoofer.
Of course, contorting myself to get into the right position to install the speakers was...uncomfortable.
Up front, I found the stock woofers and midranges in place, with some Infinity tweeters in the doors. I grabbed a Polk DB5251 component system to replace the stock woofers and broken tweeters.
I used this component setup in my Focus; I know all too well how great the Polk setup is so I decided to use it again in the M3. It comes with the 5.25" woofer, a 1" tweeter, and the necessary crossover, and can handle 100W RMS. I pulled the old woofers out of the footwell and put the crossover up in the dash, held safe and sound by mother nature's greatest achievement, zip ties. I reused the stock tweeter wiring to avoid having to pull wires into the doors.
The tweeters fit into the doors nicely and clamped in place.
I left the mids installed but unplugged.
For now, I ran a headphone-to-RCA cable to the amp through an inline volume knob and just drive sound from my phone. Eventually I'll have a more permanent sound source:
How's the sound quality? It's hard to say for sure since the amp is driven straight from a cell phone, but I have no complaints. In previous cars, I've made up for crappy, boring driving dynamics by having a nice stereo. The M3 doesn't suffer from being boring, so I don't miss having a couple amps and a sub. It's good enough to pump music during the drives to the autocrosses that are a bit further away. Bass is certainly not sub-level, but it's there in a way that the old 6x9s couldn't dream of. The front components are great, and it's all loud enough to earn a punch in the arm if I turn it up while the wife is riding shotgun.
This writeup is also on my blog, though the blog version contains 14 more hidden Taylor Swift song titles than the four already in the writeup above.
Here are all of the parts I used:
Polk Audio DB5251 front components
Polk Audio DB691 6x9s
Rockford Fosgate PBR300X4 amp
Inline volume knob
(The 6x9 adapters show as no longer available on Amazon)
Last edited by Laminar; 12-16-2015 at 01:55 PM.
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Is the tablet going to be installed in the factory head unit/climate control?
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That's the goal. I'll have to lose the storage cubby under the OBC. I'll work up a bezel and 3D print it. I have a Nexus 7 tablet running all of the Megasquirt software but it's really slow. Thinking about picking up an Amazon Fire 7, I regret not grabbing one for $35 on Black Friday.
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Looks like you have the first Nexus 7, the newer one would probably do nicely. And I'd be interested in a bezel depending on how well it fits...Originally Posted by Laminar
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Yeah, apparently the 2012 version used some crappy type of memory that hasn't fared well. I tried running Lollipop on it but it was a disaster. Back to 4.4 Kit Kat and everything's decent. My biggest worry is keeping it charged correctly.
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Easiest way to keep it charged well is to use a high quality 12 volt to 5 volt converter to USB. If you've got accessories you want to use, use a ROM that supports USB OTG
Member
Yeah i grabbed an OTG cable but have had a hell of a time installing a compatible ROM, I've tried Timur's ROM for the 2012 Nexus but he pulled it from the internet and support is sketchy.
Ideally, the tablet would know when the car's on or off. When the car's turned off, it'd charge to full then go into hibernate mode. I could set it up so the tablet gets power when the car's on, then have it wake/sleep based on whether the car is on, but some people have expressed concerns over whether the thing discharging over time and not being able to recharge over short trips.
Ambers > Clears
I had my tablet in my car and if I drove the car everyday the tablet stayed charged, but if I missed a few days the tablet would almost be dead.
1995 M3 S52 turbo (Sold, like an idiot) -----------------------------------1998 M3/4/5 (Hopefully turbo soon, Nope sold this too
)..................................E92 335i(God, I miss the E36's
)
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Yeah, I've been trying to figure out a way for it to only power down if it's fully charged, but right now the only "signal" the tablet has is monitoring whether or not power is applied, so if I remove power when the car is off to let the tablet know the car has powered down, it can't keep charging...
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