This is for people who have a streetable track car that drive their car to the track and want some tunes for the ride. If you are willing to sacrifice adding a little weight back to your car, you could get some pretty decent sound that you can hear over the loud exhaust and gutted interior.
There are many different ways to get cheap lightweight sound in your car. Of course the easiest and lightest is just listening to music on your phone from its speaker or a set of earbuds, but phone speakers suck and earbuds aren’t safe while driving. So here I will cover a few different options you have to get some decent sound in your track car.
First thing’s first. Get rid of your radio and any other sound related stuff like any amplifiers, subwoofers, etc. This is still a race car.
Speakers
Coax speakers are going to be lighter than components in this case, so I would recommend sticking with those. If you don’t know the difference, check out my Basics to Upgrading Your System post.
Factory Speakers
One option for speakers, and often one of the lightest depending on your vehicle, is just keeping the stock speakers installed. Many factory speakers use tiny magnets and have plastic baskets and paper cones. Speakers made like this are usually the lightest but won’t sound too great. But who cares? It’s a race car!
Some factory speakers (cough cough Chevy) are terribly and barely handle radio power, so hooking an amp to them will probably blow them pretty quick. Get prepared to upgrade at some point if you go this route.
Upgraded Speakers
If you want better sound quality than stock speakers even though it’s a track car, find a decent set of coax speakers like these 6.5″ Polk db651 (check price on Amazon). They are some of the best sounding coaxial speakers I have heard for the price. Amazon has the weight listed as 5 pounds. I’m guessing this is shipping weight, so just the speakers should be even less. Or you can get the shallow mount version and save a few dollars and half a pound: Polk db651s slim mount (check price on Amazon).
Some of the lightest 6.5″ speakers I found were these Infinity Reference 6032si shallow mount 6.5″ coax speakers (check price on Amazon). Amazon has them listed at 1 pound. I’m guessing that’s not the total shipping weight like the Polks.
To save even more weight, go with a smaller speaker like a 5.25″.
Most of the weight of a speaker will come from the magnet, so the smaller the magnet, the lighter the speaker generally. But this usually means a less powerful speaker unless you find with a neodymium magnet like the Lanzar VX60S VX (check price on Amazon). Speakers aren’t going to add much weight, though. Maybe 5 pounds at the absolute most.
Amplifier
This is where most of the weight savings will come in. I don’t recommend you use a big traditional style amplifier like the JL Audio JX360/2. Many companies are starting to make very small, lightweight amplifiers. Check out the mini amp section of Sonic Electronix. As you can see there are many different amps to fit any budget.
My Recommendations
Alpine Power Pack: There are many other amps similar to this one, but this is the only one I have experience with and have nothing but great things to say about it. Great size. Great sound. Great power output. It’s even bridgeable which means instead of using 2 of its single channels to get 45W, you can bridge it to 2 channels and get 90W per channel. It’s also very lightweight. Amazon has it listed at just 2.4 pounds. But that’s not it; this amp is very easy to unplug and take out of the car. So you could very easily just mount it with velcro or something similar, and when you get to the track disconnect it and take it out to save even more weight.
Make sure you get the Alpine KTP-445U model and NOT the Alpine KTP-445A as the “U” stands for Universal and the “A” stands for Alpine. The “A” model is meant to be plug-and-play to an Alpine head unit and won’t come with RCA inputs which is important as you will see later.
This amp has individual left and right channel gain settings as well as a selectable high pass filter.
Lepai LP-2020A+: This little amp isn’t necessarily made for car audio, but it will definitely work and is very light. I have one of these powering a set of speakers in my apartment and it’s a good little amp. Using it in a car, I would make sure it was mounted securely and you will be fine. It’s not quite as powerful as many of the other choices out there at only 20W per channel, but it was also only $20 on Amazon at the time of writing this (click here to check most recent price).
Just make sure to get the right center positive pigtail to wire it into a car like this one, or you might be able to get away with cutting of the AC power supply and using the other end as a pigtail to hook up power and ground.
2021 Update:
Now that bluetooth amps are so cheap and small, they are definitely worth a look for this purpose. This will use the bluetooth on your phone as the source, and all you need to do is hook the amp up like normal minus the RCA inputs and hide it away somewhere. This Herdio marine bluetooth amp also comes with an external controller, so you can keep your phone in pocket.
Connections
Now that you’ve picked out your speakers and amp, you will need to get it all hooked up. You can follow my How to Install and Tune an Amp – With Wiring Diagram post if you need help wiring up an amp.
If you chose one of these smaller amps that don’t draw much current, you can just hook up power and ground at the radio connections (though you may need to run a separate constant power wire to the battery if your amp draws more current than what the radio fuse is rated for your car). You can either cut the wires off the harness or use an aftermarket radio wiring harness to make it easier, and you won’t have to cut into the factory harness. To find what harness your car needs, go to metraonline.com and search for your vehicle. You will be looking for a female plug similar to this:
Now that you have the amp wired up, you are probably wondering what goes into the RCA input. Go buy a cable similar to one of these RCA to headphone jack Monster Audio Cables and plug it into the amp. Run the other end up to where you will put your phone or mp3 player.
Now you control everything with your music player and do away with a radio completely. This method of simple sound also works great in Jeeps or anything else where you don’t need a radio in your car.
An alternate method would be to buy a bluetooth adapter like this one. This might be a little advanced for a race car, but it will get rid of an extra wire that may be in your way otherwise. And this one uses regular RCA cables to connect to your amp.
Now you can do away with your radio and any other factory sound system you have and get way better and louder sound than what came in your car and still stay light enough for the track.
Update
My personal setup in my Miata is a Pioneer mechless single din head unit with bluetooth and the factory speakers. The mechless (no CD player) radio is lighter and has more features than the stock radio. The one I have is very similar to this newer MVH-X390BT (check price on Amazon) and it works great.
In my STi, I have an Alpine Power Pack with an auxiliary cable for the input with a volume control knob where the factory aux input jack was running the factory speakers. I will soon be upgrading the speakers to these Sony GS components (check price on Amazon) / (read my review on them here) and possibly adding some sort of bluetooth. Sony also has a version of a mini amp like this that I have had great success with, but it is not bridgeable like the Alpine (check price on Amazon).
Update (1/20/2019)
I no longer have the Alpine power pack in my STi. I did install the Sony GS components and love them. Check out my review (here) and installation videos of them (here). I also added a Zapco ST-4XSQ amp and Sony XAV-AX5000 head unit. I may do a review on this soon as it is by far my favorite radio out right now for the price, quality, and features offered. I am a Sony and Zapco dealer, so if you are near Baton Rouge, feel free to call or email me for pricing and availability.