What it takes to go BIG!A guide by faris
We've all seen the one or two sub-woofer setup in a box in the trunk. Everything from 8's, 10's, 12's and at least one guy on this forum has a 15, or at least did. But, what if that's not enough?
This is a brief write up on the aspects to be considered when going big on an audio system. Much more than 1000 Watts dedicated to subwoofers on a stock system will start causing you issues. My current build plan is calling for about 6000 Watts. This is a heads up to every issue I’ve come across while planning it.
Note: Neither myself or ElantraXD.com responsible for anything you do with this information. This is nothing but experience and educated opinions on a build. If you end up wasting $10k building a system like this because you didn’t do enough research yourself you can enter a post in the ‘flame’ section of the forum.
SIZE: The Elantra is small but not too small; this is great for containing bass. But for all intents and purposes, is a bit rickety when it comes to solid joints where large subs will rattle the **** out of them.
POWER: The engine stock produces 138 hp @6k and 136ft-lb @4.5k when attached to the stock alternator which is ‘decent’, putting out just over 50 amps at idle and about 90 amps when you're cruising. But that is a very far cry from what is needed for a big system.
WEIGHT: The Elantra is a very light car for it's class (2635 lb's curb weight), but the suspension does NOT allow you to put much past 100 pounds directly over the rear axle without it squatting. The average two subwoofer enclosure with two subs and an amp is about that alone.
These are the three main hurdles to overcome if you want to go seriously big with car audio. This is true for all cars, however out beloved Elantra has a couple setbacks that make it harder.
Reinforcement & Deadening
TRD - TrunkRoofDoors. Not to be confused with Toyota Racing Development, but handily the same acronym, are the places that sub-woofers will ruin your day from an exterior structural standpoint.
The Trunk Lid & Trunk itself can be helped in a few ways. The first place to start is Sound Deadening. There are plenty of brands and even types of sound deadening out there, anything from a simple stick on to some that require a heat gun, and others like expanding foam or even fiberglass. My choice is our good friend Dynamat, I have personally only used Dynamat in the past and it works wonderfully. The second is making sure there is clearance from the bottom of the lid, to the top of the rear bumper. If this tolerance is less than 5mm then you will have some severe rattling and you'll take all the paint clear off that section of your bumper and the bottom edge of the lid. Last to make sure you aren’t rattling around the edges, be sure that your foam/rubber seal is in good condition, and add some more to a troubled area.
The Roof, the roof, the roof is on…wobble wobble wobble. The roof in our Elantra is VERY thin and VERY flimsy. Take a good knock on the top, sounds hollow. This is also another job for Sound Deadening. HOWEVER and this is an absolutely massive however…if you have a sunroof you are in for a heck of a project unless you’d like your sunroof shattered. The sunroof assembly will flex with the car, if it flexes too hard, you will crack your sunroof. This is a matter of reinforcing the assembly. The best way I know of to do this is using MDF to create a bracing system for the entire roof of the car. That in its own will do an amazing amount to keep bass in and save your sunroof.
The Doors are pretty straight forward as well, Sound Deaden the entire door surface as you would the trunk, trunk lid and roof. If you notice rattle in your doors again check your rubber seals, make sure they’re in good condition, and you may need to either beef them up, or add rubber or foam to specific areas to deaden those rattles.
Note: This only addresses the structural aspects of the car, parts such as interior trim, handles, buttons, and molding will also be a source for rattles and other extraneous noises; however those are trial and error and will vary across each build.
All that electrical ‘mumbo-jumbo’
This is where you need to decide how you are going to use your system. Will you be parked with the car off bumping your system? Will you be driving around bumping it hard? Both?
Independent System – When the car is off all power is taken directly from the battery. If you have a large draw, that need will be placed on the battery.
Dependent System – When the car is running power is produced at the alternator, which then charges the battery, which you are pulling from. If you have a large draw, that need will be placed on the alternator.
The stock battery and alternator will serve you will up to about 1000 watts. After that you are pushing the stock system too hard and are risking burning out an alternator, or killing your battery if you sit and listen to your music too long parked. So going big there are a few steps, mainly in improving efficiency, and providing faster reliable power.
Alternators, Batteries & Capacitors
Independent: You will need a bank of batteries (# and which ones specifically are dependent on your system draw and personal preference, respectively) in parallel to provide the proper amperage, at which point the size and number of capacitors you will need (if you choose to use them), will depend on the number of amplifiers that the system is going to need. This type of system will need to be recharged after each use and doing so could potentially be done by the stock alternator in the car using an isolator. Unless your car is purely for show, it is recommended you keep your primary battery isolated out, otherwise when you drain your extra batteries, you drain the primary and can no longer start the car. It is also recommended that with battery bank systems you have them charged externally when not in use. This set up is used most commonly for SPL drag. And can provide incredible power consistency. However does not give you the freedom to play as much as you want, whenever you want.
Dependent: You will need to replace the alternator altogether, a low end high performance audio system will be drawing upwards of 200 Amps without any questions, which is more than double the maximum output on the Elantra alternator. A little simple physics here: Wattage = Voltage * Amperage. So if your car is at 12 Volts and you are providing 200 Amps you are making 2400 Watts of power. Keeping in mind that that is not a constant number, your rpm’s will go up and down, and the fact that the car itself has a current draw of its own for the cars systems such as the A/C, windows, headlights, computer, etc. You may need more than one. Once you have the alternators figured out you need to have a starter battery, in line with an isolator, which then goes to a parallel battery bank similar to, but much smaller than, the independent system. Again the number of batteries and type is completely dependent on your system. At this point you may also choose to add capacitors as well as the batteries for an extra serving of juice.
Independent & Dependant:
•The Big 3 (Alternator positive to battery positive, Battery negative to chassis, and Engine ground to chassis) wire upgrade is a MUST. Use 1/0 wire.
•Use 1/0 wiring for your power and ground connections. MAKE GOOD GROUNDS. VERY solid grounds will reduce noise incredibly and make for a better system altogether. If you are going much over 5000 watts, go 2/0 wiring.
•Use 14 or smaller gauge for speaker wires.
•Be sure to use as little length of power, ground and speaker wire as possible, as the more wire you have the higher your resistance and the higher your resistance you will lose power to heat. For example: a 6000 watt amplifier using 2/0 power wire across 10 feet will lose something about 250 watts just in the wire alone. This number will dramatically go up with smaller wires, and to some point if you go too small, hopefully a fuse will blow, but if it doesn’t, your wire will melt…electrical fires in a small enclosed area…my favorite(;
Note: Larger and especially multiple alternators will pull on the engine even harder, this will need to be dealt with by increasing the horsepower and torque of the engine to some degree. Simple things like CAI’s, and ECU modification should definitely be looked into. This issue will be much further explained in the next section.
All this darn weight
So you have your entire system installed! Great! Congrats! …Oh whats that? Your car can’t move because your suspension is bottoming out and your clutch is slipping? As mentioned earlier all of the added weight as well as added tax on the engine from alternators are going to make your poor Elantra a slug. Here are some methods to remedy this…to some degree. I can promise you however that your Elantra will never be as peppy again.
PerformanceYou can try to beat being a slug by giving the engine more power by modifying the:
•You can prevent the slipping clutch by getting an aftermarket clutch kit, this may not be needed but if your clutch is slipping, you are looking at replacing it from wear sooner or later and if you do, get an aftermarket clutch that can handle higher loads.
Weight reductionYou can also beat the total weight change by stripping the car down before you even get started
•Removing the back seats if you are going with a system this big will be more than likely
•Replacing the hood and trunk lid with carbon fiber is an easy 50 pounds of weight savings, but is expensive.
•Replacing the remaining front seats with race seats can also shave off a ton of weight.
•Removing the spare tire and jack.
•Pretty much anywhere you feel you don’t need it, then get rid of it
•In general not keeping a lot of crap in your car!
•Coil-overs or lowering springs are pretty much a must if you are going to be loading somewhere in the neighborhood of 300-400 pounds onto the rear axle, let alone what will be distributed among front and rear from Dynamat. This will also give your car a great look altogether and improve it's handling.
A few final notes:
It has been mentioned that running a high amperage Dependent system will be hard on the car, keep in mind that it can be hard enough to actually lower the life expectancy of the vehicle. This also goes double for the sheer vibrations running such a system can cause, these cars really just weren’t made with either in mind.
Your system can only be as strong as its weakest link. In terms of a dependent system, even if you strapped on two 200a custom alternators, that only gives you 400a of charging capacity to play with. Using the same math here we did to find out that the stock system can only run around 1000w, we find that even with all the extra juice were still just under 5000w. This doesn't mean you can't have a 6000w system, it simply means you cant play it at full bore nonstop for extended periods of time and still expect the car to keep up.
Be cautious when purchasing an amplifier, if the amplifier is not CEA 2006 certified, than be sure to check the amp rating on the fuses. Simple math tells us that amperage x voltage = wattage. If your “2000 watt” amp has a single 50a fuse, then its maximum output is closer to 720w using a good battery. This is by no way Absolute, but is a great reference when looking for an amplifier. For more information about the CEA 2006 rating, check the ce.org site here: http://www.ce.org/Standards/browseByCommittee_2648.asp
This is not meant to be a completely inclusive guide, there is plenty more not discussed in what I have written here but anyone and everyone who has knowledge in this area is more than welcome to add their comments and thoughts.