The big three

hi,

Looking for some help on an area where I am sub 0 (knowledge wise)

I want to upgrade the electricals setup in the car. Specifically the power / ground cables. Final objective is to have more head room with my ice. The cables I want to upgrade are: 

1. Cable that runs from alternator +ve, to battery +ve.
2. Battery -ve to chassis
3. Engine ground to Chassis
4. Battery to amps at the back.

These cables would be used as additional to whatever is there. I.E. I am not planning to replace any oem cables.

Three questions follow:

1. Can you recommend someone who can do this around south delhi or gurgaon area?
2. Gauge of cable to be used 2awg or 1/0?
3. Would this in any way affect the warranty? The car is under extended warranty till Oct 2010.

Would anyone know how much current the alternator on a fiesta generates?

Tks in advance

You probably know this( I doubt if there is anything you don't know), but make sure that you terminate the wires in parallel at exactly the same place the stock wires start and end. Wouldnt want any ground loops

hi dear,

Third attempt at posting since last night (sigh).........dont ask .

Somehow, I knew you would post a reply. In the literal sense, yes I know what to do. But I'm quite sad with mods. Have screwed up more than a few. Tks for pointing out that the termination points need to be identical. The rational behind this upgrade is as follows:

With 1000watts rms amps, I would need like 80 amperes @ 13.8v for the amps. The alternator is 60 amps. Of this the engine+ac+lights+fuel injection..... prob use up like 40 amps. Leaving a measly 20-30 amps = 450 watts total for both the amps...

Typical oem wiring for this section is like 8gg (i think. At least thats what it looks like). The 8gg is ok for a 60-70 amp circuit. If you wanted to run like a 120 amp line you would need both a 1/0 gauge cables and a 130 amp alternator. So the idea is to cahnge the wires now and do the alt when the warranty expires.........at least thats the plan. Open to suggestions / corrections as applicable.

btw tks for the vote of confidence. One of the several twisted things about this sound chase is, that when you think you've arrived, you'll discover something will knock you down and show you how little you know. The fact is, what I don't know far exceeds what I do. So I tr and stay light on my feet.....lol

Well, I would differ here - if you are putting in new wires you still have to open the connections. Connects are where things usually go wrong - so paralleling wires may not help.

IMO if putting in new cables, get rid of the older ones - you will have less wires running around and less tangling and so on. Ensure that the connections are clean, and have toothed washers between the points to be connected before tightening them. Tighten them so that the washers have a good bite and cover the joint with some anti-rust (or moisture protection) - this will ensure that the connections are reliable and last long...really long.

As for paralleling or cable amperage, it all depends on what you want - is it that you want better wires or greater current capacity. Paralleling wires will help in the latter case - but keep in mind that the current is still limited by the battery & alternator capacity - no point in installing cables that have a greater capacity than these (though a shorted battery makes the cable gauge irrelevant - a can of Ceasefire would help more here ). So determine the non-shorted or normal current draw you expect - add a little extra (15-20%) to that and arrive at the realistic target amperage.

hi rohit,

I would definately loose my extended warranty if I changed the cables. Thats why I want to run them parallel. The bit about the toothed washers and anti rust was good. Fore sure dont want rusting at this point.

This whole mod is about getting some more ampreres to the amps. This would give me more headroom. Thats what I'm looking for. Running a network that allows for greater current flow, would only put more load on the alt if its already running close to its amp load. Is that what youre saying?

Arun, I generally steer clear of ICE matters, but your figures alarmed me... 1kW RMS is waaay more than anyone would require... This power would adequately meet a large auditorium need, and if used in a car, my lead to quick onset of deafness for the occupants...

The key to good quality of car music system is its dynamic range, expressed by peak music power output - for a high fidelity 1kW RMS music system the PMPO wattage would go to as high as 12000 to 15000W. My home theater has this 1kW RMS rating, but realized only half as the rear channels never deliver full power, and I operate it at barely fifth of the power - ear response is logarithmic, so overall power delivery ever put thru may even be less than 100W RMS. If the dynamic range of the amplifier is smaller the higher RMS wattage goes straight to inducing deafness, and not to adding any sound quality.

The peak power requirement of the music system can be augmented by adding decoupling capacitors right at the power input terminals of the system. Using several capacitors in parallel, instead of one huge one would lead to lowering the equivalent series resistance of the capacitors, thereby helping smooth delivery of power to the amp. Jumbo cabling is not necessary. In fact the need for thicker cables point to the fact you are banking on raw RMS power rather than refined, low distortion, high dynamic range power.

Let me know if I am right or waaay off-track...

I whisper lest they shout!

hi binoy,

Sorry did'nt mean to scare you mate. Any sane person who knows about 2ch audio would know that its crazy to run 1000watts rms in such a small onfined space. Yet no, I have'nt taken leave of my senses and no I'm not planning on losing my hearing anytime soon. Yes, car audio is slightly different to 2ch home audio.

 I'm not a SPL guy who gets high on 140db bass hits. I get my highs from seeing and feeling Sarah Mclachlan when I hear her singing 'Bens Song'. Ofcourse I'm talking about listening with my eyes shut.  So staging, imaging and a sense of presence is vital. I'ts better with my 2ch home rig and the objective in the car is to come as close to the home one as the pocket and knowledge will allow. Pocket being the over riding factor.

Some areas where car audio is different:

1. The two polk amps have a combined rms of 1100 watts. Now, to produce the 1,100 they need around 80amperes of current. The altenator in my Fiesta does about 60. of which the engine, ac, lights, fuel injection system etc use up about 30-40. That leaves about 20-30 amperes for the amps. Hence now the 2 amps combined are only putting out 300-350 watts. Thats why car audio amps are rated for higher watts. So its about 40 watts per driver for the front comps and about 180-200 watts to the sub.

2. Next I have the gains on the amp at about 1/3. Consider this gain dial, like a master volume knob. This is the max volume I'll get even if I run my hu at max. So this is another

3. Of the 16 frequencies on the eq 13 are attenuated to -4 to -8 db's levels further reduces the sound power. Home audio buffs would never put an eq in the signal path. Thats becoz in a home environment you dont need to. The idea is to let your equipment reproduce the music as it was recorded. In a car environment, where the far side speaker is on axis but much further and the near side one almost 70 degrees off axis and closer; multiple reflection points, tons of glass that reflects and bounces frequencies above around 1khz, etc etc. The equaliser and time alignment help over come these handicaps.

So given the above in the close confines of my car I'm prob hearing about 175-200 watts combined. This whole mod is about trying to get an extra 5-7 amperes to my amps so that I can get an extra 50watts to this mix. Now you can officially call me crazy.

I too am a self proclaimed audiophile! The sound of the plucktrum striking the guitar strings is 'music to my ears' let alone the song. From my personal view point the 'car audio' is never a perfect listening enviornment what ever the gear that ones pocket and time allows to install(alteast for a SQ guy-like you and me).

My take would be that for a SPL lover investing in car audio is great but for SQ guys it would be a waste of money, cause i would rather avoid the out of control Kerala Fast passenger bus running in the middle of my lane at me rather than listening to the twrilling of Gilmore's lips rendering the High hopes Chorus!

Moreover 175-200W in the car would do permanent damage to the ears(trust me on this). Its not 'deafness' that loud sound causes but something called 'Selective frequency loss' and there wont be any evidence of the same to the individual(until quite late) unless they are subjected to something called an audiometry test.

On a lighter note-i always thought that the never ending quest for SQ and SPL by 'true audiophiles' is because they are slowly going deaf and are never quite satisfied with whatever system that they have!LOL

Arun sorry for taking the discussion OT, please dont consider the above as negativisum but rather as 'friendly banter'.

From my personal view point the 'car audio' is never a perfect listening enviornment what ever the gear that ones pocket and time allows to install(alteast for a SQ guy-like you and me).

Very true. A car is the worst environment for reproducing audio. That's the whole challenge. How well can you overcome these obstacles. I spend 5hrs a day on my commute. I listen to my home audio maybe 1 hr a day if I'm lucky. Hence focus is more on the car front.

It may surprise you, how close the car audio can come to 2ch home reproduction. In the car sq world its accepted that sound quality, is a combination of quality of ears - 20%, tuning ability - 35%, install-25% and equipment 20%. So, while you can go out and buy the genesis / zapco / butler amps and the dyn esostar or the morel supremos speakers and a sea's lotus sub and blow up a few lakhs, you would only have maybe 16-18 points (out of 20 for equip) out of the total 100. As you can see the max points are for the first two. Thats where the key lies. Tuning changes the sound presentation in the car. So with just decent equipment if you get the tuning right with an avg install, you will get the effect of home audio. You may wind up ahead of the guy who spent 5lakhs on equip but little effort on the other areas. 

The imagery of listening with eyes closed was strictly for either home audio or sitting in my car when parked in the driveway. I dont drive with my eyes closed.....lol  . I dont take my volume knob above 80% of max on the hu. I dont listen to the music very loud. I dont need to the presentation is good at decent voloume. Also keep in mind that inspite of all the damping etc done inside the car, when I'm driving I would easily lose 20-25% of the total watts to cancellations due to noise from the external environment that seeps int the car.

I can see u're also a Floyd fan. We must meet up if you come to delhi. Your comments are well recvd no issues.