I need a new alt, what should i get

[HzEmall Regal]

Originally posted by GNandTTA
The key word there being competitor, not daily driver. Big alternators deliver big current at high rpms. But they don't do jack at idle. For a daily driver stick with the factory alt.

Caps do help. Alternators and batteries are slow in comparison to caps when it comes to delivering short bursts of current. They have a much lower internal resistance than a battery or alternator. Plus most caps are usually mounted right next to the amps.

That is why most good amps (car and home) have large caps right on the circuit board. By adding an external cap you are just adding more avaliable fast current.

When was the last time you did some testing on a alternator ? Your stock one produces hardly anything at idle or low RPM. At least most higher output alternators have a much higher output rate at idle or low RPM. Wranger and Ohio are just 2 of the alternator companies that offer much higher outputs. My 180 amp alternator produces about 98 at idle. My stock one (120) in my 97 Suburban put out a measly 52 at idle and low RPM

Alternators are not just for competitors, after all these things are not big money. You can buy a 160 Amp alternator for around $400, that is just a couple of caps.

Alternators and batteries are slow to deliver current compared to a cap if the battery is dead. If you go with a large reserve battery (not a large CCA) and it is charged it will provide all the current you need.

As for the large capacitors inside home and car amps, they serve a different purpose and are at a different point in the power supply section of a amp then a outboard cap. Plus with almost all the amps on the market being regulated power supplies, a boost in current from a cap will not make the amp perform any better cause they are designed to work the same within a certain voltage range.

If you people wish to buy caps, go right ahead, we (retailers) make more money, but the couple hundred dollars people spend on them can be better used elseware in the car.

All I am trying to say is that there are 100 sides to every theory out there and opinions are like buttholes, everyone has them. BUT simple stuff like voltage, current, power and resistance can't change......you can't change the law of physics, many have tried, but failed.

Research the product and the concept before spending your money just cause some people on a board say so (me included)

If you want to go to www.carsound.com and do some research on there there have been tons of discussions regarding caps on there under Richard Clarks forum and they have all been proven they don't work.

 

[GNandTTA]

Simple physics here -- given the same case size the stator on a high output alternator is the same as a standard stator EXCEPT is has fewer windings. The fewer windings have less internal resistance and thus produce more energy (current). However, a stator with less windings has the inherent tradeoff of producing substantially less current at idle. There simply is not a strong enough field created by the stator with less windings.

I spent alot of time with this issue about 10 years ago. There is a AC Delco repair shop by me that repairs factory alternators. One of the techs there gave me the run down of how these things really work. Pretty interesting stuff. He could have taken my stock one and removed some of the windings. He had done it before and it did indeed bump the rated power (at 2000 rpms) to about 190 amps. But the idle (800 - 1000 rpms) amperage fell right off the chart. I don't remember the exact amount but he said the factory GN alt produces around 30 -35 amps at idle hot. A modded one would produce under 20.

So I bought a Rockford Fosgate (Perfect Interface) dual 160 amp alt. Lestek actually produces them for Rockford. Lestek builds alts for industrial equipment like Caterpillar. After numerous phone calls to both Rockford and Lestek I finally got a answer which was practically identical to what the guy at the AC Delco shop said. That is that there is an inherent tradeoff when using a high output alternator.

But there are different case sizes. You can get a large case alt to produce acceptable idle current levels and produce a ton of rated power. The larger case can hold a larger stator which in turn can hold more windings with a larger gauge wire. So you can get the best of both worlds with a large case. But a large case will not fit in a GN. Even with making a custom bracket. So after all of this I put the factory alt back in and have not looked back since.

Alternators and batteries are slow to deliver current compared to a cap if the battery is dead. If you go with a large reserve battery (not a large CCA) and it is charged it will provide all the current you need.

No they are electrically slower due to not being purely electrical. A battery is a chemical reaction which is limited to producing power by the chemical reaction. There are different internal resistances among batteries. These are because different battery manufacturers use different technology in the battery cells. Optima batteries IMO are the best for car audio because they have the lowest internal resistance. Thus they are able to move current quicker than a standard battery. An alternator is a mechanical device, again limited by a conversion. A cap is not bound by a conversion so electrons can travel at their full speed.

My 180 amp alternator produces about 98 at idle. My stock one (120) in my 97 Suburban put out a measly 52 at idle and low RPM

I highly highly doubt that. The alt in your suburban is a large case alt so the 52 at idle is about right. But there is no way in hell any high output (even large case) is putting out 98 at idle. It is physically impossible.

If you want to go to www.carsound.com and do some research on there there have been tons of discussions regarding caps on there under Richard Clarks forum and they have all been proven they don't work.

Maybe he changed his tune. When he was producing the Autosound 2000 tech briefs in the early 90's both him and David Navone were adamantly in favor of caps. There is a boat load of good info from these guys in the tech briefs. They were talking about 4 volt pre amps and low out put impedance pre amps years before any one else.

 

[Audiowizard]

Originally posted by Xtant Regal
Alternators are not just for competitors, after all these things are not big money. You can buy a 160 Amp alternator for around $400, that is just a couple of caps.

I have a thought if you want to really add a larger alternator.......I have a 160 amp alternator that I had built for me and the cost was $140.00 through a local vendor. I have had it for 5 years with no problems!

 

[Audiowizard]

Here is some valuable info!

Originally posted by Xtant Regal
"And since you like to quote things about Biggs and Eldridge so much"

All kidding aside.......These guys know car audio and are 2 of the top competitors in the nation and put in alot of late hours away from their families building winning vehicles. Gary Biggs has built 18+ world champion cars so who better to get all the best information from but a "World Champion competitor" like Biggs and Eldridge! I may be slightly biased about Gary because he is a close friend of mine but all in all, he is one of the best in the world of car audio.

Originally posted by Xtant Regal
"why is it that they both have 200 Amp alternators and multiple batteries ?"

I will explain all of that in the next sentence!

Originally posted by Xtant Regal
"Pick any other competitor or SPL car and they don't have caps, just big alternators and batteries........Alma has none, Shaker has none, Michael Hughes has none, Frank Rouge has none, Rob Rice has none............

I had a long conversation with Gary Biggs this morning about getting our families together this weekend and of course the topic of "capacitors" came up! Now to answer the question of why Gary wasn't using capacitors in his Buick this year!...........

Gary was running Kicker ZR amplifiers with "regulated" power supplies so the use of capacitors would not have bennifited as much in this application............

Now here is the funny part!......... For next years events, Gary will be running a crap load of "capacitors" (Yes, I did say capacitors) with his new Kicker KX amplifiers with "unregulated" power supplies where the "capacitors" will be doing their work to help supply voltage to his numerous amps and high output. Since the new rebuild on his Buick has not hit the C.E.S. show, I am unable to publish the number of capacitors and farad ratings per his request but the amount and the power that he will be running is astounding!

My whole point for this post is to let everyone know that capacitors do work dispite of what has been said negatively about their use in this post and they work very well with amps with "unregulated" power supplies (the more voltage the amp gets, the more power that they put out). Now amps with "regulated" power supplies dont benifit as much and will nut hurt performance to add them if you so desire. This information comes from a man who is one of the top competitors in the country and is there because of his vast knowledge, experience, and dedication. If anyone would like to email him directly about anything concerning car audio, feel free to email him at............

gbiggs@kicker.com

 

[KendallF]

Re: Re: Re: Re: I need a new alt, what should i get

Originally posted by Xtant Regal
If a cap was to help, and I mean IF, it would not be with transient current as that would be provided by the alternator as transient is something that is constant, it would help with Peak current for short bursts of dynamic range material, but again if you had a high output alternator with a good battery, the battery will provide that peak current over and over cause the alternator can deliver that current and charge the battery at the same time.

This thread is making me laugh.

tran·si·ent ( P ) Pronunciation Key (trnz-nt, -zhnt, -shnt)
adj.
Passing with time; transitory: “the transient beauty of youth” (Lydia M. Child).
Remaining in a place only a brief time: transient laborers.
Physics. Decaying with time, especially as a simple exponential function of time.

Caps in a power supply, whether external in the line to the supply or internal as a part of built in regulation, are there to provide just what Audiowizard says: current to support transient (short lived) demands. If you have the alternator and charging system from hell, the need for them lessens somewhat.

An alternator's response speed is still going to be slow compared to a cap (probably 100s of ms. versus a few ms.) so if the amplifier's regulation isn't sufficient, transient response will still be improved with the addition of a capacitor.

If the amplifiers have heavily regulated power supplies, part of what this means is that they've put more capacitors inside (that's a simplification, but still true).. Even a regulated power supply will "de-regulate" when the input voltage drops to a certain point; so you need batteries and alternators capable of keeping up with the average or steady state demand.

 

[Audiowizard]

Re: Re: Re: Re: Re: I need a new alt, what should i get

Originally posted by KendallF
This thread is making me laugh.

I have gotten a kick out of it too! I really do appreciate your info and will cut and paste your input in a "sticky" in the forum.