nataku

I'm adding a system in my S5, just wondering will my alternator be big enough to handle the increased load. Anybody have any experience?

things going in:
- audison amp 65Watts RMS X 2 at 4 ohms
- clarion amp bridged at around 300 Watts RMS X 1 at 4 ohms

the s5 alternator handles something like 90 amps if i remember correctly, right?

1987RX7guy

iTrader: (3)

80 AMPERES from the S5 alt. Try getting an alt from silverrotor. He sels kits with FD alternators which pump out a nice 100 amperes. I have one of these and I was satisfied with it but I had to send it back because apparantly the diodes went bad. But he is a great guy and you should look into one of these kits. He even threw in a dual belt pully for me.

Santiago

mizike

I would put a capacitor on it and possibly upgrade your alternator to a 3rd gens.....contact "silverrotor" he has a 3rd gen kit that will give you like 100-120 amps compared to 70 or 80 amps that your current alternator has.

I'm sure it will run for now, but you might overload your alternator or kill your battery if you don't have the capacitor....they are cheap, like $100.00.

Here is a link to the 3rd gen kits if you are interested.

https://www.rx7club.com/forum/showth...hreadid=172766

-Mike

Rpeck

Your alternator is fine for that sound system .. don't even sweat it. I have run alot more sound then that on my 87 Base model. Unles syou have the blower goign full power, rear defrost on, headlights on, braking, and blasting your stereo while it rains ... you will have no problems. Don't waste your money on any upgrades for that kind of draw. Though, a capsitor is a good item just to impove the sound quality of any system... but thats up to you.

Assuming your car is a N/A you have a volt meter you can Eye ball anyways .. no AMP draws it's listed power at a constant. Only during bass notes or what have you.

-Robert

Mage

I have a question along the same lines. (not to hijack) I run a mp3 computer in my car it will be a 400mhz 256Mb system 96W pw it this to much for a stock s4? with a aiwa head and 2 speakers?

nataku

yeah, i'm sure i can run it, but i'm just wondering if there will be any bad longterm effects like killing my battery faster, or something like that.

From what i've read, a capacitor is not the greatest solution, nor would it be cheap to get a decent capacitor compared to getting a more powerful alternator or 2nd battery (which I wouldn't need, but just as an example).

edit: also, I the voltmeter on the dash isn't entirely accurate isn't it? I remember hearing that before

Black13B

iTrader: (1)

The voltometer isn't very accurate. At least it's not praised for it's accuracy.

A capacitor is to keep the voltage a little more steady. When you have something pulling 500w or more in an instant, your voltage will fluctuate.

Personally I would get a bigger alternator. Inexpensive, easy, effective. Then if you upgrade stereo or other electrical components, you won't have to worry about it, because you have an alternator that will be able to keep up.

mizike

I have a apexi turbo timer and it has a digital volt meter and it says 13.8 normal driving, with lights on it goes down to 13.6 sometimes lower.....I also swapped out my gauge cluster for a n/a one so I could have a volt meter (this was prior to my turbo timer) and I found the stock volt meter sux....very inacurate. So, putting a big stereo on when I have my headlights on it would go down a lot.

S4 alternators suck in my opinon.

Mike

Black13B

iTrader: (1)

S4 alternators put out less amperage than S5s. S6s still put out the most.

S4s IMO are prime canidates for S6 alternator swaps.

Rpeck

You guys are on crack. Bateries don't last that long no mater what you do, depending on climate even more. There is not a damn thing wrong with the S4 alternator. It's not the highest aperage out there.. but save your money for a real mod. I have run 2 fosgate 1X500 amps with a 4X125 Kenwood on my highs and never had a problem with voltage .. on hard bass notes the lights dim a bit .. but it catches right up ... you will get the same thing with a higher amp alt, the problem there is instant current draw.

If it makes you feel warm and fuzzy inside do it. It might improve the life of your battery by a couple of months tops... otherwise it's just the warm fuzzy feeling. You are going to have to replace batteries every so often no matter what .. just like changing the oil. Everything in your car draw's on the battery! plain and simple, the alternator recharges it. thats just how the system works. as long as your car turns over when you turn the key your fine, A alternator won't turn your car over.. but a battery does everytime.

Save the money and time for a real mod.

-Robert

Black13B

iTrader: (1)

I'm sorry I can't find the logic in this. Why build a foundation on something that won't hold up? Get a NEW S6 alternator. Right off the bat (for not even that much money) you have a NEW alternator that puts out much more above stock amperage.

And your idea about getting new batteries all the time is pretty.. funny.. Batteries are designed to last for years. You know you are doing something wrong when you are changing batteries like oil.

I don't think you have a proper grasp on the charging system.

silverrotor

iTrader: (1)

Do you care to revise your lose statements?

S4 Alternators are hurting, Irregardless of loads applied to It. Their was a time where I had 8 Cerwin-Vega Speakers, 2 Amps and a crossover. Further, their was a time when I was going through a s4 Alternator every other season. This was with the biggest Interstate Battery you could fit under the Hood of a FC. Numerous people have upgraded to FD Alternators and consider this to be a real Mod. One that promotes an overall effect to their FC. But hey, If your s4 Alternator Is doing It's thing and you are happy with It - good for you. But to suggest to save your money for a real Mod - your just as silly as your Avator.

Rpeck

Maybe we should go at this statistically. How many S4 2nd gen RX7’s were produced? How many people do you think of those have upgraded their alternators? My guess is less than %0.3. And I would say less than %5 of the members of this forum have upgraded their alternators also. So all these people are wrong? And you are right? Maybe you live in a colder climate then I do .. Where this might barely increase the longevity of your battery. But taking good care of the charging system; new, and clean battery cables, better grounds, properly adjusted alternator belt, And possible upgrading of the main alternator positive wires. Are the best answers to any charging system woes. 2 amplifiers and a aftermarket deck do not warrant the need to replace the stock S4 alternator unless it has already gone bad.

Batteries have warranties for a reason, I am not saying change your battery every time you change your oil (don’t be a dipshit) But I am saying it IS a regular replacement item that will fail from nothing more than time.

We can sit here and bitch about this back and forth but it won’t accomplish much .. This is my opinion, and I have stated my opinion.

My personal definition of a 'real mod' is; something that improves the performance, appearance, safety, or longevity of your FC. The alternator does none of that. Thus my comment about a real mod.

-Robert

Black13B

iTrader: (1)

Well then I suggest you don't post your opinion as any type of suggestion to other users.

Statistics you pull right out of your *** don't mean ****.

Face the facts - Just because you are too cheap to buy a bigger alternator doesn't mean you should recommend everyone follows your lead.

Here is 8 pages of FC owners who have upgraded.

https://www.rx7club.com/showthread.p...hreadid=172766

While we are talking about bullshit statistics, how many FC owners actually require a bigger alternator? Not everyone has a big stereo. This signifigantly increases the number of people who have a bigger alternator because they need it. The ones who don't have a bigger alternator and need it don't have a clue.

Black13B

iTrader: (1)

This is just a blatant lie. Go get some facts on how an alternator works.

Rpeck

Relax, hot shot. Your too cheap comment is way out of line. You know nothing about me, nor the money I make or spend.

“Not everyone has a big stereo” here is nothing big about the stereo he mentions. It is average sized at best. A nice setup, but not requiring an alternator upgrade IMO. Your all fired up over a general discussion of opinions, If this is all you have to worry about in your life…… I wish I were you.


-Robert

Black13B

iTrader: (1)

No, but I can take a wild guess and then claim we are talking about statistics, right?

Do some research. The stock S4 system is basically maxed out. My voltage dropped signifigantly with my "moderate" aftermarket stereo on, lights, and wipers. This was with a fully rebuilt S4 alternator.

Actually I'm a little more worried that you will pass on your concept of a charging system. The last thing we need are guys running electric fans, big stereos, and people recommending you save your cash for a "real" mod, and stick with the wimpy stock S4 alternator.

Defprun

You also imply that an alternator is not a real mod...when does increasing power that is needed for I dont know...combustion...not a real modification?

Rpeck

I am NOT saying that your alternator should NEVER be upgraded. If you are running an E-Fan, a very large set of Amp’s and your blower motor all the time with headlights .. It might be required. What I am saying is for the mods the tread starter listed that I don’t think it is necessary IF his current alternator is still working fine. IF his current alternator packs up on him, then and only then it might be a good idea since he needs a new one either way.

Defprun- obviously IF you are drawing enough power that it effects your ignition system then an upgrade is in order. The original thread started is obviously not in that situation.


ALSO: You guys are straying way off topic, the original questions was "Is my alternator big enough?" To handle his new stereo system in a S5! now your talking about S4's, E-fans, and all kinds of other ****. I just tried to anwser his question. Yes, yes I think it is fine.

theloudroom

First off, you statistics were B.S. If you post stuff like that, expect to get flamed.

Second, did you read the thread starter's post?

He says he's got a 300w rms amp. 300W/14V = 21.4 A, and that's only the power OUTPUT, not the power input. No amplifier is 100% efficient. This means the current draw from the electrical system will be even more.

Plus 9.3 A OUTPUT from his other amp!

You're telling a guy whose car only has an 80 A alternator, that he can add well above 30 A of load to his system!

Lastly, you shouldn't be giving other people advice if you don't even have your own stereo set up right. Your lights should NOT be dimming with the bass. That means your amp isn't getting enough power to do its job properly. Your system probably sounds like absolute crap.

Rpeck

I don't have that system anymore. And it was dimming cause I did not have capasitors at the time. After I installed caps it ws fine. If you read above I recomened caps for his setup. The stas are just a rough guess, but I am willing to bet I am in the ballpark. My point was that people run after market stereo systems in these cars by the 10's of thousands without upgrading the alternators. There is NO way in hell that his listed stereo system is going to be CLOSE to a 30A constant draw on his system. You my friend have been hitting the pipe with the others.

1987RX7guy

iTrader: (3)

Ok this kind of went all out wild. dejavu

Anyways- The FD alternator is a real mod. period! I am proud to have bought an FD alt from Tony D and still stand by him as a good guy. There is no reason to say that the upgrade isn't needed. In my car if I have the stock alt the lights will dim if I turn on my rear defroster alone. BTW before you start I already did everything to my charging system to make sure it is 100% good. The only thing I could do is buy a bigger battery but they don't offer anything better without going with an optima. Simple fact is that BOTH the S4 and S5 alternators are very low output. I noticed the difference when I swapped to the FD alt. I don't use a stereo, foglamps, etc. or any major power drain AND the stock setup still sucks.

To the main poster of this thread here is what I have to say: No your alternator doesn't NEED to be replaced. But how long will your battery last? How will your charging system handle the load when its 12AM, raining, and cold as crap? I bet you will see how limited the charging system is then. My vote goes for the upgrade.

Santiago

silverrotor

iTrader: (1)

I can forsee the direction of this thread already...

Robert, West TEX RX-7 Is running 5 amps total that are putting out approximately 2000 watts rms! His s4 Alternator couldn't do It for crap. Ask him If this was a worthwhile mod. Perhaps a thread starter? As I mentioned earlier, my s4 Alternator too had to be replaced more than once. People upgrade their Alternators all the time. However, I do notice the majority of FD Alternators I sold happen to have went to s4 owners, like 85%. I know It's for obvious reasons. I consider a modification to be one that has an overall effect to your car and that Is what a FD Alternator will do for you, whether you are applying a ton of load on It or not. Right from your Heater/AC to brightness of the Headlights - the FD Alternator holds true to It's output.

Before I forget - 1987rx7guy, the FD Alternator that you speculated that didn't work, I'll be sending It back tomorrow. We found absolutely nothing wrong with It!!! I devoted a half an hour to having your FD Alternator running on the machine awhile I stood next to my guy convincing him that It Is a faulty one you received. The end result Is I upset my guy and you have a fully functionable FD Alternator. At Idle, with no load, you are getting 13.8-13.8 Volts. With a full load, at 4000rpms, you are getting over 15 Volts at 116 Ampheres. You've got to understand that he was simulating a real life event with this machine. Thus, these are applicable numbers, respectively. These diodes you spoke of, 4 positive and 4 negative In total, were verified to work as they were designed to be. Should even one go bad, you will be lucky to generate 0.5 ampheres. Your sources, that suggest otherwise don't know a damn thing about Alternators, or/and these ones for that matter.

I could have PM'd you but I thought It would be worthwhile to address this to the masses as you so blatantly did with me.

theloudroom

Riggght.....

Take this guy's word if you want your headlights to dim with the bass. Why design for the worst case when you can underdesign the system?

But look on the bright side, your headlights won't be constantly dim because he's right about the load being intermittent. You'll be able to look at your dash lights and SEE when you hit peak load.

It'll be a really cool effect while you smoke that pipe he's talking about.

Rpeck

****, I don't care about this thread anymore... You all got my opinion. I just found out the god damn rims and tires I ordered this morning are on back order until Dec. 12th at the earliest. I'm in too pissy of a mood now for a contest.

You guys win ... hell put 2 alternators in for all I care.

-Robert