Welcome to the North American Subaru Impreza Owners Club Friday September 19, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC General > Car Audio, Video & Security

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 02-02-2004, 04:22 PM   #1
WhyGog
Scooby Newbie
 
Member#: 51412
Join Date: Dec 2003
Location: South Carolina
Vehicle:
2004 WRX
Black

Question Power/Alternator Questions!!!

Questions for everyone!!
1) Planning some audio stuff and was wanting to make sure I wasn't going to kill or exced the Alternator power ratings on my 2004 WRX Sedan.
Front Speakers: Alpine SPX-177A ~60watts RMS http://www.crutchfield.com/S-6kmpW97...p?i=500SPX177A (Already purchased)

Rear Speakers: Alpine SPR-134A ~35 watts RMS http://www.crutchfield.com/S-6kmpW97...p?i=500SPR134A (Already purchased)

Sub: Polk MM12 ~500 watts RMS http://www.crutchfield.com/cgi-bin/S...7MM124&g=67700 (already purchased)

Head Unit: Alpine CDA-9815 puts out ~27watts RMS per channel http://www.crutchfield.com/S-6kmpW97...p?i=500CDA9815 (Not yet purchased)

Amp 1: Alpine MRV-T420 puts out ~340 watts RMS 1 channel bridged http://www.crutchfield.com/S-6kmpW97...p?i=500MRVT420 (Already purchased)

Amp 2: Alpine MRP 420T put out ~40 watts RMS 4 channels http://www.crutchfield.com/cgi-bin/S...0MRPF240&g=120 (Not yet purchased)

If I use this set up, I will turn off the internal amp for the head unit, leaving the 2 external alpine amps. Is this to much power to try to get out of the stock alternator for my 04 WRX? Will there be enough power left for the car to run, like the lights and such?

2) If this is to much to ask of the stock alternator, what sort of alt do I need to get? I have seen this one http://www.2kracing.com/product_info...oducts_id/3353 but I really don't think I would need one this big. Where could I find another?

Any help is greatly Appreciated.
* Registered users of the site do not see these ads.
WhyGog is offline   Reply With Quote
Old 02-02-2004, 05:28 PM   #2
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

If the alternator can't handle 380rms, then there's something wrong with your electrical system. If you get any dimming (which I doubt), you can just upgrade the big 3 and it should take care of it. You definately won't need a new alternator unless your current one is defective.
the suicidal eggroll is offline   Reply With Quote
Old 02-02-2004, 09:45 PM   #3
WhyGog
Scooby Newbie
 
Member#: 51412
Join Date: Dec 2003
Location: South Carolina
Vehicle:
2004 WRX
Black

Default

It wouldn't just be 380 though.
340 for the sub and then 40 per channel for the in car speakers
340+40+40+40+40=500watts RMS
I'm just concerned that that is pushing the limit.

And what is the "big 3"?
WhyGog is offline   Reply With Quote
Old 02-02-2004, 09:52 PM   #4
1sty
Scooby Specialist
 
Member#: 52516
Join Date: Jan 2004
Location: New Hampshire
Vehicle:
2004 STI
Blue

Default

Quote:
Originally posted by WhyGog
It wouldn't just be 380 though.
340 for the sub and then 40 per channel for the in car speakers
340+40+40+40+40=500watts RMS
I'm just concerned that that is pushing the limit.

And what is the "big 3"?
You'll be fine.
I've installed amp systems twice as powerful into cars with half the alternator power. Your lights will dimm whenthe bass hits but that from the system demabnding voltage too quickly not to much. The alternaotr can't react fast enough hence the dimm. Its nothing to worry aboout. At most, upgrade the factory wiring to the alternator, battery and main engine ground to 4 gauge.

Just so you know, I am a car audio installer as a side job at tweeter and have been for 3 years. They call me the Professor
or ficus but thats another story
1sty is offline   Reply With Quote
Old 02-02-2004, 10:19 PM   #5
WhyGog
Scooby Newbie
 
Member#: 51412
Join Date: Dec 2003
Location: South Carolina
Vehicle:
2004 WRX
Black

Default

So the "big 3" is the wiring between the battery, alt and main engine ground? And I've read that the alt on the 04 wrx is 12V, so the ratings on my amps will be a little lower if it is continuos at 12V. Just looking at it and my sub amp would be 240Watts RMS at 12V. That would give my system probably something like ~400 watts. So, I guess the big question is, what does the alt, and what would be supplied to my amps, voltage wise? (Sorry, still learning)!!

Also, does anyone have a site or some pics of where these three power cables are?

Thanks again!
WhyGog is offline   Reply With Quote
Old 02-02-2004, 10:24 PM   #6
1sty
Scooby Specialist
 
Member#: 52516
Join Date: Jan 2004
Location: New Hampshire
Vehicle:
2004 STI
Blue

Default

Quote:
Originally posted by WhyGog
So the "big 3" is the wiring between the battery, alt and main engine ground? And I've read that the alt on the 04 wrx is 12V, so the ratings on my amps will be a little lower if it is continuos at 12V. Just looking at it and my sub amp would be 240Watts RMS at 12V. That would give my system probably something like ~400 watts. So, I guess the big question is, what does the alt, and what would be supplied to my amps, voltage wise? (Sorry, still learning)!!

Also, does anyone have a site or some pics of where these three power cables are?

Thanks again!
Cars in general are 12 volts. However any alternator today will produce a steady 14.4 or higher unless is out of whack. I can go get a reading form my STi if you like.

However, when a sub amp draws a quick burst of power, the lights dim becuase the output voltage ont he alternator will drop back to 12 volts. No alternator can aviod this. Thats why amps that are rated the same at both 12 volts and 14.4 tend to more expensive. They are the only amps that will actualy give you there rated power for more thena millisecond. The others will put out only there 12 volt rating wich is the voltage the battery will catch the system at.
1sty is offline   Reply With Quote
Old 02-02-2004, 11:43 PM   #7
WhyGog
Scooby Newbie
 
Member#: 51412
Join Date: Dec 2003
Location: South Carolina
Vehicle:
2004 WRX
Black

Default

But the thing is, the STI alt puts out more power than the WRX does (from all that I have been able to get my hands on). The STI puts out 90 amps while the WRX only puts out 75 amps. Thats about 180 watts diff.

From as best as I can tell, the WRX alt can put out about 900 watts @ 12V or 1080 watts @ 14.4V

So that would give me free ~400 watts for the car under 12V and 580 watts under 14.4. Does this sound like enough?
WhyGog is offline   Reply With Quote
Old 02-02-2004, 11:47 PM   #8
1sty
Scooby Specialist
 
Member#: 52516
Join Date: Jan 2004
Location: New Hampshire
Vehicle:
2004 STI
Blue

Default

Keep in mind that music is nont contious but is created in bursts. Is not a constant load. This is refered to a duty cycle. Trust me, you are beyound fine. You could run 2 of each of those amps will little trouble. Thweres a member of my other board thats run a 2500 watt rms amp for over a year on his 60 amp alternator. 75 amps is plenty.

If your still wordied about it, I have a 180 amp alternaotr fo sale. I had it in my protege.

Last edited by 1sty; 02-02-2004 at 11:57 PM.
1sty is offline   Reply With Quote
Old 02-03-2004, 12:06 AM   #9
WhyGog
Scooby Newbie
 
Member#: 51412
Join Date: Dec 2003
Location: South Carolina
Vehicle:
2004 WRX
Black

Default

I'm just really worried about trying to install all this and then when I get done, my car goes ***BOOM***. Then Subaru says I was playing with to much power and it voided my warranty so I'm stuck with a useless car I still owe many thousands on.

That's also another question I have.
Will installing all this void my warranty? Its gotta stay covered while I pay it off
WhyGog is offline   Reply With Quote
Old 02-03-2004, 12:08 AM   #10
the suicidal eggroll
Scooby Guru
 
Member#: 51961
Join Date: Jan 2004
Chapter/Region: RMIC
Location: Broomfield, CO
Vehicle:
2005 STi
2012 WRX

Default

Quote:
Originally posted by WhyGog
It wouldn't just be 380 though.
340 for the sub and then 40 per channel for the in car speakers
340+40+40+40+40=500watts RMS
I'm just concerned that that is pushing the limit.

And what is the "big 3"?
sorry didn't notice that, you're right
you still shouldn't have any problem at all though. The big 3 are the battery ground, engine ground, and alt + to batt +. Pretty inexpensive upgrade that has as much of an impact on your electical system as a cap, if not more so.
the suicidal eggroll is offline   Reply With Quote
Old 02-03-2004, 12:17 AM   #11
1sty
Scooby Specialist
 
Member#: 52516
Join Date: Jan 2004
Location: New Hampshire
Vehicle:
2004 STI
Blue

Default

Quote:
Originally posted by WhyGog
I'm just really worried about trying to install all this and then when I get done, my car goes ***BOOM***. Then Subaru says I was playing with to much power and it voided my warranty so I'm stuck with a useless car I still owe many thousands on.

That's also another question I have.
Will installing all this void my warranty? Its gotta stay covered while I pay it off
Don't worry. The car will not blow up. To damage an alternator you have to pull a continous 120% from it. So at 12 volts with a 75 amp alternator you have to pull over 1100 watts continously to damage the alternator.

To settle your mind a friend of mine and a member here was running a JL 500/5 in his WRX. Thats over 500 watts rms even at 12 volts. Another firend ran a JL 500/1 nad a 300/4, thats 800 watts rms at 12 volts. Each system ran flawlesly. ALso keep in mind I spent the last 3 years installing car audio. I have NEVER seen an alternator be claimed by an amp. I even installed a Kenwood Exceleon 401M running at the lowest impedance possible so it made the most power in a civic with a 45 amp alternator and the smallest damn battery you'll ever see. Another guy I worked with ran 3 orian amps in his similar civic.
1sty is offline   Reply With Quote
Old 02-03-2004, 12:18 AM   #12
1sty
Scooby Specialist
 
Member#: 52516
Join Date: Jan 2004
Location: New Hampshire
Vehicle:
2004 STI
Blue

Default

Quote:
Originally posted by the suicidal eggroll
. The big 3 are the battery ground, engine ground, and alt + to batt +. Pretty inexpensive upgrade that has as much of an impact on your electical system as a cap, if not more so.
I couldn't agree more!!!
1sty is offline   Reply With Quote
Old 02-03-2004, 01:00 AM   #13
WhyGog
Scooby Newbie
 
Member#: 51412
Join Date: Dec 2003
Location: South Carolina
Vehicle:
2004 WRX
Black

Default

First off, I would like to say thank you to the both of you. I may have asked some dumb questions, but I'm always very careful about my car. As to that point, 1sty, Its not that I really distrust you, its just that I couldn't possibly hope to have my car die, and then me find some other means of transportation, so I have to be very careful(I live in a crappy little southern town with no real public transportation). But again. Thanks a bunch to the both of you. I've fix my "big 3" and then install my new toys!
WhyGog is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
*SOLD* FS (CT): Agency Power Alternator Cover olsen2420 Engine/Power/Exhaust 13 02-11-2010 11:23 PM
FS: Red Agency Power Alternator Cover mybrosride Engine/Power/Exhaust 35 01-28-2009 07:02 PM
Powering the Antenna Power Lead Question.. BONFIRE074 Car Audio, Video & Security 5 01-19-2009 07:08 PM
aem tru power alternator pulley Rickyh Car Part Reviews 5 04-24-2007 06:26 PM
FS Oh:AEM Tru Power alternator pulley iaff474 Engine/Power/Exhaust 8 01-03-2007 10:27 PM


All times are GMT -4. The time now is 08:54 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.