How do I setup a backup battery system?

[SiNFuL]

Hi guys, I have major power issues that result in a bouncy idle. When i just sit there and everythings off and the e-brake is on(no power brakes), it's 750-800rpm. When I push the brake in I lose 50rpm...with the CD player on(powered by a 600w amp) I lose about 100, and w/ parking lots I lose about 100, and with my PIAAs on as well I lose about 300rpms. I asked Don about this and he suggested the EGR valve being clogged, and it's fine. So he also said I need to set up a backup battery power system. How would I go about doing this? Thanks!
-Galen

[ca18guy]

Why don't you just get a more powerful alternator?

[gfisch]

Yeah, that makes a lot more sense.
I would just replace the alternator with one rated for however much power you are drawing.
I don't think another battery would really help for long if you're still not creating as much power as you are drawing.

[bik]

hmmm i am newbiew yet but....

if the stock small alternator makes you lose rpm on idle... in theory a biger alternator will be more heavy for the engine? O_o

[kazuo]

Get a better alternator. Huge drains on the power system are not good, and Optimas and capacitors are just band-aids and dont fix the problem.

Good luck

[SiNFuL]

That's funny you guys should mention that...that's the first thing that came to my mind but I guess you can't buy higher performance alternators, Don from PDM-Racing suggested this backup battery system.
-Galen

[CO S13]

Have you had the alternator you have checked? The one you have may just be going out. I think Auto Zone can check them. If not Sean may be able to do it for you.

[GTGuy06]

Originally posted by gfisch
Yeah, that makes a lot more sense.
I would just replace the alternator with one rated for however much power you are drawing.
I don't think another battery would really help for long if you're still not creating as much power as you are drawing.

nuff said!

[SiNFuL]

the battery and alternator were already checked by Autozone, running fine.
-Galen

[240Stilo]

Well I'm not sure about S13's but for those that have S14 which came with no foglights, you can pick up an alternator that pushes out more power than the stock unit. All you gotta do is get the S14 alternator meant for the one w/ foglights and voila, upgraded alternator. It might not be any ultimate upgrade but getting a better anything is always a plus.

[CO S13]

I told Sean about it and he said that his RX7 does the same thing. He said that it is an 80s sports car thing. Please don't tell me that it was made in the 90s because it was designed and went into production in the 80s.

[misnomer]

um. . . .

The engine RPM is dropping because the alternator must spin faster when there is greater load on the electrical system. Your alternator may be testing fine, but that doesn't mean it is putting out the same current at the same RPMs as a new one. I'd look there for your solution. Another battery doesn't change much, the alternator still has to provide the power, batteries just store it.

[SiNFuL]

alright, thanks for the help guys...is the S14 alternator bolt-in?
-Galen

[FRpilot]

Originally posted by 240Stilo
Well I'm not sure about S13's but for those that have S14 which came with no foglights, you can pick up an alternator that pushes out more power than the stock unit. All you gotta do is get the S14 alternator meant for the one w/ foglights and voila, upgraded alternator. It might not be any ultimate upgrade but getting a better anything is always a plus.

is this confirmed? this is the first time i heard about this..

[Break Beats]

is this confirmed? this is the first time i heard about this..

This is true.

80 amp alternator = S14 without fog lights
90 amp alternator = S14 with fog lights

I have a S14 90 amp alternator on my S13.

[thx247]

I'm pretty sure you can get your stock alternator rewired to turn out more juice. Talk to an alternator shop about that. Its similar to an electric motor after all

[SiNFuL]

awesome..thanks guys! Break Beats, was the install completely bolt in(same size,etc)?
-Galen

[Break Beats]

The install was straightforward. Keep in mind this is a S14 KA24DE Alt. to a S13 SR20DET Motor.

Sorry if you have the KA24E, I'm not sure it they are interchangeable.

But from S14 KA to S13 SR all I had to do it enlarge one of the mounting holes and it fit.

Good Luck.

[SiNFuL]

Yea I have a '92 KA24DE...We'll see what happens!
-Galen