Power question

CarMan1 · Post by **CarMan1** » January 16th, 2006, 12:26 am

ok, so when i turn up my stereo loud, and the subs hit hard, either my lights dim, or the rpm's drop off alot, almost choking the car... does that mean i need a bigger amp to push my subs? or what? im guessing the lights are dimming b/c theres not enough power with the subs going, b/c i ran ground wires in the engine bay...

mr1in6billion · Post by **mr1in6billion** » January 16th, 2006, 2:12 am

Problem: Alternators and batteries have slow reaction times... that and you didn't search.

Solution: Buy a grounding kit and a capacitor.

Legato626 · Post by **Legato626** » January 16th, 2006, 2:20 pm

you dont need a grounding kit or cap. Just run 4 gauge power wires. and run a 4 gauge ground to the car. and get a optuma battery. Thats all you really need. But if you have a crapy alt. a nice high out put one would work good.

Post by **Custommx3** » January 16th, 2006, 2:40 pm

The biggest issue is the alternators are weak, they are only 70 amp in an RS and 90 in a GS. The grounding sucks. What I did on my RS was added a 1 farad cap, and grounded it better (all 4 gauge), and put on an optima. It solved my light dimming issue.

My GS, I put a millenia alternator (110amp), better grounding/power wires (all 4 gauge). Adding the optima from my RS and a cap .

93_mx3_gs · Post by **93_mx3_gs** » January 16th, 2006, 6:15 pm

Custommx3 wrote:The biggest issue is the alternators are weak, they are only 70 amp in an RS and 90 in a GS. The grounding sucks. What I did on my RS was added a 1 farad cap, and grounded it better (all 4 gauge), and put on an optima. It solved my light dimming issue.

My GS, I put a millenia alternator (110amp), better grounding/power wires (all 4 gauge). Adding the optima from my RS and a cap .

Lol..i'm half way to that XD I was only running 200 watts in my GS and my lights hella dimmed out...then again..ehheheh..-secret for future show.-

FlyVFR · Post by **FlyVFR** » January 17th, 2006, 9:18 pm

CarMan1 wrote:ok, so when i turn up my stereo loud, and the subs hit hard, either my lights dim, or the rpm's drop off alot, almost choking the car... does that mean i need a bigger amp to push my subs? or what? im guessing the lights are dimming b/c theres not enough power with the subs going, b/c i ran ground wires in the engine bay...

If the lights are dimming that means that the electrical system in under stress. Which way and how far to go to enhance the electrical system depends on how much power is needed. This thread has some ways to improve efficiency of an existing power system. http://mx-3.com/phpbb2/viewtopic.php?t=48049

Custommx3 Right on track! I like the Millenia alternator idea. Is it a direct bolt on?

Nd4SpdSe · Post by **Nd4SpdSe** » January 18th, 2006, 12:56 pm

FlyVFR wrote:If the lights are dimming that means that the electrical system in under stress.

Exactly, but a capacitor is only a band-aid fix, hiding the true problem. First; a capacitor is an additional load on the system since it must recharge. The aid of a capacitor is just to basically absorbe the instant demand of s base-hit that the rest of the system isn't able to put out, but while the hit instantly took energy stored in the cap, the cap must, and slowly recharges itself from the alternator/battery. If your base-hits are diming your lights because, as FlyVFR mentioned, your electrical system is overstress, and stressed to the limit. A healthy battery (if your battery if old and/or worn) would be a good thing. As well, good power and ground wires would help gain back power that would be lost from inefficiency. The problem is to find the weakest link in your electrical system. But is those or other resolutions mentioned in this and the thread mentioned by FlyVFR, the problem is probably the alternator.

A millenia alternator is a direct bolt on for the V6's, but requires some wiring of an additional wire to "accessory on"

FlyVFR · Post by **FlyVFR** » January 18th, 2006, 5:34 pm

Nd4SpdSe wrote:Exactly, but a capacitor is only a band-aid fix, hiding the true problem. First; a capacitor is an additional load on the system since it must recharge. The aid of a capacitor is just to basically absorbe the instant demand of s base-hit that the rest of the system isn't able to put out, but while the hit instantly took energy stored in the cap, the cap must, and slowly recharges itself from the alternator/battery. If your base-hits are diming your lights because, as FlyVFR mentioned, your electrical system is overstress, and stressed to the limit. A healthy battery (if your battery if old and/or worn) would be a good thing. As well, good power and ground wires would help gain back power that would be lost from inefficiency. The problem is to find the weakest link in your electrical system. But is those or other resolutions mentioned in this and the thread mentioned by FlyVFR, the problem is probably the alternator.

For the most part it appears to be on the right track and with all due respect, I'd like to clear up a few details about capacitance as used in DC circuits as well as general "electrolytic" type capacitor usage.

Nd4SpdSe wrote:Exactly, but a capacitor is only a band-aid fix, hiding the true problem.

Actually if used in a DC circuit correctly a capacitor acts as the opposition to voltage change. So it's a good idea to use calculated capacitance to keep voltage nice and steady.

Nd4SpdSe wrote:First; a capacitor is an additional load on the system since it must recharge.

A discharged cap of large value is a huge load (almost equivalent to a short) until it's charged. After it's fully charged it becomes negligible as a load (based on the Q efficiency factor). Remember the cap is not using power it's just passing it alond as needed.

Nd4SpdSe wrote:The aid of a capacitor is just to basically absorbe the instant demand of s base-hit that the rest of the system isn't able to put out, but while the hit instantly took energy stored in the cap, the cap must, and slowly recharges itself from the alternator/battery.

So it does have a purpose! But it actually charges back up very fast as opposed to slowly. And if the right capacitance is used it will keep the voltage from dropping in that circuit!

Post by **Custommx3** » January 19th, 2006, 12:20 am

Bolt on? nope. Gotta have the bracket, harness connector, and of course the alternator. Gotta run the B+ wire to a power source thats ACC.

FlyVFR · Post by **FlyVFR** » January 19th, 2006, 1:24 am

Custommx3 wrote:Bolt on? nope. Gotta have the bracket, harness connector, and of course the alternator. Gotta run the B+ wire to a power source thats ACC.

Interesting..The things that people will do for another 20 Amps. By the way the GS has a main 80 Amp fuse!

Is there another thread that you can reference for more detail?

Correction: 92 GS has 100 Amp main fuse!

mr1in6billion · Post by **mr1in6billion** » January 19th, 2006, 1:33 am

FlyVFR wrote:
Custommx3 wrote:Interesting..The things that people will do for another 20 Amps. By the way the GS has a main 80 Amp fuse!

If I'm not mistaken the GS has a 100 amp main fuse while the RS has an 80 amp fuse. Wouldn't make sense putting an 80 amp fuse on a 90 amp alternator.

FlyVFR · Post by **FlyVFR** » January 19th, 2006, 1:45 am

mr1in6billion wrote:If I'm not mistaken the GS has a 100 amp main fuse while the RS has an 80 amp fuse. Wouldn't make sense putting an 80 amp fuse on a 90 amp alternator.

You're 100% correct. My mistake. The GS has 100 Amp main.

Grants · Post by **Grants** » January 19th, 2006, 2:36 am

Wouldn't make sense putting an 80 amp fuse on a 90 amp alternator.

I know where your coming from but "not really".

If you have a look at the first diagram here:
http://www.eunos30x.com/info/1993%20Wir ... agrams.pdf
you'll see that the fuse in reality doesn't protect the alternator output at all. It really protects the battery.

The alternator output isn't directly protected by a fuse - it just supplies power into the system. Its also interesting that the headlights and fuel injector relay don't run through that main fuse.

FlyVFR · Post by **FlyVFR** » January 19th, 2006, 2:41 am

Grants, good point. I think the alts have internal protection. Well at least some do while others simply blow the rectifiers!

FlyVFR · Post by **FlyVFR** » January 22nd, 2006, 12:39 pm

Grants wrote: Its also interesting that the headlights and fuel injector relay don't run through that main fuse.

They're on separate fused circuits because of their power requirements.

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