Right now im running...

Alpine 9805 headunit

Rockford Fostgate 4" up front

Alpine Type R 6x9's in the back

powered by a kenwood KAC-8402 amp

the speakers are getting 60watts RMS probably around 75-80 max


anyways when i turn up the volume my speedo starts jumping around my tach will stay at 0 and everything else will wiggle..

now my question is is this just because of vibrations or is my little 4 channel amp pulling enough power that i need a cap?

Im scared because i was planning on adding 2 subs both running 825 watts rms...i know im gonna need atleast a 1farad cap for each of those

after its all said and done at any given time i could have about 5600 watts pulling at one time...am i gonna need a bigger battery or alt?

 

voltage drain wouldn't effect your speedo (mechanical on yours i believe?), and as for vibrations... you don't seem to be running a sub right now? so, i'd count that out too.. you sure it only jumps around when the stereo is on? i'd say 'stare at it to make sure that it moves with the beat' but that would be dangerous
if you end up having 2 subs running 825w rms, i would definetely get a cap.. my friend had a 250w rms sub in his 95 runner and when it hit, the needle on the voltage gauge dropped (long with the brightness of all lights)

 

if your friend is having that issue his battery is bad...i run a 200watt rms sub (not now) and have no issues at all...a cap is really needed over 500watts..

ive ruled out its vibration...guess when i pull the dash to put in tnew bulbs il have to stick some dynamat somehwere in there

 

um.. you mean alternator right? cause when your truck is on, its all running off the alternator.. but yea, he threw in a cap and it fixed his problem.

 

haha sorry i was thinking in terms of the car being off....but yes his alternator probably needs a bit of an upgrade if he cant run 250watts of stuff...im running 635 right now with no problems

500watt for my 4channel amp

135 for my PIAA's

 

Caps dont do squat for light dimming. BandAid fix at best. Alternator or batteries first, then caps...

When I had 4" in my 2nd gens dash amped, my tach would jump around too. I think it had to do with the magnetic field generated by the coil....

Now with over 8800 watts rms just on bass EVERYTHING moves....lol

 

I had some funny problems with gauges and stereo in the past. I discovered all it was, was the ground from just above the passenger side exhaust manifold to the firewall. It was completely disconnected.

You might want to check and make sure there is a good connection, and it wouldn't hurt to move to a larger gauge ground wire.

 

In keeping with "ASU4runner's" train of thought, I'd suggest the "Big 4" grounding cable upgrade that I've seen mentioned on the site ("search" feature...hint-hint), although I think that the founding credit for this "mod" goes to a Mr. Roger Brown.
That will help the battery & altenator with charge recovery by helping to increase the charges flow rate (kinda liken to the intake mod to increase airflow) & thereby eliminate the "draw" factor from associated componetry when your system places it's demands on it.
It is also way cheaper than a cap (although you will need one or two judging from what you've mentioned your intentions to be), a new battery or an altenator upgrade, & is a base/starting point upgrade for all additional upgrades mentioned here.
Simply put: "You can't go wrong if you cover all of the bases."

 

omg 8800 watts RMS just for bass...and i thought my 2300 watts RMS was a lot for everything


haha oh well i keep dreaming

 

Yeah, "Bumpin' Yota's" not "Bumpin'", he's B-O-U-N-C-H-I-N-G :bounce2: with that much of a bass output! How do you keep windows in that "Bumpin'"??