Thread: RPM fluctuation due to subs?

Your fluctutation is power related.

Check all your grounds and battery cables.

All of my GP's had a noticable RPM dip at idle if I ran all four power windows up simultaneously

The electric system just isn't all that powerful to begin with. If you want to get serious about sound in these cars, you'll have to contemplate a voltage booster and/or a beefier alternator.

sorry but it has nothing to do with grounds/power its your alternator trying to make power it doesnt have, so. think of your alt like a big magnet, the more power you try and draw the stronger the field is gunna become, i do competitions and im running 2400rms or 4800 watts with 3 batteries on 2 12's, i had a 275 amp alternator on a 4 cylinder car lol. when the bass hit it dropped 300 everytime because the load on that alternator and that was with 3 runs of power and 4 runs of ground under the hood from alt to front battery, so a simple way to free up voltage is called a "big 3" so run a 1/0 from batt positive to alternator positive, then a ground from the battery to the frame, and a ground from the engine to the frame, use 1/0 for all of it and it frees up alot of voltage, normally you will see headlight dimming before you see rpm drop that hard on a bass hit with that small of an amplifier, any questions feel free to ask

You say it's not power/ground related and tell her to do the big three. That's a power/ground upgrade. If she turns off the sound system and the car doesn't do it.. she should check grounds/battery connections etc.

If you tell her to check wheel bearings...I'm going to laugh.

well if you want to get technical yes it is power and ground related, not them being loose, but the power and ground not being big enough to support what little load is on it, you have to remember alternators are meant to just put out enough power to supply what the car needs, even a small amp like 400 watts will be too much, a capacitor ( even though they are junk) should help her rpm issue, if not then do the big 3, or get an extra battery.

and yes bill if she shuts the system off it wont do it, hell if i turned mine down it stopped, and i had plenty of voltage on tap, i was idleing at 15.8v and if i was at a red light and hit a low note id sometimes see 11v and thats with 3 batteries, a 275 amp alternator, and 4 runs of wire

And yet.. I run an amp of much more power w/o the big 3 and without issues on a 125amp alt.

As the cars age, ground and power connections become corroded etc. The side terminal connections from the battery are notorious for corrosion. I have fixed a P0171 Lean Bank One by replacing battery cables on a car w/o any sound equipment modifications. Things like this are why I suggested checking those connections. Checking is totally free, takes a few minutes and a set of eyes.

LOL.. there's a "luckygirl" on the forum as well. I didn't look very closely. Sorry to remove your manhood on ya.. lol

Just be glad all the leghumpers didn't run in and ask you for pics.

yes corrosion is a big factor, and doesnt matter if the alt is new, they really arent meant for any extra power besides what comes from the factory, but go ahead and start with power/ground cleanup. ill just sit here and wait :P

i dont know much about building l67's or supercharged motors but old 350's and stereo equipment, now youre talking my language

Doesn't really have much to do with building the cars. It's more them getting older. If you remove the bolt from a battery cable and slide the boot up, a lot of times you find a fuzzy green corroded cable causing issues. Resistance, bad grounding etc etc.

We will both sit and wait, based on his comment about checking the ground at the amp....I'm thinking he's aware that the ground isn't as good as it should be.

lol yeah especially a seat bolt, its a good ground if clean, i used to use the child seat bolt on the top of the trunk in my old sunfire lol, and i can build an l67 but when it comes to what springs/injectors/rockers im pretty well clueless, and its been a while since i installed a cam so cant remember how to do the rocker tightening sequence, dad says just get em snug and run it with open valve covers and tighten as needed lol seems sketchy, and there isnt much space on the back head between my firewall