High RPM on bass kick

[cbrei1023 10+ year member]

Hey,

Trying to figure out the fix to a little problem a friend of mine is having.

She has 2 kenwood subs

http://www.woofersetc.com/p5524/KFCW3011--Kenwood-12"-4-Ohm-Subwoofer.htm

And I believe it is a kenwood 2 channel amp on them.

Not sure of the load or watts. So lets just go with RMS, 800W at 2 ohm for the pair of subs.

Now the issue is when she idles her RPMS will raise when the subs kick. What is to blame for this and what would be the easiest fix. There is a 1F cap in the mix too.

Click to read more...

 

[hornedfrog1985 5,000+ posts]

Maybe the car revs higher so the alt is producing enough power?

Take out the cap, and do the big 3.

What kind of car is it?

 

[cbrei1023 10+ year member]

1992 Honda Civic LX

Thanks, I was thinking a big 3 would do it.

 

[cbrei1023 10+ year member]

I just got this IM from her as well

recently i had noticed before the rpms would fluctuate. that i my car would idle incredibly low, and that i would be at a red light and it would be practically stalling but not dropping down that far.

 

[hornedfrog1985 5,000+ posts]

Did it do that when the stereo was turned off?

Sounds to me the alternator can't take that many watts. Do the big 3, add a battery, and you should be good to go. Check that the gains are set right too.

That car probably has like an 80 amp alt or something.

 

[cbrei1023 10+ year member]

no, the car behaves normally when the system is off. About 20 min intoa drive the idle RPM will drop.

 

[hornedfrog1985 5,000+ posts]

I guess it's a 70 amp alternator. That baby can't handle the powa.

 

[dragnix 5,000+ posts]

most likely it's the alt not being able to handle the current the system is pulling. Happened to my 94 civic i had. I fixed it by selling the car

 

[hornedfrog1985 5,000+ posts]

If she doesn't want to spend the money on doing another battery tell her too bad, and get back in the kitchen.

Seriously though, if she doesn't it will just end up killing her alternator, and she will have to buy a new one of those, but still have the problem anyway.