Stereo amp causing engine lag!?

[joe603]

I thought it might have been just me...but after my sub/amp install, if I have the system loud the car seems to slow down during bass hits. Now, I understand that the alternator could be under load from the battery, causing resistance on the engine via the acc. belts. Has anybody else had this happen with a stereo system? My lights do dim, but not as bad as my previous car did before a Cap install.

Now, would a better battery (yellow optima) or a 1F Cap solve the problem? My last car had much more torque at low RPM (V8) so maybe I just didn't notice it??

[Q45tech]

The ecu can only adjust the ignition and injector duration SO MUCH to compensate for lower than designed voltage. Once it reaches the limit the performance declines.

The electric fuel pump draws up to 8 amperes on acceleration and rpm [psi] is controlled by voltage.

What ever you do you MUST make sure injectors, fuel pump, and ignition receives the proper voltage.

The correct solution is to run the Stereo AMP off a separate trunk battery capacitor bank utilizing a multidiode isolator..........the alternator will charge the rear battery thru the diodes.

[joe603]

So you think the injectors/fuel pump are decreasing fuel? I thought it was just the alternator causing drag on the serp. belt... I only have one amp...1800W monster, but not crazy like some pro cars. My stereo guy thinks that a better battery will solve the problem...but I'm leaning towards a Cap.

[WESIDE]

Get anything above a 2 faret cap and it should hela a lot. It will also make your system bump a lot harder. Had one in my 240 and OMG..

[joe603]

The price is less than I remember...$150 for a 2F w/LCD meter! I think I'll go with a grounding kit, battery, and a 2F Cap.

[johnmully]

Hey the amp that you have is drawing at lot of juice! You should definately get a stiffening cap. 1 farad per 1000 watts is the norm. so at least a 2 farad. Maybe 2of them. It will help give your amp the extra juise during big bass thumps and make it punchier as well. Now check to see how much amperage your amp uses during it's maximum load. I suspect that the cap will only be a bandage on your problem. The extra battery will in my opinion be the same because your alternator can only do so much eventually this all will all put a strain on your charging system after a while. You should in my opinion definately get the cap/caps then look at a higher amperage alternator. I'm sure you can find a 180 amp one out there. Or just turn down the bass a little. I've had well over 1000 watts running in an older car with just a 1farad cap with no probs. But my stock alt was like 140 amps and I think the G35s is 110! Also the ground wire kit as well.

[thintzen]

i changed my system also and now i get a whine when i accelerate. i have a 2 farad capaciptor, which helps with the dimming( none at all) but the acceleration whine, i cannot get rid of. i tried every audio fix, but nothing has worked so far, my next step is to either upgrade my alternator, and/or get a vehicle grounding kit.

[Q45tech]

The whine is the ripple frequency [3 phase and harmonics] superimposed on the quasi dc from alternator..........................not enough smoothing from the battery and capacitor vs the amount of ripple.

Many higher than oem alternators may have excessive ripple..........you must look at the dc with an oscilloscope MEASURE and FIX THE RIPPLE.

A separate battery in rear just feeding amps will fix the problem.

[joe603]

Anybody running a higher amp alt in their G35/350Z?

Q45tech: The separate battery in the rear will still need to be charged correct? Won't this have the same effect on the charging system?

[Q45tech]

In this case the rear battery thru a diode acts like a really giant capacitor and the engine and oem electronics are unaffected [ISOLATED] from the peak power draw, since the length of cable/diode act as a variable resistance to the rear.

Plus if the front battery needs a jump you carry a spare plus the front can never be run down by the rear amplifier

[audtatious]

You are correct, but at some point the drain of the second battery must be replenished which will add additional load to the alty (tho probably not a dimming effect like is happening now). The proper answer to dimming lights and such is to install an appropriate hi-current alternator. Of course, this can be quite expensive.

[thintzen]

so if i use a isolator, and a second battery i should be fine?

what if i changed my battery to a yellow top optima battery, will this do me any good?

[audtatious]

Keep the factory specs. A larger battery will simply make things worse.

[joe603]

I would say that changing to an optima would be a good choice. My system isn't that crazy, so I think I'll stick to an upgraded battery and 2F CAP....maybe an upgraded alt if they're not crazy expensive.

[Q45tech]

Be sure to compare the current [amperes] vs engine rpm of oem vs any new potential alternator.

Some high ourput alternators don't provide as much at idle as oem!

Then you can have a recharge running problem!

[joe603]

Thanks Q45, good advise as always! Do you have any recomendations for a replacement? There has to be a larger oem alt. thats built by nissan for another vehicle, that would fit in the G35....Murano/Quest/Titan maybe???

Anybody have any ideas?

[The_Scooch]

Seems like a lot of cost and pain in the *** just to permanently damage one's hearing.

Call me old... I guess.

[joe603]

You forgot to mention expensive....

[Q45tech]

Wheels and sound systems are related [in their minds] to organ size in males.

Most of us [I'm 58] had something similar 30-40 years ago......I added 2 speakers to my AM radio [1962 Ford] and a giant FM to AM convertor..........no amps when tubes were involved.

Conservative talk radio and NPR don't require a moded sound system.......having 4 small speakers is enough for me.

I've had tremendous experience with 12 volt to 120 volt high wattage power invertors to run test equipment in cars since 1967............as 2000 watts is the same no matter what you use it for................I would destroy rental cars electric systems over a 2 week period.............it became easier to build a special station wagon with multiple batteries and alternators and just drive rather than fly...............one year the Impala had 4 giant batteries in the lower storage compartment and I would change them every month.

Actually 1800 watts of peak MUSIC power amps are tiny compared to 100% duty cycle 1000 watts SINE WAVE RMS INVERTORS running 8 hours.

[mikeatx]

I agree with joe's suggestion.

2F cap, good battery and a grounding kit. I'm putting a 900W Hiphonics Brutus in my '03 Maxima and do the Cap and grounding kit and see how it goes. If I still have dimming lights I'll upgrade the battery.

Make sure you have the proper size power and gound wires as well, altho I think thats an obvious one.

The price is less than I remember...$150 for a 2F w/LCD meter! I think I'll go with a grounding kit, battery, and a 2F Cap.