Oops yeah I did BRAIN < Basically I'm hoping to do exactly this...Make a list of the cars ACTUAL voltage/amperage and then have a list of add-ons for those in the future so they can know when they're reaching the limits of the electrical system instead of running through alternators.

Spelling owns you jackass its Brian hahaha

I know this maaaaaaaaan. BRAIN because I always pick you for odd questions that noone should know.

Had to look at my PMs. I told you to look for a sensitive 4 ohm driver, which would delete the bulk of the proposed system, as there would be no need for 0awg wire, an extra battery, a huge amplifier, etc. In essence, what I said here. Now you need to do a little legwork.

Below is link to a post from my last system thread. It discusses the constraints we face in our cars:

https://www.evolutionm.net/forums/8697674-post3.html

Now that's a good write up! I'd love to see your house surround system if you're this picky with your car stereo

All of that is over my head. Sorry my line of work is in a different field. I've asked some of the editors at Crutchfield as this is one of their responses to the alternator upgrading in regards to subwoofers.

"There are some things to consider before knowing for sure, though. Are you planning on playing loud music or bass tones? Will there be another amplifier in the system? Let's say you want to put in a 1500 watts RMS system. Factoring in the efficiency of the amp (50%) and the automotive working voltage of 13.8 volts, you would need to draw up to 217.4 amperes from the system. But, if you're playing music, that demand drops to a third of that, or about 72.5 amperes. Now, the rule of thumb on most stock alternators is that 40-50% of their rated power is available for non-automotive usage, like aftermarket amplifiers. Whether bumping tones or loud beats, it looks like you may have to upgrade that 90-amp alternator you've got".

He was going off the basis that the speakers I would be buying are capable of doing it at 2 ohms.

It's a complicated topic. That's about as simple as it gets. I can't tell you which gear to buy.

Let me give you an example of a more streamlined approach. A Blaupunkt something-12 woofer - forget the exact name, though I have one - that's ~92dB sensitive at 4 Ohm in a 1.25ft3 braced Baltic Birch enclosure weighing in at less than 40lbs total can be driven with a quality 100w amplifier to levels that visibly flex the quarter panels. This, with a decent measure of sound quality after tuning. No alternator upgrades, no extra batteries, no real drain on the electrical system. Ask me how I know.

I mention the sheetmetal flexing, because it's a consequence of trying to get bass into the cabin from the trunk. I discuss this, as well, in the link'd post. A better approach is to work with the car, but you can forget about big woofers.

[Totally OT]



Heh, the serious system has 2-channels and a turntable. The surround rig is on the TV, but it does have a sizable sub:





The pics were shot years ago, shortly after we moved into the home. The sub uses a ~46ft3 alcove as its enclosure and the entire house for reinforcement. Expositions and the like in movies can literally shake one's pant legs. At full song, the garage door moves off its hinges. Not a whole lot of distortion, either. It's a MLTL alignment.

[/Totally OT]

Some data gathered recently that I will copy and paste. So with this in mind, you would be approaching the "efficiency range" of the stock alternator.

"the COP needs nearly 30 amps and each Walbro 255 when modified at high fuel pressure will exceed 16 amps each. I personally ru am electric water pump too, another 20 amps."

I think, without a doubt, that I will end up needing a bigger alternator... I have a compiled list together that shows some of the data that we can use to determine individual needs.

Again, all the data that you have collected about how much amps a car would use is again at wot. The car will use whatever it is needed during normal driving conditions and wot it isn't gonna matter. Now if your system was running 100% amp draw 100% of the time then yeah you would need it. But the fact that we discussed thats what they are being used or wot, then not needed. If your in the 2% at wot, and or even less but only at wot, I still wouldnt worry about it being your not in wot all the time and the battery still has time to charge in other areas driving. I mean I know the way your thinking and wanting to go, but for others that may think along the same line, unnecessary. I mean I am not gonna say anything about those who want to go and waste the money on something like that. If they feel they need it cool, glad they got that kinda money to burn on something they prob don't need. But in my opinion just cause one person kinda thinks one thing and thinks they need it, and the shop goes and wants to sell it, I see it as a ploy to make more money on something different. I mean I know they are smart, and I do not want to take anything from then or insult them in any ways, but lets be real.

I stand corrected, the double pumper uses that amerpage at WOT but the waterpump, other single pump will still use the 36 amps. I am not sure of the COP amperage at idle or partial throttle so that will have to be answered by someone who has logged it.

Hopefully I can get someone to chime in that has this information since I can't check for myself off of my personal car at the moment.

First post updated

I know a single walbro should not draw more then 20 amps at wot. Any kind of rewire kit they usually come with a 20 amp fuse. Again I can see the water pump using a 10 to 15 amp fuse as well. But with that said that doesn't mean it is using those kinda amps all the time. The fuses are used for fail safes, so that they will not impede whatever fuse is used amp wise to do the system damage.

A wally 250 and I am pretty sure the 255 is the same only uses 1 amp at 43psi with 13v. So at idle it uses only 1v. Now under any type of load with the amps go up? sure but your not gonna keep constant 13v to the pump. Oh wait that is what your tring to accomplish correct? With that said even if you could keep 13v at the pump your only gonna draw maybe a maxium of 5v. I mean atmospheric prssure your only gonna use say at cruise double the voltage it is at idle so 2 amps. I am aware the more load it uses the more power it will use and the amps will go up so don't think I'm a total idiot, but looking at it this way, you could do the math if you had whatever load you were at and find out what amps you would be using.

According to this site: http://www.autoperformanceengineerin...l/fpspecs.html the 255 draws 7.2Amps @ 40psi @ 13.5Volts, and looks like the max draw of current is 17amps. Not sure how official these results are though

Everything I saw was off Walbro's website. I am not interested in testing anything for this being I know how it works. Again if you look at it a single walbro at 100 psi still puts out 15 amps. For most of us if your car idles at -15 in vacume thats what 85 psi of boost. Ok so that means that is a hell of alot of amps at a boost level we are not running. Now realistically for my car even a double pumper my car idles about -12 psi in vac, so according to this is 6.8 amps for one, so even double thats 14.6 amps. So just fuel at wot is only 14.6 amps according to this. Ok lets add my amp I have to run my front speakers being I have an rs and I added that. I have a 75 amp fuse up front on top of 2 20 amp fuses in the back for the amp. Obviously it isn't at 100% operating so I do know everything is under 20 amps back. I never have that thing 100% volume so I know I am drawing no where near 100%. Then throw in the factor I have everything else stock I am way under what amp rateing my alternator is.