lexondubs

Hey guys i have a 93 ls400 curious on who did a big 3 upgrade ? and is there a writeup that i havent found ? and also wheres the best ground for the amp ? the previous owner had a crappy little screw with 8 gauge wire so ive been redoing the whole thing adding my stuff will take pics along the way

GABE_LS400

I would say anywhere under the carpet around the spare tire area. There is also a ground near the tailights area you could just add to that. Or you could just run a long ground wire all the way to the front behind the stereo is acouple of good grounds. Id say since you are already running the amp wire there and the power supply wire is going the same direction you could just get a long ground wire and tap into that.

edtbjon

Eh, "big 3"??? Anyhow, there are lots of threads on audio installments in both LS and other Lexus cars. You can find a sticky general audio thread close to the top of the first page of the LS 400 forum. Apart from that there's a subforum dedicated to audio, navigation and such. Even though that forum is for all Lexus models, there is a lot of good information to be found.

About the ground, it depends on where you have your amplifier(s). Now, an 8 gauge wire will cope with up to 65 Amp if the wire is not more than 4 feet. As you don't have to route the ground wire to anything but the closest possible ground point, usually one or a maximum of two feet is required. So it's fairly safe to say that say 1½ feet of 8 gauge wire will cope with at least 80 amps or so. (Which equals about 1000 watts RMS, it that is enough for you.) Also an 8 gauge wire is easier to connect to the amplifier, where most amps usually don't have connectors for 4 gauge wire.
(The plus wire which is routed from the battery is another story. If you have your amplifier(s) in the boot, we're talking about 20 feet of 4 gauge wire. If you use a capacitator close to the amplifier, the wire between the cap and the amp will be fairly short and the same rule applies as for the ground wire above.)
All of this is basic electric knowledge based on rules used by all serious audio installers, so it's nothing I've made up.

//Björn

nervekiler

"All of this is basic electric knowledge based on rules used by all serious audio installers, so it's nothing I've made up."

but if your amp accepts 4g inputs then there is a reason they designed it to be that way. dont skimp on only doing 8g because u think itll be enough.
as far as where to place the ground, i usually do it on the floorboard of the trunk of most cars i work on. do not ground it to a peice of metal that is tack welded in for support (like bracing).

also worth noting that JL audio has grounding posts u can drill into the floorboard which will give u a much better ground than a standard self tapper screw.
dont forget to scrap the paint away!!!! and use some kind of anti-corrosion spray on the connection... to keep it from rusting in the future. i use the red spray they put on battery posts makes the grounds last a longer.

BLKonBLK98

wire gauge should be chosen by the total amp draw of your system. the best way to do it is to just add up the fuses and use the next gauge up (fuse the wire for the gauge, not the amps). some use the "bigger is better" method and just run 0 gauge the first time around, which should cover everything short of competition spl systems, but that's a lot of waisted money and effort if you don't need it.

the "big 3" (not sure if someone was implying it was made up, but's it's legit) is the same regardless of what car you are doing it on. alt -> +, chassis -> -, engine ground -> -. just run wire, no need for a step by step.

as far as the absolute best ground; it would be running wire back to the - battery post. short of that it go directly to the frame (spaceframe). floorpans, seatbolts, existing bolts etc. may work (mine is actually to an existing bolt for the time being with no problems) but are not the best.

Calyko22

lol the big three!!! I have a 90LS and I did the big three on mines its not hard. Ground from the batter to the frame of the car, from the frame of the car to the chassis, then from the battery power to the alternator...only thing I had an issue with was looking for a place to ground on my chassis other than that it took me about 15mins to do.

lexondubs

Thank you for the info guys i have my trunk gutted and my ground done and some dynamat on my trunk lid will get pics this weekend im upgrading all to 4 gauge because the previous owner did a pretty hack job and also used the cheapest rca's ive ever seen lol