Lexus LS400/SC400 Battery Relocation How-To

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In order to fit the supercharger into my LS400, I have to relocate the battery.  People have many reasons to relocate battery.  Some for weight distribution other for space.  To relocate the battery is pretty simple task, however it will require some money.  There are two ways of do this modification. 

First thing is to pick what type of battery you will be using.  Optima battery is widely use by the audio enthusiasts.  Here are some advantages of using Optima Battery.  One of the advantages of using Optima batter is that it does not require a battery relocation box/kit.

However, the price range from $150-$200.  Since I have a relocation kit.  I would recommend that you get two Battery Box (part # SUM-890102) relocation kit.  I chose Trojan Battery  because is cheaper and Trojan Batteries are the strongest battery you can find on the automotive market today.  Trojan batteries are widely used in semi-trucks, marine boats and hydraulic system in low riders.  The cranking ampere for Optima battery is around 750 CCA and Trojan is about 1000 CCA.

Why do we need a new and higher cranking power battery?  OEM battery doesn’t provide enough juice or cranking power to start the car.  When I relocated my battery, the OEM battery did not have enough juice to start the engine.

The starter would just click, but doesn’t turn.  The reason why the oem battery does not turn because the distant have increased and therefore the cranking ampere decreased.  Not enough juice!

After I put in a higher cranking power battery, the car start right up.  The batter is held down by two 10mm screw.  The battery tray is stabilized by 4 10mm screws.  They all need to be removed.

The new positive cable provided with the kit will run inside of the car under the carpet.  There is an opening from the inside of the car to the engine bay.  Its near the gas pedal.  All the positive wires are connected with the new cable.  The ground will be connected to the frame in the trunk.  The relocation is a piece of cake, but getting all the parts and some money is involved.  The task takes about an hour.

If you feel this is too big of a job, you can take your car to a local audio shop and they can do it for you.  However, they might charge you about $100 for that job.  Make sure you have all the parts for the project before u arrived.  Once you relocate your battery than you are ready to do forced induction.  Secondly, you might notice your car handle slightly better since you have redistribute the weight to the rear of the car.

There are two 10 mm screws that hold the battery bracket down.
Picture here is the second screw for the bracket. Remove both screws and take out the battery bracket.
After you remove the battery, there will be 4 10 mm crews for the battery tray. Loosen those screws and remove the tray.
This is how it looks like when the bracket, battery and the tray is removed.
The positive cable will be run parallel to the engine bay. After the picture, the cable was zip tied for stablization.
A second look at the positive battery cable. Make sure keep it away from heat like exhaust and engine.
The positive battery cable runs inside of the car through the firewall. There is an opening near the gas pedal. Run the wire under the carpet.
This is the ground cable and its attached to the car frame.
This is the relocation box with strap. I will screw the box down once everthing is working properly.
This is the picture of the Trojan 1000 cranking amps battery. This is heavy duty battery.
This is the positive battery cable existing from the interior of the car.
Positive cable is above and negative cable is below.

Do you have any questions? If so, please head over to the forums to get a quick answer or share your experience!

This is a freelance site with no support by huge companies.  I have been doing most of the R&D and technical write-ups by myself with my personal money and literally thousands of hours of my time.  I have taken extra steps to demonstrate in details how things are done.  Currently I am one of the few people doing Lexus V8 research and performance enhancement.  This effort comes from my personal love for this wonderful engine.  Most of the modifications are from trill and errors.  There is no cookbook for the 1UZFE modifications and its a virgin territory for performance.  The parts, labor, web development and site hosting are from my personal hobby money.  If you feel my efforts help you in any form, please do not hesitate to donate any amount of money to support this site. You have no idea how much I appreciate it!

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