With Project S13 out of the paint booth and back at the office, I was eager to start rebuilding it from the ground up with practically all-new parts. From ball joints, to brakes, to interior, I have a laundry list of to-do’s long enough to keep me occupied for weeks.
With such a large build at hand, there isn’t necessarily a certain order that upgrades need to be installed. Since the car isn’t going anywhere until it’s all put together, I decided I would tackle the easier things first, then make my way to the engine since it’s going to be the most complicated part of this project.

A plug-and-play option, the DeatschWerks 300-lph fuel pump drops right into the stock fuel
Fuel Pump
Believe it or not, the first modification that I made on the S13 was the fuel pump. I figured it would be good to get it out of the way early since the DeatschWerks 300-lph in-tank fuel pump is an item that can easily get lost in the piles of boxes I have in my office.
The LS3 is going to need more fuel than the now-retired KA24DE, that’s a given. The DeatschWerks 300-lph fuel pump is a great replacement because, with a fitment kit, it drops into the stock fuel pump location but delivers over double the flow of the stock unit. DeatschWerks also claims that it’s remarkably quiet compared to other high-flow pumps on the market, and I’ll report back on that claim when I actually start the car.

Installing the 300-lph fuel pump requires removing the entire fuel pump assembly from the
Swapping fuel pumps is about an hour’s worth of work. Removing the old pump and assembly is done by disconnecting the fuel lines and removing the bolts holding the pump assembly in the tank. Be careful with the fuel level bobber because it has to be disconnected inside the tank. Once out, with the supplied fitment kit from DeatschWerks, you’ll have the new 300-lph pump swapped over in a matter of minutes, then it’s back in the tank and you’re done.
Rear Subframe & Differential
My particular 240SX came with a HICAS system. For those of you who are unfamiliar with that, it’s essentially a rear-wheel steering system that’s supposed to improve handling. Judging by the amount of people who remove or disable the system, I’m not so sure Nissan succeeded with it, but that’s beside the point. I was intent on removing it, and after pondering a simple HICAS delete bar that would lock the steering in place, I opted to just swap the entire subframe over to a non-HICAS unit to prevent any future headaches.
This also provided a great opportunity to swap out the factory arms and replace them with some adjustable pieces from Circuit Sports. I replaced the rear toe links, camber arms and traction rods with Circuit Sports pieces that have Teflon-coated, durable rod ends and enough adjustment to get my camber and toe settings to whatever I need. I’ll also install some Circuit Sports subframe collars when I put the subframe back on, as they get rid of any slop that occurs during hard driving.
Some S13s came with a factory-optioned viscous limited slip differential that helps put power down evenly to the rear wheels. Unfortunately, being 20 years old, this VLSD, like many out there, has seen better days; at best, it operates at a fraction of its full potential. Considering the 424 ft-lbs of torque the LS3 will be transferring to the rear differential, an upgraded diff was in order. There are many good differentials on the market, but most are setup aggressively for track use, which means they aren’t very street friendly. I have a clutch-type LSD in my Integra that works amazing on the track, but driving it on the street is a huge nuisance because it clunks around almost every corner. I wanted a diff that would suit street-driving conditions but handle some minor track duty if need be. Enter Quaife and its ATB helical-type LSD. Using gears instead of clutch packs provides smooth operation with no clunking, zero maintenance and long-lasting, consistent performance. With the ATB LSD you’ll maximize traction and effectively put power down to both wheels without ever experiencing any harsh engagement — it truly is the best solution for a street-friendly LSD.
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Installing the 300-lph fuel pump requires removing the entire fuel pump assembly from the
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Removing the HICAS subframe is rather easy — four larger nuts hold it up to the frame. Rem
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A vast array of Circuit Sports parts ready to make their way onto the front and rear of th
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The new (used) non-HICAS subframe with Circuit Sports rear toe links, camber arms and trac
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Howard Watanabe of Technosquare tears down the VLSD differential.
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Quaife’s ATB helical limited slip differential. The perfect blend of smooth, quiet operati