Six years ago I set out on a quest to build a car that was fast, could go unnoticed by most cops and, more importantly, was the complete opposite of anything I drove before it: rear-wheel drive. I found that when I picked up a '91 Nissan 240SX for roughly $5K-it had a SR20DET already. You've seen it in various stages of completion, from its humble beginnings of quality HKS bolt-ons and its conversion to five-lug suspension, leading all the way up to this, the grand finale where I show you the last of the parts, the initial stages of tuning and the big sendoff where the damn thing finally made power. It's a tech build-up long overdue, but it's DONE. Stick a freaking fork in it.
Baseline Tuning the GT-RS
At the point where we last left off, in a galaxy far, far away, we had just finished installing the HKS GT-RS turbo to our SR20DET with stock internals at SR20Store. From there, the car was moved down to Dynamic Autosports, where an HKS F-Con V-Pro engine management was installed. I picked a V-Pro because of its tuning flexibility and it's cool because it gives you lots of options, especially if you're the kind of person who wants to mix things up with tuning for drifting or Super Lap Battle-it's really up to you and your tuner. This standalone unit plugs in easily like an ECU through HKS' plug-and-play harness (custom wiring harnesses are available by request through HKS), which is great since you don't have to hack up your original wiring harness. It's equipped with a quick processor and is set to a 32x32 resolution for fuel and timing maps. Sounds complicated, but it's really tits.
The V-Pro is not for the faint of heart. It's a serious computer that only certified HKS Pro Dealers can tune, which is why I turned to Dynamic. Hooked up to their Mustang dyno, their tuner, Jeff, began a simple base map for the car to operate on safely since neither an EVC nor an A/F Knock Amp had been installed and both are a must for any tuning. With limited tuning options, he mirrored a near "stock"-like map, no increased boost to prevent damaging the engine; figures at that point were 180 hp and 173 lb-ft. Keep in mind, however, that a Mustang dyno tends to read anywhere from 10- to 20-percent lower than a Dynojet and Jeff explains it as "like driving on the road with a proper load." Factoring in those percentage losses, the car could've realistically been putting out power in the range of 198 to 216 hp. I took 2Fizzle home somewhat disappointed because I couldn't really go boost happy-well, I couldn't really boost at all. I figured that would be a good time to work on other parts of the car until the electronics were wired up.
Mynismo.Com Lends A Helping Hand
I've discovered that the key to making the 240 a lot of fun to drive is to have the right suspension in place. It takes more than just slamming it on a set of coilovers to do it justice, although it always looks like slamming it is the best way to go. You may recall last month's discussion on the 240 as one of the top tuner cars and what Eric Hsu had to say about setting up a 240 right: "The car benefits big time with a good coilover suspension along with good suspension components and alignment. To properly slam a 240, you must use roll center correction kits and bumpsteer correction kits, and physically mount the rear subframe higher up in the chassis with aluminum subframe bushings or heavy fabrication." That's a serious way to approach suspension on a 240. I didn't go as extreme, simply because it was going to be primarily street driven, but I looked to Andy Kim at MyNismo.com to help me out with a set of rear upper control arms from Battle Version and a NISMO Power Brace. The Battle Version arms are used to help adjust camber since it's usually thrown way out of line once the car's lowered; other options would've been to add forward and toe links to the mix. The NISMO Power Brace's function is to work with the Peak Performance front tension rods and minimizes movement of these rods while cornering, giving you much better handling.