Like any adrenaline junky, I craved more power--a LOT more power. The only way to satisfy this appetite was via glorious forced induction. In the summer of 2003 I underwent (rather unknowledgeably) the task of turbocharging the KA24DE. I had researched it for months and had even written a fifteen page paper on it for Honors English in high school. I decided the KA24DE was stout enough to handle the boost, and indeed it is, with its iron block, oil-squirters for each piston, and an incredibly beefy bottom end:
I longed to be able to put the "-T" at the end of KA24DE to signify "turbo", and wished even more for the power, sound, and thrill of forced induction. I did not have much money even though I had been saving all winter and spring ($7.35 an hour was not exactly a good salary to fund expensive projects). There were a variety of pre-fabricated kits available for the 240sx from Nsport, FMax Engineering, XS Engineering, etc. All of these kits were around $3500. The cheaper GReddy kit available right now was not yet in existence at this time.
So with few options and a tight budget, I blindly bought a "kit" from a guy in California with whom it turned out to be an incredible headache to deal. The kit would allow me to run 5 psi non-intercooled, and I told myself and my dad that the power from this kit would be plenty and would finally satisfy (perhaps even satiate?) my sweet tooth for power. The "kit" included an extremely small AiResearch T3 turbo with a .48 a/r turbine, .42 a/r compressor, the oil feed and drain lines, an unknown Bosch fuel pressure regulator, steel piping for an intercooler (I was planning on intercooling it eventually), an air filter, the turbo inlet pipe, a cheap Bosch bypass valve, a crappy, crush-bent downpipe, a well-built log-manifold with cuts in between the ports to prevent cracking of the engine-side flange, and all of the couplers/clamps needed to let it run.
While we started to turbocharge the engine, we took a preventative step by installing a front-mount oil cooler, thermostatically controlled, to help keep oil temperatures down. It worked extremely well since it was installed, except for a near catastrophic failure due to one of the oil lines going to the cooler coming off. This was promptly fixed by purchasing very high quality, high-temperature, high-pressure oil lines. The previous oil-lines had a higher pressure and temperature rating than any of the oil flowing through them, but apparently not high enough.
The whole turbo install was an incredible learning experience, with many valuable lessons being learned. First off, the couplers the guy included for the piping were designed for basic PVC piping, as were the cheaphose-clamps; together, they could barely handle 5 psi. I learned this the hard way when one of my intercooler pipes blew off and landed in the woods beside the road. Sadly, after all the money ($1375) spent for a crude turbo kit, I was initially not very impressed with the power delivery.
Needless to say, the kit was a very sloppy one at best, and despite sound installation it was held back by the poor quality of the parts. Here is a picture of how the kit initially looked. It looks very rudimentary, which I wouldn't have minded if it performed well.
A (very) rough start...
I decided the kit needed some major tweaking and upgrading to quality parts.
The tiny T3 turbo originally hanging off the side of the KA was far too small to make any impressive power. The KA is a rather large four cylinder at 2.4 liters of displacement, and this turbo was simply too small. After "upgrading" to what turned out to be the EXACT same size T3 turbo, I realized I couldn't live with the boost falling flat after 4000 rpm. So instead of buying a second-hand, used turbo whose specs I didn't know, I opted for a freshly remanufactured T3 Super 60B turbo, which is very similar to the T3 "60" trim. This larger, more efficient turbo has a .48 a/r turbine and a significantly larger .60 a/r compressor (compared to the .42 a/r of the previous unit). The turbo on the left is the T3 Super 60B.
This turbo was significantly better than the old one and the boost did not fall off until around 5000+ RPM now. It made the car feel quite a bit faster. While I was at it I replaced the plastic Bosch bypass valve with a CNC'd aluminum Turbo XS engineering bypass valve with adjustable springs instead of a rubber diaphragm. I replaced most of the crappy black rubber coupling with real silicone. Because I knew I wasn't intercooling it for a while, I had the "intercooler piping," which ran through the bumper, replaced with a much more direct one piece pipe that a muffler shop fabricated and that went from the turbo outlet to the throttle body without unnecessary bends. I replaced the cheap black-plastic turbo inlet piping with stainless steel, and dropped the air filter down in the lower bumper area so it drew only fresh, cool air instead of the hot engine compartment air. I also added a manual boost controller as well as a very effective and cheap heatshield.
I wanted to up the boost, but not without an intercooler or some other signficant preventor of detonation. My dad had the idea of using alcohol injection, and had most of the pieces lying around from when he used it on our old Volvo turbo. We used a 1.0 gallon per minute RV-pump that we got from Northern Tools and Equipment, high pressure water-line from home-depot, and a very expensive alcohol injector nozzle that finely atomized (misted) the alcohol into the intake manifold right before the throttle body. The alcohol injection was programmed to come on at 6.75 psi using a Holley adjustable pressure switch which had a pressure source from a T coming off of the intake manifold. The pump drew its source of alcohol from the windshield washer fluid reservoir. A second pressure switch was hooked up so that whenever the methanol was being injected, a blue light, mounted below my boost gauge on the steering column (blocking any paltry speed below 45 mph), would illuminate. A Blitz R-Vit monitor was added soon after so I could monitor twenty vital engine parameters. The boost was increased to around 9 psi from 6-7 psi once it was alcohol injected, and along with 94 octane gas, the car ran very nicely and never ONCE pinged, the entire summer.
She looks like she means business now...
The car got a slight face-lift with a Nismo bumper, gunmetal 5zigen typhoon rims, and the extremely rare SE mud-flaps painted body color. It ran very strongly throughout the summer and I never experienced any problems with cooling, oil, etc. It was a blast to drive and it was beginning to feel like the engine was finally approaching parity with the chassis to which it was bolted.
0-60 time in seconds, as measured by G-Tech Analyst
Bored one day, I decided to see what kind of 0-60 mph time the car would post. I stupidly chose an 85 degree, muggy summer day. The 5.72 second time, although respectable, could have been a lot better if a few things weren't working against me:
(a) Slipping clutch. Yep, it slipped like crazy in first and second, which means not all of the power was getting to the ground. (b) Traction. Despite the slipping clutch, my rear tires still got smoked in first gear. Spinning tires means you're not going anywhere, which is not good for trying to post a fast 0-60 time. (c) Driver. I have NEVER "drag raced" the car, or raced anyone for that matter. Hitherto, I had never launched the car hard to prevent wear-and-tear; I was clearly very inexperienced as to what was the most effective way to get the power to the ground. Dropping the clutch resulted in excessive wheel spin; releasing the clutch gingerly and getting on the throttle gently to reduce wheel spin was the way I ended up launching it to get the 5.72 second time, but clearly that's not the fastest way to go as the car was only at about 1000 rpm when I launched it.
But excuses are for losers, and I figured it was time for some more upgrades :)
