Heavy Throttle

Speedoptions.com 320hp Project

	We set out to build a S13 240sx (89-93) to be a street/Strip car. Target HP was between 300-325 WHP to drop the ¼ mile times into 12 second territory. On the route to that goal we have swapped out the stock KA24DE in favor of the JDM SR20DET. The automatic transmission was swapped to a 5 speed, to give the car its deserving feel.

	To bump the power up to the 300+ WHP mark we upgraded the turbo to the Heavy Throttle custom T3/T25 hybrid turbo, installed Apex'i 550cc injectors paired up with a 255 liter/hour high pressure Walbro fuel pump. Jim Wolf retuned the ECU to run a Z32 300zx MAFS and the larger injectors.

	We started out with about 12 lbs of boost, which turned out to be the wastegate setting. The engine reached 12 lbs of boost around 3500 rpm and a pulled very strong to 7200 rpm. The power delivery is very smooth with this new turbo, it feels like the power gradually increases to about 4500rpm and then stays level to redline.
Click on Dyno Chart to Enlarge	Next step was to bump up the boost and go to the dyno. We set the boost to 20 lbs and kept 93 octane fuel in the tank. At the dyno the car made 300 WHP with 330 WLBS of torque. Looking at the dyno chart that compares the stock power curve and the new one, we can see a large difference in the power around 4500 rpm. That's right in the sweet spot. Great result.



	The brakes were upgraded to the 26mm 300zx setup up front. All four rotors were replaced with the Heavy Throttle Brembo Rotors and Axxis metal pads.