Record Breaking: PZ Tuning’s 531 WHP RSX!


This picture was taken during the last week of October, while Will was testing the tune and traction control updates. I want you to look closely at the splitter and canards. We will talk more about them in a few moments.

Between the custom exhaust manifold and the custom downpipe is the highlight of this engine build. The Borg Warner EFR 7670 is a turbo built from the ground up to be a race only setup. EFR stands for Engineered for Racing. Many turbo's are adapted for race use from more sedate applications thus often have to compromise – but there’s no compromise with the 7670. Borg Warner sponsors the PZ Tuning RSX (Borg Warner also sponsors the Land Speed record holding Nissan 240SX). The wastegate and blow off valve are both built-in with this turbo, meaning that your setup will be easier with this all in one turbo. The integrated blow off valve or compressor recirculation valve releases excess charge air directly into the compressor wheel as Borg Warner seeks to reduce turbo lag. For more details about the Borg Warner EFR series turbo, check out this article.


This massive Borg Warner EFR 7670 turbo assists the RSX in making some incredible power with a strong torque curve. Pic by Will Au-Yeung.

Engine management is handled by Hondata K-Pro and, while Will usually does his own tuning in conjunction with OnPoint Dyno’s DynoJet system, this time around Sasha Anis took over the tuning role. This freed up Will to focus on other preparations for the trip to Buttonwillow. Before hooking up the dyno Will and Sasha talked about aiming for a solid 525 WHP. Sasha looked at Will when he quickly hit 531 WHP, wondering if they should keep going. But it was a great curve with lots of torque, exactly the powerband Will was hoping for to take advantage of the Californian track, so they buttoned it up. That flat torque curve will make a difference! This power level is up 60 WHP from the setup that was on track at Road Atlanta.


Sasha Anis from OnPoint Dyno and Race Service could have found more than the 531 WHP and 385 ft-lbs of torque. That's a few more than were found in the stock K20 engine. Chart provided by Will Au-Yeung.

Combined with the Hondata K-Pro is a Hondata traction control module, with is integrated into the ECU. The RSX has a Mugen LSD, however, as everyone who has driven a powerful front wheel drive car knows, traction can still be a challenge. The Hondata Traction Control  monitors the ABS wheel speed sensors and reduces power when the driven wheels are going faster than the undriven wheels.  There is a dash mounted switch to allow a wide range of slip rates, including having this completely off. Will tested this system for the first time on October 22 at Toronto Motorsports Park and was very pleased.


The cabin of the PZ Tuning RSX is all business while still taking full advantage of stock equipment. The dash instruments are stock. Sparco Pedals mounted on stock equipment. And, pardon the blurry mid-picture segment, on the left hand side is the far from stock adjustment panel for the Hondata Traction Control Module.

Now with this much power under the hood the question that I know you are pondering is how to get this power safely to the wheels. In addition to the Mugen LSD and Hondata Traction Control, Competition Clutch provided a twin disk setup. This setup comes with a forged steel flywheel for ongoing racing durability. This sends the 531 WHP to the outwardly stock transmission and the K-Tuned billet shifter. The transmission has WPC treated gears and 5.0 final drive. It was built with a great deal of attention to detail. Power then goes to Insane Shafts 1000 HP axles. From there it is transferred to either our Volk Racing CE28RT or Enkei RPF1 race wheels. Our current race set up uses 17×9.5 fronts and 17×9 rears with Hankook Ventus TD 255 40 17.


The Competition Clutch Twin Disk setup can handle the 531 WHP but it also provides a light weight and durable setup that is ready for the rigors of Time Attack events. Pic by Will Au-Yeung. 
Here is the K-Tuned Billet RSX shifter box. This very strong unit is designed to create a flawless shifting mechanism.

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