A prototype version on a KL03 with a ZE intake manifold dyno'd an impressive +3 HP and +13 ft/lbs over the stock ECU control!  Brian last dyno results: *174* HP at the wheels: ZE intake on a stock short block with the VRTuner makes more power than a full KLZE!

Download the Installation Manual (pdf format)

Main Features

- Fully adjustable open and close settings for each VRIS valve from idle to 8000 rpm
- Fully adjustable load threshold from 0-100% WOT
- Load bypass mode for racing/KLZE
- LED indicator for load threshhold/power
- Regulated and heat sinked power supply for consistent operation
- Each unit *individually* calibrated during manufacture for 20 fold increase in controller accuracy over general/prototype units
- Expandable wiring harness and circuits, so the controller can grow with your setup
- Made specifically for KL series engines (KL03, KLZE and hybrid 03/ZE's)
- Easy hookup, all wires connect to ECU wiring harness inside cockpit- no wires to run through the firewall!
- Custom Aluminum box and wiring harness
- Handcrafted in the USA!
- Small size allows mounting in the ashtray slot of a Probe as well as a variety of other places
- Retune your VRIS any time you make a mod!
- No soldering, no risk, no mess
- Unit can be removed from car without affecting driveability, stock ECU takes over
- Prototype units tested for months on the street and at the track

Download the Installation Manual (pdf format)

VRTuner FAQ

What is the VRTuner and what does it do?
VRTuner stands for Variable Resonance Tuner. It allows full control over the Mazda Variable Resonance Induction System (VRIS) of the 93-97 Ford Probe GT, 93-98 Mazda MX6, and 93-02 Mazda 626. The VRTuner allows you to adjust the open and close points for each VRIS solenoid independently, as well as the load threshold, to maximize power for your specific application.

What is the adjustment range?

The VRTuner allows you to set the open and close points independently, anywhere from idle to 8000 rpm. Load threshold can be set anywhere from 0% (not pressing gas pedal) to 100% (pedal to the floor). The factory setting is fixed at 75% for the US spec ECU.

Does it work on a KLZE?
Yes! People with US spec ECUs running KLZE engines have flat spots in the rpm band as well as a loss of power at high rpm because of improper VRIS switching points. The VRTuner lets you adjust the VRIS points to J-spec points to regain lost power.

What if I have a KLZE manifold on my KL03?

This is what the VRTuner was designed for; it lets you take full advantage of the KLZE’s superior flow characteristics

Will it work if I have a ported manifold?
Yes, as long as the VRIS butterflies have not been removed. You will need to make a few runs on the dyno to determine the optimum settings.

I’m running nitrous on my KL03/KLZE. Will this work for me?
Yes. The VRTuner is also expandable, an optional add-on module gives you control of nitrous delivery as well, with fully adjustable open and close points. There’s also an optional adjustable shiftlight output for activating aftermarket shiftlights.

Will using the VRTuner result in a Check Engine Light (CEL) code?
No. Apparently the ECU doesn’t care if the VRIS system is working or not. Using the VRTuner never resulted in a CEL code on any of the test cars. Driving around with the VRIS solenoid wiring harness unplugged also doesn’t result in a code.

If the VRIS system in my car is not working, will the VRTuner make it work again?
No. The VRTuner requires that your VRIS system is working properly. If you have bad solenoids or vacuum leaks, the VRTuner will not help you until you repair the VRIS system.

Can I hook it up myself?
Yes. The VRTuner comes with detailed installation information. Installation couldn’t be easier; all wires are connected to the ECU wiring harness. If you are not comfortable with wiring, have a friend who is do it for you. RPMTuners will have a forum, online installation help, and feel free to email.   We will make sure your VRTuner gets installed properly!