1990-1997 Mazda Miata Adjustable Fuel Pressure Regulator

What is being offered is YOUR factory OEM Mazda fuel pressure regulator (FPR) modified by 5X Racing to become adjustable. Just follow the shipping instructions we send you within 24hr of your order and 5X will transform it into a trick adjustable factory quality regulator.

•  If you send us a known good & working FPR we’ll refund you $50 for your core.
• We can use one of our cores; you’ve already paid for it.

 Please check the customization year car you have

Why is this better than the other adjustable fuel pressure regulator kits out there?
The 5X unit is better because:

• It utilizes the OEM FPR, which is a practically flawless part to begin with. We've never had or heard of a problem with one for the 5+ years we've been racing Miatas.
•  It does not have anything to do with modifying or altering the path of your fuel lines. We don't require cutting into your fuel lines, which causes potential for leaks and fire.
•  It uses the factory vacuum line, which keeps the pressure consistent, something that you will not get with a universal adjustable fuel pressure regulator. Universal fuel pressure regulators dip and spike with different engine loads and rpm spikes (missed shifts); ours stays consistent just as your factory regulator would.

What will it do for my Miata?
The 5X fuel pressure regulator will allow you to adjust your fuel pressure at your fuel rail from a low point of 22 psi to a high of 58 psi (all regulators might not be the same and individual results might vary depending on the quality of regulator sent to us) by simply turning an adjustment screw which in turn alters your air/fuel ratio by increasing or decreasing the fuel pressure to your engine. Adjusting your fuel pressure lower or higher will lean or richen your air/fuel ratio, which is essential for tuning your Miata's engine for maximum horsepower, especially in stock based classes like Spec Miata where modifications are extremely limited. For example: dialing in more fuel equals a richer mixture of air and fuel, which will benefit low rpm torque and horsepower for tracks that are tight and have low speed corners. Dialing in less fuel will lean your mixture of air and fuel, which will benefit high rpm horsepower for tracks that are 3rd gear through 5th gear tracks and do not have tight turns. So, in essence, this product will allow you to adjust your fuel pressure freely, which in turn adjusts your air/fuel ratio for different tracks based on your need of more horsepower or more torque.

What will I need to use this regulator on my car?
Using the 5X regulator is as easy as removing the factory regulator on your car (two bolts), sending it to us and then reinstalling it back on your car. It is the factory regulator, so there is no worry about the fit and finish. When you install your new regulator, simply follow your cars repair manual for "fuel pressure regulator removal/installation". We suggest setting your fuel pressure to the factory setting range of 32-38 psi at idle, then tune from there.

To properly tune, you MUST have a fuel pressure gauge either installed full time inline with your fuel line, or an external attachable gauge to dial in your specified fuel pressure while idling in the shop. In addition we HIGHLY suggest picking up an air/fuel ratio gauge, such as the Innovate Motorsports LC-1 kit to be able to accurately monitor and dial in your fuel ratio. If you don't have a fuel pressure gauge, or air/fuel ratio gauge, our regulator is practically useless to your tuning needs.

Ok, you want one! What happens next?

1. Upon purchase, we will confirm your order and email you (within 24hrs) with a shipping instructions to send us your known good & working regulator.
2. We will confirm the arrival of your regulator and convert it to a 5X Racing Adjustable Fuel Pressure Regulator.
3. Once we complete the work, we will provide shipping info on your order status when it ships back out to you.
4. The whole process will take about two-weeks.