Is the JB4 Tuner Worth It for My New BMW M3/M4?

by Ashish Mishra

If you recently bought a new BMW M3 or M4, you may be wondering if installing a custom tuner such as the JB4 is worth the investment. The JB4 tuner by Burger Motorsports (BMS) is one of the most popular plug-and-play tuners for BMWs, providing significant power and torque gains with little to no setup.

In this blog post, we’ll take a close look at what the JB4 has to offer and help you decide if it’s the right mod for your BMW.

What is a JB4 Tuner?

The JB4 is a piggyback tuner that plugs into your BMW's stock wiring and lets you modify the vehicle's computer for greater power. It's called a "piggyback" because it doesn't replace your ECU as a flash tune would.

Instead, the JB4 intercepts messages between the engine sensors and the ECU to fool the computer into adding more boost, advancing timing, and making other performance-oriented changes.

Some key features of the JB4 include:

  • Easy plug-and-play installation with no permanent modifications.
  • Multiple user-adjustable maps are available for different fuel grades or bolt-on mods.
  • Adds 80-150whp on pump gas, even more on E85.
  • On-the-fly map switching from steering wheel buttons.
  • Advanced safety features to protect the engine.
  • CANbus integration and OBDII connectivity.
  • Compatible with the JB4 Mobile app for added functionality.

JB4 Gains for M3/M4

Independent dyno testing has shown the JB4 can add major power gains to the S58 engine:

  • 80-100whp on 91 octane pump gas
  • 150-175wtq on E85 or pump gas and methanol injection

These gains make a very noticeable improvement in speed and throttle response.

The JB4 increases torque in the mid-range, which is where the power increase is most noticeable, and 0-60 mph times decrease by more than half a second.

For larger power gains, the JB4 stacks well with other bolt-on modifications like downpipes, intakes, intercoolers, etc.

JB4 Tuning Safety Features

While adding more power is fun, keeping your BMW engine safe and reliable is the top priority. The JB4 has several built-in safety features to protect your S58:

User-adjustable torque limits: Prevent dangerous spikes in torque

CANbus monitoring: Take readings directly from engine sensors to monitor safe parameters

Cylinder-specific knock control: Retard timing if knock is detected to avoid detonation

OBDII integration: Read and clear codes if any crop up

The JB4 has been tested thoroughly on the S58 motor, with no reports of engine damage when used responsibly.

Always run 91 octane or higher gas and get your car tuned if adding more bolt-ons.

Is the JB4 Worth it?

At around 650 bucks, the JB4 is a fairly reasonably priced way to get a lot more power out of your M3 or M4. And because it's reversible and retainable, it won't void your warranty or hurt resale value later on.

Pros of the JB4 Tuner:

  • It gives you 80-150 extra horsepower for much faster acceleration and speed.
  • You can install and remove it whenever you want with ease.
  • You can switch between power maps on the fly while driving.
  • It has safety features to protect your engine.
  • It doesn't affect warranty or resale value.

So, if you want big power gains from a simple plug-and-play install, the JB4 is worth the money.

It's a great entry-level mod that's flexible and safe when used right.

Just be sure to use high-octane gas and complement it with supporting mods like intakes, downpipes, intercoolers, etc.

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