The jb4 IAT spoofing is a game changer - my experience

[mike@XPH]

Let's start with the basics; there are two significant ways for a turbo car to make power. 1- add boost 2- increase the ignition timing.

Since most piggybacks cannot alter ignition timing, they use method #1, which works very well with BMW turbo cars since they come detuned from the factory.

The JB4 has always had an advantage over other piggybacks since it has CANbus to read and modify additional data other than boost; it can be more aggressive with boost and make more power safely, especially with E85.

But now, with the IAT spoofing feature, The JB4 is reaching a new level, especially in warmer climates.

IAT spoofing tricks the ECU into thinking that the intake air temps are much lower than they are. The DME takes advantage of cooler air by slightly reducing the boost but increasing the ignition timing significantly.

Here are my results:

Stock

• IAT: 113
• Ignition timing: starts at 18, ends at 4.5
• Boost: 19-24 PSI

JB4 Map 2

• IAT 113
• Ignition timing: starts at 18, ends at 4.5
• Boost: +4 PSI over stock boost

JB4 Map 2 with IAT spoofing

• IAT set at 64 by the JB4
• Ignition timing: starts at 22.5, goes to 9.5, then back to 13
• Boost: DME set boost ~18/19 PSI, +4 PSI added by the JB4

The result was a little less boost but more timing and better actual world performance.

I did not compare stock vs. all JB4 maps, but the power difference is easily noticeable with the extra 4 PSI.

I did compare the JB4 map 2 to Jb4 map 2 with IAT spoofing. And here are my results.

I shaved a full second in my 40-100 mph run by switching from the JB4 map 2 to JB4 map 2 with IAT spoofing.

It's a huge difference made by the JB4.

Now before you get all hyped up, here are some thoughts:

This feature is most useful in warm weather when your IAT is over 100 degrees. It should only be done on quality fuel like E30 or race gas. Everyone's car reacts differently, so it's best to test it and look at logs to ensure everything is working as expected.

To enable this, you first turn on option 2 (full-time IAT spoofing), then in the 6cyl field, you enter what temp you want the JB4 to target.

I used 65 degrees. You could go higher or lower to dial it in.

This is a JB4-only feature; it's a game changer to make even more power from your M3/M4 :dance::dance::dance:

[Greekstyle]

How do I enable this on the PC software? I do not see an Option 2 or a 6cyl field to modify.