3 liter ignition ECUs

[Bkeenom]

I am curious what the difference between 300 Pro Max ignition ECU and 250 Pro XB ignition ECU. I know the pro Max has a higher rev limiter, but what other difference?

[bsumner]

More timing. Many are matching the 300 ProMax ignition box with the 250XB fuel box.

[Bkeenom]

More timing. Many are matching the 300 ProMax ignition box with the 250XB fuel box.

That is what I am trying to do, but am having trouble locating the 300 ignition. I have an xb ignition and was wondering about the difference. I will run the xb until I can locate a 300.

[bsumner]

I was told the XB has 2° more timing and the 300PM has an additional 2° more, making a total of 4° over a stock EFI box. Just adding the ignition box will not raise the rev limiter. Both boxes (ign. and fuel) should be adjusted accordingly. A stock fuel box will go pig rich at 5850 and kill RPM.

[Bkeenom]

A stock fuel box will go pig rich at 5850 and kill RPM.

A stock 250 xb fuel box will do this? I currently have the xb fuel and ignition.

[bsumner]

No the 250 XB box shouldn't, but a standard 225 EFI box will.

[Bkeenom]

thank you for taking the time to answer my question. It is much appreciated.