[cjpp78]

I've been running the jb+ on a 440i for a few weeks now at default setting. I later turned it down to the 1 oclock setting as the drivability is better and top end pull is smoother.
I then decided to try some sunoco 260GT, 100 octane unleaded. Ran it straight and turned jb+ back up to default setting. The car was transformed and the power felt great now and it pulled very hard and smooth to redline. I checked boost pressure via obd2 port and noticed that in 4th gear I hit as high as 18.9psi once. It never did this on 93 octane..I know reading from obd2 is not accurate due to jb+ sending false signal to the Dme but, that was still a higher reading than I ever got on 93 octane at same setting.. Is it normal for the stock tune to make that much boost when on a high quality, high octane fuel?
AFR IS 14.1 across the rpm range as well..Just wondering what others have got for boost when running race gas on stock tune and if the boost levels I'm seeing are safe?

[mike@x-ph.com]

Stock boost should not change based on Octane

If you want to know how the car is handling the boost, get a Jb4 and datalog. If you do not want to make this investment, keep your Jb+ at default settings and call it a day.

[cjpp78]

Originally Posted by mike@x-ph.com

Stock boost should not change based on Octane

If you want to know how the car is handling the boost, get a Jb4 and datalog. If you do not want to make this investment, keep your Jb+ at default settings and call it a day.

This is a lease and the reason I have a jb+..i will be buying a used 340/440 or M240 probably next year though and will go full JB4 then..

I was running default setting and that was the boost level reported by obd2 port. My question is, is my actual boost level in the manifold at least as high or higher than what odb2 reports? 2. Is that generally safe considering quality fuel? like can hpfp keep up with that?