[COBB Tuning]

Originally Posted by bmxcamel

Cobb wtf?

We're happy to try to help and apologize that you're having issues. Have you contacted our Customer Service team or Rob directly? Either one is a good first step towards getting us more info about the problem and hopefully on the road to finding the solution. As mentioned, this is a beta release and we're still polishing things up for a final release, so your feedback is very important.

Looking forward to digging in further!

Cheers

Lance

[BMWsky]

Originally Posted by COBB Tuning

...As mentioned, this is a beta release and we're still polishing things up for a final release, so your feedback is very important.

Looking forward to digging in further!

Cheers

Lance

Hey Lance (or anyone else from Cobb reading this), could you weigh in as to why some of us are reporting negative boost numbers at idle? It seems like we're seeing -6 to -9 psi before hitting the throttle. For me, the car seems to pull stronger than it ever has, but that reading is weird. At WOT, boost seems to peak for me in the high 14ish range for a split second before heading down to 12~13psi sustained.

[mithiral67]

Originally Posted by BMWsky

Hey Lance (or anyone else from Cobb reading this), could you weigh in as to why some of us are reporting negative boost numbers at idle? It seems like we're seeing -6 to -9 psi before hitting the throttle. For me, the car seems to pull stronger than it ever has, but that reading is weird. At WOT, boost seems to peak for me in the high 14ish range for a split second before heading down to 12~13psi sustained.

I am curious about the negative reading boost.

For the second item, sounds like you are overshooting boost due to wastegate differences and its being controlled by TP closure.

Run some logs and if you see tps dropping belwo 80 right after hitting peak boost, then thats what is occuring.

[BMWsky]

Originally Posted by mithiral67

I am curious about the negative reading boost.

For the second item, sounds like you are overshooting boost due to wastegate differences and its being controlled by TP closure.

Run some logs and if you see tps dropping belwo 80 right after hitting peak boost, then thats what is occuring.

Agreed...not that it worries me because of where it reads boost (I know it really isn't that high). I will check my logs to see my TPS...thanks for the advice.

[korben dallas]

Originally Posted by mithiral67

For the second item, sounds like you are overshooting boost due to wastegate differences and its being controlled by TP closure.

That is my current theory on my throttle closures, though I'll have to pull some logs in the next day or so to try to confirm. I now generally see about -8.5psi on idle, dunno why I was only seeing -6.5 that one day.

I'm thinking they changed where boost is measured so you now get the vaccum pressure at idle correctly. -8.5psi is something like -17inHg and I think the consensus is that -18 to -21 is 'normal'.

[Jeff@TopGearSolutions]

Originally Posted by korben dallas

That is my current theory on my throttle closures, though I'll have to pull some logs in the next day or so to try to confirm. I now generally see about -8.5psi on idle, dunno why I was only seeing -6.5 that one day.

I'm thinking they changed where boost is measured so you now get the vaccum pressure at idle correctly. -8.5psi is something like -17inHg and I think the consensus is that -18 to -21 is 'normal'.

Correct

[mithiral67]

Originally Posted by Jeff@topgearsolutions

Correct

Where is the pressure being measured now?

[dzenno]

Originally Posted by mithiral67

Where is the pressure being measured now?

Still in the intake manifold, post throttle body, just now the logging is showing vacuum as well as before it was just showing boost (positive pressure)..

[mithiral67]

Originally Posted by dzenno

Still in the intake manifold, post throttle body, just now the logging is showing vacuum as well as before it was just showing boost (positive pressure)..

ah, simply a programming change.

[BMWsky]

Cool, that makes sense. Again, thanks everyone.

[vasillalov]

Originally Posted by dzenno

Still in the intake manifold, post throttle body, just now the logging is showing vacuum as well as before it was just showing boost (positive pressure)..

Umm, I thought the boost sensors are before the throttle body, no? I have a P3 gauge which taps into the vacuum line for the DVs for its internal sensor which displays true manifold pressure.

[Joshboody]

MAP on TP and in manifold. DME uses TP sensor to control boost, but you can log manifold MAP with BT and Cobb.

Not sure if they Cobb was using manifold MAP before since the Cobb logs show boost spikes from throttle closing... i thought anyway.

[lawwailok]

wondering if we want to log timing, which channel should we "check" now... the whole new thing im confused... i tried to do a log last night... can't log the right timing.... anyone knows how to log the correct channel with the new thing?

[mithiral67]

Log timing on one and the correction on all other 6. Then review the 6 correction logs. If they never show a negative number, that means that all 6 cylinder's ran the programed timing curve inline with what Cobb's programming.

If they show negative numbers, then you can use the cylinder one timing to see what curve you had on any other cylinder.

[Joshboody]

any word on how sample rate changes with quantity of log channels... cobb? Dzenno?

[dzenno]

Originally Posted by lawwailok

wondering if we want to log timing, which channel should we "check" now... the whole new thing im confused... i tried to do a log last night... can't log the right timing.... anyone knows how to log the correct channel with the new thing?

For the most straightforward timing logging you can just log cylinder 1 timing and then to that add timing correction 1-6 channels...this way you'll know based on cylinder 1's timing where the others should be while the corrections will show you how far off from the ideal/set curve the other cylinders are...is that clear?

Originally Posted by Joshboody

any word on how sample rate changes with quantity of log channels... cobb? Dzenno?

I don't recall seeing any degradation of channel quality logging as long as you have less channels selected than what gives you a warning on the number of channels..

[Joshboody]

Originally Posted by dzenno

I don't recall seeing any degradation of channel quality logging as long as you have less channels selected than what gives you a warning on the number of channels..

So like 10 channels probably... man I was under the impression you can log all at once. I don't see why you can't though, since all these channels are sent to each canbus node. With BT I thought the limitation was the USB and a dedicated logger would be different. I don't know

[dzenno]

I've managed to log 22 channels at once without encountering the warning...haven't really tried more than that...here's a sample

[Joshboody]

Originally Posted by dzenno

I've managed to log 22 channels at once without encountering the warning...haven't really tried more than that...here's a sample

yep, that's about 18 samples/s... pretty good for 22 channels. Being able to log all 68 for every log, the plethora of information would be awesome... and overwhelming.

[dzenno]

Originally Posted by Joshboody

yep, that's about 18 samples/s... pretty good for 22 channels. Being able to log all 68 for every log, the plethora of information would be awesome... and overwhelming.

Its really hard to see why you'd need to look at 68 channels to debug/track an issue but yeah, if they offered 300 i'm sure ppl would ask to try to log all 300

[lawwailok]

yea last night i only "check" the timing correction, without individual cylinder and it showed 0, i was like WTF? hahahahahaha

[dzenno]

Originally Posted by lawwailok

yea last night i only "check" the timing correction, without individual cylinder and it showed 0, i was like WTF? hahahahahaha

it really should be a "happy" feeling NOT to have cylinder timing corrections lol