[micvite]

Anyone else take their cars towards the electronically limited speed? I've noticed my car has easily 22-24 lbs of boost in 1st and 2nd, drops to around 17-19 in third and 4-5th towards redline I was maybe around 12-14, 6th towards redline I was looking at like 10 lbs. Is this normal? Honestly took the f90 longer to get to 170 than my camaro with 460 hp did... and by 180 was almost struggling... 70 degrees outside and wasn't pushing the car too hard prior so definitely not heat soaked or anything. Coolant was around 170-180 (drops when you floor it) and oil around 200. This is all based on the in car boost gauge so not perfectly accurate as far as readings go (you have 0 15 and 30 so it's guesstimates in-between those values) but still when it's reading under 15 at WOT I'd say somethings not quite right...

[m5_mbb7]

Yeah mine doesn’t do that, it keeps full boost up to 193

[micvite]

Originally Posted by m5_mbb7

Yeah mine doesn’t do that, it keeps full boost up to 193

Interesting, mine definitely drops off towards redline, comes back a bit after the shift and immediately drops off again... it's just gets lower and lower, are you stock? Not even sure how I'd bring this up to bmw... so hey I was doing 180 and noticed my boost was super low... it'll be one of those "customer states" videos lol. Like how would they even verify that kind of fault since I know they won't test drive the car over 80 and it's more or less fine until 100...

[AHall]

Originally Posted by micvite

Interesting, mine definitely drops off towards redline, comes back a bit after the shift and immediately drops off again... it's just gets lower and lower, are you stock? Not even sure how I'd bring this up to bmw... so hey I was doing 180 and noticed my boost was super low... it'll be one of those "customer states" videos lol. Like how would they even verify that kind of fault since I know they won't test drive the car over 80 and it's more or less fine until 100...

I assume you were on a track and not a public road so they should not have a problem with you going 180 under those circumstances. You stated the boost drops off in 3rd and 4th gear. They should be able to verify that. Are you past the break in service?

[pbonsalb]

I’d be more curious why the boost is dropping. Seems like an indication something is wrong. Buy a JB4 for logging even if you don’t want to use the piggyback tune features.

[micvite]

Originally Posted by AHall

I assume you was on a track and not a public road so they should not have a problem with you going 180 under those circumstances. You stated the boost drops off in 3rd and 4th gear. They should be able to verify that. Are you past the break in service?

It's not that anyone has a problem, just not sure how they'd verify complaint since boost only drops off towards redline in 3rd and 4th or rather at higher speeds. And I know they won't take the car that high.

And yes I'm at 3k miles now, did break in just under 1200 last week or so.

[pbonsalb]

My car is tuned and gains boost or stays pretty steady (drop is slight if any) to redline in 3rd and 4th and 5th according to my data logs. For example, one log shows 5th gear, 6750 rpm, 145 mph, 22 psi.

That is what impresses me so much about this car - the way it keeps pulling at high speeds — over 100 (fastest I have been so far is an indicated 164).

[micvite]

Originally Posted by pbonsalb

My car is tuned and gains boost or stays pretty steady (drop is slight if any) to redline in 3rd and 4th and 5th according to my data logs. For example, one log shows 5th gear, 6750 rpm, 145 mph, 22 psi.

That is what impresses me so much about this car - the way it keeps pulling at high speeds — over 100 (fastest I have been so far is an indicated 164).

Yeah I'm dropping significantly towards redline in pretty much all gears... just a couple of screenshots from the video since it's a bit wobbly to show what I'm seeing and honestly feeling too. For 5th gear I don't even hit the peak boost that I had in 4th, it goes up a bit and then just drops right down again with the rpms rising, once I hit 6th gear it goes almost to the peak I had in 4th and then drops as rpms rise again, seems per the video and still frames as soon as I hit 6k rpm it starts dropping. Happens pretty much every time, rarely it doesn't do it. Not sure if that's just how the tune is stock or If my car has an actual issue lol....
https://youtube.com/shorts/NhQm2PNke6s?feature=share

https://youtube.com/shorts/NhQm2PNke6s?feature=share

[onfireX5]

Originally Posted by micvite

Yeah I'm dropping significantly towards redline in pretty much all gears... just a couple of screenshots from the video since it's a bit wobbly to show what I'm seeing and honestly feeling too. For 5th gear I don't even hit the peak boost that I had in 4th, it goes up a bit and then just drops right down again with the rpms rising, once I hit 6th gear it goes almost to the peak I had in 4th and then drops as rpms rise again, seems per the video and still frames as soon as I hit 6k rpm it starts dropping. Happens pretty much every time, rarely it doesn't do it. Not sure if that's just how the tune is stock or If my car has an actual issue lol....
https://youtube.com/shorts/NhQm2PNke6s?feature=share

https://youtube.com/shorts/NhQm2PNke6s?feature=share

You need to log boost vs rpm with a OBD2 scanner and app like DashCommand.

The factory gage is not very accurate based on our logs vs gage.

[HelloM8s]

Originally Posted by micvite

Anyone else take their cars towards the electronically limited speed? I've noticed my car has easily 22-24 lbs of boost in 1st and 2nd, drops to around 17-19 in third and 4-5th towards redline I was maybe around 12-14, 6th towards redline I was looking at like 10 lbs. Is this normal? Honestly took the f90 longer to get to 170 than my camaro with 460 hp did... and by 180 was almost struggling... 70 degrees outside and wasn't pushing the car too hard prior so definitely not heat soaked or anything. Coolant was around 170-180 (drops when you floor it) and oil around 200. This is all based on the in car boost gauge so not perfectly accurate as far as readings go (you have 0 15 and 30 so it's guesstimates in-between those values) but still when it's reading under 15 at WOT I'd say somethings not quite right...

Did you ever figure this out? I have an M8 GC comp doing the same exact thing. 1-3rd seem okay, 4th higher RPM’s boost starts dropping off. 5th for sure is now between 16-17. I logged it using JB4 and scan tool and it’s confirmed. Even on Map 0

I got new plugs and dinan coil packs and it didn’t help.