E90Post
 


GT Haus
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Interpreting V2 Max Boost



Reply
 
Thread Tools Search this Thread
      01-11-2008, 03:11 PM   #1
andrewflk
Private First Class
United_States
1
Rep
122
Posts

 
Drives: 2007 335i Sedan
Join Date: Mar 2007
Location: Maryland

iTrader: (3)

Interpreting V2 Max Boost

I’ve been searching the forum but I can’t find a clear answer on the following…

When I did a series of 2nd to 3rd gear data logs boost in 3rd gear read ~14.6psi gradually tapering down to ~14.0psi at 5500rpm with 90% settings. During all of these runs the 3rd gear pull started at 4200rpm. I’m at sea level, outside temp was 60F and I was able to duplicate these results several times.

In the V2 instructions to adjust the user torque table it states that the boost peak should steadily climb from ~10-12psi at 4500 and reach a peak at 5500. It also states the maximum not-to-exceed 15psi at 5500rpm. I have also seen other member’s posts with tapering curves (like Hokie hitting >15psi) and then others with rising boost curves as described in the V2 read me.

So is this tapering just a normal variance on my car? Is the rule 15psi at 5500rpm or just never exceed 15psi no matter what RPM?

By the way…the car feels awesome! I love the way V2 pulls and the fact that we have the ability to dial it in…I just want to see if I can adjust up a few more points.

This is an example boost log (Notice how I can’t keep traction in second gear):

Appreciate 0
      01-11-2008, 03:16 PM   #2
ThomasMartin
First Lieutenant
8
Rep
321
Posts

 
Drives: BMW 335i Coupe
Join Date: Jun 2007
Location: South Africa

iTrader: (0)

Quote:
Originally Posted by andrewflk View Post
I’ve been searching the forum but I can’t find a clear answer on the following…

When I did a series of 2nd to 3rd gear data logs boost in 3rd gear read ~14.6psi gradually tapering down to ~14.0psi at 5500rpm with 90% settings. During all of these runs the 3rd gear pull started at 4200rpm. I’m at sea level, outside temp was 60F and I was able to duplicate these results several times.

In the V2 instructions to adjust the user torque table it states that the boost peak should steadily climb from ~10-12psi at 4500 and reach a peak at 5500. It also states the maximum not-to-exceed 15psi at 5500rpm. I have also seen other member’s posts with tapering curves (like Hokie hitting >15psi) and then others with rising boost curves as described in the V2 read me.

So is this tapering just a normal variance on my car? Is the rule 15psi at 5500rpm or just never exceed 15psi no matter what RPM?

By the way…the car feels awesome! I love the way V2 pulls and the fact that we have the ability to dial it in…I just want to see if I can adjust up a few more points.

This is an example boost log (Notice how I can’t keep traction in second gear):

I Hate you guys at sea level with such flat torque curves so much air boost hardly drops
Appreciate 0
      01-11-2008, 03:29 PM   #3
PresaMat
Major
PresaMat's Avatar
United_States
17
Rep
1,170
Posts

 
Drives: 67 GT500,69 Boss 429, 335i
Join Date: Sep 2006
Location: Houston,TX

iTrader: (0)

Garage List
Quote:
Originally Posted by ThomasMartin View Post
I Hate you guys at sea level with such flat torque curves so much air boost hardly drops
Only problem is when racing NA cars... they are at full power too. Yall people up high might loose a little power but still crush the NA guys
__________________
-Mat

Tuned E92 335, Riss Racing downpipes! And hopefully over 400RWHP!!
Appreciate 0
      01-11-2008, 03:35 PM   #4
CanadianTSi
Second Lieutenant
CanadianTSi's Avatar
2
Rep
230
Posts

 
Drives: 97 Eagle Talon TSi
Join Date: Feb 2007
Location: Ontario, Canada

iTrader: (0)

Yes the Taper is normal.
Appreciate 0
      01-11-2008, 04:44 PM   #5
andrewflk
Private First Class
United_States
1
Rep
122
Posts

 
Drives: 2007 335i Sedan
Join Date: Mar 2007
Location: Maryland

iTrader: (3)

I agree that the data logs I posted look healthy. I’m just curious as to why the variance from one car to the next regarding inclining or declining curves, and should I adjust my user torque settings by the 5500rpm boost psi? Or just peak regardless the rpm?

Shiv, can you comment on this?
Appreciate 0
      01-11-2008, 04:52 PM   #6
CanadianTSi
Second Lieutenant
CanadianTSi's Avatar
2
Rep
230
Posts

 
Drives: 97 Eagle Talon TSi
Join Date: Feb 2007
Location: Ontario, Canada

iTrader: (0)

Quote:
Originally Posted by andrewflk View Post

In the V2 instructions to adjust the user torque table it states that the boost peak should steadily climb from ~10-12psi at 4500 and reach a peak at 5500. It also states the maximum not-to-exceed 15psi at 5500rpm.
I would follow the Instructions.
Appreciate 0
      01-11-2008, 04:52 PM   #7
shiv@vishnu
Tuner
United_States
702
Rep
17,616
Posts

 
Drives: X1, 335i
Join Date: Sep 2006
Location: SF Bay, CA

iTrader: (0)

Quote:
Originally Posted by andrewflk View Post
I agree that the data logs I posted look healthy. I’m just curious as to why the variance from one car to the next regarding inclining or declining curves, and should I adjust my user torque settings by the 5500rpm boost psi? Or just peak regardless the rpm?

Shiv, can you comment on this?
I'd say the variance has 80% to do with differences in testing conditions and 20% to do with car to car differences. If you datalog your car on two different days, you'll get different results. Stock or modified. The variance does tend to increase the more power you make though. This is normal.

Shiv
Appreciate 0
      01-11-2008, 05:26 PM   #8
andrewflk
Private First Class
United_States
1
Rep
122
Posts

 
Drives: 2007 335i Sedan
Join Date: Mar 2007
Location: Maryland

iTrader: (3)

Thanks Shiv…Of course I was ultimately trying to see if I can increase my user torque settings but it actually sounds like there are so many variables that I should continue to do some more testing…Darn, I hate doing those full throttle mad acceleration tests again and again.
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 01:42 AM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST