Cobb AccessPORT data log

Lambobimmer · 01-29-2011, 05:16 PM

I was doing some spirited driving this afternoon and playing around with the AccessPORT data log. The only question that I have is about the boost. The Accessport will show current boost and it will also show the hightest boost. I saw a high of 21psi. I thought that the highest boost that we would see running the 93 map would be around 15psi.

Is this normal?

I am sure that it only hit 21psi for a milisecond but I don't want to break anything.

ESC OFF · 01-29-2011, 05:39 PM

I've been watching my boost gauge and so far after installing AP my max boost has been 16.5 on the 93 Octane Map, it was still spooling however I ran out of room....I hate traffic! 21 seems high, but ??

Lambobimmer · 01-29-2011, 05:55 PM

At WOT it was around 12 to 14 in the lower RPM's and the upper RPM's. I think that it hit the highest boost around 5k to 6k. Let me now what boost number your car hits when you are able to open it up.

Clap135 · 01-29-2011, 06:41 PM

Its a shift spike, nothing to worry about.

1trip5 · 01-29-2011, 07:37 PM

what you are experiencing is a boost spike after throttle release. the inlet manifold pressure goes negative (vacuum), spikes for a millisecond, then returns to 0 psi. Under constant throttle, the boost should be right around 14 psi at lower rpms and slowly taper down to 12-13 as you near redline. This is the 93 octane map we are talking about, correct?

Edit:

Do a datalog with the Stg 0 map and see if there are spikes above 8psi. I'm pretty sure there will be.

Lambobimmer · 01-29-2011, 09:10 PM

Quote:

Originally Posted by 1trip5

what you are experiencing is a boost spike after throttle release. the inlet manifold pressure goes negative (vacuum), spikes for a millisecond, then returns to 0 psi. Under constant throttle, the boost should be right around 14 psi at lower rpms and slowly taper down to 12-13 as you near redline. This is the 93 octane map we are talking about, correct?

Edit:

Do a datalog with the Stg 0 map and see if there are spikes above 8psi. I'm pretty sure there will be.

That makes sense. I am sure that is what it is. Maybe Cobb will chime in.

escobar929 · 01-30-2011, 09:10 AM

sounds like a boost spike to me

ESC OFF · 01-30-2011, 04:46 PM

Quote:

Originally Posted by lamboworld

At WOT it was around 12 to 14 in the lower RPM's and the upper RPM's. I think that it hit the highest boost around 5k to 6k. Let me now what boost number your car hits when you are able to open it up.

I had the car out on some country roads today, nothing better than dry roads and cold weather!!....After numerous runs from standstill, from 5-10 mph and while running through the gears my max boost has leveled off between 13.8 and 14.2 with 14.0 being pretty consistent. I had a high boost of 16.5 the other day but not today, I assume that was shift related.

Lambobimmer · 01-30-2011, 07:15 PM

Quote:

Originally Posted by ESC OFF

I had the car out on some country roads today, nothing better than dry roads and cold weather!!....After numerous runs from standstill, from 5-10 mph and while running through the gears my max boost has leveled off between 13.8 and 14.2 with 14.0 being pretty consistent. I had a high boost of 16.5 the other day but not today, I assume that was shift related.

At WOT I am around 14 to 15. The spikes that I am seeing are between shifts as was mentioned before.

Amazing how fast this car is with a good tune.

ESC OFF · 01-31-2011, 09:43 AM

Quote:

Originally Posted by lamboworld

At WOT I am around 14 to 15. The spikes that I am seeing are between shifts as was mentioned before.

Amazing how fast this car is with a good tune.

Looks like we're getting pretty similar numbers, I agree on the fast comment, the change is amazing...enjoy!

RX-BMW · 01-31-2011, 09:47 AM

I'm in love with my car now. COBB ftw

ModBargainsTech · 01-31-2011, 10:49 AM

+1 on boost spike

_dopehead_ · 01-31-2011, 01:43 PM

i can't wait for COBB to do the Euro version.....please let it be soon :-)

Makkasteez · 01-31-2011, 07:12 PM

i want my COBB! C:

COBB Tuning · 02-02-2011, 02:53 PM

A few questions for the OP. What gear were you in? Were you driving up a hill in high gear or did you floor it in high gear? Is it very very cold outside? Can you give me a general idea of what was going on? Do you have any logs that you can post? Sometimes lugging the engine from low rpm in top gear can cause lots of load that will increase boost beyond what is called for in the map. So if you are driving a long in 5th at 3,000rpm and lay into the throttle, that can put a lot of load on the engine and boost can spike. Dropping a gear helps alleviate this a bit.

Thank you for your help and I look forward to your feedback.

Travis
COBB Tuning

Yuchi · 08-12-2011, 12:39 AM

Quote:

Originally Posted by COBB Tuning

A few questions for the OP. What gear were you in? Were you driving up a hill in high gear or did you floor it in high gear? Is it very very cold outside? Can you give me a general idea of what was going on? Do you have any logs that you can post? Sometimes lugging the engine from low rpm in top gear can cause lots of load that will increase boost beyond what is called for in the map. So if you are driving a long in 5th at 3,000rpm and lay into the throttle, that can put a lot of load on the engine and boost can spike. Dropping a gear helps alleviate this a bit.

Thank you for your help and I look forward to your feedback.

Travis
COBB Tuning

I definitely need to log mine. Because at idle i'm at 14.5, 3/4 throttle I'm at 29......??!?!

01-29-2011, 05:16 PM	#1
Lambobimmer Major 292 Rep 1,473 Posts Drives: 2022 X3 M40i, 2018 TTRS Join Date: Jan 2010 Location: Tarheel iTrader: (14)	Cobb AccessPORT data log - BOOST I was doing some spirited driving this afternoon and playing around with the AccessPORT data log. The only question that I have is about the boost. The Accessport will show current boost and it will also show the hightest boost. I saw a high of 21psi. I thought that the highest boost that we would see running the 93 map would be around 15psi. Is this normal? I am sure that it only hit 21psi for a milisecond but I don't want to break anything. Last edited by Lambobimmer; 01-29-2011 at 05:24 PM..
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01-29-2011, 05:39 PM	#2
ESC OFF Major 40 Rep 1,058 Posts Drives: 1M, CaymanS, 914, 500 Abarth Join Date: Oct 2009 Location: Chicago iTrader: (0)	I've been watching my boost gauge and so far after installing AP my max boost has been 16.5 on the 93 Octane Map, it was still spooling however I ran out of room....I hate traffic! 21 seems high, but ?? __________________ The faster you go, the better it feels
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01-29-2011, 05:55 PM	#3
Lambobimmer Major 292 Rep 1,473 Posts Drives: 2022 X3 M40i, 2018 TTRS Join Date: Jan 2010 Location: Tarheel iTrader: (14)	At WOT it was around 12 to 14 in the lower RPM's and the upper RPM's. I think that it hit the highest boost around 5k to 6k. Let me now what boost number your car hits when you are able to open it up.
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01-29-2011, 06:41 PM	#4
Clap135 Brigadier General 102 Rep 3,460 Posts Drives: 2009 N54 Join Date: Jul 2009 Location: Sticky's Mom House iTrader: (1)	Its a shift spike, nothing to worry about.
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01-29-2011, 07:37 PM	#5
1trip5 Captain 48 Rep 627 Posts Drives: Emme Tres Join Date: Aug 2010 Location: Dallas iTrader: (3) Garage List 2002 BMW M3 [0.00]	what you are experiencing is a boost spike after throttle release. the inlet manifold pressure goes negative (vacuum), spikes for a millisecond, then returns to 0 psi. Under constant throttle, the boost should be right around 14 psi at lower rpms and slowly taper down to 12-13 as you near redline. This is the 93 octane map we are talking about, correct? Edit: Do a datalog with the Stg 0 map and see if there are spikes above 8psi. I'm pretty sure there will be. __________________ E46 M3
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01-30-2011, 09:10 AM	#7
escobar929 Brigadier General 154 Rep 4,528 Posts Drives: M2 CS Join Date: Aug 2009 Location: Hollywood, FL iTrader: (14) Garage List 2020 M2 CS [10.00] 2020 M240i [0.00]	sounds like a boost spike to me
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01-31-2011, 09:47 AM	#11
RX-BMW Second Lieutenant 18 Rep 268 Posts Drives: 2009 135i sport package 6AT Join Date: Aug 2010 Location: St. Louis iTrader: (0)	I'm in love with my car now. COBB ftw
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01-31-2011, 10:49 AM	#12
ModBargainsTech Private 0 Rep 79 Posts Drives: E92 335i/E90 335i/ E82 135i/ Join Date: Jan 2011 Location: La Habra, Ca iTrader: (0)	+1 on boost spike
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01-31-2011, 01:43 PM	#13
_dopehead_ Private 6 Rep 75 Posts Drives: BMW 135i AW 2008 Join Date: Aug 2009 Location: Denmark iTrader: (0)	i can't wait for COBB to do the Euro version.....please let it be soon :-)
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01-31-2011, 07:12 PM	#14
Makkasteez 1nt3n5ity 39 Rep 390 Posts Drives: 08' 135i Join Date: Jun 2009 Location: San Francisco, CA iTrader: (1)	i want my COBB! C:
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02-02-2011, 02:53 PM	#15
COBB Tuning Major 233 Rep 1,051 Posts Drives: 335i Join Date: Dec 2010 Location: Austin, TX iTrader: (0)	A few questions for the OP. What gear were you in? Were you driving up a hill in high gear or did you floor it in high gear? Is it very very cold outside? Can you give me a general idea of what was going on? Do you have any logs that you can post? Sometimes lugging the engine from low rpm in top gear can cause lots of load that will increase boost beyond what is called for in the map. So if you are driving a long in 5th at 3,000rpm and lay into the throttle, that can put a lot of load on the engine and boost can spike. Dropping a gear helps alleviate this a bit. Thank you for your help and I look forward to your feedback. Travis COBB Tuning
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