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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Cobb AP Boost Too High



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      05-06-2011, 04:25 PM   #45
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Quote:
Originally Posted by E90Vader View Post
Hey guys, can I confirm that for safety I should ONLY be running 91 octane map with my AFe DCI? I wont lie.. I am inlove with 93 octane map, it pulls so much harder up top compared to 91 octane. However, for the 2 - 3mph i'm averaging less, and if it puts to much strain on the engine for long term use I dont think it will be worth it...

COBB Can you please comment?



In addition, if I could " ONLY " buy either an FMIC, or a Catless Downpipe.
What mod should I purchase to be able to safely run 93 octane map? Downpipe because it is less restrictive? Or FMIC because it keeps the engine temps cooler?

Again this is if I only could purchase either or.

Thanks guys
Cobb had another thread the other day where they did some testing and stated 93 oct map on a stock car would be fine.
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      05-06-2011, 04:51 PM   #46
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Quote:
Originally Posted by E90Vader View Post
Hey guys, can I confirm that for safety I should ONLY be running 91 octane map with my AFe DCI? I wont lie.. I am inlove with 93 octane map, it pulls so much harder up top compared to 91 octane. However, for the 2 - 3mph i'm averaging less, and if it puts to much strain on the engine for long term use I dont think it will be worth it...

COBB Can you please comment?
Run logs of 3rd or 4th gear runs and review. You want to review the AFRs, Boost, and timing. During a full gear pull in either gear, ensure that AFRS sit around 11.8 - 12, boost doesnt sustain greater than 15psi for more than 500 rpms and timing doesnt decrease by greater than 1 degree throughout the pull. These figures will jump all over the place when letting off the gas, flooring the gas, when shifting and when traction control goes off.

If you see your logs outside of these expecations, then graph them and post and let others comment.

Note that psi's 15 can be safe, but if you are seeing sustained boost that high, posts it can't hurt. Note, my procede auto tuned to greater than 15psi and still ran fine.
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      05-06-2011, 05:05 PM   #47
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I was thinking about boost when comparing FBO and non-DP car... Clap versus others. Clearly the boost is lower for Clap. And the explanation is that FBO flows more volume and less boost needed to hit load target.... BUT

DME is calculating load from MAP, temperature, and RPM is my understanding. DME would not know if VE was raising due to hardware. If these are the only calcs then boost should be similar.

Curious...
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      05-06-2011, 05:28 PM   #48
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Im sticking with 91 now, max psi is 12 to 13 psi. Temps have been in the 80's. Car doesnt run hot though with multiple WOT runs.

Thanks

Quote:
Originally Posted by Rob@Cobb View Post
Hey Everyone,

Running 16 psi in the mid-range is well with in the ability of the stock turbos and stock exhaust. We're found the stock exhaust to be pretty good so far. I would suggest a good FMIC before an exhaust.

On your log, the 18 PSI spike was due to the throttle closure given the sensor is outside of the throttle body. This means the cylinders were not seeing the 18 psi. As far as the 21 psi spike, we use two different monitors to gather a relative boost reading. The two monitors get out of sync here and there causing what looks like a big spike.

What kind of ambient temps have you been seeing?

Cheers,
Rob
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      05-06-2011, 05:45 PM   #49
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Which option do I click for my AP unit when recording logs?

As far as pings and nocks, I'm not sure what they sound like but the engine sounds super healthy with 93 octane map.
I have also been driving quite hard lately and I never run over 120 degrees.
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      05-13-2011, 02:54 PM   #50
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Quote:
Originally Posted by E90Vader View Post
Which option do I click for my AP unit when recording logs?

As far as pings and nocks, I'm not sure what they sound like but the engine sounds super healthy with 93 octane map.
I have also been driving quite hard lately and I never run over 120 degrees.
Don't know if you're asking how to log?
If that's the case you can find it here:
http://www.1addicts.com/forums/showthread.php?t=524144
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