Turn off pbx for high altitude driving?

BAMxi · 05-06-2011, 11:08 AM

So the wife and I are going to be cruising from KC to Colorado this summer, and I started wondering how the higher altitude of mountain roads might affect the car's performance. Do you think I should turn off (or change the map to throttle mapping only) when we get up into the mountains? I wasn't sure since the pbx alters the oxygen levels, and obviously there's less o2 to be had up there. Let me know what you think. Thanks!

AlpineSwift · 05-06-2011, 04:10 PM

Doesn't matter. We run them up here obviously. Your car will adjust to the altitude with or without a tune.

fdriller9 · 05-06-2011, 05:15 PM

PBX is a piggy back "tune." It alters the ECU reading to the engine. And like AlpineSwift said, our cars adapt to different conditions.

So what the PBX does is based off of what your car's ECU is sending to the engine.

You'll be fine.

Tom K. · 05-07-2011, 04:23 PM

Figure on approx. 3% less power per 1,000 ft. of altitute. So if you are heading through any 11,000 ft. passes, your 328ix peak hp should be around 155. Of course, if you park the car & try to run for a few hundred yards at that altitude, you'll soon understand why.

Both my Z4 and 128i adapted to high altitudes with no problems. My lungs were another matter entirely!

Tom

BAMxi · 05-09-2011, 09:07 AM

Haha thanks for the replies, everybody. Yeah I figured it was nothing to worry about, but better to ask than get stranded on a mountain road somewhere!

05-06-2011, 11:08 AM	#1
BAMxi Lieutenant 30 Rep 487 Posts Drives: E90 328xi Join Date: Aug 2010 Location: Columbia, MO iTrader: (3) Garage List 2007 328xi [10.00]	Turn off pbx for high altitude driving? So the wife and I are going to be cruising from KC to Colorado this summer, and I started wondering how the higher altitude of mountain roads might affect the car's performance. Do you think I should turn off (or change the map to throttle mapping only) when we get up into the mountains? I wasn't sure since the pbx alters the oxygen levels, and obviously there's less o2 to be had up there. Let me know what you think. Thanks! __________________ Eibach Pro Kit \| 19" Avant Garde M341 \| BMS PBX
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05-06-2011, 04:10 PM	#2
AlpineSwift Colonel 77 Rep 2,114 Posts Drives: 2008 335Xi Coupé Join Date: Feb 2010 Location: Castle Rock, CO iTrader: (3)	Doesn't matter. We run them up here obviously. Your car will adjust to the altitude with or without a tune. __________________ E92 '08 335Xi 6AT - Cobb AP3 Tuned by MAC Autosport, Original Prototype Xi DOCRace 6266 Single Turbo Swap, VRSF CP w/Synapse BOV, VRSF 7" FMIC, BMS Cowl, H&R Coilovers, Renn Motorsport RS-51's, Stoptech Stage 2 Slotted, xHP Stage 3, Earl's Racing Oil Cooler, Turner Boost Gauge, M3 Lip Spoiler. Standing Mile Record Holder for Xi over a mile high: 168.2MPH @ 5512'; The Colorado Mile hosted by The US Mile.
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05-06-2011, 05:15 PM	#3
fdriller9 Banned 252 Rep 7,089 Posts Drives: '06 AW 330xi Join Date: Mar 2009 Location: North Jersey/Philly/NYC iTrader: (4) Garage List 2006 330xi [6.44]	PBX is a piggy back "tune." It alters the ECU reading to the engine. And like AlpineSwift said, our cars adapt to different conditions. So what the PBX does is based off of what your car's ECU is sending to the engine. You'll be fine.
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05-07-2011, 04:23 PM	#4
Tom K. Major General 124 Rep 5,627 Posts Drives: '07 328iT, '13 Boxster Join Date: Mar 2008 Location: Maryland iTrader: (0)	Figure on approx. 3% less power per 1,000 ft. of altitute. So if you are heading through any 11,000 ft. passes, your 328ix peak hp should be around 155. Of course, if you park the car & try to run for a few hundred yards at that altitude, you'll soon understand why. Both my Z4 and 128i adapted to high altitudes with no problems. My lungs were another matter entirely! Tom
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05-09-2011, 09:07 AM	#5
BAMxi Lieutenant 30 Rep 487 Posts Drives: E90 328xi Join Date: Aug 2010 Location: Columbia, MO iTrader: (3) Garage List 2007 328xi [10.00]	Haha thanks for the replies, everybody. Yeah I figured it was nothing to worry about, but better to ask than get stranded on a mountain road somewhere! __________________ Eibach Pro Kit \| 19" Avant Garde M341 \| BMS PBX
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