Map 3 at altitude

hideNseek · 03-05-2015, 11:55 PM

I live at high elevation (4,600 ft). The highest normal octane here is 91, though there is a station nearby that offers 100. I know that at higher altitudes you can run a lower octane rating because of the thinner air. My question is, with my JB4, would I be able to safely run map 3 on 91 because of the higher altitude, or is it still a bad idea to run map 3 on anything less than 93 regardless of elevation?

bmw0bsession · 03-06-2015, 09:51 AM

Quote:

Originally Posted by hideNseek

I live at high elevation (4,600 ft). The highest normal octane here is 91, though there is a station nearby that offers 100. I know that at higher altitudes you can run a lower octane rating because of the thinner air. My question is, with my JB4, would I be able to safely run map 3 on 91 because of the higher altitude, or is it still a bad idea to run map 3 on anything less than 93 regardless of elevation?

Map 3 is a Meth map, are you running meth? If so you should be fine, I have ran 91 Octane with meth at 4500ft before with no issues

hideNseek · 03-06-2015, 08:25 PM

Oops, sorry 'bout that. I was half asleep when I posted this. I meant map 2.

AB M2C · 03-07-2015, 09:20 AM

4600 feet is not really high elevation... sorry. There is not a significant O2 drop off until about 7000 feet, then oxygen levels start to drop off very fast and combustion greatly loses efficiency. Personally I wouldn't risk a 93 octane only map at that low of elevation (nor any elevation for that matter I would always be worried about it when driving hard). Stick with the 91 map.

mike@x-ph.com · 03-07-2015, 11:00 AM

Quote:

Originally Posted by hideNseek

I live at high elevation (4,600 ft). The highest normal octane here is 91, though there is a station nearby that offers 100. I know that at higher altitudes you can run a lower octane rating because of the thinner air. My question is, with my JB4, would I be able to safely run map 3 on 91 because of the higher altitude, or is it still a bad idea to run map 3 on anything less than 93 regardless of elevation?

Since you have catless DP, you should be fine running that map.
If you are worried just do a datalog and post it .

03-05-2015, 11:55 PM	#1
hideNseek New Member 7 Rep 29 Posts Drives: '12 135i Join Date: May 2013 Location: Sierra Vista, AZ iTrader: (0)	Map 3 at altitude I live at high elevation (4,600 ft). The highest normal octane here is 91, though there is a station nearby that offers 100. I know that at higher altitudes you can run a lower octane rating because of the thinner air. My question is, with my JB4, would I be able to safely run map 3 on 91 because of the higher altitude, or is it still a bad idea to run map 3 on anything less than 93 regardless of elevation? __________________ 2012 135i DCT. JB4 l BMS Intake l VRSF Downpipe l Berk Street Axle-Back l BMS Catch Can l APEX EC-7 wheels. 13K miles.
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03-06-2015, 08:25 PM	#3
hideNseek New Member 7 Rep 29 Posts Drives: '12 135i Join Date: May 2013 Location: Sierra Vista, AZ iTrader: (0)	Oops, sorry 'bout that. I was half asleep when I posted this. I meant map 2.
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03-07-2015, 09:20 AM	#4
AB M2C First Lieutenant 74 Rep 312 Posts Drives: 2019 M2C Hockenheim Silver Join Date: Aug 2012 Location: Colorado iTrader: (1)	4600 feet is not really high elevation... sorry. There is not a significant O2 drop off until about 7000 feet, then oxygen levels start to drop off very fast and combustion greatly loses efficiency. Personally I wouldn't risk a 93 octane only map at that low of elevation (nor any elevation for that matter I would always be worried about it when driving hard). Stick with the 91 map. __________________ Current -- 2019 M2C MT Sold -- 2009 E82 135i MT Widebody Track Car Sold -- 1989 E30 325i MT Showcar Sold -- 2005 E46 M3 MT
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