JB4 E85 Boost Range

PTek Will · 08-06-2013, 06:58 PM

Hey Guys,

The first time I tried E85 (about 30%) mixed with 91 on map 5 I hit 17 psi consistently. Now it doesn't even reach 15 psi with the same mixture. It hovers right below the 3/4 line (14.5psi?), whereas before it was about 2 ticks above 3/4. Any ideas why?

BoostAddict · 08-06-2013, 08:03 PM

Map 5 auto tunes to conditions. Perhaps the weather was cooler last time you tried, your fuel quality was higher, or maybe it just hadn't fully adapted yet. A number of outside factors could do it.

Mike@N54Tuning.com · 08-07-2013, 11:16 AM

You'd want to do a datalog to see what you're actually targeting. If the JB4 detects knock, higher temperatures, running lean, or other issues, it will lower it's target. If the target is high but boost is well below it, then that indicates another range of issues with the car. Boost leak, wastegate issue, vacuum line loose, etc.

Mike

BEAR-AvHistory · 08-07-2013, 11:20 AM

Also E85 is not exactly E85. The blend changes by state & month. You can do a search on the EPA site to get the blends & months for your state.

08-06-2013, 06:58 PM	#1
PTek Will Second Lieutenant 18 Rep 268 Posts Drives: 335i coupe Join Date: Jun 2012 Location: san jose iTrader: (0)	JB4 E85 Boost Range Hey Guys, The first time I tried E85 (about 30%) mixed with 91 on map 5 I hit 17 psi consistently. Now it doesn't even reach 15 psi with the same mixture. It hovers right below the 3/4 line (14.5psi?), whereas before it was about 2 ticks above 3/4. Any ideas why?
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08-06-2013, 08:03 PM	#2
BoostAddict Banned 48 Rep 932 Posts Drives: SGM 335i Join Date: Jan 2010 Location: Boynton Beach, FL iTrader: (4)	Map 5 auto tunes to conditions. Perhaps the weather was cooler last time you tried, your fuel quality was higher, or maybe it just hadn't fully adapted yet. A number of outside factors could do it.
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08-07-2013, 11:16 AM	#3
Mike@N54Tuning.com Joint Chiefs of Staff 4908 Rep 115,980 Posts Drives: 2007 335i, 2015 M3 Join Date: Dec 2008 Location: N54tuning.com iTrader: (89)	You'd want to do a datalog to see what you're actually targeting. If the JB4 detects knock, higher temperatures, running lean, or other issues, it will lower it's target. If the target is high but boost is well below it, then that indicates another range of issues with the car. Boost leak, wastegate issue, vacuum line loose, etc. Mike
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08-07-2013, 11:20 AM	#4
BEAR-AvHistory 2020 Z4 M40i - 2022 M4C Convt 3126 Rep 5,264 Posts Drives: 2020 Z4 M40i - 2022 M4C Convrt Join Date: Jun 2011 Location: Raleigh, NC - OIB, NC iTrader: (0) Garage List 1965 COBRA (FFR rep ... [8.57] 2023 Jeep Wrangler ... [9.50] 2009 Yamaha V-Star [0.00] Cars 2-BMW, 2-FORD, ... [0.00] 2023 Ford Expeditio ... [0.00] 2020 Z4 M40i [10.00] 2022 BMW M4C [7.25] 1998 FORD Ranger 4X4 [0.00]	Also E85 is not exactly E85. The blend changes by state & month. You can do a search on the EPA site to get the blends & months for your state. __________________ Kevin Dravit Gray, Black Leather, Moonlight Roof, Red Calipers 2022 M4C - 2020 Z4 M40i - 2023 FORD Expedition XLT Max 4X4 400BHP - 2009 V-Star - 1998 Ranger 4X4 5MT - 1965 Cobra (R) 5MT - 2023 Jeep Wrangler Sport S 6MT
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