N54 335i: Can JB4 auto tune (Map 5) overwrite MHD octane flash?

IISevv · 09-22-2018, 12:41 AM

Bought a 2007 335i with full bolt ons and all the supporting mods: downpipes, stage 2 fuel it pump, etc. It’s running a JB4 with MHD on a 91 octane backend flash. My question is this: if I put some E50 in the tank, can I use the JB4 to auto tune for octane and overwrite the MHD 91 flash? The previous owner kept his tablet and tuning license and the K+dcan cable I ordered is defective so I’m not able to just flash E50 on the MHD side. I’m not sure which flash the DME defers to.

IISevv · 09-22-2018, 04:06 PM

Anyone?

LMB335IS · 09-22-2018, 05:01 PM

I haven't used a JB in forever but I don't think so. With the backend flash the JB4 just becomes an expensive boost controller. Fueling, timing, everything else is controlled by the BEF

IISevv · 09-22-2018, 05:06 PM

Quote:

Originally Posted by LMB335IS

I haven't used a JB in forever but I don't think so. With the backend flash the JB4 just becomes an expensive boost controller. Fueling, timing, everything else is controlled by the BEF

That’s what I figured. Thought maybe it would work if I turned off Back end flash mode from the JB4.

09-22-2018, 12:41 AM	#1
IISevv Private First Class 38 Rep 111 Posts Drives: 2007 335i FBO Join Date: Jul 2017 Location: Scottsdale, AZ iTrader: (0)	N54 335i: Can JB4 auto tune (Map 5) overwrite MHD octane flash? Bought a 2007 335i with full bolt ons and all the supporting mods: downpipes, stage 2 fuel it pump, etc. It’s running a JB4 with MHD on a 91 octane backend flash. My question is this: if I put some E50 in the tank, can I use the JB4 to auto tune for octane and overwrite the MHD 91 flash? The previous owner kept his tablet and tuning license and the K+dcan cable I ordered is defective so I’m not able to just flash E50 on the MHD side. I’m not sure which flash the DME defers to. Last edited by IISevv; 09-22-2018 at 12:50 AM..
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09-22-2018, 04:06 PM	#2
IISevv Private First Class 38 Rep 111 Posts Drives: 2007 335i FBO Join Date: Jul 2017 Location: Scottsdale, AZ iTrader: (0)	Anyone?
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09-22-2018, 05:01 PM	#3
LMB335IS Sua Sponte 1299 Rep 2,850 Posts Drives: 2013 LMB 335is Join Date: May 2008 Location: FOB FL iTrader: (21) Garage List 2013 BMW 335is [8.84]	I haven't used a JB in forever but I don't think so. With the backend flash the JB4 just becomes an expensive boost controller. Fueling, timing, everything else is controlled by the BEF __________________ 335is/DCT-M3 GTS software-M3 drivetrain-M3 GWS-KOMBI-DSC-SZL/MHD/BQ Tuning IG@ClustersandCoding
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