[henrywort2000]

Hi everyone, i have tried to find the answer to this question for ages and cannot find a definitive answer online, so apologies if this is a stupid question.

With the JB4 alone it is possible to switch maps on the fly using the steering wheel controls, so when using a BEF with MHD i understand it us possible to change some smaller parameters on the fly, however is it possible to switch the entire map on the fly such as switching to map 8 once you get onto the motorway?

[dmckmc]

Yes, JB4 maps can be changed while driving using the steering wheel controls or JB4 mobile app. A Back End Flash (BEF) is a dme/ecu overwrite and requires MHD or BB and a OBD2 port connecton and several minutes (not done while driving).

JB4 maps (0-8) are piggybacked or fed into the dme/ecu. Each map alters information or input signals fed to the dme/ecu to change the cars output or performance.

A BEF actually changes or reprograms the dme/ecu. Because piggyback style tuners have limits to what and how much they can change, it can be beneficial to alter or reprogram actual dme/ecu programming to further enhance engine performance.

JB4 maps and BEF can all work together. For instance I've added the e85 BEF to my car and can use any JB4 map (0-8) with the e85 BEF. Use logging to help determine which map ultimately works best for your car and situation.

[henrywort2000]

Ok thank you, how long roughly does it take to rewrite between maps on the DME when using a BEF? Is it the same sort of time to rewrite as using MHD only?

[dmckmc]

It takes just a few minutes for MHD to load/write a different BEF to the dme.