[Deebo]

Hey guys,

Just a quick question, I'm planning on switching over to a Cobb unit from my JB4 with the BMS E85 flash loaded via BB software. Do I need to flash my car back to stock before installing the Cobb for the first time? I have no functional need to bring my car back to stock, out of warranty and such. Maybe need the stock map so PTF can work their magic on it? Should I uninstall the JB4 before doing so? Thanks for the help.

[11SEC]

You can do a Cobb/JB4 stack.

You might as well run the BMS backend flash until you get a protune because the OTS maps are garbage in comparison.

[Torgus]

Originally Posted by 11SEC

You can do a Cobb/JB4 stack.

You might as well run the BMS backend flash until you get a protune because the OTS maps are garbage in comparison.

This.

[Deebo]

So can someone explain the benefits of stacking? I would think 18.5 psi is the same regardless of tuning device. I'm looking to switch so I can easily switch between maps for 91 and E60, since I don't always have access to ethanol and the car runs like poo on straight 91. It's easy to switch maps on the JB4, but the fuel scalar can't be changed and that's what causes my issues. Hence the Cobb so I can switch back and for between maps in around a minute when I change the fuel I'm using. I was going to switch to cobb standalone flashes unless someone can explain the benefit of stacking. I've heard the PTF tunes are smoother and less jumpy at low-mid rpms as well which is something that's bothered me in the past with my current setup.

[11SEC]

Use the Cobb to run your flashes, i.e BMS E85 Backend, Pump Gas, PTF, whatever.

Use the JB4 for your maps in terms of boost control, safety features, gauges, etc.

Basically the JB4 only controls boost and cool features. Fuel and timing is all done through the flashes you load with your cobb.

Done.

[Deebo]

Ok, so I found the maps I need on N54 tech. Do I need to get my car re-flashed to stock before flashing with other maps via the Cobb? Settings on the Jb4 while flashing via Cobb?

[GoldRush24]

Originally Posted by 11SEC

Use the Cobb to run your flashes, i.e BMS E85 Backend, Pump Gas, PTF, whatever.

Use the JB4 for your maps in terms of boost control, safety features, gauges, etc.

Basically the JB4 only controls boost and cool features. Fuel and timing is all done through the flashes you load with your cobb.

Done.

So I'm a noob and I've only recently begun digging into the plethora of options this platform has to offer. Can you explain the bolded comment a little more? What boost control features does the JB4 have that can't be accomplished with Cobb or PTF? I have JB4 right now but I just set otto map 5 and left it alone. Thanks for the clarification, I'll try and do some searching on the topic now…..

[Torgus]

Originally Posted by Deebo

So can someone explain the benefits of stacking? I would think 18.5 psi is the same regardless of tuning device. I'm looking to switch so I can easily switch between maps for 91 and E60, since I don't always have access to ethanol and the car runs like poo on straight 91. It's easy to switch maps on the JB4, but the fuel scalar can't be changed and that's what causes my issues. Hence the Cobb so I can switch back and for between maps in around a minute when I change the fuel I'm using. I was going to switch to cobb standalone flashes unless someone can explain the benefit of stacking. I've heard the PTF tunes are smoother and less jumpy at low-mid rpms as well which is something that's bothered me in the past with my current setup.

Hi regarding the flash tune vs. just JB4: "For pump gas it basically allows them to program in boost curves that are a lot fatter down low as there is no longer a fuel trim limitation at lower RPM. It's also easier to reshape the advance curve on the flash side than using CPS which they never felt comfortable doing more than 4-5 degrees with. The VANOS changes, speed limiter delete, and some other tuning tricks also make it a worthwhile way to load."