Have cobb may go JB4

[RnmEvo9]

Well I bit the bullet and will be trying out JB4 iso with the BMS E85 flash after using the OTS Cobb E30 map for so long. I'll post my impressions once I go FBO with the inline pump next week (returned to stock so I could get my turbos replaced under warranty).

[Mike@N54Tuning.com]

Originally Posted by foghat

I assume you are implying jb4 map 5 is the way to go?

This is one of the things I have always wondered about: doesn't the dme itself adjust accordingly based on conditions? I mean on a stock car, dme will do what it can to make the power output similar whether you are at sea level or way up there in altitude. of course there comes a point where it can't make the same power, but still.

With a flash tune you are obviously overriding stock parameters, but the dme must still adjust things based on conditions? No? you get a bad batch of fuel or run 89 octane with your 94 octane tune, will it not compensate and keep things safe?

Isn't this super smart dme one of the reasons jb4 has continues to be so popular on this platform? Where on most other platforms piggybacks are usually first to market, but typically go the way of the dodo bird once flash tunes become available.

Not trying to start anything, I am genuinely curious.

The DME does some thing really well and other things not very well. Here is a simple example. If you set the boost & timing for say E60 using a custom flash map but accidentally mix in E30, the DME will do a good job of reducing timing advance to match the new octane as best it can. But it won't back down the boost or adjust the fuel trims for you. Same goes if you are tuned for E30 but mix in E60. The DME handles timing very well but won't adjust boost or adjust the fuel
trims for you.

When the fuel trims go out of whack the DME will allow the car to run super lean with no limp mode thrown. The JB4 has over 10 different auto tuning parameters and safety features at work that either don't exist at all within the DME or exist but are not very effective. Map 5 is just one small part of what it. Even on say map 7 there are many safety systems and learning algorithms in place that do not exist within the factory DME.

Mike

[foghat]

^ Thanks for the info Mike.

[PeteA]

I think I waited for over a year for Cobb support for my vehicle as I thought it was the most streamline/clean solution. After giving up on the wait, I pulled the trigger on the N55 JB4 and installed it a few weeks ago in ISO mode.

I am very impressed with the integration, the smoothness of the power delivery, the ease of installation and the features. On the fly autotuning on fuel grade quality/mixture is just one of the very big features that no other tune has support for. Being able to put whatever you want in the tank is a big benefit, especially as ethanol mixtures can vary wildly at the pump.

Has my endorsement.

[RnmEvo9]

So, as former Cobb owner now back to camp BMS, I got to say the BMS e85 flash is legit and I'm glad I made the switch. Kinda sucks I didn't try out this flash when I had my 135i, but now I get to enjoy it on my 335i.

[Freon]

Originally Posted by mike@x-ph.com

Piggy back can get to boost faster than flash, be a lot more accurate, hold boost for a lot longer on higher rpms.

How exactly did you come to these conclusions?

[mike@x-ph.com]

Originally Posted by Freon

How exactly did you come to these conclusions?

Lots of testing.
A lot of tuners who deal with both have come to the same conclusion too.
Not saying the Piggys are a better tune, but in terms of boost control they do a better job.