Thread: JB4 large turbo flash mapping
07-31-2012, 11:20 PM #1Supporting Vendor
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JB4 large turbo flash mapping
Just as an update we are working on developing a backend flash map for use with the JB4 for those of you running larger turbos or nitrous. Like the RB turbos I have sitting around waiting to get installed. For those of you expecting to make more than ~475rw the JB4+flash approach will offer some key advantages over the JB4 alone.
A few random comments:
1) We've shifted the fuel control, including open loop adjustment, over to the flash side. This means improved AFR targeting at high boost levels and a higher fuel trim ceiling without the need for open loop adjustment. This change sets the JB4 up to accommodate power levels up to the 600rw level and beyond.
2) We've remapped advance out on the flash side producing an overall cleaner and more predicable result than CPS offsetting can.
3) The flash maps being tested now are fairly simple but we expect many more changes to follow as we get more seat time with 500rw+ vehicles.
4) These changes will allow the JB4 to focus on what it does best for higher HP cars. Boost control, CANbus integration, meth integration, safety features, etc.
5) Note none of this applies to customers targeting less than ~475rw. For you, the JB4 on top of the OEM flash is still the best way to go.
6) We'll provide the flash maps free of charge to JB4 owners. They will be unlocked so you can open them and make fine tuning changes to advance, etc, as you see fit. For those unfamiliar with how this works you'll need to have a Cobb AP tied to the car to load the maps.
Here is a short 3->4 log I did using 91 octane + boost juice. Open loop is zeroed out on this so I can view the true fuel trims. But this gives you an idea of the basic curves. Currently advance is around 10 degrees at peak HP and AFR is 12.0:1 across the board. Once we get the RBs installed much more extensive testing and tuning will follow but I expect this advance and AFR curve will wind up providing a good match for 19-20psi levels with meth on pump gas. Note those of you running stock turbos + meth at say 17psi would find likely this curve overly conservative.
If anyone has large turbos installed, a JB4, and has access to Cobb, feel free to email me to help test these maps out.
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