Brake Boosting

Japanjay

Just out of curiosity, I am hoping to single turbo right after chirstmas this year, but is this possible? I know I have tried playing around with the Z going down the road and holding the brake while applying the gas and get nothing. I also know you can not power brake the car. The ECU recognizes you are on the brake and doesn't apply power.

Again just wondering, I tried searching and came up with nothing.

Jordo!

Allegedly, some of the ROMS in uprev now have a option that turns off the brake on/throttle kill issue.

EDIT: see this thread. ECU ; stock ECU Vs Nismo ECU difference this post ECU ; stock ECU Vs Nismo ECU difference

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esfourteen

I have a 2010 and my rom isn't supported :/

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SouthArk370Z

Won't pulling the brake light fuse enable one to power brake? Or am I thinking of something else?

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phunk

Cut the brake signal wire to the ecu and put a switch inline. Turn off the switch when you want to do it.

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Jordo!

^^^ these are the other two ways

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Japanjay

Phunk you got a link for a DYI on locating and which wire exactly? Would I just splice in at the fuse box? Also I remember reading somewhere on here the fuse pulling method which I am assuming will accomplish the same as splicing and switching it throw all the dash lights on? And then I could have swore to turn them off you have to disconnect the power terminal and reconnect?

SlowZ

I had a switch built into my 350z that would turn off the brake lights when I wanted to do a burn out

Jordo!

I think details can be found here How to completely disable the VDC

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phunk

I dont, but I can help you with some information from the FSM.

Pulling the fuse is the easy way to do it, but I believe this will cause your brake lights to no longer work, which is not suitable for street or road course use.

Information from the Nissan FSM, copied and pasted (property of Nissan):

P1805 BRAKE SWITCH
Description: Brake switch signal is applied to the ECM through the stop lamp switch when the brake pedal is depressed. This signal is used mainly to decrease the engine speed when the vehicle is being driven.

DTC detecting condition
A brake switch signal is not sent to ECM for extremely
long time while the vehicle is being driven.

3. Check the continuity between stop lamp switch harness connector and ECM harness connector.
Stop lamp switch Connector E110 Terminal 2
ECM Connector M107 Terminal 122


Looking at the ECU Pinout I confirm that terminal 122 at the ECU is the stop lamp signal input. Looks like it is a pink wire.

Also reconfirming this is the Connector M107 layout from the FSM. I have attached an image of a screen shot I took of this connector.

So in summary; You have 3 large connectors at the ECU. Find the one that matches the attached image and pin 122 is the pink wire for brake signal input. If you disconnect this wire, you can brake boost without losing your brake lights. But if you leave it disconnected too long you will get DTC Code P1805. This is why you would rather put a switch inline here rather than just cut the wire... so you can open the circuit when you want to brake boost without interference by the ECM, and then reconnect the signal later so you do not get the code. An alternative could be to disable P1805 in the ECM if you have UpRev. Which I think I might go ahead and do now next time I am in my ECU... then I can just de-pin terminal 122 without cutting the wire... to this day my cars wiring is all un-cut minus my injector sub-harness... prefer to keep it that way personally.

Attached Images

370zM107.gif (30.4 KB, 128 views)

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Japanjay

Thank you, will be going this route and saved the whole comment in my build info file.

R3drckt09

So putting a switch on the purple wire turns off all electronic nannies, but a switch disconnecting the yaw sensor removed everything except ABS?

phunk

The switch on the pink wire will only allow you to give throttle input while pressing the brakes. It should have no other known effects on the "nannies". At least, nothing is mentioned of it in the service manual description of the circuit's purpose. But perhaps it could have its own contribution to your freedoms when applied with other nanny-reduction techniques.

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Jordo!

BTW: Update on the brake/throttle limiter -- apparently that is NOT available at present for VHR engines as in the 370Z, confirmed by Megan370z (thanks again for checking on that! ).

So, for now, you need to follow the other methods if you want to do this.

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esfourteen

I just did this myself and disabled the DTC P1805 code with uprev, so far no issues at all, brake + gas working as expected without ecu interruption. For anyone looking to do this, the wire color is actually Pink (P), not purple, its the last ecu connector furthest from the firewall. Be sure you cut the correct pink wire, the other pink wire is for the vehicle CAN.

Once you disconnect the plug and remove the pin cover you can trace the wire you want and cut or de-pin, I highlighted the wire here when looking from the back of the connector which is how the FSM picture phunk attached above shows it:

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