The EU has always had the functionality to do a two step launch. For clarifaction, two step allows you to set a lower rev limit for launch, and when the EU detects speed signal input, the lower rev limit is released. By doing so, you can floor the throttle at the line, and build about 2-3psi of boost just before you launch the car. But to do this, you need a speed sensor signal, which has been a bit elusive on the 350Z ECU.

I finally got around to digging out the speed signal wire on the car. The one I am using is located in the HVAC module just behind the AC controls, and its pin #3. See below. You tap this to the "Speed Signal Input" wire on the eManage Ultimate.



After you have completed the wiring, goto the "Parameters" screen on the eManage Ultimate software, and select IGN (for ignition settings). From there, you just set the launch point, the TP level where the launch control will kick on (I used 50%), and put "2" for the number of speed pulses needed to disengage the two step, and return to your normal redline.

The look on people's faces when you perform the two set is priceless....sounds like a large caliber machine gun.

 

thats awesome.. if this utec dosnt pan out ill be going with the EU.. the utec is supposed to have this function also correct? either way great news once again sharif!

 

Yup, the UTEC will have this function as well.

 

Great find and thanks for posting a very clear picture of where the speed sensor signal is!

Would you happen to know if this particular tap returns to the ECU? I am trying to hook up a Apexi RSM and in order to set the speed limiter, the speed line that you use must return to the ECU in order for the Apexi RSM to interupt the circuit. I will probably never use this particular feature, however I am one of those guys who tries to enable all features of a particular unit just in case.

Also, would you have any idea on where I would tap to enable the rev limiter feature as well. I know I can tap the tach signal at the ECU, which is where I tapped for my SAFC II, but would you happen to know if this is the same tap I would use to enable the rev limiter function of the Apexi RSM.

Your help finding the speed signal is greatly appreciated and thanks in advance for any future assistance.

Bill

 

interesting

 

cool stuff shariff! i like playing with 2 steps... i built you could build more then 2-3 psi if you really wanted to tho!! But watch how the EGTs skyrocket when you play with that!

How smooth is the two-step with the EU? Is it very tunable? I never played with the FCONs twostep in my car yet... but I did activate it on a customers car and it was very tuneable and smooth... im curious how well Greddy has integrated it into the EU?

 

That is a pretty neat feature!

 

Can you take a small video? Id love to hear your Z....

 

The speed sensor wire does NOT go to the ECU. It is developed from the wheel sensors and transmitted primarily over Can bus. There are a few devices in the car that need the speed signal though, so you must find one and tap it there.

 

Hey Charles, yes you are correct...you can build more boost. It has the option of retarding timing when the two step kicks in, and that will build more boost. And you bet....you dont want to lay into the two step for too long...just enough to launch, becuase it creates a lot of heat in the turbos, the block, and your EGT's will rise.

The 2-3psi I saw was just using the two step at only 4000rpm launch point. I am sure there is more on tap for the more adventurous among us.

 

Great idea...will do.

In regards to the direction in which the signal travels...I didnt determine that. There are several speed signal wires on the 350Z ECU, and unfortunately, its not clear which one travels back to the ECU...or if it actually does travel back to the ECU. To my knowledge, there is no "speed signal" wire on the main ECU harness...so it's anyone's guess at this point.

And Charles, in regards to tunability of the 2-step..it looks pretty straightforward, and its smooth in its release and operation.

 

Cool.

Ive been in a mates CRX with this functionality from his Hondata system. He dials in about 6000rpm (near his vtec point) with foot flat to the floor, the car is bouncing off the new rev limit and he drops the clutch taking off with the tyres screetching.

Its quite something and your right about the looks on peoples faces.

 

Hey Kevin, thanks for the input...much appreciated.

Are you aware of which signal to intercept, in order to "trick" the ECU into thinking you are going slower than you really are. This is the method I need to figure out, in order to eliminate the speed governor.

The EU has a speed input and speed output wire...so I need to intercept that sucker.

Any ideas?

 

Awsome, You beat me to it. Any one with a clear pic like this for but for the G35? I am dying to try this. GREAT WORK as usual.

 

In the G35 the speed sensor signal is super easy to find. The wire can be found at the AC display unit. Remove the trim piece around the air conditioning display (it pulls straight out) and remove the two screws that hold the display in place. Pull the display out and in the harness attached to it you will find a white/green wire (Pin 4 from memory). Thats the same signal that Sharif is referring to in the Z.

As far as tricking the ECU in to thinking the car is moving slower then it is, that is going to be a hard feat to acomplish. The VDC controller monitors the speed of EACH wheel (using a fail safe hall effect sensor). The VDC controller then transmits the vehicle speed to the unified meter and A/C amp via CAN. The unified meter then retransmits the vehicle speed to the BCM and ECU.

You would basically have to trick all four wheel sensors (which are very sensitive due to the fail safe aspect). The best bet for something like that is to try and find out as much information about the wheel sensors. With more information it may be possible to hack them.

 

Dang... i didnt know we had speed limiters! ahhhh good ole FCON

 

What is it about brake boosting (or 2 step in this case) that causes EGTs to skyrocket any more than boosting during regular driving? I blew a headgasket slightly (got a little detonation) about 2 months ago prior to racing BriGuyMax while I was brake boosting, I only saw about 9-10psi while I was brake boosting, but I had no detonation problems prior (or after that) running 14psi just under WOT driving (no brake boosting).

 

Also when you say you "got it working finally" do you mean you just got around to hooking up the speed input and thus its working now? Or do you mean there was something else more involved that prevented you from using it before, such as firmware?

 

I can't think of any reason why I'd want 2-3lbs boost off the line until I can actually control my wheel spin/hop with all the tq this car puts down. But, cool nonetheless.

 

Your probably not tuned for the load induced during brake boosting at those certain RPM's.