Author Topic: racelogic traction control install = lean AFR's  (Read 17828 times)

Offline ex-ctr

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Re: racelogic traction control install = lean AFR's
« Reply #15 on: December 28, 2008, 09:19:32 pm »
very interested in this as im fitting rltc to my Nissan S14a running vems, how does the vems handle the mixture leaning out when the rltc cuts injector pulse

Offline PeepPaadam

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Re: racelogic traction control install = lean AFR's
« Reply #16 on: December 29, 2008, 02:13:58 am »
I wonder how hard would it be to implement this kind of traction control to VEMS? We have the capability of monitoring wheel speed (ok, just one but it's enough for 2wd cars.


Offline BigD

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Re: racelogic traction control install = lean AFR's
« Reply #18 on: August 26, 2014, 06:26:25 pm »
Just FYI for anyone trying to do this too, I have a 3.6 box and it looks like it has the same issue. With it plugged in, it barely idles, lambda swinging 1-1.25+. Bypassed it's fine.

I'm using the deadtime strategy and I'm using ID1000 injectors. I noticed my tuner must have messed with the deadtimes to make it work better. I put in the ones from the site and it's buttery smooth now. The 3.6 might be better but it's clear as day, the car idles much leaner with the racelogic box plugged in vs bypassed.

Offline fphil

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Re: racelogic traction control install = lean AFR's
« Reply #19 on: August 27, 2014, 03:41:05 pm »
Hello BigD,

Could please explain this (same) issue somewhat? What is plugged in and bypassed. Is it the RaceLogic Box?  (I suppose so)
I have understood that the RL box when plugged in takes control of the injectors using the genboard opening value as a set up (and that its control circuit is different from genboard 
Then the effective opening time of the injectors is probably changed compared to the one given by Genboard.
If, when RL box is plugged in, idle is leaner, this should mean that the effective opening time is shorter than with Genboard. So I am led to say that the Geanboard control is better done by Genboard and that the RL injector opening and closing are slower (sorry Rob ;) )
But nevermind, in any case I believe the injector dead times values have to be changed when using the RL box

Philippe

Offline BigD

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Re: racelogic traction control install = lean AFR's
« Reply #20 on: August 27, 2014, 09:58:16 pm »
Sorry if I was vague, was posting in a rush.

Yeah the RL box splices in series with the VEMS injector outputs.  It doesn't actually open or close the injectors, it simply breaks the given circuit when it wants to misfire a cylinder during a loss of traction situation. So when idling, the RL box isn't doing anything actively.

The way these boxes are wired into the injectors is that you add a male and female connector inline, and the RL harness has a matching set for each end. So it's easy to eliminate the RL box from the circuit to see the effect. With the RL box plugged in but not doing anything, the car idles much leaner.

I think I follow your logic about this meaning that the injectors open/close slower but then I don't understand how the calculation works then, why would it go leaner if the injectors are slower, and then richen with a higher deadtime? As I understand it, the deadtime is basically like an extra area under the pulsewidth curve, sloped sides instead of a square pulse. To get the amount of fuel right, the shallower the slope, the more the ecu will reduce the pulsewidth, to keep the area as desired. So if the slope becomes shallower than what the ecu thinks, wouldn't that result in too much fuel?

Purely symptom wise, it seems to indicate that the injectors open and close faster - leaner = less fuel going in. So with the pulsewidth being the same in both cases, the only factor is the deadtime being lower. But instead, INCREASING the deadtime made the engine run right.

Maybe the lean values were actually incomplete/failed combustions from too much fuel

Offline fphil

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Re: racelogic traction control install = lean AFR's
« Reply #21 on: August 28, 2014, 08:28:30 am »
Thanks for your explanation
When you say that with RL box  plugged in, the box is not doing anything, I would refer to the plots given by Multiplex here above.  So I understood that even when there is no traction control done but the RL box plugged in, at least the flyback circuit of the injectors is changed
 (I do not know if the RL box directly command the injectors from its own gate when there is no traction control (doing nothing?), but I guess it does, this would be much easier then to control the opening when traction control is ordered)

The deadtime given to the genboard is be compensated by the algorithm. So, if I am not wrong, the greater this deadtime value, the greater the genboard pw is. 
This is open loop, There is no adjustment done by the genboard to get the amount of fuel right, that is the shallower the effective slope, the ecu will not reduce the pulse width to keep the area as desired.
Hence if the flyback circuit allow a faster effective closing time of the injector (effective deadtime) then the mixture is richer, slower, leaner.

Philippe

Offline BigD

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Re: racelogic traction control install = lean AFR's
« Reply #22 on: August 30, 2014, 08:07:57 pm »
Interesting, I guess I just assumed that the deadtime is used to subtract from the PW. If it doesn't then this behavior makes complete sense.