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Unread 12-03-2011, 07:13 AM   #21
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I have just reread this thread and it looks like I forgot to answer some questions.

Vic, throttle response when I blip the throttle is very good. It is slightly better than with my previous Motronic-based equipment that I used with 83 lbs/fr injectors. It may not be quite as sharp as on a modern NA engine but I must say I am still running Injector Timing as Single Zone mode and I feel it can be improved when I switch to Table mode.

Dea and Pauly, the console below the stereo is home-made. It can hold a standard-sized (52mm) gauge and features a tray algonside.

Hally, the J&S is purposed to act foremost as a safety net, but it can be a decisive tuning tool depending on how it is wired to the ECU.

In full sequential mode the J&S is plugged directly to each ignition coil and monitors knock activity individually in each cylinder.
Vic also has the J&S wired to the Vi-PEC so that the user can see and log ignition timing decrements applied by the J&S as knock activity triggers its closed-loop algorithm.

Through a log the user can see exactly when/where on the ignition map the J&S retarded ignition, which allows him to either decrease ignition when the J&S applied retard, or increase it, then see on the next run/log if his adjustment got him below or above the knock threshold.
This dichotomic process sums up how improving the shape of the timing curve consists in, and will have to be repeated as many times as necessary so that the engine eventually runs right before the knock threshold, which is where it will make all of its power without detonating.
The closest image I can think of is that of a surfer on a tall wave - always trying to surf slightly ahead of the upper edge and constantly readjusting his line for not falling behind the wave.

As values in the timing map can be adjusted with a precision of 0.1, this means that many WOT runs may be necessary, but this is a small price to pay for being able to pin-point, without even the need for a dyno, the optimal shape of the timing curve for a given engine configuration.

Vic explained it all here already.

The side benefit of wiring the J&S to the ECU is being able to trigger a secondary boost table so that the user can choose to run different boost settings when a certain level of ignition decrement is applied - namely to run against the wastegate spring when "too much" knock takes place.

All in all the safety functionality is exactly the same as on a fully standard Bosch Motronic 951 DME/KLR set up, with the obvious advantages being :
- a modern, more powerful, faster-processing & fully configurable ECU
- a full sequential set-up
- more powerful spark ignition

Last edited by Thom; 03-02-2012 at 05:53 AM..
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