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R32 GTR table

Posted: Fri Nov 02, 2007 12:30 pm
by Bernardd
Matt, what does the boost duty cycle map do? It's not referenced to rpm or load......

Posted: Sat Nov 03, 2007 8:52 pm
by Matt
Thats because in the code I couldn't find any scalers near the routine. I'm not too sure yet how it controls boost, since I found the table and nothing else associated with it.

If you are interested in using it I can add an investigate item to find at least the scalers for it

Posted: Sat Nov 03, 2007 10:57 pm
by Bernardd
yes please investigate..........i wasn't aware that the skyline controlled boost thru the ecu

Posted: Fri Nov 09, 2007 7:22 pm
by AndyStuttgart
Hi Matt, I´d be glad, too, if you could find out how to control boost with the stock ECU!
(OT: any news on ER34 boards?)

Posted: Sat Nov 10, 2007 5:04 am
by Bernardd
do any nissan ecu's control boost?

Posted: Sat Nov 10, 2007 7:30 am
by MartinC
The S14 and the RB series ecu's control boost very well, if there was a way to modify the table to hold say 1bar then that would be fantastic.

Posted: Sat Nov 10, 2007 1:10 pm
by GZ@hybridka
A better approach to understand oem boost control would be to start with analyzing the boost control hardware itself.

Any sort of dynamic boost control is going to be done using one of two methods, in combination with the appropriate hardware for that method. The two methods that could be used are PWM (pulse width modulation) using a high speed solenoid valve much like a fuel injector except it is metering air instead of fuel, or a stepper motor valve which would allow steady-state metering of the valve orifice to control air flow.

These two (true dynamic boost control) methods vary greatly in the way the ecu hardware would control them. Generally, the main microcontroller (in the case of r32 it would be hd6303) is utilizing all of its available timers, counters, capture and compare match features for fuel and ignition control.
Because these same functions are required for an additional PWM, the system must off-load the task to an external companion processor.

Because the system is built around shared-ram, it is possible for the main microcontroller (hd6303) to perform the simple tasks of deriving an actual value that corresponds to a pulsewidth that would be appropriate for the booost controller. It then places in this value in RAM that is shared with the companion processor(s) which actually turns the value into a real-world pulsewidth that is sent to the valve itself with a certain frequency.

A stepper motor system is a little different, and could potentially be controlled using only the main microcontroller itself, or by a companion processor. The difference between the stepper motor and the PWM is that the stepper motor does not require the timers/counters, but what it does require is quite a few microcontroller pins.

A method I did not mention that could be considered boost control, but not true dynamic boost control, is the utilization of multiple simple vacuum solenoid valves attached to different orifices (manual boost controllers) to provide different boost profiles. These are very easy to control using the main microcontroller using only a few pins, and many oem turbo vehicles use this method (nissan and others). It is also very easy to apply this method to other previously non-boost controllable ecus with a few simple code modifications.

So, what I am getting at is that all boost control is not created equal, in order to discuss it in context, the type of boost control valve must be known. R32, Z32, S14....etc.. may not be the same or even similar.

Check out the valve that is actually controlling the boost/wastegate and go from there.

Posted: Sun Nov 11, 2007 1:13 pm
by Bernardd
the r32 has a boost solenoid.

Posted: Fri Nov 16, 2007 11:24 am
by Fusion Ed
The S14 has a rather nice boost duty table. It would at least in theory be possible to alter this table to run more boost. Pete L says it works great, so its worth a try (I have not yet done so myself)

Ed

Posted: Fri Nov 16, 2007 12:13 pm
by Matt
ER34 has a boost table similar to S14 with scalers, so you should be able to modify the duty cicle on this

I've finally finished fixing up logging and a few outstanding bugs in the NIStune software and am back to getting Type 4 running Y33/E34 since I have these two ECUs still sitting here on my bench to get going. Y33 is running without dropouts which is good, but doesnt write so I'm looking into that one at the moment. Good ECU to use to compare against ER34 on the logic analyser

Posted: Fri Nov 16, 2007 12:29 pm
by Fusion Ed
Fantastic Matt, progress is great, I have had no problems since the update to the latest version either. Strange but I am not complaining at all!

Posted: Wed Dec 19, 2007 1:59 am
by Matt
Update on this Investigate issue
10560 BNR32 Boost map. Find more information
There is no scalers for this map at all
Uses 0x149A as index to 256 byte map (indexed as AB+AB/16)
So the value at this address is an index to the map

You can only maptrace this by monitoring the value in the consult RAM table and then try and calculate the display... unless we made a custom consult entry to the table, streamed that then printed it

But I probably wont do that.... the moates maptracing stuff will be worked on soon and you can use hardware maptracing for stuff like this if you have one of these units

Posted: Sun Dec 23, 2007 11:32 pm
by Matt
I'll try the hardware maptracing out on the boost table when i get the next chance