View Full Version : ECU Questions again ... Ping Micah

Felix Da Cat
12-31-2003, 07:44 PM
Hi guys, Happy New Year (2004 here already)

Still waiting for my Factory to come in, but doing some research in the meantime.

Can you please tell me the make and model of the ECU in 2004 RSVR? It's a Siemens-VDO, but I need more details if possible.

I'm looking at a new programming tool for the ECU and hopefully this device will assist us in manipulating certain parameters within the ECU. As soon as I have confirmed the details, I will post the details.

In the 2004 Dyno work post (btw, great info and great development from you, well done mate!) you mention the spark occurs ATDC. This could just be the way I'm reading this, but I was under the impression that the spark would occur BTDC, ie. advancing the timing, assuming RPM above idle speed.

The delay/time required for the combustible gas mixture to ignite in the chamber is preset by virtue of physics, with some variables (eg. temp and fuel quality/type), so this would mean that one would need to advance the spark to ensure that it occurs before a piston has reached it's TDC, thereby allowing time for the mixture to burn and to force the piston back down during the power stroke.

Did I misread or misunderstand you?

Originally posted by Micah / AF1 Racing
In a 4-stroke the goal of ignition timing is almost always to acheive a peak combustion pressure 12-14 degrees ATDC to give the maximum push down on the connecting rod.

All of the best for you and your families for 2004.


12-31-2003, 10:45 PM
micah can i take a stab at this one?

he is refering to the peak combustion pressure at 12-14' ATDC which means that the plug would fire at somewhere around 20' BTDC depending on rpm.

the factors involved in chosing the firing is compression, squish, rod ratio dwell time piston speed etc.

what is known is that you can generally open your exhaust cam based on your peak combustion pressure (ie. force on the piston) which will open quite a bit before BDC depending on the power you are chasing.

long story short, if you can come up with a device to crack the CAN protocol so ignition timing can be manipulated it will make some of us very very happy :D

Micah can correct me on this

Felix Da Cat
01-01-2004, 02:31 PM

Thanks for the explanation. I did mis-understand the statement. It was with reference to exhaust cam timing and not ignition timing - my bad.

Just got a reply from the vendor of the system that I was looking at. Great tool with immense potential, but at a cost of about $10k it's definetly a no-no! :eek: :eek: Damn, that's a lot of money for a system.

From what I have found in the meantime, even though I don't have the exact ECU model number, a similar type of ECU is used in the Mercedes class cars S-Type and E-Type.

Clarkie, any chance that you could check the ECU on your bike and let me know what system the RSVR is using?

I'll keep at it and hopefully find something that we can all use.