GSXR Engine - Cam Position Sensor

[FastGSX]

We are running a 2001 GSXR 600 engine. The engine comes stock with a cam position sensor in the valve cover. I assumed that this sensor detected TDC, and was using it to align my trigger signal for the MSD. Using a scope, I looked at the CPS signal, and the trigger signal while cranking the motor (with no spark). I adjusted the rotor until the trigger signal lined up just before the CPS trigger (I put it about 20 degrees before). However, this was completely wrong when I tried to add spark and fuel. Does anyone know where in the rotation the CPS sensor actually identifies? I know that it is NOT top dead center...

Thanks
Jason

[Ben Beacock]

I recall its 5 crank teeth after TDC on #1cyl, so 5x45deg = 135deg ATDC. The service manual is at the shop, I can confirm it tomorrow.

Ben Beacock
Chassis Design and Technical Coordinator
Gryphon Racing - University of Guelph

[FastGSX]

Can you check it for me? That would be awesome...

Thanks
Jason

[Ben Beacock]

yep.. 135deg.

Have Fun http://fsae.com/groupee_common/emoticons/icon_smile.gif

Ben Beacock
Chassis Design and Technical Coordinator
Gryphon Racing - University of Guelph

[Ben Beacock]

hold on.. my math isn't too great.. LOL, it should be 225 deg

Ben Beacock
Chassis Design and Technical Coordinator
Gryphon Racing - University of Guelph

[FastGSX]

for some reason this doesn't sound right... Based on trial and error on where I can get the engine to run, it appears that the cam sync is 90 degees BEFORE TDC. Are you sure that is what the shop manual says? This is a 2001 GSXR.

Thanks

[A Reinke]

Motec's way of finding the crank reference sensor offset is goofy. it can range from -10 to 720 degrees. using their way of finding it, we got around 460-470.

[FastGSX]

AOD, what kind of engine is it on? Also, is this the cam sensor offset, or crank sensor offset?

[MoTeC]

It's not goofy. http://fsae.com/groupee_common/emoticons/icon_smile.gif What we have set up is something that can work with any crank/cam setup so it needs to be fairly adatable. It all works like this, most crank setups (not so much these days) have multiple teeht (more than one tooth per TDC) so for a sequential setup these teeth are seen twice per engine cycle. If they come up twice in the cycle you need to know which time is for the firing stroke and which is for the exhaust stroke. If you put in a single tooth on the cam it will only come around once per cycle and as long as you have not cam chain/belt problems it will alays preceed the same crank tooth. Our ECU uses the cam tooth to identify which crank tooth and which rev to reference to TDC firing cylinder one. This is how most sequential systems work. To work out the reference crank position we start at TDC firing No 1 and wind the engine over till the cam sensor fires, this is where the ECU starts to take notice and will assign the next crank tooth it sees as the index position, from this tooth we tell the ECU how many crank degrees it it back to TDC firing No 1....simple. http://fsae.com/groupee_common/emoticons/icon_wink.gif On a standard setup if you move any of the sensors or teeth the ECU will not know where the engine is in its cycle, ours you would simply recalculate the index number.

Donna

[Ben Beacock]

the shop manual (2002) has a signal timing diagram. from what I see on there, there are 16 sine waves from #1TDC to #1TDC for the crank sensor and the cam sensor sine wave coincides with the 5th crank wave after #1TDC (just a bit after #2TDC)

90 BTDC sounds close if it was off by 360 deg for some reason(135 BTDC if that was the case).

I can't see them changing the timing from 2001 to 2002, but its a definite possibility.

Ben

Ben Beacock
Chassis Design and Technical Coordinator
Gryphon Racing - University of Guelph