SQ6 360/720 sync, how to setup the Cam position

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SQ6 360/720 sync, how to setup the Cam position

Postby MarcoV6T » Thu Apr 15, 2010 1:36 pm

Hi Neel,
I’ve a 60-2 crank wheel, with a inductive sensor, and a 4-window intake cam wheel with a hall-effect sensor, using the ‘N MINUS M’ configuration mode.

The crank position is 282° ATDC, this one is easy, but how do I setup the intake cam sensor position, as it triggers four times in each cycle?

I understand that the cam latch values represent the angle at which the ecu waits for a cam trigger event, but what about the cam latch offset? Is this the value subtracted from the cam position, used to calculate the cam advance?

When I setup all the tach intervals, to look for the intake cam, I get some stable numbers in the measured values for the intake cam, but when I try to use those numbers as reference for the cam latch, the measured values sometimes jumps.

The engine runs, but it switches between 360/720 sync all the time, but when I configure the ‘720 synchronization count’ to '2', in the advanced N MINUS M menu, it doesn’t synchronize anymore to the 720 mode(which I thought it wouldn't, that's why I changed it from '1' to '2' as a check).
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Re: SQ6 360/720 sync, how to setup the Cam position

Postby Neel » Thu Apr 15, 2010 2:16 pm

In short, you can't. N-M setup only works with a single pulse per cam rotation. If you have more, we have to write a custom map for you - which requires knowledge of where each tooth begins and ends with respect to TDC #1. Tell us what application it is for and we might already have done it.
Neel Vasavada
Apex Speed Technology
2947 S. Sepulveda Blvd
Los Angeles, CA 90064
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Re: SQ6 360/720 sync, how to setup the Cam position

Postby MarcoV6T » Fri Apr 16, 2010 12:59 am

It's a 2.8l VR6 24V BDF engine from the VAG group, the cam wheel pattern is the same used as in the 1.8L 20V turbo engine(better known as 1.8T) from the same group.

If I understand it a bit, I need a user defined crank/cam pattern to start with, and cam latch values which are set for the rising and falling edge, and a lot more…

I guess my engine’s crank/cam pattern looks a bit like the baseM3 map, only from what I understand , the M3 base map isn’t setup to run full sequential(720 synchronization = disabled, in the sequential pattern 1).
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Re: SQ6 360/720 sync, how to setup the Cam position

Postby Neel » Fri Apr 16, 2010 3:24 am

It's not that simple at all. The M3 maps are absolutely sequential. Although the setup is called "user defined" the details on what each setup parameter means and how it works is not published and at this point Pectel insists on doing all setup in-house. If you send me info on the patterns I'll get you a setup.
Neel Vasavada
Apex Speed Technology
2947 S. Sepulveda Blvd
Los Angeles, CA 90064
(P)310.314.2005
(f)310.496.0951
neel@apexspeedtech.com
http://www.apexspeedtech.com
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Re: SQ6 360/720 sync, how to setup the Cam position

Postby MarcoV6T » Sat Apr 17, 2010 12:22 pm

Pattern send.

edit: Here are my cam timings;

Inlet cam 4-tooth wheel
- TDC - 1.5° - 109.5° - 170.5° - 190.5° - 361.5° - 398.5° - 541.5° - 681.5°
> H ---> L ---> H -----> L ------> H -----> L ------> H -----> L -----> H --->

I machined this wheel to one tooth only, because the early DTA firmware could not cope with a 4-tooth cam wheel, this wheel was previously mounted on the intake cam to run the engine in full sequential mode on the DTA. When the upgraded DTA firmware was able to read the 4-tooth cam pattern, I switched the 4-tooth cam wheel from the exhaust cam with the 1-tooth inlet cam.

Exhaust cam 1-tooth wheel
- TDC – 117.5° - 153.5°
> H ----> L -----> H --->

Crank tooth reference angle 284° ATDC (checked with a timing light).
Last edited by MarcoV6T on Mon Apr 19, 2010 4:52 am, edited 1 time in total.
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Re: SQ6 360/720 sync, how to setup the Cam position

Postby Neel » Sun Apr 18, 2010 3:06 pm

As long as you have a single pulse on either camshaft and an evenly spaced tooth pattern with only 1 gap (equal to the width of any number of teeth) then you can run an SQ-6 in n-m mode. Variable camshaft timing is completely user-definable.

So if you have a 60-2 crank, single tooth exhaust and 4 tooth intake on a motor with variable cams, no problem!

-Neel
Neel Vasavada
Apex Speed Technology
2947 S. Sepulveda Blvd
Los Angeles, CA 90064
(P)310.314.2005
(f)310.496.0951
neel@apexspeedtech.com
http://www.apexspeedtech.com
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