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Old 04-12-2010, 11:22 AM   #121
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Will the device still work if I've bolted an N/A CAS to the back of my engine and don't use the NB sensors
The NB sensors are necessary to control the VVT.
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Old 04-12-2010, 04:40 PM   #122
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Bugger! How come if you don't mind me asking?!
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Old 04-12-2010, 04:58 PM   #123
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1) the VVT cam sensor output resembles the NB1's.
2) The software thus far has been written to read off of the NB crank sensor

It's not too hard to fit an NB crank trigger wheel and sensor onto an NA. j_man's done it.
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Old 04-12-2010, 05:32 PM   #124
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1) why would that matter?
2) that's fair enough

And I have a 2001 motor fitted, I have the sensors, but little inclination to build the circuits to use them.

If it ain't broke
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Old 04-12-2010, 06:45 PM   #125
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Originally Posted by JasonC SBB View Post
1) the VVT cam sensor output resembles the NB1's.
2) The software thus far has been written to read off of the NB crank sensor

It's not too hard to fit an NB crank trigger wheel and sensor onto an NA. j_man's done it.
doesn't the NA exhaust cam sensor have the same or similar unevenly spaced four teeth? or are they even?
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Old 04-13-2010, 11:29 AM   #126
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Quote:
Originally Posted by richyvrlimited View Post
1) why would that matter?
2) that's fair enough

And I have a 2001 motor fitted, I have the sensors, but little inclination to build the circuits to use them.

If it ain't broke
The VVT control is closed loop. It uses the difference in timing between a sensor reading a wheel attached to the cam and a sensor attached to the crank to determine where the cam advance currently is. The NA CAS is only attached to the cam... there goes your ability to compare separate readings.
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Old 04-13-2010, 12:14 PM   #127
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The VVT control is closed loop. It uses the difference in timing between a sensor reading a wheel attached to the cam and a sensor attached to the crank to determine where the cam advance currently is. The NA CAS is only attached to the cam... there goes your ability to compare separate readings.
the NA CAS will fit on the exhaust cam--which is fixed.
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Old 04-13-2010, 12:40 PM   #128
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The biggest problem is you can't compare the CAS to itself. If you had one sensor on a fixed cam and the other on a moving cam, it may be possible to write code for it. But it sounds like it would be less trouble to just wire up the stock sensors.
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Old 04-13-2010, 01:00 PM   #129
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Right... I was assuming that the 01 valve cover would have an 01 style cam sensor stuck in it
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Old 04-13-2010, 02:51 PM   #130
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doesn't the NA exhaust cam sensor have the same or similar unevenly spaced four teeth? or are they even?
The NA CKP signal does resemble the NB CKP. The rising edges IIRC are in the same place, but the NB pulse widths are very short. A rising edge detector aka hipass filter with possibly an inverter, will make the NA CAS output be NB computer friendly. However I would recommend a real NB crank sensor for more accurate timing.
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Old 04-22-2010, 12:27 AM   #131
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Wow, yeah, asking questions like that (about using a CAS signal) means you probably don't care enough about performance to even need something this advanced. GAWD. Run the crank triggers or go home.

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No need for any circuitry, just connect them up and go.
You mean two high impedance inputs won't bother each other? Up to pull ups, perhaps....


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The output timing signals are essentially passed through during the interrupt that was triggered by the input timing signals within the MCU. Essentially, the output signal that is generated occurs within a few microseconds of the input trigger -- basically enough time for a few instructions to be executed at 8MHz. I won't go into the nuances of execution time per MCU instruction, but you get the idea. There is no buffering of the signal.
Yeah - as long as it's fixed, as long as it gets the highest priority interrupt, fine - but add 50 microseconds of variability and that DIRECTLY translates to 2.5 degrees of additional retard I'd HAVE to run to keep the motor together.

I'm not sure on the relations between gains in cam timing and degrees of timing, but the first trick to engine tuning as I understand it is running as much advance as possible.


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I've been running the box for quite some time now, but have otherwise been cleaning up the rough edges.
Meaning the tuning software will be awesome? :-) Windoze, linux, ???
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Old 04-22-2010, 02:20 PM   #132
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Meaning the tuning software will be awesome? :-) Windoze, linux, ???
Tis just a simple Windows app with a 12x12 table and some settings. It's pretty boring to look at . It's no Tuner Studio, that's for sure.
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Old 04-22-2010, 02:29 PM   #133
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I'm awake now.... I've got all the NB sensors and NA sensors on my engine. I think a local guy is selling a VVT head.
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Old 04-22-2010, 02:53 PM   #134
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Wow, yeah, asking questions like that (about using a CAS signal) means you probably don't care enough about performance to even need something this advanced. GAWD. Run the crank triggers or go home.
Oh GTF outtahere sure it's no the be all, but there's some damn high powered MX5's still running from a CAS.
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Old 04-22-2010, 09:02 PM   #135
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Wow, yeah, asking questions like that (about using a CAS signal) means you probably don't care enough about performance to even need something this advanced. GAWD. Run the crank triggers or go home.
running cas on my engine. still has some power tho..
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Old 04-23-2010, 11:58 PM   #136
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Ok, a bit of a tease - but it is true as well... Going away from the CAS is a really, really good thing. Rock stable timing, and as I was implying above, you're giving up advance when you give up stability, and giving up advance is giving up horsepower. Why would you do that to yourself when the sensors are already there? Buy a $200 CAS when you can use a $0.15 op amp?
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Old 04-24-2010, 02:57 AM   #137
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So uh, people who are making this, nothing really to add other than...

Please let me buy it soon.

Been waiting on this and i don't know how much longer i can wait to do my engine swap.

Thank you. -.-
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Old 04-24-2010, 06:50 AM   #138
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Ok, a bit of a tease - but it is true as well... Going away from the CAS is a really, really good thing. Rock stable timing, and as I was implying above, you're giving up advance when you give up stability, and giving up advance is giving up horsepower. Why would you do that to yourself when the sensors are already there? Buy a $200 CAS when you can use a $0.15 op amp?
This is digressing from the thread a tad but....

I have all the 2001 sensors and my MSII I built 2 opamp circuits for the CAS inputs. it works great, and I'm wont to 'fix' something that isn't broken, BTDT...

I've not researched into the mods required for the MK2 inputs, but I've read of people having lots of issues, true? Or will my two opamps suffice?!

P.S. My CAS was free it came off my old engine :P
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Old 04-24-2010, 07:17 AM   #139
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If it ain't broke
...it might be soon. Ever measured the timing slop that occurs from your CAS? How close are you to the detonation threshold? How much power are you giving up by using a cam triggered sensor vs. a crank triggered sensor?
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Old 04-24-2010, 11:22 AM   #140
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well that snowballed. i just wanted to point out that it could be done with the CAS.
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