Open Source Rb Trigger Kit

[black bnr32]

I plan on scraping the PFC for a new ECU anyway.. I thought the PFC had no issues with timing fluctuations anyway, and it was just the newer ecu's

my car:

pfc, stock belt, ati balancer, big cams. see the bottom plot. that's too much timing scatter for my liking.

Edited January 11, 2015 by black bnr32

[black bnr32]

All,

Why are some crank sensors mounted parallel to the crank axis (like the Ross), while others (like this kit) are perpendicular? I assume both designs work fine, correct?

[GTSBoy]

Just looking for a tooth or a gap. Comes down to personal preference I expect. There might be some paranoia involved the choice - thinking that accidental damage risk or space constraints exist with one layout lass/more than the other.

[murrayis]

That is correct GTSBoy - A Gap is a gap which ever way it is mounted, This style keeps it compact and safe.

[XGTRX]

I still think its the optical pickups in the cas that are the problems, because even with a 24/1 aem trigger disc i still saw issues, when we hacked up the cas with a hall effect pick up with 24/1 set up, had no problem.

[GTSBoy]

It could well be. The optical slots are very narrow and they whizz past the sensor pretty bloody quick. I would have thought that diffraction effects might become apparent with such small openings. The apparent effect of different timing belts might compound the problem. Add in a few extra harmonics from a belt that does something different to what Nissan used and maybe some scary shit starts to happen.

What's really needed is a decent engine dyno type experiment where the output of the actual sensors on an optical CAS might be tested. Some effort spent on extending the drive and passing it through the engine's installed CAS onto a second CAS just used for the experiment would make a nice electro-mechanical engineering undergrad project.

[XGTRX]

I spun em up on a drill and still had the above mentioned problems. So it eliminated the belt theory.

[GTSBoy]

I spun em up on a drill and still had the above mentioned problems. So it eliminated the belt theory.

I had a thought about that when you first mentioned it but didn't say anything because I'm not sure if it would be significant enough to cause any problems. But.....just in case.....AC electric motors do not spin at a constant angular velocity. They move at a range of angular velocities centred on the average velocity. For something like a power drill, I'm not sure how big that variation is relative to the average velocity. I think DC motors may also have some speed jitter (depending on the motor type - stepper motors certainly do).

As I said, possibly not relevant, but worth considering when designing experiments!

[SimonR32]

my car:

pfc, stock belt, ati balancer, big cams. see the bottom plot. that's too much timing scatter for my liking.

Looks like 1000rpm fluctuations on the last rpm pull which I assume is 3rd gear. I agree that's too much scatter, mine is only a few hundred rpm max which I can live with

[XGTRX]

We spun them at varying rpm and rev synch captured the triggering waveforms and saw that the optical sensors missed triggers and also moved the edges, as in the tdc trigger was moved ahead or behind a 24 pulse trigger if that makes sense. With the hall effect trigger on the cas there was no such discrepancy. It was exactly the same events that were occurring on the engine and they were occurring at the same time. So the conclusion drawn was that the optical sensor was the problem, seeing that the same issue is common place with rbs, I thinks its a reasonable conclusion to draw, and to solve the problem any hall effect setup off the crank or even a cam only hall effect trigger will work.

I have never seen a hall effect trigger system not work.

[Scott Black]

I will admit as a mechanic i have seen more problems with optical sensors on stock cars than hall sensors

[GTSBoy]

You're right - when doing back to back of what the optical does compared to the hall effect when both are driven the same way, then if one works and the other doesn't, you've proved that hall effect is better. I still wonder if drive speed jitter might (or might not) have an effect on exactly why the optical sensors don't work, but ultimately it doesn't matter. They're demonstrated to have a problem, and really that's all we need to know.

[Badgaz]

I still think its the optical pickups in the cas that are the problems, because even with a 24/1 aem trigger disc i still saw issues, when we hacked up the cas with a hall effect pick up with 24/1 set up, had no problem.

agree with you on this...we had this same wavey cas signal on the dyno...replaced it with another cas and no more wavey. the bearings on both cas were fine but the signal was different. initially thought it might be cas because when we put timing light on the marks were moving forward and back about 10mm.

Edited January 12, 2015 by Badgaz

[XGTRX]

I still wonder if drive speed jitter might (or might not) have an effect on exactly why the optical sensors don't work, but ultimately it doesn't matter. They're demonstrated to have a problem, and really that's all we need to know.

Not sure on this only because the cas disc runs both cam (360) and crank (6) so ultimately if the cam belt is slapping away it still wouldn't affect the phasing or referencing of the cam to crank triggers because they are on the same disc. The two triggers are not separated by the cam belt. However by the optical sensor missing counts on the 360 cam triggers then you could see how the rpm trace variations occur. 3-10 missed counts and you have 3-10 degrees timing variations as can be seen on a few traced posted up. If the cam belt was slapping around at extreme levels then you would have other issues, but the rev signal trace itself would not be affected, as in, it would not change the phasing between cam and crank triggers because they are on the same disc

[GTSBoy]

No I was talking in general about speed jitter - wondering whether diffraction effects might be affected by it and so on..... and this would extend to being driven by supposedly stable drives like a drill too.

One reason why the 360 slots might behave differently to the 6 slots could be because they are narrower. Would definitely affect diffraction (if diffraction was an issue).

[r33_racer]

This is how I made the cam bracket to hold a Honeywell gt101dc sensor and the trigger edge to bolt in place of the exhaust camgear washer.

Its all kept close to the gear and it attaches to the factory cas bracket.

Might help others if they want another way to go about it.

Nice work on your setup too mate! Another kit out there will certainly help the RB community.

[Badgaz]

This is how I made the cam bracket to hold a Honeywell gt101dc sensor and the trigger edge to bolt in place of the exhaust camgear washer.

Its all kept close to the gear and it attaches to the factory cas bracket.

Might help others if they want another way to go about it.

Nice work on your setup too mate! Another kit out there will certainly help the RB community.

whats required to wire this up?

[r33_racer]

Honeywell sensors (1gt101dc). Is that what you meant?

[Badgaz]

its alright i think i found the answer when i looked up the honeywell part.

[murrayis]

Ok guys I've had alot of PM's from people interested in buying a set once they go full swing so I've decided to compile a public list.

If you are interested in the second full batch post your interest and I'll add you to the list.

Currently the first batch has been delayed as the factory producing the first/sample batch has had no power since Sunday so they have not been able to ship my items but I was promised last night when I finally got them on the phone that they would ship today....

Cheers

Cameron