SR20DET CAS Woes

[DanielCPG]

Hello

I've come accross a very detrimental issue with the SR20 Cas. Most people are aware by now that if running a stock nissan 360 optical sensor and disk you will most likely experince sync issues in the higher rpm. One possible solution is too fit a 6/12 tooth disc.

I have run the 6 tooth disc with success on 2 ADM S15 cars, and failed on 2. 

On the cars i claim it does'nt work on, this issue is this.

Whilst cranking i experience an Extra tooth on the trigger scope. It shows 6 defined teeth and a quick blip making a 7th tooth. I tried running new shielded wire to the ecu, completely separate to the original loom. I tried running 12v power source directly to battery, but i could not eliminate this eradic signal. In the end i believe that when the Cas voltage drops, while the starter is running, the CAS sends erroneous signals. On this specific vehicle i replaced the starter motor, and low and behold the 7th tooth disappeared and the car runs fine. 

On another vehicle i fitted an aftermarket trigger kit, eliminating the stock cas, but utilising all factory wiring,. Same results, went from not being able to start, to running.

I wanted to provide a scope of the issue but i currently have run out of 6 tooth discs, I did however do a trigger scope with the disc removed completely. I shows many pulses from 0v to 3+v. I could be wrong but i dont think this is correct.

In summary im at a point where i dont believe i can satisfactorily tune a link ecu in a 200sx/skyline without some alternate Trigger system in place, Which is a cause for concern as i believe customers will want to use competitor ecus. 

Im keen to know if anyone is experienceing any similar issues and how they are correcting it because, as far as i can tell, the issue is only localised to me, which i find hard to believe.

 

 

Dimi Cranking no disc, car power supply.llgx

[Adamw]

I have done 3 SR20’s on G4X with stock CAS with no drama.  Only mild cars with stock cams however.

I believe the optical sensor in the Nissan CAS doesn’t like long slots/ windows on the outer ring, they start to behave random like you have seen generating extra teeth or skipping teeth etc.  Generally the 24 slot ones work ok if they are cut well.  I had an AEM one years ago that the slots weren’t on quite the right PCD and that done weird stuff too.  

Having said that, there have been a couple of adjustments to the 360 opto triggermode recently that gives a couple of extra degrees tolerance to the sync positions which makes it a bit more robust, so make sure you are using the latest firmware.

[Brad Burnett]

On 11/27/2020 at 5:41 AM, Adamw said:

I have done 3 SR20’s on G4X with stock CAS with no drama.  Only mild cars with stock cams however.

I did a couple SR20s on stock cas with no drama 2 weekends ago.  This was on beta software/firmware for the comms issues.