RB26 CAS Issue

[Dennis Wiese]

First of all, sorry for my bad english.

I have some trouble with my stock Nissan Opto 360 CAS. Revs are fluctuating. I tried the Low resolution mode, it is a little better but the problem isnt solved.

My question:

Once i had my Opto 360 engaged (24 Degree widest slot, it works, so i think it is the right slot, isnt it?), can i tell my link to use only trigger 2 with the opto 360 (for widest slot) and set trigger 1 to Hall sensor with one of your Triggerplates (which one should i use, where do i get one?) boltet onto the crankpulley?

Can i order one of your triggerwheels und one of your hallsensors here.

Thanks a lot,

Dennis

[Adamw]

Yes the RB26 CAS is often troublesome.  There are two issues - 1. the decoding power needed at high RPM & 2. the mechanical backlash in the drive system when coupled with valve train harmonics/belt whip.

To change to a proper crank trigger setup does involve quite a bit of engineering work or money to do it right.  Not only do you need to mount a trigger disk and sensor on the crank but you also need to modify the cam sensor to give only one pulse per cycle.  There are kits available from companies like ross balancers but you are looking at ~$1500. 

For a high output big dollar race engine then crank trigger is the best option. However for a less serious engine you can usually get reasonably solid triggering without going to such an extreme:  Ensure all mechanical elements are good - the cam belt, pulleys, tensioner and the CAS spline drive must all be in good condition with no play.  Change the disc inside the CAS to an aftermarket one with less slots (google AEM 30-8761) and you should be good to go.

 

[Dennis Wiese]

Thanks a lot for your quick answer, Adam.

I´ve ordered one of these discs. How do i have to set the triggers with the new disc?

[Adamw]

Setup like this:

Then just do the trigger offset calibration as per the manual.

[Simon]

If the single sync goes past the sensor before TDC on compression #1 by say 30deg then the offset will be -30

So to get close you need to know the position of the sync.

[youask]

got it right and started

 

but my trigger signal/rpm jumps around above 2500rpm , if i log it can go from 5300-5600-5500, ive checked the wiring and also tried new wiring between cas and ecu

[Simon]

Try changing the trigger two edge. This might help.

Ensure all mechanical elements are good - the cam belt, pulleys, tensioner and the CAS spline drive must all be in good condition with no play

[youask]

i'll try to change from falling to Rising on trigger#2 (cam sync) when I get home from work.

Cam belt pulles, tensioner etc is brand new. Spline drive is without slack, I get the same problem when I try running the CAS with a drill and the coils and injectors unplugged.

PCLink also reports quite alot of trigger errors, especially aroung 2500rpm but also in the higher range. ( Trigger1 Err Count) both sync signals says OK and car runs but as smooth as it should.

I've tried with 2 other CAS's also and tried to hook up +12v and ground direcly from the battery as well as a new shielded signal wiring from trigger#1 to the ECU.

[youask]

(not as smooth)

[youask]

partially solved.

going from falling to rising did nothing on trigger#2

 

but i taped 2 holes on the 24 hole trigger making it a 24-2 and left the cam sync hole

Change settings to tooth/missing and setup 24 with 2 missing and left trigger2 as it was before.

Now all trigger errors is gone and rpm is MORE stable (not as stable as i want but way better)

 

Doing some more testing this weekend.

[Steve1436215419]

Example of the sollution to your problem can be found here.

 

http://blog.rossperformanceparts.com/category/crank-cam-trigger-kits/

 

Do something like this or live with timingscatter.

[Simon]

The Ross kit really is very good and on big HP applications a almost must have.

[youask]

i can live some scatter :S

the ross kit is so expensive

I did a testrun with the car yesterday, now the trigger errors is gone when i use drill on the CAS but when i drive i got SERIOUS missfires (AFR = ok and spark is great (VAG coils) above 6000rpm. It's undriveable above that. Showing up lots of Trigger errors.

I'm gonna try Another CAS first then if that don't work i'm gonna fabricate a 60-2 crank trigger with a gt101 sensor and used the stock cas and aem disc as a camsync

[Simon]

If you go with the GT101 avoid using the high tooth count, go for a 12 tooth wheel. The GT101 is not good at high frequency.

[Simon]

Also forgot to mention that if its only becoming an issue a high power levels be sure to check for any sources of electrical noise like a coil arcing out the side.