Timing Fluctuations In Rb26/30

[D_Stirls]

i have heard of CA's having the same problem, there is a data log file in the Haltech formus that shows the CAS signal from a CA that was inflicted with this issue.

EDIT!! Here is it.

[KiwiRS4T]

Talked to the Link factory in regards to high revving RB26s and they say they reccommend an alternative triggering system. Doesn't apply to me as my RB30 won't be going over 6800 so I don't know what people are doing but there are two or three different approaches. I read about a year or so ago that Unigroup had such an alterrnative triggering system?

[Scooby]

The Unigroup one is the one they developed with Ross. $2k (plus $1k fitting). It's happening in my car and another on here at 5500, so well before high revs.

I'm going to talk to CRD again today to see if I can find out more about what they do.

Edited January 27, 2011 by Scooby

[JAGR33]

Paul from Red R Racing had similar problems but came up with a cheap solution by modifying the standard CAS. Maybe get in contact with him to modify yours before spending the big bucks?

[Scooby]

Sounds promising, I'm betting Paul's solution and the CRD solution are one and the same since Paul used to get his Vipec tuned there.

[Marko R1]

mark - the way you fix your issue is take it to crd

a few of us here have heard this timing issue more than a few times with unigroup, however, jim @ crd has NEVER raised this sort of glitch with my setup (food for thought)

ive heard very good things about yavus though

[Dose Pipe Sutututu]

Interesting read, I've never had this problem because my old R33 wasn't a power house, but I'm imagining that because of the massive ramp in RPM, the alternator could be producing sht loads of current and the rectifier isn't keeping the voltage flat.

Perhaps try soldering an inline capacitor to the +ve of the CAS or just run a big car audio capacitor to minimise voltage fluctuation.

Hope that helps.

Imagine people were just soldering on capacitors? $2 piece of silicon charging $500+

[Beer Baron]

I don't think it's so much electrical interference as it is physical 'noise'. cas is rotating fast and if a bit worn etc gets problems. the other side of it is the type of ECU being used. some are definitely more prone than others. there is a cheap trigger disk solution, or the best fix is the crank damper pick-up but as stated above it's not cheap.

[SirRacer]

what are the symptoms of this issue?

[RRob]

The cars I deal with suffered misfiring on ramp up and at high RPM.

[Aleckr33]

The Unigroup one is the one they developed with Ross. $2k (plus $1k fitting). It's happening in my car and another on here at 5500, so well before high revs.

I'm going to talk to CRD again today to see if I can find out more about what they do.

Is this what price im looking at to get my CAS fixed..? :S or is this a new one?

Edited January 28, 2011 by Aleckr33

[Scooby]

The symptoms are described here in a thread from the Haltech forum:

http://forums.haltech.com/viewtopic.php?f=23&p=28152

and here

http://ljracing.co.nz/

Spoke to Haltech today, they said that their Platinum ecu has no problem handling the Nissan CAS signal but they're aware that some ecus do. Also read that somewhere that one got their hands on the patent for the Nissan CAS signal sensing and it was very impressive in terms of sophistication, so could probably work well with a 360 slot CAS trigger wheel.

Also Mark from Godzilla was as always very helpful, he hasn't invested in the trigger disc solution but has heard of it and was talking to Speedtech NZ who apparently have trigger discs made up. Then it's just a matter of telling the ecu to run 12+1 or 24+1 depending upon the wheel. Irrspective of who's solution it is, modifying the CAS can't be much mre complicated than that as there's not much in there.

Yeah Marko there's no doubt that CRD will know what to do, but I like to have some idea of what's being done to my car for future reference, no matter who does it, and at the moment they're not giving anything away. Respect their position but hey, it's my car.

Richard you refer to a cheap fix but do you know anyone who actually does this in Sydney?

Jack thanks for the tip re Red R, I'll get in touch.

Aleck no mate that's for a full crank trigger system that's good probably good for 10k ish rpm plus. Hence why I'm after what appears to be cheap and effective solution.

Edited January 28, 2011 by Scooby

[Scooby]

double post

Edited January 28, 2011 by Scooby

[Rolls]

could the trend be the ecu thats being used?

Most of the trigger issues are with particular ecu's not liking the nissan pattern.

Maybe post the ecu's (and engine combo) that are having the issues?

I can say its not inherent in nissan CAS's especially in these cars which are being mentioned.

A simple way to tell would be to just an oscilloscope on the CAS signal and see what it looks like at 7000rpm pre and post loom, if its clean on both then the issue must lie with the ECU.

[Scooby]

Quick update, used another CAS and got to 6k rpm before the scatter appeared. As per Jack's suggestion got in touch with Red R Racing, Paul was very helpful and is sending down a CAS with a 24 (?) slot trigger wheel to try so looking forward to the results. Will post again when results are known.

[Supa Steve]

If its the same one i have on my engine then it should solve the issue. 24+1 i think is whats in there, Paul gets them lazer cut locally and they work a treat.

[JAGR33]

Quick update, used another CAS and got to 6k rpm before the scatter appeared. As per Jack's suggestion got in touch with Red R Racing, Paul was very helpful and is sending down a CAS with a 24 (?) slot trigger wheel to try so looking forward to the results. Will post again when results are known.

Good stuff mate, it will be interesting to see if it eliminates the problem.

Keep us updated......

[Guilt-Toy]

steam ftw

i have heard of CA's having the same problem, there is a data log file in the Haltech formus that shows the CAS signal from a CA that was inflicted with this issue.

EDIT!! Here is it.

[HYPED6]

Wow, I really didn't think this was a topic that was soo miss understood.

Timing jitter is something that has plagued RB engines since the dawn of time. The worst is the 30 single cam.

Now fact of the matter is, you are measuring the crank off the camshaft. Now between the crank and the cam sensor we have......

A bearing that the sensor shaft runs on.

The shaft it self that goes in the camshaft.

A rubber belt.

Now, there is an easy way to diagnose if you have timing jitter. Lock your ignition timing. Grab a timing light and slowly rev your engine..... and watch the timing.

You will see as your belt gets harmonic vibrations so will your timing. Every RB does it. Just some do it worse than others.

Now, there are some fixes. using a dual pulse disk can help. It basically dumbs down the CAS so its not as accurate but helps jitter.

The best option is measure the crank off the crank. I have just been involved in making a bolt on billet kit for RB series engines. We started with a 72+1 then tried 72+1 with a missing tooth.

The problem we had was the sensor we where using wasn't fast enough to read it at 9000+ rpm.

We ended up with a 24+1 setup so RPM is never an issue and still more than enough teeth for accuracy.

I have personally seen engines sooooo bad that the timing marks disappear off the balancer.

[Scooby]

Gday Sean

Ross make a kit, it's $2k or $3k fitted. How much is yours? Bring it on, the Ross set up is the only RB crank trigger kit I can find.

Care to post a few pics?

Edited February 7, 2011 by Scooby