[EF Ian]

Sorting out the specs on my wiring harness for my RB26 Swap.

I'm wondering if its worth upgrading to a crank trigger setup or not?


I'm sure it would be an improvement but how much? My engine will be mainly road use but will also be used for track and drag days with an 8000rpm limiter.

I guess I can't run sequential fuel injection without it so it would be worth it for this alone possibly.



ECU is a Link G4+ Extreme.

 

[R32 Combat]

If you can, do it. Massive stability gains to be had.

 

[EF Ian]

I guess if possible I might aswell as I guess there are no downsides to using this upgrade. I am thinking of using the MGT kit.

 

[Sub Boy]

Well worth it.
This is inherent problem with the RB CAS system, it will mean you will be able to get a more accurate tune without having to pull timing out to be safe.

 

[MGT Motorsport Ltd]

Sorting out the specs on my wiring harness for my RB26 Swap.

I'm wondering if its worth upgrading to a crank trigger setup or not?


I'm sure it would be an improvement but how much? My engine will be mainly road use but will also be used for track and drag days with an 8000rpm limiter.

I guess I can't run sequential fuel injection without it so it would be worth it for this alone possibly.



ECU is a Link G4+ Extreme.

Hi Ian



It is a no brainer. We have done lots of cars with the trigger kit and the results speak for themselves. In our opinion, the best thing anyone could do as an upgrade to their car is fit a trigger kit and get rid of the old cas sensor.





Regards Mark

 

[Piggaz]

Below are some logs taken off my own car. A picture always tells 1000 words.

Nissan OEM CAS

Ross Trigger

Pretty clear really.

 

[MikeyB571]

Just a little something to add here.
As you have all pointed out that oe cas sensor is not very stable and getting a trigger kit will solve that issue.

But the other main reason for going to a trigger kit is because the nissan engine does not have a crank sensor at all which is really crap actually. Almost all other engines have a dedicated crank sensor and a separate cam sensor. The oe cas sensor provides a fake crank sensor output which is always aligned to the cam position.
So effectively adding the dedicated crank trigger wheel means that you can actually spark at the correct crank position regardless of timing belt induced timing skater.

I use the MGT trigger kit and works lovely.

 

[R32 Combat]

Typically, a cam sensor gives the ECU the engine position in the firing sequence and the crank sensor tells the ECU crankshaft rotational position.
The CAS unit is very good and has a massive accuracy advantage over any other system, its just a shame it's mounted on a belt driven camshaft. If the camshaft was gear driven, like it should be, it would be perfect.

 

[FRRACER]

Is it the belt stretch that throws the cas out of accuracy with an OEM ecu? I know the issues with aftermarket ECU's not being able to read 360 pos trigger disc and most change to an AEM 24 pos.

 

[R32 Combat]

Is it the belt stretch that throws the cas out of accuracy with an OEM ecu? I know the issues with aftermarket ECU's not being able to read 360 pos trigger disc and most change to an AEM 24 pos.

Its not belt stretch, its whipping that cocks it up. Well, the cas always reads camshaft position but the ECU really wants piston position.
Older CAS units fail due to the glass degrading and fogging up. So, as the ECU cannot read 1deg increments it defaults to 60 deg marks.

 

[Asim R32GTR]

Is it the belt stretch that throws the cas out of accuracy with an OEM ecu? I know the issues with aftermarket ECU's not being able to read 360 pos trigger disc and most change to an AEM 24 pos.

If you open up a CAS you will see there are 360slots for each degree of crank rotation, and there are 6 other slots for TDC on each cylinder.

When the cambelt flexes, it does not take much movement of the camshaft to disturb the 360 slots, and that makes the ignition and rpm of the engine unstable, as seen on the log`s by Piggaz.

The worst case i have seen is 9degrees of ignition movement due to the flex in the cambelt. And you dont want that at 8000rpm and 2.5bar boost

 

[lightspeed]

Other issue is worn spline drive in cam or CAS. Also the O ring should be a tight fit.

 

[FRRACER]

Are the later R34 cas units any better? Better just to buy a new cas?

 

[Piggaz]

Is it the belt stretch that throws the cas out of accuracy with an OEM ecu? I know the issues with aftermarket ECU's not being able to read 360 pos trigger disc and most change to an AEM 24 pos.

Ever seen the timing belt on the dyno with the cam gear cover off? It's a good thing that cover is there. Out of sight, out of mind. It flops around like a pogo stick. Definately a design oversight.

 

[Piggaz]

Are the later R34 cas units any better? Better just to buy a new cas?

New CAS or not, it won't fix the issue. It may improve, MAY, but won't fix the cause of this problem.

 

[nightcrawler]

thinking of getting this kit but on a fast road standard internal engine car? the graph comparison suggests it is better to have a trigger kit but is this not an overkill for road use cost wise? or spend the money on something else instead?

 

[MikeyB571]

In my opinion it is worth it, even modern fuel efficient cars benefit from this. Accurate timing is essential for power and economy.

 

[Piggaz]

thinking of getting this kit but on a fast road standard internal engine car? the graph comparison suggests it is better to have a trigger kit but is this not an overkill for road use cost wise? or spend the money on something else instead?

Have seen a low km very basic build (-9's, Power FC, exhaust, etc etc) low kms R34 V Spec II suffer from this quite bad. It definately isn't limited to "built/angry cars".
It generally isn't cheap, however.

 

[nightcrawler]

^^^ definitely because its not just the trigger kit alone, its the damper as well. but the rb26 was fine before this came up. definitely a good upgrade, however is there a massive noticeable difference?

 

[EF Ian]

Thanks for the replies, can see a good difference on those graphs.


I'm going to definitely try and use a trigger setup now, don't want to skimp on my setup, not going for crazy HP but rather have everything else spot on so that I can get the best from my choice of turbos. I believe I can't use sequential injection and ignition without a crank and cam trigger which is another good reason for this.


Wonder why they used a belt instead of a chain, there must have been some advantage because the RB is based on an L series and the L series used a chain so seems weird why they would skimp on an engine as complicated as an RB26.