I’ve seen these billet crank triggers but don’t know much about them, I’m building my motor now and I’ve removed the balance shafts. Is it worth putting one on? My motor will be a powerful one! Haven’t seen any info on them on here so any info will be great cheers

 

These are for stand alone ECU's. Nothing to do with how much power it might make.

 

Just to expand on what Sean said, you cant run that trigger with OEM Ecu. At least I havent seen code that will adapt to it.

You need it for something like AEM that requires a full signal cycle before setting the bit to enable starting. With OEM you'll end up cranking a full revolution before itll try to actually start (basically like a ducati).

Beyond starting, maybe someone else knows better if AEM (or other standalones) use the finer resolution for anything more.

 

Its going to offer more resolution for a standalone for starting,crank position,timing and knock events etc.. Its a good idea to upgrade to one with most aftermarket ecu's IMO.

 

Yes I’ve got a link g4+ ecu for my car so would it be worth getting the kiggly with this?

 

I would ask your professional tuner. I've heard a link ecu on an evo and the rpm cut was clean/crisp and not rough/jagged.

Here is a thread I found on it. This is what link stated.
"At steady state RPM there is not a lot of noticeable difference between a high or low tooth count. However there is a big difference when the crankshaft is accelerating or decelerating at high rates. A low tooth count wheel doesnt update engine position as often so the ignition advance calculation will lag behind the change in engine speed. That results in significantly more ignition advance being applied during acceleration. Many years ago when I first started playing with EFI most ECU's could only decode "1 edge per TDC", back then it was not uncommon to see 10-20deg of timing drift with a quick throttle blip. Starting was often an issue also as the crank acceleration at low RPM caused lots of timing scatter.

On low tooth count wheels like the OEM evo one we look at both the rising and falling edge to improve the situation a little (so 4 updates per rev) but still it is not ideal for a high performance engine."

http://forums.linkecu.com/topic/7038...trigger-setup/

 

I'm fortunate enough to work for a major OE doing engine development and we have encoders on our cranks that are accurate to 0.5* of crank rotation.

Being able to see combustion pressure vs crank position, and thus have real time knock detection is a real eye opener after you start working with advanced systems.

I can't imagine how poor the data would look with a 2 tooth trigger wheel. Knock detection is pretty much a shot in the dark on a system like that. As well as the aforementioned part about ignition timing during nonsteady state crank speeds.

For reference, most engines nowadays use at least a 36-1 or 60-2 tooth wheel. So 12 may be the best we can do right now but it's still a large step in the right direction.

 

12t - 1 (for zero location needed on AEM) would give you 22 edges. They're 15deg spread between edges except where the tooth is missing for orientation. Much better than the ~60deg and ~120 deg spread (just guessing off picturing stock crank trigger in my head). Certainly nothing compared to looking at crank speed with 0.5deg of resolution. Thatd be interesting to see a standard graph of the crank speed and how much it changes in a single rotation.

 

The Kiggly stuff doesn't use a -1 config, just 12 teeth. So it should still need a cam sensor to locate #1 TDC. Not really an issue, just makes for a slightly different starting fire trace.

3 cylinder stuff is usually pretty unstable between power strokes but even on 6 cylinders if you don't filter the torque channel you can see torque spikes from individual power strokes at low speeds <2500rpm. There's a LOT of torsional stress from it and once you look at 100hz data of crank speed it becomes pretty obvious.

Getting to see how pressure curves change as knock gets more intense is also pretty interesting. You'd be surprised how many counts of knock you have to have to actually get undesirable pressure spikes, but that's also highly dependent on detection sensitivity so YMMV.

 

A 1-tooth trigger wheel with a very precise edge can, in theory, provide decent angular resolution at steady-state RPM. I'd bet the ECU even estimates 2nd order effects during acceleration. Obviously it's working well enough for everyone to pull high power out of the OEM Evo ECU all of these years.

A 12-tooth trigger wheel is always going to provide more resolution and more accurate values during rapid RPM changes, but I don't know how significant that is for normal operation. Can tuners normally operate closer to the knock threshold with aftermarket ECUs and 12-tooth wheels?

I don't know the answer, but if I was investing in an aftermarket ECU I'd definitely change the trigger wheel out. The only problem is that you can't easily swap back to the OEM ECU for emissions testing, so you're full race car at that point.

Cylinder pressure sensors are at the top of my dream list of engine sensors. Kistler and a few other companies make spark plug cylinder pressure sensors for tuning use. I haven't checked the price, but I'm guessing a set of 4 of those would cost more than a 4G longblock.

A while ago there was some research about using ion current across the spark plug gap to measure cylinder pressures after ignition. I'm still holding out hope that some company turns that into a usable product for us lowly consumers.

 

You've never find vibration compensation controls in an ecu. It's not a limiter for power, moreso for engine stability, NVH and not accelerating wear. But at the end of the day there's no way to control natural frequencies with electronics. We look at anywhere up to 6 orders on cranks, usually you just kinda have to shoot for whatever is the least of all evils on design.

We have some of those Kistler spark plug transducers around still. They're kinda old school and from an OE perspective their resolution is meh. They run a couple grand a piece. Cylinder pressure is not something that will be portable data anytime soon. You need a TON of computer processing power to be able to log data at a useful rate and any trigger that gives more than 2* of crank rotation for accuracy is useless above a few thousand rpm. Even with 0.5* it's a struggle to get good data on high cylinder count motors that spin over 7k. They also die pretty quickly after they've been exposed to enough knock.

 

When I was looking into AEM stuff, It was mentioned a bit that it was needed to cut one tooth. But I haven't looked at it for a while and may misunderstand whats needed.

 

I really dont like the 12 tooth since you have to remove the balance shafts and stuff. I might go a different route. We had some 60-2 wheels cut a while back so that we could run Lexus engines off GM ecus. It looks like I may be able to bolt it on my ATI balancer and run an external sensor. I will find out later today when my balancer shows up but I really think this is the route I am going to go, even if I have to get a different reluctor custom made.

 

Balance shafts? Hah, not an issue here

 

And when using the 12 tooth crank trigger, one of the cam sensor triggers is modded to have one tooth. At least on the infinity I know it does. So your correct.

OP, since you have an aftermarket ECU, if it supports running the 12 tooth trigger, it's definitely a good idea.