Canada 1993 gtr ready for action

[r32-25t]

The trick is to make sure the home signal is halfway between 2 teeth, then the slack in belt can’t allow it to count an extra tooth/one less tooth because the home signal moved 

[BK]

17 minutes ago, r32-25t said:

The trick is to make sure the home signal is halfway between 2 teeth, then the slack in belt can’t allow it to count an extra tooth/one less tooth because the home signal moved 

Exactly. This is precisely why the cam home housing is adjustable to achieve this. On a Haltech Elite you have to set it up reading the channel "Home percentage of valid travel" and aim for 50%. When running I know mine fluctuates between 48% - 52%, showing indeed how much belts do deflect.

Not sure if this channel is on the Platinum - hope it is.

[Unzipped Composites]

56 minutes ago, BK said:

I believe (pretty sure) it doesn't support a missing tooth on crank anyway. The Elite can support lots of different trigger types / patterns and the Platinum supports just one. It uses a 12+1 setup (which in that ECU is configured as a 24+1),

 

 

This is exactly why they make the crank trigger wheel as a simple 12 tooth wheel and just give you the option of removing a tooth yourself, because it gives you flexibility. Not every ECU supports every style of trigger wheel (and there are dozens of styles, it can get really pretty confusing). It isn't hard to remove a tooth, so it's better to provide it with all 12 teeth and let the end user decide what they want to run.

 

And yes, it is obviously more complex than my short post could sum up. Realistically you've got 3 ways of using a crank trigger wheel; multi-tooth missing is the simplest because it tells your ECU how fast the engine is spinning, but it can't support sequential ignition because it doesn't know if the engine is on it's compression stroke or it's exhaust stroke. Which is why using the camshaft is easier, because it only has one rotation per engine cycle, so the ECU knows which stroke it is on. But because you have the issues with belt slap and the associated inaccuracies which is why we are all here in the first place, the cam is also a bit unreliable. So then you have your multitooth wheel plus sync input from the camshaft, so now your ECU knows how fast your engine is spinning AND where it is in the cycle. But now your whole ignition system is completely dependent on that sync signal from the camshaft, and it becomes critical that your sync signal is exactly half way between your two crank speed signals. Which is easy to setup at idle and low rpm, that's fine. But at high RPM, you go back to having the inaccuracies from the cam signal because of belt slap and the harmonics of the valve train, and you need to watch that those signals don't cross over teeth and the engine loses it's position. And that's where the multi-tooth missing plus sync input improves reliability, because as long as your sync signal doesn't occur where crank wheel is missing a tooth then the ECU is always going to be able to know where everything is.

 

Obviously at the end of the day, it is all a trade off and there is no 'correct' answer. The more teeth you have, the smaller the gaps are between the teeth and the more information the ECU has about the engine position and the more accurate your timing can be - BUT, it is also harder and less reliable to get the sync right. A 12 tooth wheel is more forgiving with the sync signal, because the gaps between the teeth are larger and you have a larger window for the belt slap to play out and the sync signal to move around without crossing over teeth and losing position. But it is also less accurate because of those bigger gaps between the teeth which is essentially dead time where the ECU doesn't really know what is going on. Which is why a 36-2 trigger wheel is so commonly used in high end setups, because it has more teeth and allows a much finer resolution with timing, and still has the 2 missing teeth to make it a bit easier and safer with regards to the sync timing.

 

Realistically, you're moving from an optical cam-only based sensor which is really inaccurate at high RPM, to a crank speed plus sync sensor - you're already going to be SO much more reliable than the OEM system was. So is removing a tooth going to make your engine run any better or safer? Probably not. But on the other hand, you're moving to this style of ignition input because you wanted a more reliable system, so why not remove a tooth and give yourself that little bit of wiggle room? Obviously the decision is taken out of your hands if your ECU doesn't support it. But otherwise, if your ECU supports a multi-tooth missing configuration, I don't know why you wouldn't do it. Timing accuracy is really the only argument for it, but honestly if you need your timing to be more accurate than a 12-1 can provide then why are you not using a 36-2?

[BK]

12 tooth is generally enough for most setups, A V8 supercar a 6 or 8 tooth from memory ?, no missing teeth. Sensor type matters too. Hall effect seems to not like high crank tooth count like a 60 tooth, which is when you really have to move to a reluctor sensor with an AC wave signal. Then they become a pain because they are a lot less forgiving on the air gap, requiring definitely less than 1mm. Where a hall effect definitely has more room to move regarding air gap size.

It's enough to really make your brain hurt chasing the exact setup you want and knowing the pros and cons of each as you mentioned I guess. One point to mention is Ross crank triggers are on the balancer, so you really don't want to go cutting teeth off them, but obviously if you want missing teeth it can be ordered with the 36-2. 

[MoMnDadGTR]

the hone signal being between the 2 teeth i understood through some research and ben had given me a bit of info prior to when i bought the trigger kit...thats when my research started. i just read the last 5 posts on my own thread and heres what i got from it. IM A FAKIN IDIOT AND HAVE LOTS TO LEARN, thanks for your guys help its humbling. i might actually have a car that works at the end of the day because of you guys. thanks ben and to the rest. cheers

 

[MoMnDadGTR]

this nitto cover doesn't quite fit right with the prp trigger kit, it hits the prp bracket before it touches the backing plate. i want to cut it around the trigger kit so it doesn't interfere with it at all then ill be good i think, anyone else ran into this issue.....

[MoMnDadGTR]

Well when things are just about -60 find a fricken corner where the heater is in your house and hide. Absolute joke of a brutal winter this year. People are gunna die today from this shit.

[Ben C34]

Holy shit

that is crazy.  Stay safe

[Duncan]

looks like it is a no thongs outside day today, bummer.

hell of a swing in maximum temps over a week from -5 to 28 too.

[MoMnDadGTR]

Yeah i don’t understand.

my wife works 911 and on these days people drop like flys. People get drunk pass out and picked up like popsicles next morning. 

[MoMnDadGTR]

On 13/02/2021 at 6:40 AM, Ben C34 said:

Holy shit

that is crazy.  Stay safe

all is well mate we know how to survive this shit...side note my motor is finally fricken done and we are going to fire it up next weekend so little light at the end of a tunnel after months of ordering parts and feeling broke everyday, this process is finally almost over and yeah the common term slippery slope is an understatement when doing a 1000ish build in an area where i am the RB guy in the area, pathetic i know. been spending money, sleepless nights researching, calling companies, days at machining shop which is 400km away, tuning, wrenching on this piece everyday for the last 4 months. time to spend some time with the family and give back the time to my wife she gave to me to make this all happen. i would not own this car without her and am grateful for her ever day! where would anybody be without family really. cheers

[MoMnDadGTR]

Well even when we stuck In
The house we are still swapping twins to a single, just gotta make downpipe now lol

[MoMnDadGTR]

couple little finishing pieces from prp-canada and we will post a picture of the finished product here in the next few days. cheers

[MoMnDadGTR]

On 14/02/2021 at 10:25 AM, MoMnDadGTR said:

Well even when we stuck In
The house we are still swapping twins to a single, just gotta make downpipe now lol

Downpipe complete ready for power/dishes lol. Not well to cold to get out the house....loosen it a bit here

[Dose Pipe Sutututu]

Things are simpler with a single, better efficiency.

[MoMnDadGTR]

Finally got our new/used trucks done for the upcoming tree season. Another month and it’s hammer down time. Tracks will be open this year so let the good times role.

[Unzipped Composites]

One of the most immersive builds on SAU, its like reality TV but without the super annoying American's. Lucky you guys are Canadian! 😆

[MoMnDadGTR]

On 19/02/2021 at 8:11 PM, Unzipped Composites said:

One of the most immersive builds on SAU, its like reality TV but without the super annoying American's. Lucky you guys are Canadian! 😆

i had to google the word immersive. i work on my trucks as much as my gtr but yeah i hope not to annoy the boys under. ill stick to car posts for now on. sorry mates.

[Unzipped Composites]

No no, I wasn't being sarcastic man! I actually like it, I'm not sure why... im possibly getting old. And have read too many build threads with picture after picture of GTR + billet + Precision. Like being stuck on someone's Insta feed.

 

You do you man!

[MoMnDadGTR]

Haha all good mate, downpipe complete today!