Jump to content
SAU Community

Recommended Posts

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 

  • Like 1
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.

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?

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. 

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

 

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.....

engine complete.jpeg

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.

EDEA9838-6497-4A64-B446-BA40E6FCC4A6.png

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. 

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

  • Like 1

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

big prp.jpg

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

60240AB1-3A91-42F9-B843-296E56989199.jpeg

630FE0DE-F0A6-4A68-B590-AB0CF669B47F.jpeg

99B5CD67-DECB-4B09-A17C-54524D4E4ABB.jpeg

29E52E2F-FA6B-43E2-9DC3-8E4771FC899E.jpeg

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

BCD07A12-B5CD-4F30-94C2-2356FCFE7B24.jpeg

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.

631F07A1-4C6D-45BD-A3F2-B6AC3152CC6B.jpeg

332AE918-4F6E-415B-ACC1-9C8B9ED3B18A.jpeg

  • Like 2
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.

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!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • More assembly going on, with all sorts of "bolt right on bro" scenarios going on here. Smartly, PTV clearance was checked. And I say smartly because it turns out that the intake was 0.009" from piston meeting valve. This is 0.23mm. This is very not okay. A fast meeting was facilitated between engine builder in Australia and engine builder in the USA which was actually incredibly helpful and constructive actually, various ideas thrown around to get around this issue including: 1) Retard the cam timing which would have brought the exhaust valve closer to meeting piston (it was 0.065") which was uncomfortably close to begin with, and change the cam profile making it 'laggier' 2) Much larger head gaskets which would reduce compression, but half the point of this was to increase compression. 3) New set of pistons ($$$$$$$$$$$$$$$$$) 4) All of the above 5) Get ghetto The concept is you get sticky sandpaper and stick it back to a valve, slightly larger than the valve you/I'm using, like say from a LS3/rectangle port head. You now have a very super advanced flycutting tool to modify your pistons in your block. Then you install it in your head, and attach the other end of the head to a drill. Then you just replicate your valve smashing into a piston with your spinning drill.   This is the result. Repeat many times. It is strongly recommended you have some kind of fixed stop when doing this for extremely obvious reasons because if you press too hard then you're well into apocalyptic repercussion land. The minimum clearance on the intake valve is now 0.075" this is still in the "Too close to be really comfortable" and into "It should be fine" land. Supposedly in the real world the clearances will be slightly bigger. Guess this is what happens when people push envelopes for N/A engines instead of adding boost! Time to move onto the new, upgraded, higher ratio roller rockers from Yellaterra, all tapped and threaded with a stronger bolt for better stability. Very nice. Lets see how they fit. For f**ks sake. Time to bring the grinder out for these aftermarket, machined and CNC'd heads. Looks like the new, beefier rocker from YellaTerra has gone from Bolt on part to "Bolt on part". Well, lets see how this bolt on crank scraper and windage tray goes then, shall we? There actually is more clearance than they specify for this thing, but seeing it all move as you check it is terrifying when you see it all so very very very very nearly hit things. But after all, this is what the item is designed to do after all and actually did bolt on perfectly and have enough clearance to everything and some very clear and direct instructions. So +1 to Improved Racing I suppose. As above with the windage tray on. Photo of breaker bar wonkiness for added lols. Next up: Oil pump/front cover/water pump/sump and then it's time to actually install the heads, pushrods, head bolts, valve cover gaskets and such is all there and ready to go. (except the oil pump bolts which were previously longer for more clearance with the previously perfectly installed double row timing chain). There's definitely a sense that someone other than us has been here before and done everything perfectly, or at least considered it and came up with working solutions. Perhaps the previous cam was 6deg advanced to avoid PTV issues with the milled stock heads? In any case when I attempt to sell this stuff the buyers are going to be very directly informed.
    • my catch can is pretty easy to empty but it overflows due to the blowby/crank case pressure etc. max I have drained is ~600ml even with a ~2.3L capacity. So it is not just about having to drain it out its the mess it makes down the firewall and under the car and rear passenger tyre from the overflow oil being blasted by screamer + air in general. Ending up on the ground cleaning the oil up and having oil on your arms when everyone else can chill and watch the other sessions gets old fast
    • Yeah - the secret learned a long time ago is that the RB likes to belch oil out the covers, and/or starve the pump because it drowns the head in oil, because the upflow of crankcase gases from piston blowby comes up through the oil drain holes in the block and prevents the oil from flowing back down. The external vents from sump are about creating an alternative path/much more XS area for gas flow to decrease the gas velocity up through the oil drains and allow the oil to get back down. So, it's not about pressure at all. It is about flows - gas up and oil down - or when it's not working, gas up and oil not going where it is supposed to after it arrives at the top, except out through the cam cover vents. And regardless of whether the catch can is vented to air or vented to the turbo inlet, it must still be vented because a sealed system would blow out the crank seals, or something equally bad.
    • I just used a can that's easy to empty after every session and pour it back into the fill hole. Takes about 40 seconds when you have 40 minutes between runs :p I don't see how changing any catch can stuff will reduce pressure if the system is sealed. And if it's vented - Does it matter where it's vented with regards to overall pressure?
    • Welp, too late already committed to the cam cover breathers to be welded on. I did think about adding a catch can in line with the drivers side sump breather as a phase 2 along with a drain to the sump on the original catch can but with an inline ball valve so I can have it closed if needed.    Likely a single breather would have been enough but I think I’m overcompensating to hopefully not have to empty my catch can and clean up oil over flow every session.    out of curiosity has anyone actually measured crank case pressure before and after various mods? I’m considering adding a sensor for science 
×
×
  • Create New...