Autronic SM4 vvti cam timing/position sensor - eccentric lobes?? a problem??

[MWP]

A common event when building a car seems to be to spend your money on quality parts.
...blah....
People are happy to spend $15 - $50 Grand building an engine over months or years with top quality parts. But then they cry about having to spend $6 or $700 dollars or so to tune it or having to leave it overnight.

I think you have already... since when was this discussion about where and what to spend $$s on?
Im sure we have all made bad judgments on this kind of thing before. Live & Learn.

ED - The Autronic will run a VVTi Toyota if configured correctly, some of the VVTi toyotas have a trigger pattern that is still in Beta testing (yes we are doing some of this testing at SAS) I do not believe this to be the case with yours. Either way, Toyota put 3 lobes on it for a reason, don't remove them unless your confident your tuner actually knows what he is doing. As a general rule Toyota don't add bits or make them harder to manufacture just for the hell of making a vehicle less profitable to produce.

Ok, yes they are there for a reason... now why?
Im here for the tech discussion. Ive designed & built my own ECUs before, i want to know why you need more than one lobe, i cant think of a reason for it other than increased positioning resolution.
Surely you cant move the cams fast enough, or have the engine change state quick enough that you need to update the position of the cams more than once per cam rev.

[The Real Roadrunner]

Ok, yes they are there for a reason... now why?
Im here for the tech discussion. Ive designed & built my own ECUs before, i want to know why you need more than one lobe, i cant think of a reason for it other than increased positioning resolution.
Surely you cant move the cams fast enough, or have the engine change state quick enough that you need to update the position of the cams more than once per cam rev.

i think what ed is trying to find out is who knows about setting up the VVTi in the 1UZ with an autronic,
of which i don't believe any workshop in the country has done so far.

the 3 lobes are only there for better resolution and having the unequal lobe seperation is to allow the ecu to know the exact cam location (i believe but i may be incorrect).

there is no reason we can't get it to work but it would be nice if someone could give exact info rather than " buy X and it will work" or "take it Y and they can get it running".

all we need to know is if anybody has measured the output on a scope and what signals it put out.

anything can be made to work with money and time, but we are trying to spend as little of both as possible to get this working correctly.

its nothing that a fabricator and a mechanical engineer can't get around but previous experiences with the system would be nice to hear.

any body know the exact timing of the cam pickups?

just to note there are 4 pickups on the engine.

1 crank signal = 36-2 (home signal)
2 cam signal = single pulse at Xdeg's for TDC No1 input (sync signal)
3 cam angle ref for left bank (3 prong unequal)
4 cam angle ref for right bank (3 prong unequal)

cheers
linden

PS toyman75, i also have access to the BETA tuning software

[ed]

its not just the beta software, i understand its an entire chipset

if required ill look into this beta release

however, the suggestion is that the sm4 i have 'should' be able to do it. what the cost is out of my pocket to find this out is the scary bit, with no known likelyhood of success. its not the absolute $ figure at all

speaking to mark yager today, he reckons no-one should EVER have to grind off a lobe, and only somone trying to find an easy way out would do it this way (though he was speaking regarding motec control systems)

the 3 lobe system he described as a 4 minus 1 trigger? the ecu logging the absence of the 4th trigger, or something like that anyway??

[oldcorollas]

if you have a picture of the sensor from on end (as close to axis as possible) it is easy to measure the angles (send a pic?) and maybe reference to a cam lobe if visible

[ed]

looks like a Y basically

ill try and find a photo of it

[gianttomato]

Motec VTC function runs it no probs with 3 lobes - needs one for ref and the other two to know how far advanced or retarded it is just like Glenn said.

No idea re Autronic, but do you just buy/switch this function on as you do with a Motec?

[The Real Roadrunner]

speaking to mark yager today, he reckons no-one should EVER have to grind off a lobe, and only somone trying to find an easy way out would do it this way (though he was speaking regarding motec control systems)

the 3 lobe system he described as a 4 minus 1 trigger? the ecu logging the absence of the 4th trigger, or something like that anyway??

no you shouldn't HAVE to grind off pickup's but sometimes the ECU's software won't always allow you to run EVERY trigger system known to man (the only shortfall i have actually found with the autronic ecu's) which is why sometimes pickups have to be removed.

and what are the exact reasons to need more than 1 lobe per cycle?

ill have a look through the software later tonight myself to see what is doable and have a chat to chris tomorrow to see what he has done with similar systems, im sure he'll have no probs handing over his interlectual property

would just be nice to have some definate answers to begin with.
tuning is the easy part, the setup is what takes time.

RE, motec vs autronic software = chalk and cheese dude, completely different systems designed to do the same job,
just sucks that autronic don't allow everything to be fully programmed straight out of the box ie pickup wise.

cheers
linden

[The Real Roadrunner]

ed, ill have a file that should run it today/tomorrow (friday fuckin) afternoon.

love me much?

ahh the wonders of favours.

[JustCallMeOrlando]

Subscribing. I have evil thoughts about a vvti 1UZFE so I need to pay attention.

[thechuckster]

looks like a Y basically

ill try and find a photo of it

looks more like a 5 tooth wheel but with 2 non-opposite teeth missing?

fwiw, with processor speeds these days the ECU is constantly calculating crank position so any support feature (e.g. VVTi) only needs to ask the ECU where the crank is and worry about tracking and moving each cam.

My guess is that it uses the upper arms of the Y for confirming cam position and the lower arm could be used by other bits of code to correlate rotated cam position against a reference TDC timer? The arrival of the reference mark gives the ECU time to undertake any repositioning before the cam the two closer marks arrive. I'd say that that moving the cam takes a fair while (anyone know how many ignition cycles to move the cam a few degrees?)

[ed]

one other thing worth mentioning...

the vvti does not get told 5deg advance or 6deg retard etc etc

it simply gets told 50% or 20% or 100% etc. now if 100% means 26deg, then 50% means 13deg, but the deg value is completely academic

[oldcorollas]

it's a non-feedback system?
(or you mean the feedback, if any, is just within the ECU?)

[MWP]

it's a non-feedback system?
(or you mean the feedback, if any, is just within the ECU?)

Feedback of VVTI position is via the cam lobes.
Ie, the ECU wants a new cam position, it changes the valve PWM moving the cam, then monitors the lobes for actual change in position.

[The Real Roadrunner]

ed: call Mark @ MRC tuners (castle hill) and ask him how he did mine.I know he was going to mke it trigger off 1, and as a last resort it was lobe trimming time - cabn't remember the outcome tho

your car, which has a ver 1:06 or 1:07 couldn't support the 3 equal teeth setup at that time so the 2 extra teeth were removed and it just runs off a single tooth (and works perfectly well obviously), i spoke to mark about it this morning to find out if he had checked the spacings of the pickups and which way he went about doing yours.

apparently the later software has been changed to support this config, but i havn't had time to look as yet.

MPW, yep thats how it runs it and you can set variables as to how far the cam can be out of position for a given amount of time before recording errors etc.


cheers
linden

[clubagreenie]

So a soft/firmwareupgrade and all will work without mods.