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I'm not at all sure on that one. It was likely setup mechanically as on/off so even if you could pulse the solenoid to control it differently I'm not sure how effective that would be. Pretty sure later cars 197 etc. were PWM and variable between their limits. I'd probably just take a look at the torque curves with it on/off and then decide if it was worth the effort of doing something unconventional.Yeah that would make sense on quickest way to do this for figuring whats best on and off point considering all the other veriables that may affect whens best to activate on any given build
Did read on one of these posts that even thou the function isn't used on the standard ecu that the 172 vvt is capable of taking command through pwm to give it transitial veriation if then used on a standalone?? Is this true?? If so is it best to go through setting that up or stick with the simple off/on functionality as was used as standard
To do it proply you would, so ecu could then tell where it is. But theoretically if the solinoid can take a PWM signal it can take that off a graph of tps/rpm so it could still send a PWM signal based on perameters it does have and have the solinoid modulate the cam, it's just its effect of that modulation just wouldn't be fed back, it would just mechanically shift the inlet blindly to a PWM graph based on thous 2 parameters of rpm and tps position so theoretically it could.. if... the original vvt solinoid can take and function to a PWM signal.
It would be something to try.
I've never heard of anyone trying it, so you could be the first
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It would still work as 'open loop' but you and @Brigsy are c**k on and I agree that it wouldn't work at all well. For a number of reasons, main reason imo is that with a sensor as oil pressure changes the cam position would stay static due to some closed loop type feedback from the sensor, also as oil changes temperature you will get the same outcome.
Also if you did choose to do this you shouldn't select closed loop. What ECU is this? looks like the one from motorsport electronics?Well going to fit a flyback diode 1N4001 in parallel to the solenoid being ill be pulsing it and run the pwm graph and setup below see how it takes it.. seems the old solinoids flow is rather large so be like trying to pulse control flow on a very large tap so once at 50% pwm you should be at max position of the cam already so where see how it takes it come dyno day to get some transitional effect to its modulation
Yes is an ME ecu. And to open loop aint an option on there is "closed or switched as only option" which is why im looking at basically a open loop setup run in closed loop mode..
(i have taken account for this and is why over load my veration of pwm and thus degrees is very little, and on the other axis is very gradual in its transition of slope progression over the higher rpm.)..
TLDR; Honetly mate its your car so have fun doing whatever you are going to do, my solid advice is to just run ON/OFF because oil viscosity and pressure changes far more than I think you appreciateYes is an ME ecu. And to open loop aint an option on there is "closed or switched as only option" which is why im looking at basically a open loop setup run in closed loop mode..
as for your comment to oil pressure and oil temp variation of change.. fair comment and agreed I realise to without the cam sensor the system would be primitive in its accuracy which is why all later vvt's had that so could have larger more snap response of change within there vvt.
im aware to its function like this would be of very basic at best in doing this but to some form of transition effect with a slight veriation within the transitional reaction time in relation to temp i cant see would be that bad, rather than run no transitional effect at all I would have thought having some would be better?
It isn't like its seeing the major transition of oil viscosity or pressure from cold to hot engine change being its got to be upto temp anyways before running. Any incorrection towards afr through that slight change of cam veriational speed change will be picked up in the wideband trim anyways and im not running boost or high compression pistons so i wouldn't think it to be risk of det on the timing graph changing of anything dramatically in the shift of change.
For behaviour If anything as the engine got hotter the vvt rate of transitional change would become faster and sooner. So as I apply load it would go to full on advance sooner (same as if it was just on but with still abit of transitional effect feeding in there) and as it hit higher rpm it would raise hp and drop torque off abit more quickly when hot as be transitioning a fraction faster to turning the vvt down but would still have of transitional effect rather then just nothing.
So yeah my print out on dyno be slightly more torque favourable above 5k on first pull and alittle more hp favorable above 5k afew pulls later on dyno but wouldn't think would be really measurable within drivability over what you would get from the transitional benifits on the power within drivability is my thinking
I maybe still wrong but felt to be worth ago.
Awesome, thanks for the update and glad you had fun.Yeah I get what your saying and it's me mapping it for myself. I'm borrowing a mates rollers to do It with on days there closed. All the main map etc I've already done with the on/off switch set vvt of the base map. I just felt to try this being nothing ventured nothing gained to refine it and try it before and whilst finding if not best switched..
I'm aware there was going to be fluctuation which is where it was always saying to this would be of primitive setup if it paid off (as you say this is why OEM all have that additional sensor set to allow correction I'm not disputing that.) And with VVT on both cams of most later cars though's fluctuation would be even greater, but being this was single cam and a mild veriability anyways i felt it worth a try.
I've now had chance to try this and I can confirm the valve did take to being fed PWM once nailed the frequency and got it to function in that manner fair consistant. As confirmed there was fluctuation, little more than I exspected granted (and as you said) but wasn't hideous by the end of an afternoon of tinkering with it. You would have transition which i got nicely but then after few pulls the transition would fade out and be same as to if it was simple on. Let it back down for abit and cool, the transition would return then when hot would fade out to being of simply on again.
In the end the best stable setup I could get from the PWM was still not as good a curve as to refinement from switched which from the basemap setup of 1450-8000rpm. Refined down best to being ran at 1700-6750rpm on my setup.
So yes you was right but was a fun day and a good afternoon none the less.. nothing tried nothing gained
.Final setup after improving the exhaust and intake flow have managed to get a peak of 228bhp out of it, with a vvt set of 1800 - 7750rpm so yeah right to the end in simply on/offYeah I get what your saying and it's me mapping it for myself. I'm borrowing a mates rollers to do It with on days there closed. All the main map etc I've already done with the on/off switch set vvt of the base map. I just felt to try this being nothing ventured nothing gained to refine it and try it before and whilst finding if not best switched..
I'm aware there was going to be fluctuation which is where it was always saying to this would be of primitive setup if it paid off (as you say this is why OEM all have that additional sensor set to allow correction I'm not disputing that.) And with VVT on both cams of most later cars though's fluctuation would be even greater, but being this was single cam and a mild veriability anyways i felt it worth a try.
I've now had chance to try this and I can confirm the valve did take to being fed PWM once nailed the frequency and got it to function in that manner fair consistant. As confirmed there was fluctuation, little more than I exspected granted (and as you said) but wasn't hideous by the end of an afternoon of tinkering with it. You would have transition which i got nicely but then after few pulls the transition would fade out and be same as to if it was simple on. Let it back down for abit and cool, the transition would return then when hot would fade out to being of simply on again.
In the end the best stable setup I could get from the PWM was still not as good a curve as to refinement from switched which from the basemap setup of 1450-8000rpm. Refined down best to being ran at 1700-6750rpm on my setup.
So yes you was right but was a fun day and a good afternoon none the less.. nothing tried nothing gained
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So for I personally used the standard loom, pin swapped it around so I could run the me360 ecu to give me ability to set the vvt on/off rpm.
Don't forget the 197 head is not just a straight swap as it need to be modified to work on a 172 block.
Yes i have manage to have the an extra hole drilled and tapped to accommodate the pulley already.
Who did this for you ? Im now building an engine (1*2 block 197 head/cams) so will need this doing
