I`m wondering what affect (if any) that Synthetic oil has with a motor like mine. (the variable valve timing) I have PU 5W30 in it right now, and when I hold down the accelerator i.e getting up to speed, or passing somebody on the highway. I have noticed an almost low pressure turbo feeling now,that when I run conventional oil, I simply dont feel? In other words, I can feel the vvti kick in when using Synthetic, over conventional oil. Does this make any sense? Or am I imagining this?
variable valve timing
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VVT is actuated by oil pressure...pretty easy for those passages to become restricted by sludge/varnish, etc...so, it may be that your use of syn has cleaned them out somewhat, allowing more effective (rapid) VVT system response...
Originally Posted By: Astro14
VVT is actuated by oil pressure...pretty easy for those passages to become restricted by sludge/varnish, etc...so, it may be that your use of syn has cleaned them out somewhat, allowing more effective (rapid) VVT system response...
And thanks again for serving Astro, I salute you my friend.... 
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Some of the systems on the market that are usually call VVT-I or I-Vtec, which is just VVT with intelligence. The main difference in these setups are that a actuator tells the cam when to phase, it is still actuated by oil pressure but the computer has to tell it to switch before the oil will move to phase the cam. In a system like this the type of oil has no impact on the performance, assuming it meets the minimum pressure requirements.
Originally Posted By: 09_GXP
Some of the systems on the market that are usually call VVT-I or I-Vtec, which is just VVT with intelligence. The main difference in these setups are that a actuator tells the cam when to phase, it is still actuated by oil pressure but the computer has to tell it to switch before the oil will move to phase the cam. In a system like this the type of oil has no impact on the performance, assuming it meets the minimum pressure requirements.
You don't normally feel a power surge with Toyota's VVT-i system like you sometimes do with Honda's VTEC system. What you are likely feeling is the operation of a variable intake manifold system. Operation of it likely didn't change with the new type of oil, but it's possible you were looking for a change in operation with the synthetic, so there may be a bit of a placebo effect going on there.
Originally Posted By: Hokiefyd
You don't normally feel a power surge with Toyota's VVT-i system like you sometimes do with Honda's VTEC system. What you are likely feeling is the operation of a variable intake manifold system. Operation of it likely didn't change with the new type of oil, but it's possible you were looking for a change in operation with the synthetic, so there may be a bit of a placebo effect going on there.
You cannot just assume the oil has zero effect on the cam phasing. That's counter to the specification of an oil in the first place!
of course oil weight does affect the operation of some cam moving devices, on others it may not. It depends on the particular nature of the design.
For years Chrysler warned against heavier oils in their MDS equipped Hemis, but it was quickly discovered that heavier oil never hurt a thing, just changed it ever so slightly.
Originally Posted By: SteveSRT8
You cannot just assume the oil has zero effect on the cam phasing. That's counter to the specification of an oil in the first place!
of course oil weight does affect the operation of some cam moving devices, on others it may not. It depends on the particular nature of the design.
For years Chrysler warned against heavier oils in their MDS equipped Hemis, but it was quickly discovered that heavier oil never hurt a thing, just changed it ever so slightly.
Kestas
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I once had an episode where my car ran sick, faulted, and stalled after switching to 20W-50. The VCT (variable cam timing) solenoid couldn't take it, and this was during summer. The car was a 98 Escort ZX2 with the Duratec engine. Switching back to 10W-30 took care of the problem.
So, yes, I believe the type of oil and cleanliness of the engine has a big effect on VCT.
Originally Posted By: lexus114
Originally Posted By: SteveSRT8
You cannot just assume the oil has zero effect on the cam phasing. That's counter to the specification of an oil in the first place!
of course oil weight does affect the operation of some cam moving devices, on others it may not. It depends on the particular nature of the design.
For years Chrysler warned against heavier oils in their MDS equipped Hemis, but it was quickly discovered that heavier oil never hurt a thing, just changed it ever so slightly.
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What is scary, is with the Nissan VQ motors, they dyno differently every run. People that data log attribute this to the cam phasing not being consistent from run to run. Due to oil? ECU? Who knows. It makes it hard to really know when something makes a positive change.
You can do a few runs with a dip in the midrange, then it goes away or moves somewhere else.
We have the same issues with ours. The PCM is so sensitive to heat soak that it pulls timing at the slightest provocation, and the new ones move the cam as well.
Just another reason I am no fan of dynos. Many dyno operators have become very skilled at giving their clients what they asked for: bragging rights.
Oil viscosity and type does make a difference in operation and, in the case of some Fords, cam phaser lifespan.
It is well known that certain (seemingly random years and miles) 5.4L cam phasers "knock" or rattle here in S. Florida on 5W-20 oils. Ford actually recommends 10W-40 synthetic as a possible cure! At least the Ford techs do...
Originally Posted By: CBR.worm
What is scary, is with the Nissan VQ motors, they dyno differently every run. People that data log attribute this to the cam phasing not being consistent from run to run. Due to oil? ECU? Who knows. It makes it hard to really know when something makes a positive change.
You can do a few runs with a dip in the midrange, then it goes away or moves somewhere else.
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