VVT Tuning Noise - ADDED: Comparison Video

[regal]

Originally Posted by shiv@vishnu

Fuel pressure channels (target and actual) are in MPa. Here is a WOT run from ~1800rpm:



Fuel pressure is pretty spot during the VVT intake advance change and everywhere else. This has been the case with the other cars I've data logged as well. Hopefully more customers can add their own data to this discussion.

Cheers
shiv

Thanks for some real data.

Originally Posted by steve99

Just went for a drive up some twisty mountain roads and thought I'd try out new Open flash tablet logging

lot of driving in 3000 to 5000 range where the "rasp" held it a few times at around 4000 and you can modulate the noise with accelerator pedal while engine revs pretty much the same.

does seem like intake noise/resonance (they have a lot of resonant chambers in standard intake which I still have most of them (perrin intake tube only , removed sound tube) standard filter box and snorkel.

does not seem to be any consistent loss of fuel pressure when you hold it around 4000-4500 where noise is. It a long log but can be zoomed. 1.5 vishnu tune.

http://datazap.me/u/steve99/mountain...7-8-9-10-11-12

Anyone logged oil pressure thru this zone ? Oil pressure is more sensitive than fuel pressure.

[wparsons]

^^ Not disagreeing, but what does oil pressure have to do with noises coming from the DI pump?

I can pull some logs with whatever anyone wants tonight, gives me an excuse to play with the OFT more

[regal]

Originally Posted by wparsons

^^ Not disagreeing, but what does oil pressure have to do with noises coming from the DI pump?

I can pull some logs with whatever anyone wants tonight, gives me an excuse to play with the OFT more

I and others are talking about the cam noise that kicks in at mid revs, sounds like an exhaust leak. That was before someone postulated that the DI pump was to blame (its the ft86club punchng bag.) Sometimes I think I am the only 2012 build owner on here with the original pump.


With my 100% stock car the noise started around 5k miles. This is a good thread though because its the first I've seen discussing this noise which to me is a more serious issue than crickets.


Heck if it wasn't for this cam phasing noise I could be convinced I bought a Toyota in a blind drive test.

[Element Tuning]

Shiv,

Thanks and that's exactly what I'm seeing on a normally functioning FRS. Just that initial dip as onset of tip in to into the request for intake advance. It catches up and holds pressure target after that. At higher rpm its not there, I would assume because pump lobes are spinning fast enough to maintain optimal fuel pressure.

So if anyone else is logging and things the DI pump is making noise your log won't have this dip and then rise to target. It will have a "wave" in the DI pressure log. If you don't see this odds are the noise is just normal intake noise you get from running more overlap with the advanced intake targets.

Oil pressure issues and or oil viscosity can result in more noise from the variable cam sprockets. For me this was most notable at cold start with a substantial "rattle." When I went turbo our race car I knew high rpm oil pressure would be an issue at racing temps so I went with Redline 40w race oil. This totally silenced the cam sprocket rattle at start up or what I presume was from the sprockets. The better the oil pressure the easier it will be for the ECU to hit the target advance. Now I'm recommending people put 40w race oil in their street car but its not a bad idea to step it up a little on N.A. and with boosted don't be afraid to put in 10-30 or 10-40 as your engine bearings will thank you in the long run.

[Luckrider]

Originally Posted by Element Tuning

Shiv,

Thanks and that's exactly what I'm seeing on a normally functioning FRS. Just that initial dip as onset of tip in to into the request for intake advance. It catches up and holds pressure target after that. At higher rpm its not there, I would assume because pump lobes are spinning fast enough to maintain optimal fuel pressure.

So if anyone else is logging and things the DI pump is making noise your log won't have this dip and then rise to target. It will have a "wave" in the DI pressure log. If you don't see this odds are the noise is just normal intake noise you get from running more overlap with the advanced intake targets.

Oil pressure issues and or oil viscosity can result in more noise from the variable cam sprockets. For me this was most notable at cold start with a substantial "rattle." When I went turbo our race car I knew high rpm oil pressure would be an issue at racing temps so I went with Redline 40w race oil. This totally silenced the cam sprocket rattle at start up or what I presume was from the sprockets. The better the oil pressure the easier it will be for the ECU to hit the target advance. Now I'm recommending people put 40w race oil in their street car but its not a bad idea to step it up a little on N.A. and with boosted don't be afraid to put in 10-30 or 10-40 as your engine bearings will thank you in the long run.

Is this really advisable with such tight bearing clearances? I have been hearing that this is a concern from the guys who have blown motors or a building the block.

[regal]

Originally Posted by Element Tuning

Now I'm recommending people put 40w race oil in their street car but its not a bad idea to step it up a little on N.A. and with boosted don't be afraid to put in 10-30 or 10-40 as your engine bearings will thank you in the long run.

This is interesting because I experienced the opposite. I started with 5w-30 (a heavy one) and switched to real 0w20 Mazda (high moly GL5). My thought is the screens and passages in the heads are sized for thin oil. We've already seen that the true 0w20 keeps the engine cooler (more flow.)


You are probably right about the crank and rod bearings but those are cut differently than the Ej's also.


The vvt had to be designed around a certain viscosity range as its all hydraulic with the oil being the fluid.


I think many with the complaints are using redline 0w-20 which is really a 30 weight.


I've got an open mind and not saying you are wrong but I swear my engine is quieter and smoother at low revs with real 0w20.


An oil pressure gauge would settle the question? May be more of an oil pump issue than anything.

[SirBrass]

Isn't oil pressure also measured by the ecu? I know oil & coolant temps are.

On phone I am. Therefore, if mistakes I make, Frank Oz blame you should.

[wparsons]

Originally Posted by regal

I and others are talking about the cam noise that kicks in at mid revs, sounds like an exhaust leak. That was before someone postulated that the DI pump was to blame (its the ft86club punchng bag.) Sometimes I think I am the only 2012 build owner on here with the original pump.

I know what you're talking about, I'm just curious how oil pressure comes into play when the suspected issue is a poor performing DI pump?

I haven't actually ever checked the build date on mine, but I took delivery in July 2012 and am on the original DI pump as well. The only thing replaced on mine was the tail lights from condensation build up.

[Wepeel]

This is one of the best threads on this forum.

Originally Posted by Element Tuning

Shiv,

Thanks and that's exactly what I'm seeing on a normally functioning FRS. Just that initial dip as onset of tip in to into the request for intake advance. It catches up and holds pressure target after that. At higher rpm its not there, I would assume because pump lobes are spinning fast enough to maintain optimal fuel pressure.

So if anyone else is logging and things the DI pump is making noise your log won't have this dip and then rise to target. It will have a "wave" in the DI pressure log. If you don't see this odds are the noise is just normal intake noise you get from running more overlap with the advanced intake targets.

So I'm confused - from what you were initially saying it sounded like there was a fuel pressure dip due to the advanced cam angles being requested, but now it seems like it's the dip is due to tip-in occurs at most lower RPM. So if someone has a suspect fuel ump the potential pressure wave resonance noises (marble noise) should be apparent after any tip-in event, regardless of RPM?

[Element Tuning]

0-20w is all about emissions, fuel economy, and power (less friction). More power and rpm has a higher requirement for oil pressure which has already proven problematic at track temps. Bearing issues are from a lack of oil pressure and not because of tight bearing clearance. We build hundreds and hundreds of Subaru engines and have the best reputation in the industry and the FA20 engine will have an even higher requirement for oil pressure boosted than the EJ motors due to the narrow bearings (more pressure per square inch).

Ok I've sidetracked everyone so back on track, oil pressure doesn't effect your DI fuel pump.

PM or start a new thread please on oil but it's probably been beaten to death already

Thanks,
Phil Grabow

[regal]

Originally Posted by Element Tuning

0-20w is all about emissions, fuel economy, and power (less friction). More power and rpm has a higher requirement for oil pressure which has already proven problematic at track temps. Bearing issues are from a lack of oil pressure and not because of tight bearing clearance. We build hundreds and hundreds of Subaru engines and have the best reputation in the industry and the FA20 engine will have an even higher requirement for oil pressure boosted than the EJ motors due to the narrow bearings (more pressure per square inch).

Ok I've sidetracked everyone so back on track, oil pressure doesn't effect your DI fuel pump.

PM or start a new thread please on oil but it's probably been beaten to death already

Thanks,
Phil Grabow

I appreciate your input and not arguing, its just opposite of everything they are saying over at the oil forum (Bob.)


I think a far as the heads its got to be revel lent, I mean the whole VVT is using the oil for its blood. We've got several reports of camshafts blowing out the sides of the heads on this forum.


If anyone is interested you can get a high VI 0W-30 by mixing TGMO with Mobile One 0W40 (been OK'd by mobile who makes both.) I guess I'll try that next oil change.


But for 2 decades we've had Subaru engines leaking oil at the head gasket and blowing camshafts. So I doubt we will solve Subaru's cylinder head problems any time soon.

[Element Tuning]

Regal, I'll tweak this so it applies to the thread and the camshafts. Your oil pump has a pressure relief valve and will blow off oil pressure when it gets too high so if a camshaft seal pops out it was just an installation issue (or too much crankcase pressure). Once up to operating temps the oil pressure differences won't be huge and you'll be lucky to get +10 psi from a thicker oil. 10 psi however can be the difference from spinning a rod bearing and not. On our Subaru STi race engines at 60 psi of oil pressure we're skimming bearings (think short motor life), and at 50 psi the bearings are wiping and engine failure will happen in short order. The above is why FA guys are spinning bearings because they aren't holding enough oil pressure with the added power a supercharger or turbocharger adds. The oil wedge at the bearing cannot be overcome by the cylinder pressure so NA power requirements for oil pressure are very different than with boost.

So with thicker oil it's just more about stable oil pressure and hopefully holding ideal oil pressure all the way to redline under extreme temps. The FA20 motor unlike the EJ has both enough oil pressure and the action of the cam sprockets to allow movement even at idle oil pressure unlike the EJ which will not move the cam until about 2500 RPM as there isn't enough oil pressure.

So from a tuners perspective a thicker oil that gives a little more stable pressure my result in quicker action from the request to advance the camshaft. Again don't forget what I said and that pressure is regulated by the oil pump's bypass valve and not the viscosity of the oil (that will only effect pressure if it's dropping below the bypass valve's spring pressure which would be at high rpm/high heat).

Thanks,
Phil Grabow

[regal]

Originally Posted by Element Tuning

So from a tuners perspective a thicker oil that gives a little more stable pressure my result in quicker action from the request to advance the camshaft. Again don't forget what I said and that pressure is regulated by the oil pump's bypass valve and not the viscosity of the oil (that will only effect pressure if it's dropping below the bypass valve's spring pressure which would be at high rpm/high heat).

Thanks,
Phil Grabow

Thanks again. I understand what you are saying, so the bypass valve is open in the torque dip area? And all my comments are referring to stock,not boosted.

[Element Tuning]

Originally Posted by Wepeel

This is one of the best threads on this forum.


So I'm confused - from what you were initially saying it sounded like there was a fuel pressure dip due to the advanced cam angles being requested, but now it seems like it's the dip is due to tip-in occurs at most lower RPM. So if someone has a suspect fuel ump the potential pressure wave resonance noises (marble noise) should be apparent after any tip-in event, regardless of RPM?

Nothing's different. Whenever you tip in the cams will need to advance if you were off the throttle. The DI pump has to compensate for the cam phasing (that is the whole discussion). If you are off the throttle and then punch it at 3000 RPM we'll probably see the same thing in the log. At higher RPMs the pump lobes are spinning much faster and therefore will be able to create more fuel volume so it's less of an issue.

So when you're looking at the log I can see where he's dipping into the throttle because the direct injection pulse width increases, the DI fuel pressure is trying to increase, and the cams start to advance

Not everyone is going to be totally capable of analyzing all the data properly so it's easy to get confused.