VVT Tuning Noise - ADDED: Comparison Video

[vtmike]

Is the factory header design the reason for needing the quick shift in cam phasing and overlap? Someone earlier mentioned after getting a header and tune they don't have the rasp. So do most tunes for cars with headers not have the rapid cam phasing change and overlap?

Sent from my XT1060 using Tapatalk

[Luckrider]

Originally Posted by vtmike

Is the factory header design the reason for needing the quick shift in cam phasing and overlap? Someone earlier mentioned after getting a header and tune they don't have the rasp. So do most tunes for cars with headers not have the rapid cam phasing change and overlap?

Sent from my XT1060 using Tapatalk

I believe it has been attributed to having EL headers that makes the rapid cam phasing necessary to reduce/eliminate the dip.

[Dezoris]

Originally Posted by arghx7

I think there's still a debate (well, in my mind at least) whether the noise is a problem for everyone to be concerned about, beyond being annoying. Is it like a creaking suspension--not necessarily a sign of anything actually wrong, just undesireable, or is it like spark knock or rod knock, indicating some damage could be occurring?

Not concerned about if it is a problem, just want to know how to eliminate the "sound" the tuning created in the quest for dyno sheet, sales brochures.

[Shiv@Openflash]

Originally Posted by Element Tuning

@arghx7

I always respect your input. Because it's normal or the industry standard doesn't mean it will work how we need it to in the aftermarket tuning world as we expect more than what's given to us. Shiv's logs are a little slow on the data rate but you can see the fuel pressure drop every time there is request for a significant jump in intake advance.

We are sampling at 12hz so it should be good enough to see fuel pressure related issues. We exactly are you seeing the pressure drop during intake advance jumps? Just so we are looking at the same thing.

Regards
Shiv

[vtmike]

Originally Posted by Luckrider

I believe it has been attributed to having EL headers that makes the rapid cam phasing necessary to reduce/eliminate the dip.

So uel headers do not?

Sent from my XT1060 using Tapatalk

[Shiv@Openflash]

Originally Posted by vtmike

So uel headers do not?

Sent from my XT1060 using Tapatalk

Tunes that are dialed in for UEL headers require as much of a jump in VVT timing and tend to subdue this sound. It's still there (just like with the stock tune) but it's not as noticeable.

[Element Tuning]

Originally Posted by Dezoris

So can you guys sum up the solution to the marbling for tuners? I understand some may not have it while others do, like in my case.

Is it just a matter of de-tuning the cam angle change to less degrees?

If you have "marbles" try reducing the intake cam advance target in the area of the noise. On Shiv's map he's pushing the intake came about +5 cam degrees more than I am. It's not because I don't agree it could make more torque, it's because I know it can cause an issue on some people's cars so for the base map I'm just being more conservative and I'll leave the fine tuning to push that little extra for the final tuners on that particular car.

Also you can try lowering the "DI Pressure Target." This will not run the pump as hard which can help.

[SirBrass]

Except the torque dip has been eliminated through tuning + aftermarket exhaust. No trouble.

So, I wouldn't put it all on the di pump design & calibration.

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

[Element Tuning]

Originally Posted by shiv@vishnu

We are sampling at 12hz so it should be good enough to see fuel pressure related issues. We exactly are you seeing the pressure drop during intake advance jumps? Just so we are looking at the same thing.

Regards
Shiv

Shiv, zooming in may allow you to see it better but right at "load" spike and "intake advance" spike you'll see the fuel pressure dip before it rises back up. Track your "load" to see it better. I was logging at 48 hz so it's easier to see the dip over time.

What units is the OEM ecu logging for DI pressure?

Originally Posted by SirBrass

Except the torque dip has been eliminated through tuning + aftermarket exhaust. No trouble.

So, I wouldn't put it all on the di pump design & calibration.

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

Correct but as a result we are all pushing the DI pump harder to eliminate the torque dip because it requires more aggressive intake advance to increase torque there. This is why some have problems and others do not.

By no means is this a gloom and doom scenario but it will answer why some people have no idea why one member say's his engine is making a different noise than others. One noise normal and one noise bad.

Thanks,
Phil Grabow

[SirBrass]

True. I am hearing noise, but it doesn't sound too serious. Just a different sound is all. Next time I have my tuner in the car with me, I'll draw his attention to it to just make sure it's not the bad noise, just the "that's normal but noisy" noise.

I do want to see if deleting the stock header cat and then tuning for that would help as well, as that cat presents a significant air restriction.

[Shiv@Openflash]

Originally Posted by Element Tuning

Shiv, zooming in may allow you to see it better but right at "load" spike and "intake advance" spike you'll see the fuel pressure dip before it rises back up. Track your "load" to see it better. I was logging at 48 hz so it's easier to see the dip over time.

What units is the OEM ecu logging for DI pressure?

I'm pretty sure the stock ECU monitors the analog signal so CAN logging rates don't apply for it. Can you tell me the point(s) (time stamps) that you are seeing this pressure dip?

[vtmike]

Originally Posted by shiv@vishnu

Tunes that are dialed in for UEL headers require as much of a jump in VVT timing and tend to subdue this sound. It's still there (just like with the stock tune) but it's not as noticeable.

What about stock header vs aftermarket. Do aftermarket headers reduce the necessary cam phasing compared to stock?

Sent from my XT1060 using Tapatalk

[Element Tuning]

Originally Posted by shiv@vishnu

I'm pretty sure the stock ECU monitors the analog signal so CAN logging rates don't apply for it. Can you tell me the point(s) (time stamps) that you are seeing this pressure dip?

I'll pick out one point for you starting at 89.375 to 90 seconds there is a 52% drop in DI pressure (10.58 to 6.95) before it recovers. Now I'm seeing this a "normal" for this car, it's the up and down, up and down, that is abnormal which I'm not seeing in the logs for this particular car.

Thanks,
Phil Grabow

[Shiv@Openflash]

Originally Posted by Element Tuning

I'll pick out one point for you starting at 89.375 to 90 seconds there is a 52% drop in DI pressure (10.58 to 6.95) before it recovers. Now I'm seeing this a "normal" for this car, it's the up and down, up and down, that is abnormal which I'm not seeing in the logs for this particular car.

Thanks,
Phil Grabow

Hi Phil,
That drop you are seeing occurs as engine goes from deccel (no fuel, injectors shut off) to accel (injectors on). You can see this by looking at AFR and DI on-time. That is what causes the short term fuel pressure drop. And that is present in the stock tune and to be expected.

There is no discernible fuel pressure drop that occurs during the VVT intake swing which occurs a moment later. This point is driven home in the last few WOT runs which add 5psi of boost to the equation.

-Shiv