VVT Tuning Noise - ADDED: Comparison Video

[Wepeel]

Originally Posted by Element Tuning

This client suspected all along his DI pump was defective and he did have it replaced under warranty recently. . The weather has been so bad here we haven't had a chance to test how the new pump reacts with the more aggressive tuning but I will try an update.

Were there other symptoms that led your client to believe that the DI pump was faulty other than crickets (that everyone has)?

[86-tundra]

Dunno why people are attacking @Dezoris ... he brought up a valid concern. lots of interesting info on this thread. I will drive my girlfriends BRZ this weekend that is completely stock everything and see if I can hear it. I only have a catback and it is very prominent to me.

I think "marbles" is a good way to describe it.

whether anyone wants to hear the noise or not, I think it is a valid concern for engine health...

[Dezoris]

Originally Posted by trevorovert

Dunno why people are attacking @Dezoris ... he brought up a valid concern. lots of interesting info on this thread. I will drive my girlfriends BRZ this weekend that is completely stock everything and see if I can hear it. I only have a catback and it is very prominent to me.

I think "marbles" is a good way to describe it.

whether anyone wants to hear the noise or not, I think it is a valid concern for engine health...

Thanks!

[DAEMANO]

Originally Posted by trevorovert

Dunno why people are attacking @Dezoris ... he brought up a valid concern. lots of interesting info on this thread. I will drive my girlfriends BRZ this weekend that is completely stock everything and see if I can hear it. I only have a catback and it is very prominent to me.

I think "marbles" is a good way to describe it.

whether anyone wants to hear the noise or not, I think it is a valid concern for engine health...

Shiv has never denied the rasp sound at around 4k RPM, it's there, clearly. It was also there in the stock tune, just to a lesser degree. Shiv says that it is safe and caused by more aggressive VVT. Perrin also. both are experienced tuners. Understandable his experience doesn't guarantee anything, just look at Visconti. However with anyone providing any service we have to place a degree of trust in the servicer. Both Shiv and Perrin have solid businesses, have been in the business a long time and don't have the degree of irresponsible & combative behavior we've seen with vendors/tuners (and members of the community). That brings us to Dezoris.

People are questioning Dezoris' characterization of both the sound and that it seems like he's trying to make an issue out of something that he doesn't have confirmation if it actually is. If Dezoris likes he could simply look at a tune he has with a more experienced friend. I'm sure he has many tuner friends that can help to explain what he's hearing. Or even better, simply call Shiv and talk to him directly. Instead he uses both this board and folksy sounding "common sense" like "if it doesn't sound right it probably isn't" to spread his own feelings of fear, uncertainty and doubt. This is simply not the way to constructively handle his curiosity and one of the reasons why his query about the sound seems to have ulterior motivation (even if it doesn't). I will say this much, in both his videos and forum posts Dezoris generally comes off brash, bro-ish and sometimes even belligerent. In general however I think he's harmless and respect the work HE has done too.

[Element Tuning]

Too many to quote an answer but I'll try and make some blanket statements to help people understand an off the shelf flash is just that, works great for some and not so great for others. If you don't have an end user tunebable ECU software or Hydra EMS it's harder to come to a conclusion or even a solution.

If the sound you hear is minor like a "ticking" then you could probably make a minor adjustment to either the DI pressure target or smooth/lessen the intake cam timing advance. The more rapidly you advance the intake the harder it is for the DI pump to keep up due to the phasing and the three lobe cam. At higher RPM it's a non-issue since it's easier for the DI pump to keep up.

Look at these two logs from the Hydra EMS from two different FRSs. This log is from my personal FRS and you can see as I advance the intake cam (blue) the DI fuel pressure (yellow) drops rapidly. This is normal but not ideal and any "marbles" or "ticking" could be tuned out on this car with a combination of intake advance and DI pump tuning.



On this Hydra EMS log from a car with the symptoms of a faulty DI pressure pump you can see the DI pressure wave (pink). These pressure waves are 400-1000 psi apart and that's what causes the "marbles" or when it's less significant "ticking."



This could not be tuned out.

Hopefully this sheds some light on what some are probably experiencing while others are not even with the same mods and tuning.

Thanks,
Phil Grabow

[Dezoris]

Originally Posted by DAEMANO

Shiv has never denied the rasp sound at around 4k RPM, it's there, clearly. It was also there in the stock tune, just to a lesser degree. Shiv says that it is safe and caused by more aggressive VVT. Perrin also. both are experienced tuners. Understandable his experience doesn't guarantee anything, just look at Visconti. However with anyone providing any service we have to place a degree of trust in the servicer. Both Shiv and Perrin have solid businesses, have been in the business a long time and don't have the degree of irresponsible & combative behavior we've seen with vendors/tuners (and members of the community). That brings us to Dezoris.

People are questioning Dezoris' characterization of both the sound and that it seems like he's trying to make an issue out of something that he doesn't have confirmation if it actually is. If Dezoris likes he could simply look at a tune he has with a more experienced friend. I'm sure he has many tuner friends that can help to explain what he's hearing. Or even better, simply call Shiv and talk to him directly. Instead he uses both this board and folksy sounding "common sense" like "if it doesn't sound right it probably isn't" to spread his own feelings of fear, uncertainty and doubt. This is simply not the way to constructively handle his curiosity and one of the reasons why his query about the sound seems to have ulterior motivation (even if it doesn't). I will say this much, in both his videos and forum posts Dezoris generally comes off brash, bro-ish and sometimes even belligerent. In general however I think he's harmless and respect the work HE has done too.

Good post, excellent.

Keep in mind this build was not just thrown together. We spent months testing the car stock, have baseline dynos, track time and autox. All was documented.

We also have a second set of dynos with just radiator and headerback no tuning, to see the differences. And finally months of testing with the tuned supercharger including dyno, track and autox.

So to say, I somehow missed a valvetrain resonance in the stock tune. Nah, and I have professional sound recording equipment in the car with 5 mics during all the dyno testing, including the track day.

Before: http://www.freesound.org/people/dezoris/sounds/183654/
After: http://www.freesound.org/people/dezoris/sounds/191194/

Every person who had taken a ride in my car, driven it and even those who have over 30 years in racing don't like the sound of this VVT "resonance". They said it does not sound normal. Now these guys don't tune FA20s for a living but you have to understand the warning signs.

So here we are today, tuning has greatly advanced from a year ago.
A few weeks back, I started the car after 3 months of storage and fixed the cam plate leak. In the cold this sound is even worse. Amplified, to the point where I am avoiding revving to the crossover point.

I am just very very skeptical at this point, and feel its fair to raise these questions.

[Element Tuning]

So now that we know DI pressure drops rapidly with aggressive intake cam advance at low RPM, why do you think Subaru/Toyota left that torque dip in there?

I think they've known all along the DI pump was an issue and they dialed the the intake cam timing back in an effort to mask a problem with the DI pump performance. It's easy to sit back and say the OEM tuning sucks but these calibrators aren't dumb and they sometimes tune this way on purpose.

[stugray]

I now have what I describe as a "heat shield vibration" when discussing it with my son (he noticed it when I didnt even mention it).

I was going to check to make sure nothing was coming loose, but now this thread explains it.

[OrbitalEllipses]

Not as bad as in the video in the OP, but that noise is definitely there to an extent on my stock tune. You can definitely hear that distinct change in the tone of the noise there on the stock tune. It may not be as pronounced and I'm not making a statement towards any one "side" or the other, I'm just saying I have heard that tonal quality under stock tune conditions.

I will mention I have one of the first few thousand cars, with original ECU mapping (aside from the thermostat reprogramming from last winter) and original chirpy DI pump.

[s2d4]

Originally Posted by Dezoris

Good post, excellent.

Keep in mind this build was not just thrown together. We spent months testing the car stock, have baseline dynos, track time and autox. All was documented.

We also have a second set of dynos with just radiator and headerback no tuning, to see the differences. And finally months of testing with the tuned supercharger including dyno, track and autox.

So to say, I somehow missed a valvetrain resonance in the stock tune. Nah, and I have professional sound recording equipment in the car with 5 mics during all the dyno testing, including the track day.

Before: http://www.freesound.org/people/dezoris/sounds/183654/
After: http://www.freesound.org/people/dezoris/sounds/191194/

Every person who had taken a ride in my car, driven it and even those who have over 30 years in racing don't like the sound of this VVT "resonance". They said it does not sound normal. Now these guys don't tune FA20s for a living but you have to understand the warning signs.

So here we are today, tuning has greatly advanced from a year ago.
A few weeks back, I started the car after 3 months of storage and fixed the cam plate leak. In the cold this sound is even worse. Amplified, to the point where I am avoiding revving to the crossover point.

I am just very very skeptical at this point, and feel its fair to raise these questions.

Thanks for clarification, perhaps you can update the op with this info.
Mine doesn't sound like this however, more in line with increased air volume passing through the exhaust.

[DJCarbine]

Originally Posted by Dezoris

Good post, excellent.

Keep in mind this build was not just thrown together. We spent months testing the car stock, have baseline dynos, track time and autox. All was documented.

We also have a second set of dynos with just radiator and headerback no tuning, to see the differences. And finally months of testing with the tuned supercharger including dyno, track and autox.

So to say, I somehow missed a valvetrain resonance in the stock tune. Nah, and I have professional sound recording equipment in the car with 5 mics during all the dyno testing, including the track day.

Before: http://www.freesound.org/people/dezoris/sounds/183654/
After: http://www.freesound.org/people/dezoris/sounds/191194/

Every person who had taken a ride in my car, driven it and even those who have over 30 years in racing don't like the sound of this VVT "resonance". They said it does not sound normal. Now these guys don't tune FA20s for a living but you have to understand the warning signs.

So here we are today, tuning has greatly advanced from a year ago.
A few weeks back, I started the car after 3 months of storage and fixed the cam plate leak. In the cold this sound is even worse. Amplified, to the point where I am avoiding revving to the crossover point.

I am just very very skeptical at this point, and feel its fair to raise these questions.

Mine sounds nothing like that. That sounds like a failed VANOS unit on a BMW engine, classic marbles in a can.

Mine is more like someone rapping a bolt on a stainless steel table trying to wake someone up.

I can't remember, but are you running the stock exhaust manifold?

[Dezoris]

Originally Posted by DJCarbine

Mine sounds nothing like that. That sounds like a failed VANOS unit on a BMW engine, classic marbles in a can.

Mine is more like someone rapping a bolt on a stainless steel table trying to wake someone up.

I can't remember, but are you running the stock exhaust manifold?

Stock manifold, thats what I am saying does not sound good. And I have heard this on multiple tunes now. And as element said, its probably some weakness worse on my car than others.

[Dezoris]

Originally Posted by Element Tuning

So now that we know DI pressure drops rapidly with aggressive intake cam advance at low RPM, why do you think Subaru/Toyota left that torque dip in there?

I think they've known all along the DI pump was an issue and they dialed the the intake cam timing back in an effort to mask a problem with the DI pump performance. It's easy to sit back and say the OEM tuning sucks but these calibrators aren't dumb and they sometimes tune this way on purpose.

I was thinking this in the car today, the engineers and people responsible for setting up this car had to have a reason for leaving a nasty dip there. If it was so easy to tune out you would think they would have done it.

Your explanation makes the most sense at this point.

[DJCarbine]

Originally Posted by Dezoris

Before: http://www.freesound.org/people/dezoris/sounds/183654/
After: http://www.freesound.org/people/dezoris/sounds/191194/

Also this sounds fantastic on a set of dynoaudio DBM50 monitors