Engine idle chirping (cricket) noise poll.

[HunterGreene]

Originally Posted by SirBrass

Got direct injection? Let me play you the song of my people.

I lol'ed. Nicely done.

Originally Posted by Vis101

@SirBrass, I looked up the boiling temp of Ethanol and it is at a low 173*F, whereas petroleum is at 410*F ( http://www.engineeringtoolbox.com/bo...ses-d_155.html). What I believe you are sizing is that the Ethanol is boiling when it gets to the fuel pump, resulting in bubbles in the fuel. These bubbles interact with the fuel pump in such a way that we hear crickets. We would need to sample fuel and measure fuel temperature at the fuel pump to confirm this. Given that most people (including myself) only experience crickets one the car warms up, that lends some credibility to the theory. I am probably over simplifying things though.

Thoughts?

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Not quite. Cavitation is different than boiling. Also, I would doubt that the fuel is warm enough at the pump to flash boil, or we would have major problems with our cars. Heating the fuel to engine temperature does take a little bit of time, and I would guess the amount of time that it spends in the fuel lines before being injected is not quite long enough.

Cavitation is much more likely the culprit (and I believe Toyota has already come to this conclusion). For those who haven't Googled it already, Cavitation is a process (usually in liquid) where pockets of low pressure are created when a solid body moves through it quickly (or vibrates quickly), creating turbulence. This creates isolated, short-lived vacuum "bubbles." If you think of a submarine, they have a speed limit at which they can move "silently," above which their prop creates cavitation, which creates a rushing water noise.

Our fuel pumps move at a relative high speed, which with the lighter ethanol in the fuel is more likely to cavitate, creating those temporary bubbles and ergo the chirps. Fortunately for us, those little vacuum bubbles are gone by the time the fuel gets to the injectors.

Sorry for the long-winded post, but I am a bit of a subject-matter expert, as cavitation due to vibration was part of my Bachelor's Thesis.

[Vis101]

Originally Posted by HunterGreene

I lol'ed. Nicely done.



Not quite. Cavitation is different than boiling. Also, I would doubt that the fuel is warm enough at the pump to flash boil, or we would have major problems with our cars. Heating the fuel to engine temperature does take a little bit of time, and I would guess the amount of time that it spends in the fuel lines before being injected is not quite long enough.

Cavitation is much more likely the culprit (and I believe Toyota has already come to this conclusion). For those who haven't Googled it already, Cavitation is a process (usually in liquid) where pockets of low pressure are created when a solid body moves through it quickly (or vibrates quickly), creating turbulence. This creates isolated, short-lived vacuum "bubbles." If you think of a submarine, they have a speed limit at which they can move "silently," above which their prop creates cavitation, which creates a rushing water noise.

Our fuel pumps move at a relative high speed, which with the lighter ethanol in the fuel is more likely to cavitate, creating those temporary bubbles and ergo the chirps. Fortunately for us, those little vacuum bubbles are gone by the time the fuel gets to the injectors.

Sorry for the long-winded post, but I am a bit of a subject-matter expert, as cavitation due to vibration was part of my Bachelor's Thesis.

The education is much appreciated. What do you suggest is the solution? If cavitation is the culprit, and yet we still need the pump to operate at its current rate with the ethanol fuel, it sounds like either they need to take on some CFD analysis to redesign the pump. That or just figure out a way to insulate the pump so we don't hear the crickets anymore. I won't mind abding a couple pounds to my BRZ in order to quiet the pump.

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[HunterGreene]

Originally Posted by Vis101

The education is much appreciated. What do you suggest is the solution? If cavitation is the culprit, and yet we still need the pump to operate at its current rate with the ethanol fuel, it sounds like either they need to take on some CFD analysis to redesign the pump. That or just figure out a way to insulate the pump so we don't hear the crickets anymore. I won't mind abding a couple pounds to my BRZ in order to quiet the pump.

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The cost effectiveness of redesigning a pump just to eliminate a nuisance noise isnt worth it. Toyota would rather just replace than bother with the costs associated with redesign. The pump works, this is just an annoying side effect. FR-SMatt had the alleged insulated pump, but he can still hear the crickets faintly.

I've gotten used to them, and now that I am starting to hear them in other cars, I think we're just going to have to get used to the new normal.

[FR-S Matt]

Originally Posted by HunterGreene

The cost effectiveness of redesigning a pump just to eliminate a nuisance noise isnt worth it. Toyota would rather just replace than bother with the costs associated with redesign. The pump works, this is just an annoying side effect. FR-SMatt had the alleged insulated pump, but he can still hear the crickets faintly.

I've gotten used to them, and now that I am starting to hear them in other cars, I think we're just going to have to get used to the new normal.

The sound insulated fuel pump works more than it fails. I haven't heard crickets in some time since it warmed up now. They blew through the insulation when it was 40 degrees outside. Still feeling indifferent about the insulation, but Toyota put it on so I'm not touching it.

[MaddBaggins]

2014 FRS, build date 10/13, just under 2k miles. E10 is all I can get around here. I have crickets. I just noticed them recently. Usually the stereo is too loud for me to notice, but I happened to hit a break between songs while at a stop light the other day while the windows were down and I heard it.

Just keep the tunes turned up.

[mothespaceman]

2014 BRZ purchased in early March... 2000 miles later and the idle chirps have begun.

[ZZT86]

These noisy HPFP's ruin what is otherwise a nice sounding engine . . . . . pity :/

[extrashaky]

FWIW, I have been running E10 Chevron ("with Techron™") exclusively for a few weeks now, and yesterday for the first time in a while I noticed that the crickets were completely gone. I had noticed that the pump was quieter when I switched from Shell to Chevron, but as I said, yesterday there were no chirps at all.

I'm sure they'll come back, but I'm encouraged by this development. Of course, it could just be that they switched over to summer gas so that I'm not running butane through my engine.

[BRZJunkie]

I'm one of many who find the crickets totally unacceptable but... I can also lighten up occasionnally. SO... for those who don't have the crickets I found what you need for the infotainment.

[Thrustin]

Originally Posted by BRZJunkie

I'm one of many who find the crickets totally unacceptable but... I can also lighten up occasionnally. SO... for those who don't have the crickets I found what you need for the infotainment.

Those guitars much be heavy if if takes two men to hold each if them.

[ZZT86]

Originally Posted by ZZT86

These noisy HPFP's ruin what is otherwise a nice sounding engine . . . . . pity :/

Especially with a Perrin unres CBE

[Mooseknuckle44]

So in the spirit of trying something different, l filled up my car with ethanol free gas today($4.49 per friggin gallon) just to see if it helped the chirping. Prolly had about a gallon of QT 93 left in the tank. By about 40-50 miles into the tank, no chirping at all. Outside temp was around 70°.
I dont fully know what the "90" rating on the pump meant tho. That isn't the octane rating is it? May be in my head, but the car felt more sluggish. Like the torque dip is more apparent and lasts longer.


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[strat61caster]

Originally Posted by Mooseknuckle44

I dont fully know what the "90" rating on the pump meant tho. That isn't the octane rating is it? May be in my head, but the car felt more sluggish. Like the torque dip is more apparent and lasts longer.


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I'd wager you put 90 octane in the car, no big deal really, it'll pull timing to protect the engine, top it off with 91/93 next time you get the chance.

E0 tends to be at mom & pop shops, they probably don't get the same stuff as the chains.

[aristo]

700 miles '14 BRZ reporting in to cricket master race