decibels of a top fuel car (1 Viewer)

[Jamie]

Thanks for that. The comparison chart at the bottom was kind of cool.

All these years and I NEVER realized that decibels were logarithmic!!!!

Yeah its pretty neat. In physics in college we did some calculations with the logs to show that double the sound pressure level was 3 dB, etc. But its confusing since doubling the sound pressure level isn't double the volume perception, and doubling the decibels is way more than double the volume perception. There really is no scale to represent "sound volume perception."

 

[Bob]

Yeah its pretty neat. In physics in college we did some calculations with the logs to show that double the sound pressure level was 3 dB, etc. But its confusing since doubling the sound pressure level isn't double the volume perception, and doubling the decibels is way more than double the volume perception. There really is no scale to represent "sound volume perception."

Exactly! The human ear is a pretty amazing instrument in that it actually compresses sound waves.

 

[BaldyLochs]

Connie Kalitta is nearly deaf; he didn't wear earplugs for many years around the cars. Infact even today he says he can hear the valves only without earmuffs. But, per Doctors & family's orders... he now uses them pretty religiously. You should hear Doug's funny story about flying with him: Connie uses an amplified headset, so he can hear the radio better. And Doug, sitting right next to him could hear Connie's through his own headset because it's so loud. So then Doug had to get a better headset to muffle out Connie's noise.
It's funnier when Doug describes it.

 

[robinjackson]

I seem to recall, about 15 years ago, Joe Amato had a smart new push-truck/van which died on its first visit to the startline after a pair of cars ran. Turned out to have an impact sensor on board to shut it down in a collision.

I seem to recall National Dragster once reporting seismologists measuring 2.3 (I think -- maybe 2.5) on the Richter Scale -- at Bandimere? Also 150dB -- at any rate, apparently around 10dB louder than a jet fighter taking off, measured from the same distance.

I seem to recall ... annoying, isn't it? Got all this info archived away in several cupboards upstairs, but would take a year to dig it out.

 

[BrettV]

I think you might be confusing audio power relationships to SPL with actual SPL increases. If you double the power being sent to a particular speaker, the SPL will increase by 3dB. Such an increase is noticeable, but not significant. To double the SPL to a particular speaker, the power must be increased 10 fold. In other words, 1000 watts is twice as loud as 100 watts, an increase of 10dB.

OOPS! I switched the power and amplitude definitions of decibels.

Jamie, thanks for the interesting link.

Brett

 

[Jamie]

OOPS! I switched the power and amplitude definitions of decibels.

Jamie, thanks for the interesting link.

Brett

Again, I think the lines got crossed since there's the difference between perception and actual sound pressure, but you were 100% correct in what you said "Actually, decibels are logarithmic, so a difference of 10 dB is 10 times, a 3dB difference is 2 times." But again, it might have twice the power, but the ear doesn't perceive it as twice as loud.

Think of it this way. One top fuel car goes down the track. Say it's x decibels. The next run, 2 go down at the same time. There is twice the sound power, but does it sound twice as loud? Does the decibel value double? No. It should increase by 3 dB.

Here's another link with the math behind it: What is a decibel?

 

[r2]

I find the decibel readings all very fascinating, but Sheryl's question was about a T/F car breaking glass!!
Now we have all seen those demonstrations of an opera singer breaking a wine glass...
And I have had a few girlfriends that could come close...
But what will acually break glass??

 

[r2]

Ray, you are an absolute fortress when it comes to keeping secrets!! Are you serious...........the motor used to be in the front on the T/F cars?..........what will they think of next? Airplane wings on the back? Seriously, I first heard a nitro car run at Bristol in '85, it was in the pits and I thought, "Man, this is gonna be good!" .............I almost peed myself when KB blipped the throttle! I remember thinkin' this is what the wrath of God must sound like!

Terry
I may have let the cat out of the bag on that one...
However!! Did I mention, Blower overdrive, Nozzle sizes, Pump pressure, oil wt. and type, Mag timing, Piston size, Rod length, Valve sizes or lash, Spring pressure, Plug Gap, Launch RPM, Air Gap or clutch weight, Rearend Ratio, Tire pressure, Wheelie bar height, vehicle weight, the thing under the terrible towel, Drivers middle name and or height and weight after lunch or Barrel Valve, that would take days... Or the brand of WAX we use?? I DONT TINK SO!! Now!! I gave you all of the info Ray Alley had... So try and get a car down the track without taking orange beer can holders back to the pits with you... LMAO Sorry Bro, You so funny...
My lips are sealed with green Loc-tite...

 

[TJ]

Ray....you mentioned in an earlier post about the need to cut nitro w/alcohol for it to light?? 100% nitro will ignite as long as cylinder temp is warm....simple-warm engine w/ gasoline and then divert nitro to engine...Ormsby used to run 100% all the time in the 80's....
Nitro is a non-propellent fuel....
Fuel racing is not as much rocket science as people think. It is loud but if ya took away the noise it's only a modern day V-8 w/ a wind box (huffer)....
When I was licensing (2B) my mentors (Plueger/Mauriello) would constantly downplay funny car racing as I was very intimidated @ after the first half-track pass...Afterwards I realized its not that big a deal...fast...but not rocket science like I thought beforehand...
It's all mechanical so what you give it is what it gets in regards to fuel delivery...not that complicated...just expensive...