Our blog has “Google translate buttons”, but the translate is not clear. So we received a message to please rewrite in English about the article of muffler sound quality. I’m sorry if English not so well. This article based on past article.
This time, I considered about the “muffler sound”.
Good muffler sound is very difficult. Because it depends on individual preference, “good sound” is completely different.
But, my favorite sounds is F1 sound (*'∀` *)
like this!!
It ’s the best!
However, these cars have different numbers of cylinders in the first place, and the revolutions per minutes(rpm) also different, so such a high sound (high Hz sound) appears.
However, from the desire to get as close as possible to this sound, I wondered if there was anything I could do to get a high tone.
In general, there are several ways to make the muffler treble
1) straight pipe
2) the pipe diameter reduction
So, why does these could make a high tone? ?
①Why does the straight pipe make high tones?
First of all, a sport muffler generally absorbs sound in a cotton-like material called “glass wool” to mute it.
In summary, the exhaust pressure is reduced by glass wool, so the sound pressure is suppressed and the result is that the sound is muted.
What is important with this structure, the high tone sounds are easily absorbed, and the low tone sounds are not easily absorbed. If you often heard a sports muffler sounds, the bass sounds of “bow-bow-bow-” that couldn't be silenced by glass wool.
So, if not using glass wool, of course, the sound pressure is high, and if it is a straight pipe, the high sound is emitted as it is without being absorbed.
Along with this, how can I turn off the bass sounds? There is a silencer (baffle) that often thrusts into the muffler end.
> Speaking of baffles, most of them are installed at the end of muffler, but if you have heard the difference in sound quality between installing and not installing it, you can feel the difference that ... , Only the bass sound is pressed down(muted). If you say it, it will sound like a “pas-pas-pas…” like a fart sounds.
It was written. I think so too this is such a sound on the street.
This is efficient to have done in a multi-stage expansion type silencer has been adopted well, such as genuine muffler.
With this structure, it ’s not a dream to turn off the bass and create a dream-like muffler that leaves only the target sound range!?
However, it is quite difficult to have such a structure in a after parts muffler. Because it is costly and there is no sound chamber volume calculation know-how to control the target sound range. I watched at the facilities of the Honda S2000 muffler manufacturing company on web, but I remember that it was a very big research facilities.
By the way , I using GP-SPORTS EXAS EVO TUNE has strange structure.
(GP SPORTS is major after-parts brand in Japan. The company usually make DRIFT parts, also muffler, knuckle, arms, catalyzer, suspension and more.)
The image says “power chamber”. But it seems to be generally called “Helmholtz resonator”.
In F1, it is sometimes used to balance pressure according to the opening and closing of the accelerator.
In GP-SPORTS, it seems to use for reduce the volume of muffler sounds.(it might be use reflected shock wave in the muffler)
② Why does a high tone sounds come out when the muffler pipe diameter is reduced?
I think the dual pipe muffler sounds a little bit high-tone sound, right??
Most of AE86 muffler sounds are extremely high-pitched, but looking at the muffler is extremely thin(narrow).
(*AE86: TYOTA SPRINTER TRUENO. It is a major DRIFT machine in Japan. It is main car of InitialD animation. And most of AE86’s are NA and implement a high-rpm engine, so they make awesome high-tone sounds.)
First, I have a inquiry about “Why are they make high-tone sounds?? Because there is not only from high-rpm engine, but also from narrow muffler should have an effect!!”
So I understanding of them, studying the “structure of the whistle” to solve this inquiry.
The sound of a high tone often means that the Hz (hertz) is high.
In addition, there are two types of whistle structures, open tube type and closed tube type.
It is also written in the above-website. The acoustic wavelength λ seems to be a little longer than the tube length.
The open end correction value is about 0.6 times the pipe diameter, which means that the open end correction changes depending on the pipe diameter.
Since the muffler of the car is an open tube type, I solved it a little. (But different from the actual muffler conditions, we believe as the sound of the fundamental vibration)
3.5m(meter) of the pipe assumes a muffler as a condition to be used, at the speed of sound 340m/sec, how it changes of fundamental vibration(Hertz ) emitted by different diameters.
A) In the case of an 80Φ tube, which is often implemented in a turbo car
Open end correction = (80/2) x 0.6 = 24mm
Wavelength = (3500 + 2 x 24) x 2 = 7,096mm
Hz = 340 / 7.096 = 47.91 (Hz)
In case of 80φ(mm) pipe might make 47.91Hz.
B) In the case of a 60Φ tube, which is often implemented in a NA car
When the diameter changes by 2cm, the change of sound Hz is only about 0.2Hz… (ToT)
The number of Hz is very slight, but this is just the fundamental frequency. And the engine frequency is multiplied here, so the human can distinguish the difference of sound.
By the way, it is often said that when titanium is used, a “dry muffler sound” will be heard.(*As an expression of titanium muffler sound in Japan)
It is the sound speed(sound velocity) in the above formula changes depending on the
sound velocity = √ metal elastic modulus (Pa) / density (kg / m3)
Stainless steel (SUS430) has a longitudinal elastic modulus of 204KN / ㎜2 and a density of 7.7g / ㎝3, while titanium has 106 and 4.51, respectively, so the sound speed seems to change slightly.
- Conclusion -
In order to acquire high-tone sound from the above and to produce a good sound
・ Straight pipe rayout(or structure without using glass wool) ⇒ I tried it
・ Try to make a narrow pipe’s muffler
・ Use of good material for sound velocity
However, it is not possible to make a straight pipe to run on the general road, and it seems to be a slight thing although there is a difference even if you use narrow diameter of pipe or choice to the material. I would like to make a multi-stage expansion silencer if possible, but I can't calculate that precisely (ToT).
Then, I came up with a new idea. If I could raise up the frequency(Hz) of the sound. . .it might get good sound??
If you do not think about the cost and exhaust efficiency, you can get a higher sound…? It is no dream to make the engine sound of the straight 4 into the sound of 8 cylinder !?
However, I learned about sound more… and I found that it is very difficult to make 8 cylinder sounds…. If you interested in and want to read more, please read next article.(It is still Japanese article. So please press “translate buttons” )
If you would like to read the other articles, please refer to the related pages ↓↓
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https://outlaw-atsu.blogspot.com/2019/12/muffler-sounds-like-racecar.htmlHow to make muffler sounds like a race car?? (English article)
Our blog has “Google translate buttons”, but the translate is not clear. So we received a message to please rewrite in English about the article of VALINO TIRES. I’m sorry if English not so well. This article based on past article.
We wrote about the new tire manufacturers today.
New maker stand up in Japan, the name is VALINO TIRES.
These days, we get the information that famous D1(Formula D) drivers such as Naoki Nakamura’s are testing a new tire.
This is Varino (Barino?) Tire.
When I check the website, they says Japanese manufacturers. But they work only design and sales, producing countries is China.
Also it seems to be related VALINO with ZESTINO TIRE JAPAN company.
But products seem to exert a powerful grip than Gredge series of ZESTINO, it is easy to heat enven if in the wet condition. Even if there has over 500 horsepower, the power eaten by awesome grip of VALINO.
According to the SNS of Mr.Naoki Nakamura, a photo with the front of the machine lifted was uploaded.
This!
It seems that the design target field of the tire is DRIFT.
when I in charge of a ZESTINO Gredge series test engineering driver, I felt ZESTINO was easy to control slide but difficult to master the “true limits” of grip. It seems that VALINO is similar specifications.
Development testing of VALINO tire, Mr.Tetsuya Hibino is not involved. It seems mainly Mr.Naoki Nakamura has been in charge.
For now, VALINO has two brands, so called PERGEA 08R 08RS 08SP and GREEVA 08D.
High-grip tire is PERGEA, optimum scraping hard rubber to drift practice is so called GREEVA. High-grip PERGEA has three types of tread-wear(compounds), that numeric is 200,160,140.(08R, 08RS, 08SP)
（I tried and reviewed of 08RS.（Sorry, still Japanese. So pls press translation button.））
- PERGEA Series -
PERGEA series was designed to win match, such as D1 and the other drift events. Therefore, the race always starts with cold tread temperature condition, so the rubber is designed to be easy deflection.
(But it is called the “hysteresis loss”, there has been touched on in past blog.)
In addition, not only soft rubber itself, it is also contemplated that immediately heat enters to win in the cold start also the tread surface is immediately softer.
Thus it is not suitable for use of several laps of the circuit(long stint run: heat up the tread condition too much is not good).
Conversely, there is good lap time can be expected in wet condition and winter short time-attack (like autocross.)
And the deep groove makes bad steering feel. If you use to time attack, I heard from engineer that good results can be obtained by shaving the tread to about 3mm of the depth.
- PERGEA 08R -
08R is the most hard rubber in PERGEA series.
It is also good to heat, and even if it laps the short(middle size) circuit two times, the rubber doesn’t peel off.
Furthermore, in gymkhana(autocross, autox, solo), when we analyze the movie from outside both of them, the vertical direction is better than ADVAN A052.
But the side wall and tread rubber is too soft for the transverse direction.
Sometimes it makes disturb the car’s posture.
(If the groove will be shave to shallow, it might be solved though.)
The deterioration is less than other compounds(08RS, 08SP), because of the
tread surface’s melt is less than the other models.
So those who used in the drift, I think that this 08R is the most safe choice in VALINO.
If used in the grip, short time attack (about one to two minutes) without in summer and it may make you good lap-time than the more expensive tire if the wet road surface.
- PERGEA 08RS -
08RS is the middle model of PERGEA series.
This model is further soften rubber than 08R. If you thought "I wanna a little bit more to the front!!" at the start dash of twin drift, you should be choice this model.
The rubber is softer than 08R, therefore also rise up the temperature of tread might be faster than 08R.
(No matter how good grip it has, not good tread rigidity and side wall rigidity is going to not good cornering. There has been touched in past blog.)
It is perfect characteristics in gymkhana(autocross, autox, solo) and wet condition lap attack.
But it is too soft, even if it is gymkhana in summer, it may not suitable for use…?
The price is not so different from 08R. It seems to be an awesome tire depending on the usage environment.
（I tried and reviewed of 08RS.（Sorry, still Japanese. So pls press translation button.））
- PERGEA 08SP -
This is the most high-grip tire of PERGEA series, the VALINO says.
It has the most soft rubber in PERGEA, and it is not necessary to heat the tread before start, seem to exert a powerful grip.
Conversely, It is too soft to use time attack usage, and someone says that is only use in rainy game of DRIFT.
I have never seen(touch) this model, so I can’t review of everything about it. But in my imagine, it is only suitable for wet gymkhana or short-stint time attack in winter… maybe??
The first place , it come out only size for D1 vehicle size, the other vehicle such as small FF or light-weight vehicle can’t be installed.
- GREEVA Series -
- GREEVA 08D-
The rubber of GREEVA is quite harder than PERGEA, the model was developed with the aim that the against abrasion.
It might be the same kind of concept of ZESTINO ACROVA series.
Perfect model for those who want good abrasion tires and want to practice the drift longer.
It might be a good for the city riding tire because it is hard to wear down in the general road.
GREEVA has not only big size(17 to 18 inch),but also has 15-inch size, so that can suitable for small car such as A to C segment vehicles too.
Those who has the purpose of how to use, VALINO is good choice.
Not suitable for those who are long running at the circuit(without GREEVA series), but is perfect for the purpose, such as "I want to win in the drift match" "I want to win in the winter and wet time-attack".
If you would like to read the other articles, please refer to the related pages ↓↓
And if you want to order the articles, not translated by Google, wrote in English, please inform us under the comment or facebook.
https://outlaw-atsu.blogspot.com/2019/12/Valino-tires-EN.htmlWhat is VALINO TIRES (Tyres)??（English article）
