Exhaust theory- dun be fool

[rollakid]

eh tauhu, the header we go buy that day abit rough on the inside ler...

 

[Acoustic]

haiya, I also don't know lah, especially, fluid dynamics..... i also unable to apply vibration theory directly.

Frequency also cannot directly apply .... pulse also cannot directly apply....

All not ngam one ......

but rely on a few small thing, like from sub-woofer port theory, which is ..... frequency (rpm) doubles when port length doubles... something like that..... so this is tips 1

then port length need to quadruple when port mouth area double, so big no no to increase mouth area, this is tips 2

there is a "plug" of air "sticking" onto the mouth of the port, very reluctant to leave ...... i.e. a brother of the air sticking to the inside wall of the pipe.

then air is compressible from turbo and has a decaying effect as time and distance lapse......

So, lets see who else can put out what they know and we play from there......

 

[Useless]

TauhuTauhu,
Why choose a smoother internal piping when after 5000km or the next oil change, the piping internals are going to be covered in soot? Are there aftermarket aluminium/stainlesssteel/titanium/what other materials they have out there maintain a smoothflow of its walls?

Acoustic,
I think the concept of NA exhaust in performance talk is flowrate; which has its relationship with length, diameter and joints. Remember we had this talk that if car manufacturers were to abide in the laws of maintaining flowrate in the exhaust system, the headers would have to be bent in a rather complex arrangement to fit in the engine bay, or have long straight fugly looking arrangement which would make fitting in the cat and silencers too far back below the car. I have no experience in exhaust but i think that pulse tuning is that little part where designers improve from an existing exhaust design, rather than start from scratch for it.

Rgds
Useless

 

[TauhuTauhu]

Bernard,

i have a stainless steel pipe for my exhaust and a mild steel header. Even with the carbon layer, u can still feel the smoothness of the stainless steel's inner wall. Unlike the header, the rusted surface inside is really rough.


whn an aftermarket company design a header, i believe the 1st thing they consider would be the pulse/acoustics/vibrations which have a really big effect on the power band....

i THINK, they will 1st get the length needed for each part to have the wanted power band, only then they work on to get the diameter of each part for the best flowrate..

 

[Useless]

Tauhu,

As the behaviour of exhaust gas is transient which is affected in more ways that one can imagine, the effect of pulse tuning would strike as a benefit in a particular power band region. This is what people call optimizing the volumetric flowrate at a particular engine speed via pressure wave tuning.

What i was trying to say earlier is that the design of the headers would have a more significant effect vs materials employed.

Please note that all that is spoken here is inter-related; diameter, length and joint. But from my unexperienced point of view, its easier to tune via measuring the pressure points in an exhaust route, rather than measuring the frequency (at relatime or simulation).

quote :
i THINK, they will 1st get the length needed for each part to have the wanted power band, only then they work on to get the diameter of each part for the best flowrate..

the above statement is correct :) way to go man. simplifies alot of things here.


an aftermarket company would tune headers to "improve" higher and wider power bands (different compared to stock lengths). but i would still think they would not consider pulse tuning on top of it all, unless there is already little to play with the lengths. Sorry lost of words in the morning to explain dee. Simplified: i think there are more gains by looking into the relationship of pressure loss vs header design , rather than pulse vs header design. see it as macro vs micro scale?

cheers!
Useless

 

[CelicaIzPower]

sorry for the really late response. IMHO, i believe what they are trying to say is:

1.> it does not matter what exhaust muffler you use, but the best is without any muffler
2.> your mid pipe must be good to capture the unwanted items/materials that can kill us all.
3.> a good extractor = more HSP?
4.> Piping diameter depends on the HSP the car can produce?

er.. did i got this right?

 

[sprinter cielo]

so.how about supercharger.what piping size.extractor 2' bullet 2.2' n muffler 2.5'is't ok n suitable 4 supercharger

 

[LevIn92_gze]

what is the best piping settin for 3SGTE with standard engine but trying to boost 1 bar ?