exhaust too loud?
- Thread starter Quinton Exler
- Start date
Quinton Exler
New member
Lmao, that's a bit more than what I was thinking. but it would definitely do what I had imagined.
ThatTmoGuy
New member
I guess what I'm trying to get at is that although in theory that piping setup could be beneficial it most likely will just add extra weight. I wish you the best in your pursuit of the ultimate exhaust.
Also maybe some drawings or sketches would help me understand better but all it seems like to me is stock pipe to something super huge which i don't think will get you the result you're expecting.
Also maybe some drawings or sketches would help me understand better but all it seems like to me is stock pipe to something super huge which i don't think will get you the result you're expecting.
Quinton Exler
New member
okay, if the gasses were still carried safely to the back of your car and your car still sounded the way you liked it what would you rather run.
A stock downpipe and absolutely nothing else after it.
or a 2.5" straight pipe?
A stock downpipe and absolutely nothing else after it.
or a 2.5" straight pipe?
ThatTmoGuy
New member
If it was a stock downpipe with nothing after it, than it would not carry to the end of the car lol. As is right now my Sonic has no exhaust after the second cat. If I could get away with it I would have a fender exit DP lol
As for a street able daily driver. Just get a 3" system with catless DP maybe a high flow cat where 2nd one is with no muffler and maybe a resonator.
As for a street able daily driver. Just get a 3" system with catless DP maybe a high flow cat where 2nd one is with no muffler and maybe a resonator.
Quinton Exler
New member
You didn't choose though lol. Which would you pick? if the stock downpipe only could still carry gasses to the end and sound the way you like it with all the performance gains. VS. a 2.5" straight pipe. I may be a weird person here but I think the stock downpipe alone would yield better gains.
ThatTmoGuy
New member
2.5" straight pipe no cat's no muffler no resonators.
That initial restriction from the Stock DP is a real drag on spool.
That initial restriction from the Stock DP is a real drag on spool.
Quinton Exler
New member
Indeed, but there is absolutely 0 pressure behind it. Meaning everything coming out of that downpipe is being pulled by outside and pushed from the engine. Just like I said with a funnel.
Eric Smit
Enforcer
unfortunately for exhaust gasses, it's affected by the smallest bend in the piping, or restriction. The downpipe would be the most restrictive, therefore it wouldn't be as effective as you think. a 2.5" turbo back straight pipe will be more effective than a downpipe only. Your choice depends on if you want power or sound.
-Eric Smit
-Eric Smit
Quinton Exler
New member
If I end up doing a dyno before I get this done, then go to the exhaust shop and get something crazy like a 5" pipe from the downpipe back. and then dyno again. and have gains more significant than a normal straight pipe. Then what happens?
ThatTmoGuy
New member
I eat my words.
ThatTmoGuy
New member
replace cute puppy with an awkward Smit
ThatTmoGuy
New member
Google...
Dlowwoc
Chubby Rubber City
sorry for the derp picture. it's dark here.
-Eric Smit
not the 3" tip i was waiting for....j/k
sx sonic
New member
Ol there's a lot in here so I'm just gonna cover what I've picked up from reputable sources and observations. Some of this has already been cover.
1. Engine exhaust does work in pulses. There are + pulses and -pulses (ppositive and negative). In an ideally setup engine the timing of when a positive or negative wave reaches the exhuast valve it is time to help evacuate spent charges (the - wave is what scavenges the cylinders). Some all out reace engines have exceeded 110% volumetric effeciency with proper intake and exhaust tuning. (Normal NA engines have approx 80% VE, forced induction regulary exceeds 110%) *note the engineers designers of these systems do NOT car about back pressure their tuning skills are way beyond it. Its flow, velocity, pressure waves, and timing to them*
The exhaust tuning to scavenge cyclinders is affected by HEADERS: primary pipe lenght, primary pipe I.D., collector length, collector dia. Secondary pip length and dia. Header design has a huge role in power generation and where the rpm band is maximized. After that its Pipe size, type of muffler device (glass pack and chambered exhuast affect pulse tuning. A big reason is when the waves enter a chambered muffler it sees a bigger cross section and reverberates back. The waves travel trhu a glasspack simialry to how they would a straight pipe). And finally total exhaust length.
Full exhaust tuning is most apparent on motocross bikes, race cars and sport bikes. Traditionally exhaust tuning. Could be setup to favor a narrow RPM range and really maximize effeciency there at expense of other areas or it could be setup to boost most of the rev range but not as strongly (or if goobered up take power away or even shift it to an rpm range never used). As has become common place on motocross bike exhaust they are now adding steps in the header (pipe I.D. increases) or helmz holz resonators (similar to what an earliar poster had on his Audi A6) to get the gains of of more targetet exhaust without the downsides of a narrow RPM band.
I do not know of anyone going to these tuning lengths just for sound or even how much of affect in sound output it would have. BUT nearly everycar that the builder went thru the challenges. Of not only selecting the right dia exhaust but also carefully choosing every dimension of the exhaust sounds amazing. I'm sure its more a chicken and the egg thing, the exhaust followed an awesome buold and was not the sole reason for the awesome sound.
Here's the kicker, the exhaust after the turbine on a turbo car will not benefit from this tuning. It wants a couple feet of exhaust that is roughly the same size or marginally larger than the turbine outlet size (3in on our cars) to help convert the flow of exhaust from axially (think toilet flush) to turbulent). After that as long as the exhaust is large enough to flow the maximum amount of exhaust it really don't care.
So unless your really planning some big power mods in the future anywhere between 2.25" to 3" will be fine. If you want the performance throw on a catless downpipe (top cat/1st cat). Then either have a shop build you a downpip back or wait for ZZP to make their "flex pipe O2" section of pipe and put on a 2.25" or bigger exhaust from there back and add a glass pack or chamber muffler to it (check out the build threads and lesson to different members sound bytes and when you find one that sounds good use that muffler)
Oh and FYI only running the catless downpipe sounds like SH!T, don't even think about it haha, its got a horrible sound at idle, coasting, revving and WOT under load, not a pleasant sound, and suprisingly not as loud as a full straight exhaust.
1. Engine exhaust does work in pulses. There are + pulses and -pulses (ppositive and negative). In an ideally setup engine the timing of when a positive or negative wave reaches the exhuast valve it is time to help evacuate spent charges (the - wave is what scavenges the cylinders). Some all out reace engines have exceeded 110% volumetric effeciency with proper intake and exhaust tuning. (Normal NA engines have approx 80% VE, forced induction regulary exceeds 110%) *note the engineers designers of these systems do NOT car about back pressure their tuning skills are way beyond it. Its flow, velocity, pressure waves, and timing to them*
The exhaust tuning to scavenge cyclinders is affected by HEADERS: primary pipe lenght, primary pipe I.D., collector length, collector dia. Secondary pip length and dia. Header design has a huge role in power generation and where the rpm band is maximized. After that its Pipe size, type of muffler device (glass pack and chambered exhuast affect pulse tuning. A big reason is when the waves enter a chambered muffler it sees a bigger cross section and reverberates back. The waves travel trhu a glasspack simialry to how they would a straight pipe). And finally total exhaust length.
Full exhaust tuning is most apparent on motocross bikes, race cars and sport bikes. Traditionally exhaust tuning. Could be setup to favor a narrow RPM range and really maximize effeciency there at expense of other areas or it could be setup to boost most of the rev range but not as strongly (or if goobered up take power away or even shift it to an rpm range never used). As has become common place on motocross bike exhaust they are now adding steps in the header (pipe I.D. increases) or helmz holz resonators (similar to what an earliar poster had on his Audi A6) to get the gains of of more targetet exhaust without the downsides of a narrow RPM band.
I do not know of anyone going to these tuning lengths just for sound or even how much of affect in sound output it would have. BUT nearly everycar that the builder went thru the challenges. Of not only selecting the right dia exhaust but also carefully choosing every dimension of the exhaust sounds amazing. I'm sure its more a chicken and the egg thing, the exhaust followed an awesome buold and was not the sole reason for the awesome sound.
Here's the kicker, the exhaust after the turbine on a turbo car will not benefit from this tuning. It wants a couple feet of exhaust that is roughly the same size or marginally larger than the turbine outlet size (3in on our cars) to help convert the flow of exhaust from axially (think toilet flush) to turbulent). After that as long as the exhaust is large enough to flow the maximum amount of exhaust it really don't care.
So unless your really planning some big power mods in the future anywhere between 2.25" to 3" will be fine. If you want the performance throw on a catless downpipe (top cat/1st cat). Then either have a shop build you a downpip back or wait for ZZP to make their "flex pipe O2" section of pipe and put on a 2.25" or bigger exhaust from there back and add a glass pack or chamber muffler to it (check out the build threads and lesson to different members sound bytes and when you find one that sounds good use that muffler)
Oh and FYI only running the catless downpipe sounds like SH!T, don't even think about it haha, its got a horrible sound at idle, coasting, revving and WOT under load, not a pleasant sound, and suprisingly not as loud as a full straight exhaust.
Quinton Exler
New member
I have done a 3" exhaust just after the Flex pipe and all the way back. It looks RIDICULOUS... I made it long enough to show out the back and kept it straight all the way (no bend down like stock was) so from far away you see the huge beast floating under the car... As for performance I got a Dyno before and I am going to do a dyno later for difference... I have honestly noticed a MUCH lower note in the exhaust and the throttle response is much better than before. The car also seems to shift a lot smoother and has more pull when shifting.
