12Sonic440
New member
I have a full catback Bolra exhaust but I'd like it to be louder. I know if I had a straight pipe it'd be louder or maybe some headers. Let me know any ideas.
Making exhaust/car louder
- Thread starter 12Sonic440
- Start date
12Sonic440
New member
Would you suggest me cutting apart a Borla exhaust though lol.
12Sonic440
New member
Where can I get other pipe for it? Porla has straight pipe I could buy. Could I have someone just weld it and would it be legal?
Eric Smit
Enforcer
It would not be legal, and you can find pipe almost anywhere online.
http://www.mandrelbendingsolutions.com/servlet/StoreFront
-Eric Smit
http://www.mandrelbendingsolutions.com/servlet/StoreFront
-Eric Smit
rdss
Junior Member
I guess you're not happy with that borla you've been saying is the best exhust available any more........... I recommend cutting out the resonator and going to Advanced Autoparts and picking up a 18" section of 2 1/4" slip fit pipe. You will need a clamp for each end and that with a DDM test pipe will get you a good deal louder than dual cats and a resonator and muffler.
american_tuner
New member
You could just leave it alone at 1st and see how the test pipe sounds. If it is still not loud enough then go from there. I wouldnt straight pipe a n/a motor. You need some back pressure. Does any company make a header for the 1.8? If so id jump on it as long as it is a good quality.
sx sonic
New member
No engine needs backpressure. Back pressure is always counterproductive.
The only things that matter are flow, velocity, and tuned length (which is tenfold more complex so I'll leave it be)
The reason for the misconception is someone puts a huge pipe diameter on their car and whammo, poor throttle response and no lowend power. It wasn't lack of back pressure that did them in, it was a major loss in exhaust velocity. Which assit in scavenging the cylinder of spent fumes and pulling in a fresh charge at lower rpms. That same exhaust will flow better which is important at high rpms where its all about getting a large amount of exhaust out quickly and scavenging is less important...
In simple terms, smaller pipe has better velocity and thus better throttle response and low end pull.. it also flows less well up top and as a byproduct has more back pressure.
Bigger pipe flows better and is good for topend power, but due to the loss of velocity can't scavenge exhaust as well at the lowend hurting response and power. The byproduct of this is less back pressure. Of course large and small pipe is relative to engine size (eg. 2.5" pipe is small for a semi but not our sonics)
You've probably noticed the previous descriptions are about pipe size, not catalytic converters or mufflers. That is because they are restrictions and simply hurt exxhaust effiecency. although it is possible for them to help the system but it is merely a byproduct of design and deals with resonance (more so on open chamber mufflers vs glass pack style than cats). Removing them or improving their flow will almost without exception improve performance even if the rest of the system is left intact..
I know its a wall post but for whatever reason the back pressure misconseption really bugs me AND I like to share knowledge
Back to topic, the othe members have given some good recomendations although aside from replacing the 2nd cat with a "test ppe" or higher flowing cat your only other options are full custom exhaust to your cat back setup (there are shops that can do this for a reasonable price ~300) or cutting out parts of your borla system and clamping in straight pipe to replace them as RDSS.
Keep us informed as you decide on which avenue you think you might try. I look forward to hearing of the results
-tyler
The only things that matter are flow, velocity, and tuned length (which is tenfold more complex so I'll leave it be)
The reason for the misconception is someone puts a huge pipe diameter on their car and whammo, poor throttle response and no lowend power. It wasn't lack of back pressure that did them in, it was a major loss in exhaust velocity. Which assit in scavenging the cylinder of spent fumes and pulling in a fresh charge at lower rpms. That same exhaust will flow better which is important at high rpms where its all about getting a large amount of exhaust out quickly and scavenging is less important...
In simple terms, smaller pipe has better velocity and thus better throttle response and low end pull.. it also flows less well up top and as a byproduct has more back pressure.
Bigger pipe flows better and is good for topend power, but due to the loss of velocity can't scavenge exhaust as well at the lowend hurting response and power. The byproduct of this is less back pressure. Of course large and small pipe is relative to engine size (eg. 2.5" pipe is small for a semi but not our sonics)
You've probably noticed the previous descriptions are about pipe size, not catalytic converters or mufflers. That is because they are restrictions and simply hurt exxhaust effiecency. although it is possible for them to help the system but it is merely a byproduct of design and deals with resonance (more so on open chamber mufflers vs glass pack style than cats). Removing them or improving their flow will almost without exception improve performance even if the rest of the system is left intact..
I know its a wall post but for whatever reason the back pressure misconseption really bugs me AND I like to share knowledge
Back to topic, the othe members have given some good recomendations although aside from replacing the 2nd cat with a "test ppe" or higher flowing cat your only other options are full custom exhaust to your cat back setup (there are shops that can do this for a reasonable price ~300) or cutting out parts of your borla system and clamping in straight pipe to replace them as RDSS.
Keep us informed as you decide on which avenue you think you might try. I look forward to hearing of the results
-tyler
ThatTmoGuy
New member
Cut off the muffler
BRNZY
New member
Totally agree with the part about the sound and louder not necessarily being better. I have heard too many 6 cylinder engine cars being set up with after market exhaust at an attempt to give it a meaner sound. There is a huge difference with that and a 8 cylinder. A 4 cylinder may sound even worse, and give it a ricy sound. Of course it is up to you because its your car, but these are not high performance muscle cars.
Eric Smit
Enforcer
no.
