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newaccorddriver
09-22-2005, 06:36 PM
im planning on getting a new exhaust system for my car very soon. i was planning on getting one custom made by a somewhat reputable exhaust shop. what i was wondering is, if i made a custom catback system for my car out of 2.5inch tubing WITHOUT mandrel bends in it, would i be able to expect some horsepower increase? and what would it sound like if i didnt use any resonators on it?
A20A1
09-22-2005, 09:51 PM
It would probably sound raspy if you didn't use a resonator.

Also 2.5" is too large, even though it's DIE BENT instead of MANDREL BENT.

You should stick with 2.25" or 2.00"

You'll gain EXHAUST FLOW with the 2.5" so you'll have less PUMPING POWER-LOSS and you'll free up some HP in that respect.

You'll lose EXHAUST VELOCITY with 2.5"

Depending on what kind of restrictions the muffler has, you'll free up top end.


You need more mods then just exhaust to expect to get any major gains, and even then you should really be thinking about what rpm range you want to make your power, and what kind of driving you'll be doing.

http://www.3geez.com/showthread.php?t=352


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BlueBead
09-22-2005, 10:03 PM
you want to go bigger if you boost, but even then 2.5 is good up to 500ponies, so 2in is probably what you should look at if you're not going turbo
Justin86
09-23-2005, 04:13 PM
but a good header is the key folowed by the correct sized exhaust and straight through purflated muffler/resnator.
NotSeen2000
09-23-2005, 05:56 PM
so how much HP and TQ do our cars come wit stock? i could figure that out it would help me out a whole lot
newaccorddriver
09-23-2005, 06:34 PM
It would probably sound raspy if you didn't use a resonator.




what exactly does raspy sound like?(i have no clue)
Low Tek
09-23-2005, 07:03 PM
2 and 2.25 with no muffler/ resonator is loud as hell.. I did it, and had to add a magnaflow muffler.. then it souned nice and deep
bobafett
09-23-2005, 07:11 PM
wow.

ok having driven cars with both 2.25 and 2.5 i will go with 2.5 from now on. also 2.5 is very reasonable on a well modded NA car. also if u have looked at 2.25 its tiny. ;-) once you start stepping up to 2.75" - 3" thats when the pipes start moving up in diameter real fast...
A20A1
09-23-2005, 08:23 PM
wow.

ok having driven cars with both 2.25 and 2.5 i will go with 2.5 from now on. also 2.5 is very reasonable on a well modded NA car. also if u have looked at 2.25 its tiny. ;-) once you start stepping up to 2.75" - 3" thats when the pipes start moving up in diameter real fast...

Yup there is quite a difference.

Here was my pipes, when I went to 2.5

http://i23.photobucket.com/albums/b351/Wendy_girl/00_pipe3.jpg


Still my next system is going to be 2" Mandrel, though I want to see if the 2" is small enough to fit under the car so it can go straight back to the muffler without so many bends.
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what exactly does raspy sound like?(i have no clue)

The higher pitched noise.

Resonators should deepen the exhaust some.

It will still be loud but not as high pitched.

You need a decent muffler to quiet things down.