I need Anwsers,... Please

[ausubaru92]

I went to the exhaust shop this arvo to check out some prices for my exhaust and the guy there said "You wont gain any more power by changing the two pipes between the heads and the cat. the factory setup is as good as it can get. Your only way to gain power is to go 2" or 2.5" cat back to gain about 6% power and add a hi-flo cat to gain 10%"

 

Is this true? ... 1... A hi-flo cat and 2" back will gain me 16% power

2... The stock 'head to Y pipes' cant be changed to equal length to gain more power.

 

Dont your Aftermarket header pipes for the Turbo have equal length to gain more power?

 

Thanks to anyone who can shine a little light on this subject:confused:

[MilesFox]

I went to the exhaust shop this arvo to check out some prices for my exhaust and the guy there said "You wont gain any more power by changing the two pipes between the heads and the cat. the factory setup is as good as it can get.

 

i would agree that the factory y is just right for the engine's characteristics. i favor a setup of a stock y pipe, with the muffler at the flange and big pipe after the muffler

 

as far as making a pipe i would keep the same diameter as the stock pipe, for about the same length to a collector or muffler. if you remove the heat shileding you can see the pipe is much smaller than it firt appears.

 

as far as a collector i would locate it just behind the engine crossmember under the tranny, where the front diff would be

 

if making a dual exhaust setup it would be ideal to make your pipes cross in an X fashion under the front diff

 

i would also agree that making a custom header would gain in performance as long as you keep respects to the dimensions of the stock y pipe

[MilesFox]

here is a picture of the dual exhaust notice how it x over under the diff

 

this is what the pipe looked like after it fell off the car. i made some changes to the design for my use. the pipe is 1 3/4". you can see the skinny class packs i though this design choked it down in the high rpm, buthad great bottom end and midrange. what i would do is make the flanges just past the x where it straightens out, and use a pair of glasspacks with a 2" outlet, and run 2" the rest of the way back.

 

this design, the 1 3/4" pipe off the heads and thru the x will give the right tuning for scavenging and exhaust pulse. the mufflers immediately after will give the backpressure for torque yet be open enough for flow. all the pipe the rest of the way back will be pure flow and sound characteristics. you can go as big as you want after the mufflers.

 

hard to see but this is a stock y with a cherry bomb immediately after, and 2.5 inch out the back. from my exhaust setups this is the one i favor for throttle response and the sound, the sweet sound, runs quiet and revs smoothly, let off the gas and SNARL. very good midrange and very good highway driving, high flow but still torquey

 

if making a custom header use 1 3/4 pipe to the collector under the diff, then 2" for about a foot to a 2" inlet and 2.5 outlet muffler (or whatevers closest) all of the pipe after the muffler is for flow and sound

[ausubaru92]

Thanks, you are a True Blue Champion

 

The main question was ... which is better, the factory pipe of differnt lengths each side, or a custom one of equal lengths?

 

BTW, the shop wanted $650 to do a 2" cat back with one turbo mufler, including a hi flo cat., i'll do it myself

 

Are the gains the guy stated, are these true?

84hp stock (carb ea82) X 15% = close to 97hp

[MilesFox]

i think an equal length header would be ideal if you keep the stock pipe diameter and run it like i had described

 

the stock y's characteristics are more from the pipe diameter than the bend of the pipes, the y pipe is shaped like it is to fit around the body and suspension.