gENERAL iNFO ON BUILDING AN EXHAUST SYSTEM

[VAAKE]

hI every one,
sorry i don't own a S-10 any more but was hoping some one could help me with general exhaust work.

The mid pipe on a truck ( which would be your Y-pipe on the S-10)
If i go with smaller pipe then what i have would it give me more lowend torque
And if i went bigger,more power on top. Do i have this correct.
I am building a pipe for a 3.5 colorado. what i have is A manifold with cat inside and then it goes in to a mid-pipe that is 2-1/2 but is smashed down to about maybe 1-1/2- 2 in. in some places. there is a O2 sensor and another type of cat, i will be keeping them, just to keep the PCM happy, it flows real well. My sweet spot or powerband starts around 4 grand clear into 6 grand. so do you think i should smaller or bigger or just replace the pipe with the same size only this time whole and not crushed.
If you know what all three of these options will do, please inlighten me.
Thank you
Vaake
sorry i know this should be in the Colorado section, but i thought i might be able to snag an expert opinion.

[nomaboy]

your first theory is faily accurate But, you will gain power in all rpm with a bigger pipe. about a 2 1/2" not smashed down. you will get better responce off Idle and more power when you get going. you won't notice any loss of torque either

[VAAKE]

COOL I may look in to this more. I have asked GM about it and all they can tell me it is probaly figured into the computer. I was going to try to get the same mid- section piece from the Exaust manufature that makes the exhaust. I believe it comes off the assembley line whole, when it isshipped to GM, Gm flatens it to fit the underside of the truck. I think Walker Exhaust makes my pipe. just need to fine a dealer to get more info.

[VAAKE]

I have a Gibson Cat-back now, i wish i had more torque, i'm thinking of putting a Y connector after the single out let of the muffler and going to the tail end with 2.25 pipe. Will this help any?

[blazen]

yeah i would say a good 2 1/2 would be your best bet. i would almost say a 2 1/4 because its a 3.5 and they say a 2 1/2 is good for a 4.3 but you say it revs to 6 grand which is higher than a 4.3 so stick with a 2 1/2.

[bvr775]

those pinches are supposed to act like a velocity stack and pull more air through the exhaust. Gm spent allot of money to get that wrong.

I don't about the 3.5 as a performance aplication.They just don't seem like their setup for anything outher than as a truck engine. I would go find a good exhaust man and ask him.

[Rhansen]

Here's some related info you might find helpful.
http://hotrodders.com/showthread.php?t=43383