YACT: Replacing Exhaust

[Viperoni]

Originally posted by: Zenmervolt

Originally posted by: Viperoni
Yet another person who thinks backpressure helps power. *sigh*.

Define "backpressure".

Backpressure itself does not help low-RPM _TORQUE_ (note: not HP), but the faster flow rate cause by a smaller-diameter exhaust system _does_. Now, this same smaller diameter that increases exhaust gas velocity at low RPM becomes backpressure at highter RPM because the engine is pushing more air. So a certain amount of "backpressure" at high RPM is indeed helpful to low-end torque because it increases the exhaust gas flow velocity.

ZV

Backpressure should be defined as the resistance to airflow at a given RPM.
Your statement is correct, of course.

I would gladly trade 10-20% of my engine's torque from idle-3k to increase a similar amount of torque between 4k-6k, but that's a completely different discussion

 

[SVT Cobra]

Originally posted by: QuitBanningMe

Originally posted by: Rent
STOCK

 

[Kadarin]

Originally posted by: godmare
The deal is you'll lose tha backpressure by opening up the exhaust. that's going to cut your low end torque, which you need, especially in a big and underpowered car like that.

This is muddy and incorrect thinking. Backpressure is force that acts against the piston as it comes up towards TDC (Top Dead Center) on the exhaust stroke. Reducing this force only helps performance.

However, you do need to take into consideration exhaust gas velocity. A smaller exhaust pipe (or pipes) has the effect of increasing the velocity of the gasses flowing through it, which increases the cylinder scavenging effect, thus improving low-end torque. However, at higher RPMs, the overall capacity of the exhaust system itself becomes a limiting factor, and backpressure increases, reducing high end performance. So ideally, you want a high-capacity exhaust that maintains enough flow velocity to help both low-end torque and high-end power. For the reason I just stated, a dual exhaust serves the purpose better than a single exhaust with a gigantic pipe.

 

[SilentZero]

Definately go dual!

 

[Kadarin]

Originally posted by: SilentZero
Definately go dual!

If it hasn't been mentioned yet, one definite factor to consider in the decision to go dual is emission regulations. Another is the way in which the car underbody is engineered: My old '83 Mustang GT, for example, required that I replace the transmission crossmember with one that had clearance for a second exhaust pipe.

 

[OrganizedChaos]

way to much bad info from people talking out there ass in this thread. i recomend you ignore all responses you got in this thread (no offence to the few who know what there talking about. and find a forum thats more appropriate for this discussion.

 

[klah]

one vote for stock.

 

[Slacker]

Dont do it.

 

[TwoBills]

Just keep it stock and use quality parts. In other words, stay away from Midas.