I found this excellent write-up on exhaust systems and how they work; thought I'd pass it along:

http://www.geocities.com/MotorCity/7...usttheory.html

 

that is pretty cool...

 

I think my exhaust knowledge just quadrupled...

 

Thanks for the post, my knowledge has also increased. Good to know the Yotatech'ers are right-on when it comes to diamater. Funny how the same goes for tire size and pipe size - bigger is not always better.

 

Great post, it confirms what I knew to be true and showed me what I didn't know. My favorites are about backpressure/ restriction, so many have stated these (3.Slows) are designed to need backpressure/restriction. Ha I knew they were wrong, and if they still don't believe let them take a leak and stop midstream and tell me "Ah this is great".

 

That is rather interesting - I wonder if Toyota designed that cross over pipe on the 3.0 with all the exhaust gas exiting in front of the #6 valve to try and get the #6 valve's "pulse" to help along the 1, 3, 5 cylinders movement of exhaust gas?

 

I doubt it.

whats cheaper, 1 exhaust pipe or 2?

 

moved to general section

 

HEY HEY, I knew all of that. and a little more. But I guess thats cause Im new to wheeling, and have spent the last 5 years of my life, building and racing import cars, and dear God exhaust is the easiest way to get hp out of anything....so I know a lot about exhaust work. I feel good now. Now, if I only knew as much about wheeling...

 

I read that link last night but take it lightly.

 

the article is correct actually.

2 stroke engines need backpressure 4 strokes do NOT. Back pressure helps on bottom end torque, but kills you in top end power.

The pulse effect it talked about is called scavanging and a good set of headers does this.

As far as exhust being too big, I agree there too. What pipe has more volume and consequently more mass a 2" one 10' long or a 4" one 10' long? Exhaust size is a balancing act, too small and you end up restricting the exhaust. Too big and the exhaust cools, compacts, and generates more backpressure.

 

yeah, but what's more useful on the street? torque or horsepower?

 

too big and there's not enough inertia so you get less scavenging, as well.