Exhaust 3 Inch Exhaust

[GoldenEagle91]

There is no magical number where a 3" exhaust is needed. There are so many factors to this that it would be nearly impossible to test because one camshaft could have exhaust timing events that favor the bigger exhaust and one could favor the smaller exhaust.

Thanks for the response. The cam in my build is a Ford Racing B303 if you are familiar. The cam specs can be found here http://www.summitracing.com/parts/fms-m-6250-b303 . What characteristics would favor the larger versus the smaller if you have any background knowledge on the matter?

 

[mikestang63]

B cam you say?

 

[GoldenEagle91]

B cam you say?

Hahaha that is awesome

 

[addermk2]

really- tell me how I'm wrong. On a dual 2.5" ehaust system, how is that not 5" of total exhaust. I guess Flowmaster, Dynomax, and every other exhaust company is wrong as well.

You would actually needs four 2.5 inch pipes to have the same overall interior area as one 5 inch pipe.

pi x 2.5^2= 19.63.
So a 5 inch pipe has an interior area of 19.63 square inches.

pi x 1.25^2= 4.9.
One 2.5 inch pipe has an interior area of 4.9 square inches. Since we are talking about dual 2.5 inch pipes let's multiply that by 2 and our total interior area is 9.8 square inches.

Therefore two 2.5 inch pipes have about half of the interior area of a single 5 inch pipe

 

[mikestang63]

well then I stand corrected. Learned that many years ago and spoke with tech at flowmaster etc who also echoed that. Hell, I even heard Stacey David say that a few months ago on Gearz. Guess some of us old schoolers learn something new everyday.

thanks for the clarification guys.

 

[Gearbanger 101]

3" exhaust will not have any noticable drawbacks in performance in a 400 hp application and it may be a smart idea to do the 3" now if you plan to make more power later.

In my experience, everyone "plans" to make big power, but few ever follow through with said plan.

If he's talking B303, I can tell right off the bat that he'll never build enough engine to warrant that much exhaust.

 

[addermk2]

well then I stand corrected. Learned that many years ago and spoke with tech at flowmaster etc who also echoed that. Hell, I even heard Stacey David say that a few months ago on Gearz. Guess some of us old schoolers learn something new everyday.

thanks for the clarification guys.

Tech advice from a TV show...


Smh.

 

[madspeed]

I agree with @addermk2, although he lost me at pi