Exhaust 3 Inch Exhaust

GoldenEagle91

Active Member

Dec 25, 2012

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Mar 17, 2015

#21

• Mar 17, 2015

• #21

90lxcoupe said:

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.

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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

SN Certified Technician

Aug 27, 2012

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Mar 17, 2015

#22

• Mar 17, 2015

• #22

B cam you say?

 

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GoldenEagle91

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Mar 17, 2015

#23

• Mar 17, 2015

• #23

mikestang63 said:

B cam you say?

Click to expand...

Hahaha that is awesome

 

addermk2

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Aug 25, 2009

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Mar 18, 2015

#24

• Mar 18, 2015

• #24

mikestang63 said:

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.

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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

 

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mikestang63

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Mar 18, 2015

#25

• Mar 18, 2015

• #25

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

Straight Outta Locash

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Mar 18, 2015

#26

• Mar 18, 2015

• #26

90lxcoupe said:

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.

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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.

 

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addermk2

5 Year Member

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Mar 18, 2015

#27

• Mar 18, 2015

• #27

mikestang63 said:

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.

Click to expand...

Tech advice from a TV show...


Smh.

 

madspeed

Colonel Mustard

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Mar 20, 2015

#28

• Mar 20, 2015

• #28

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