I would like to put true dual's on my car, but i don't know if I should put on dual 3" or dual 2.5" pipe. Just from looking under my car, I think it would be really difficut to run dual 3" pipe. I will be changing out my 305 for a 355 if that helps any on the pipe size. I want to run true duals with glass packs only and would like to have tailpipes. (not dumps) Thank You

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Twells

1992 R.S. 25th Anniversary
* Borla
* Open Element
* Hypertech Chip
* Smog pump delete

Thats all for now!!

 

I just got done getting help with the same topic. Unless you have 1000+ horse, go with the 2.5". I myself will either do that, or go with a 3" single. Hope this helps.

Nate

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1988 Camaro Sport Coupe

• Custom Interior
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• Shift Improver Kit

Homepage: www.rsdragster.cz28.comp

 

check out my page. its in my sig

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Soon to be installed:
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

Tas,

I checked out the chart on sq. in. for pipes on the link you have posted (F-Body Dual Exhaust), and I feel that it is incorrect.


The formula for finding the area of a circle is <pî x (radius squared) = area.> The chart shows a single 2" pipe as having 12.5664 sq.in. of area. That is the area of two 2" pipes. Besides that you have to subract approx. 1/16" off the radius to allow for the thickness of the metal. A 2" diameter pipe is o.d., therefore to find the i.d. you have to subtract 1/8" from the o.d. That gives you 1 7/8" i.d. then divide by two for the radius. That is 15/16" or .9375" radius. Square that and you get .8789". Then multiply that by pî (approx. 3.14159) and you come up with 2.761" sq. or roughly 2 3/4" sq. Then 2 pipes would be approx. 5 1/2" sq. That's how they taught me at trade school to find the displacement of an engine. Like a 350 cid has a 4" bore dia. and 2" radius. Well of course 2" squared is 4" again. Multiply that times pî and you get 12.5664" sq. of area. Then multiply that by the length of the stroke (3.48) and you get the area of the cylinder that the piston's movement covers. (43.731 cubic inches) Then times 8 cyl. = 349.848 cid. Round up and you get 350 cubic inches of displacement.

I ain't trying to be a smart alec. Just wanted to share the knowledge.