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opinions on true duals

aboythatskates

Hard-core CEG'er
Joined
Aug 25, 2010
Messages
1,414
Location
spokane wa
so this is my design so far for my true duals. and now i cant decide whether to go 2" or 2.25" tubing. originally i was going with 2" because the output of the headers is 2". but doing some research 2" might be too restricting.

mods
then:i put 220 to the wheels on full 3L, short ram, msds headers and ypipe. and 2.5" exhaust.
now: i have st220 intake manifolds,intake spacer(longer runners), port and polished heads to the absolute max. might run cold air. and this is the exhaust. hoping for 240 minimum horses.


so what do you guys think i should run and why?

 
I have mine setup just like that minus the flex pipes. 2.5". I absolutely love it! It's loud, has some raspberry, and drone, but I can't get enough of it when I stomp on the skinny pedal. Definitely does not sound like a v6 anymore. Gets lots of compliments.
 
ok ok. yea my single was like that. except no drone. all my friends drooled over my exhaust and they hate cougars. lol. quiet until i stepped on it. now im looking for more performance. so im probably leaning towards 2.25 now.
you got any pics? very interested in your design
 
2e1cab5.jpg


2aj6nvr.jpg


2yysi8j.jpg
 
yea i have cut stock ypipe flanges too, but i measured the they are even smaller then 2" so i will just get 2.25" ball flange and bends and make my own completly
 
Im running 11385 magnaflow in the center. 2.25 to Bosals in the rear, no rasp. Loud.

Can't comment on numbers, it ran well N/A. Don't build trueduals without a x pipe or h pipe on this car if don't want it to sound like ass
 
the muffler is the X pipe. i was going to run an xpipe and then 2 separate round magnaflows but this kills 2 birds with one stone.
 
so i did some math, it makes sense to me. but im not sure if i did everything correct or took everything into account. it shows i should run 2" now.. correct me if in wrong, im no math wiz


first i tested my current setup.i found the cfm of my piping:
2.5 / 2 = 1.25
1.25 x 1.25 = 1.5625
1.5625 x 3.14 = 4.90625 cubic inches of my piping. there is 115 cmf per cubic inch...
4.09625 x 115=564.219 cfm for 2.5" tubing

my engines cfm is..
220hp + 15% (drivetrain loss) = 253 flywheel horsepower. 2.2 cmf's required per horsepower..
253 x 2.2 = 556.6 cfm's produced by my engine

556.6 cfms vs my piping's 564 cfm's. my tubing has a little bit extra room for horsepower capacity.




____________________________________________________________________________________________________

now to test out my planned system
horse power goals 250 + 15% = 287.5 hp
287.5 x 2.2 = 632.5 cfm supposedly my new setup is going to produce

time to calculate dual 2" setup
2 / 2 = 1.
1 x 3.14 = 3.14 cubic inches
3.14 x 115 = 361.1 cfm for 2" tube
361.1 x 2 (duals) = 722.2 cfm for 2 2" tubes

according to this 2" duals is more then enough for running a decent full 3L. makes it seem like anything over 2" for true duals is just overkill
 
Yes my muffler is x piped, your probably going to want 2 more mufflers.. or another dual in dual out at the least. Its very loud.

I believe your math is right, for a n/a 3L anything over 2" probably isn't ideal.

B0ooOost!
 
I had true duals on my CSVT a long time ago and it was very loud but then again I had twin Magnaflow "cannons" w/4" tips, 2 1/4" piping, twin resonaters and gutted pre-cats. In all honesty, the stock exhaust sounds great, maybe change out the mufflers to some baffled ones and call it a day, that's what I would do if I had another CSVT right now.
 
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