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03-28-2008, 04:57 AM
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#1 |
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Smok'em Roast'em Shift'em
Join Date: Jan 2008
Location: Massapequa, NY
Posts: 110
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Exhaust
Do car motors need backpressure? (305, 350)
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03-28-2008, 06:19 PM
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#2 |
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On a budget like Fred Sanford
Join Date: Oct 2005
Location: Topeka, KS
Posts: 2,031
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Re: Exhaust
Absolutely not.....anyone who tells you otherwise is just spreading myths. You need exhaust velocity, not backpressure. You want to keep the exhaust hot and moving quickly for the best power. Too large of a pipe will allow the exhaust to cool and slow down which hurts torque production, too small of a pipe will create a flow restriction.
__________________
'85 Silverado swb: 383 stroker, 10.5:1, vortec heads, 232/238 roller cam, RPM air gap, performer 750 carb, stainless longtubes, 3" duals/super 44's, T56/4.11 383ci build / exterior refresh thread '98 Camaro z28: 370ci twin turbo 370ci build '01 Tahoe LT 4x4: 5.3, longtubes/ory, magnaflow duals, custom tune....wife's DD |
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03-28-2008, 06:27 PM
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#3 |
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1962 C-10
Join Date: Apr 2005
Location: Las Vegas, New Mexico
Posts: 4,978
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Re: Exhaust
So you need a little back pressure for torque?
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Joseph Chavez  "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4 |
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03-28-2008, 06:35 PM
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#4 |
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Size Matters
Join Date: Aug 2007
Location: Lyman, SC
Posts: 9,189
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Re: Exhaust
I agree with SWB85 that you need velocity for better torque. More volume gives you more power so you have to find a balance between torque and power with the correct size pipe. The only thing you might consider backpressure for is for the tone of the exhaust.
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"Reading the owners manual is only for quitters." Jason Harper, Bloomberg News.   ...WOOOO HOOOO!!!!
Last edited by Longhorn321; 03-28-2008 at 06:36 PM. |
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03-28-2008, 08:01 PM
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#5 | |
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On a budget like Fred Sanford
Join Date: Oct 2005
Location: Topeka, KS
Posts: 2,031
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Re: Exhaust
Quote:
__________________
'85 Silverado swb: 383 stroker, 10.5:1, vortec heads, 232/238 roller cam, RPM air gap, performer 750 carb, stainless longtubes, 3" duals/super 44's, T56/4.11 383ci build / exterior refresh thread '98 Camaro z28: 370ci twin turbo 370ci build '01 Tahoe LT 4x4: 5.3, longtubes/ory, magnaflow duals, custom tune....wife's DD |
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03-28-2008, 08:05 PM
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#6 |
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1975 C-10 Silverado LWB
Join Date: Nov 2007
Location: Sacramento, CA
Posts: 326
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Re: Exhaust
What is a good size you would reccomend for a bone stock 350?
__________________
1975 LWB C-10 Silverado - Stock - "BIG 10" - 4 Bolt 350 "Brand new" 1200mi - THM-375 "Brand new w/trans cooler" 5000mi 1995 Ford Lightning - Bone Stock - 351W - Vortech?? |
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03-28-2008, 08:28 PM
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#7 |
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Registered User
Join Date: Feb 2007
Location: Austin, TX
Posts: 3,930
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Re: Exhaust
Dual 2.25 pipes with a crossover pipe.
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03-28-2008, 08:36 PM
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#8 | |
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On a budget like Fred Sanford
Join Date: Oct 2005
Location: Topeka, KS
Posts: 2,031
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Re: Exhaust
Quote:
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'85 Silverado swb: 383 stroker, 10.5:1, vortec heads, 232/238 roller cam, RPM air gap, performer 750 carb, stainless longtubes, 3" duals/super 44's, T56/4.11 383ci build / exterior refresh thread '98 Camaro z28: 370ci twin turbo 370ci build '01 Tahoe LT 4x4: 5.3, longtubes/ory, magnaflow duals, custom tune....wife's DD |
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03-28-2008, 10:40 PM
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#9 |
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1975 C-10 Silverado LWB
Join Date: Nov 2007
Location: Sacramento, CA
Posts: 326
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Re: Exhaust
is it possible to fit a x or an h pipe and still dump before the axle infront of the rear tires?
__________________
1975 LWB C-10 Silverado - Stock - "BIG 10" - 4 Bolt 350 "Brand new" 1200mi - THM-375 "Brand new w/trans cooler" 5000mi 1995 Ford Lightning - Bone Stock - 351W - Vortech?? |
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03-29-2008, 02:11 AM
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#10 |
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Smok'em Roast'em Shift'em
Join Date: Jan 2008
Location: Massapequa, NY
Posts: 110
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Re: Exhaust
would 3" exhaust be to big?
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03-29-2008, 05:41 AM
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Right on the line, baby!
Join Date: Oct 2003
Location: Phila, PA 19130
Posts: 1,486
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Re: Exhaust
Quote:
Take a look at this- it gives you a pretty good idea. 73-87chevytrucks.com C10: A stock engine doesn't need a 3" dual exhaust. Back pressure? I think people confuse this with negative pressure waves, AKA scavenging.
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83 GMC 406 th400/3.73 Eaton Truetrac posi, headers, x pipe, & racePros. Tubular control arms, lowering rear springs, caltracs. Still ugly, but getting built right, although slowly Click and scroll down for site vendors! Subscribe here! |
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03-29-2008, 06:28 AM
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#12 |
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1975 C-10 Silverado LWB
Join Date: Nov 2007
Location: Sacramento, CA
Posts: 326
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Re: Exhaust
no cats needed
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1975 LWB C-10 Silverado - Stock - "BIG 10" - 4 Bolt 350 "Brand new" 1200mi - THM-375 "Brand new w/trans cooler" 5000mi 1995 Ford Lightning - Bone Stock - 351W - Vortech?? |
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