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Topic: Open headers make more power than mufflers...
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65_289 Gearhead Posts: 701 From: Registered: Jul 2001
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posted 03-18-2002 02:52 PM
...Or do they? That's what this debate it about.http://forums.stangnet.net/showthread.php?s=b87f93402a18c661e07c9b459dc6eda0&postid=1064858#post1064858 ------------------ 1965 Coupe, Tremec 3550, Steeda Tri-Ax, Cable Clutch conversion, 9" N case, 4.11's, Detroit Soft Locker, 31 spline Moser axles, Daytona pinion support,, Biondo Line Lock, Ford XB3 longblock, x303 heads, B-Cam, 9:1 comp., Tri-y headers, cut-outs, Ford Racing high-torque mini-starter, Pertronix Ignitor & Flamethrower coil, 650 double pumper, Edelbrock RPM intake, K&N air, Holley electric fuel pump & AFPR, dual 2-chamber Flowmasters, Summit 3-way fronts, Rancho 5-way rears, 5-leaf springs, Chrome Export Brace, Griffen Radiator, Comp. Eng. subs.
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Mpcoluv Gearhead Posts: 834 From: Charlotte NC usa Registered: Apr 2001
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posted 03-18-2002 03:56 PM
quote: Originally posted by 65_289: ...Or do they? That's what this debate it about.http://forums.stangnet.net/showthread.php?s=b87f93402a18c661e07c9b459dc 6eda0&postid=1064858#post1064858
Rarely does a full exhaust make the same power much less more than open headers. If a car installs a full exhaust and picks up power, I would suspect a poorly designed open header setup (collectors too short etc...). There is an article in this months Circle Track that details "How to build a no-loss exhaust system". The X and H-pipe crossovers can give you more torque and midrange however with the exhaust still open.
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capri man Gearhead Posts: 2689 From: doerun, ga. Registered: Nov 2000
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posted 03-18-2002 04:08 PM
i am currently running an x pipe with mufflers. if i decide to remove the mufflers, how much pipe should i leave coming out of the x?------------------ mike r racing is real everything else is just a game. 81 capri-7.56 @88mph 1/8 1.56 60 ft.
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kid vishus Gearhead Posts: 3894 From: middle of NC Registered: Oct 2000
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posted 03-18-2002 04:12 PM
In my opinon, if you are running a poor muffler, of course open headers will make more power. But a good muffler, will make just as much if not more average hp over the entire rpm range than open headers. DRUSA did a test on a BBC super gas motor on a dyno, they made pulls wihtout mufflers, recorded peak hp and torque, and average hp and torque over th test range (which was the same as a full power pass), then installed Borla collector mufflers and made five more pulls. The Borlas lost around 3 or 4 peak HP, but gained 5 hp average. The result with the torque was the same. All I know for sure is, my car runs exactly the same times with or without my Borlas. The only difference is the loss of a little weight (24 lbs total), and the additon of A LOT of noise without them.
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Moneymaker Administrator Posts: 18704 From: Lyons, IL, USA Registered: May 99
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posted 03-18-2002 05:03 PM
As a rule, 100% of the time an engine will make more power with open exhaust. Only whn an engine is specificaly engineered for mufflers via cam and induction will it make more power with mufflers. ------------------ Alex Denysenko Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator NHRA/IHRA/SRA member NHRA and IHRA SS/LA National Record Holder '00, '01, & '02 Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 Part time secret agent license #0089 US Class Nationals link
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chips67 Gearhead Posts: 651 From: louisville, ky, usa Registered: Jul 2001
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posted 03-18-2002 05:50 PM
will a motor make more power with turndowns just after the muffler than full exaust going out the back or does it matter? ive got 2.5 inch pipes out the back...not mandrel bent....thinking of cutting off at muffler and going to turndowns.....how much more noise also?------------------ 67 coupe, 650dp and rpm intake on 5.0 with afr 165 heads, 4 speed, 4.11's.....best so far is [email protected] in 1/8 mile with 1.79 60ft. time.
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mustangboy Gearhead Posts: 520 From: Ont, Canada Registered: Mar 2002
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posted 03-20-2002 08:18 PM
I know my motor sure picks up with open headers.I used to cut about 3 tenths off by running open headers vs my old 2 1/4 inch system with midas turbo mufflers.Switched to 2 1/2 pipes from the headers to some new flowtech afterburner mufflers and now I only lose about .15.I still have crappy unmandrell bent 2 1/4 tail pipes that I want to replace.
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