Whats the conensus?? I'm going to be replacing my exhaust system in the very near future. Oh, and I have a 2bbl 360 if that makes a difference.
2.5" or 3"
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Hi Adam...
I went with 2.5" and a 50 series Flowmaster and am quite happy.
The 3" would look cooler, but the gain would not be noticeable on a stock engine. I know there is someone here that went 3" but said that it got really tight going over the rear axle. Your SOA might alieviate this though. A friend of mine put a 3" 50 series Flowmaster on his Dodge p/u and it was noticibly quiter than mine. We figured that the larger pipe was slowing the exhaust pulse down.
$.02 ?
kris.89 Waggy
AX-15 swap info threads...
http://www.ifsja.org/forums/vb/showthread.php?t=83102
http://www.ifsja.org/forums/vb/showthread.php?t=97262
http://www.ifsja.org/forums/vb/showthread.php?t=104163
Theres more but that should get you started
Originally posted by JeepinPete-If it wasn't for bad luck, you wouldn't have any luck at all-
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For the kind of low revs our FSJ's crank, I doubt that the 3" system would provide any measurable benefit over a 2.5" system. Now, bragging rights are another area and 3" just sounds better than 2.5"!
People are usually going to tell you they like whatever they have or did. I've got 2.5" systems on my 360CID Waggy and my 402CID 400HP Chevelle. I don't think either one is limited by the performance of the exhaust system.
-Mike A.
'87 Grand "Steel Brick"
Sunnyvale, CAMike Ahlmann<BR>\'87 Grand Wagoneer <BR>\"Steel Brick\"<BR>Sunnyvale, California
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I just went with 3' with Flowmaster and where it sounds great I doubt it improved my performance whole lot versus 2.5. But still it sounds aewsome and it gives it the "Big Truck" look. In my case the cost wasn't much more going with the 3 in. Thats just my 2 Abe's worth.\"The Beast of Burden\" 83 Wagoneer Ltm. Stock exp. 3inch exhaust with Flowmaster.
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I like the 3in I just got on my rig. No complaints as far as performance losses in comparison to the duals I had removed.Paul Hartman
79 waggoneer
AMC360/TH-400/203/205
DANA 60/14 BOLT 5.13'S AND DETROITS
39.5 IROKS C.B.I OFF ROAD TUBING GALORE
www.cbioffroadfab.com
WWW.PLANET4X4.NET
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I went from Headers (Hedman $99) to 2.5" flex pipes ($9.00 Autozone) and 2.5" cherry bomb glass packs ($15.00 Autozone)to a custom bent single 2.5", no cat, to a 14" Super Turbo. The guys at the shop (good bunch too, do lots of custom work) said that on the 360 a 3" really wouldn't gain me that much. I love the way mine sounds (especially the look on the unsuspecting punk SUV owners that try and beat me off the line) when I romp on it, the exhaust roars and I chirp the rears off the line. It is a loss in overall performance from my improvised (though audibly kick a$$ loud, cool and intolerable) exhaust. Mine cost $250.00 . . . kind of pricey.
Adam . . . I would talk to Ken's Muffler on North College. They usually pitch some attitude, but they make excellent systems for a fair price. They just initially try to talk you out of a custom set-up."Hooper Drives the Boat, Chief!" from 'Jaws'
'85 G-Wag, AMC 360 - Edelbrock Performer Cam and Intake, Megasquirt TBI, TF 727 with TCI Kit, NP-208, 4" Skyjacker Softride, Detroit EZ Locker front and rear.
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You certainly aren't going to gain enough using a 3" system to justify the cost, over a 2.5", or even a 2.25" system, especially with duals.
With a single, the 2.5 would be sufficient, and cost a lot less than the comparable 3" system would.Jeep Grounds
RRV Homepage
Texas Full Size Jeep Association
1987 Grand Wagoneer
AMC 360/TF727/NP229
1999 Wrangler Sport
4.0L/AX-15/NV231
?Freedom is never more than one generation away from extinction? by Ronald Reagan.
Formerly of DFW/Gun Barrel City, TX - eventually to return...
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Remember, the road to torque, which is what we want for off road, and towing, is to keep the gasses flowing at the highest possible speed, and a relatively "smaller" intake/exhaust will do that for us.
By smaller, I don't mean to the point that the engine gets choked, but a 2.5" single, or a 2.25" dual system is all that's necessary. I don't think that bumping up one more size on either will hurt, at least nothing aside from the pocket book.Jeep Grounds
RRV Homepage
Texas Full Size Jeep Association
1987 Grand Wagoneer
AMC 360/TF727/NP229
1999 Wrangler Sport
4.0L/AX-15/NV231
?Freedom is never more than one generation away from extinction? by Ronald Reagan.
Formerly of DFW/Gun Barrel City, TX - eventually to return...
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I have to disagree on the cost issue, at least in my area. The whole 3 in system cost $270 a 2.5 cost only $240. Of only a savings of 30 dollars, I decided to go ahead and do the 3in. The only other reasoning I had was that since the whole system had to be built and bent at the shop and all the bends would be at about 2.5 in. I thought it better to start out with the larger diameter. Like I said before I had 2.25 duals and there was a significant gain going to the 3in. I'm not advicating that 3in is the only and ideal way to go. I'm just stating I'm happy with the results I have obtained.Paul Hartman
79 waggoneer
AMC360/TH-400/203/205
DANA 60/14 BOLT 5.13'S AND DETROITS
39.5 IROKS C.B.I OFF ROAD TUBING GALORE
www.cbioffroadfab.com
WWW.PLANET4X4.NET
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i love my 3" it just sound sweetyaya looks nice,but does she GO!?<br /><br />1981 cherokee lerado 360/727/208/d44/amc20 Wt<br />posi fnt & bck<br />.030\" overbore <br />crank shaved .010\" and line bored<br />balanced blueprinted<br />crane cam ,lifters<br />edelbrock preformer intake<br />edelbrock 650cfm four barrel carb<br />Tfi upgrade<br />3\" dynomax ultra flo exaust<br />custom lift springs <br />31\" bfg at\'s<br />CBR929 firblade<br />68 roadrunner 383 12.2 1/4 mile<br />original #\'s car
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I was recomended 3" by Thorley.
As far as price I know the guy at the muffler shop.
And yes I did drive right infront of the police station with open headers to drop it off.
The sound is sweet with a Flowmaster 50! Great rumble to it when you get on it.
Later
Larry Miller88GW "Mississippi" 401,Edelbrock heads,and stuff,
4" Skyjacker, BFG AT's,OBA,Air Horn.
'89GW "Mutt" wood for now, 360, 1405, Edelbrock cam,
4"Rusty's,3"body,33"BFG. Detroit Truetrack Warn Hubs
The Metal Workshop
http://www.themetalworkshop.com/index.html
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well with all the rocks iv gone over having a madrel bent $$$ ex system that i wood ahve to repair over n over , was not the ticket.
sooooo im using the jc whitney bendable stuff and have been for 9 years. ez to fix and rebend out of the way of this part or that part.
im running dual 2" with equal length pipe b4 and after the muffs. 2" is small, but it slides over the leeder pipes descending from the OE ex manis.
100$ for 25' of tubing, 40$ for the muffs, 20$ for clamps and such.
one thing tho...the dual system i installed to replace the single system i had b4 of the same size/material is much louder. y wood the duals be louder than the single??Ken's:
1966 Super Wagoneer
5.7L 2BBl. Th700R4. NP-208. Opens. 3.31s. 4core. 4Discs. PS,PB,AC,CC,Cassette.
(Soon to be TBI)
"If it aint leaking, it's empty!"
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Ken, it's probably as much the quality of the pipe, as anything else. I've had duals on hipo cars, that weren't as loud as the single with glass pack on my Cherokee.
Then again, the exhaust on my Chero is a real hodge podge at the moment. I will be fixing this in the near future.Jeep Grounds
RRV Homepage
Texas Full Size Jeep Association
1987 Grand Wagoneer
AMC 360/TF727/NP229
1999 Wrangler Sport
4.0L/AX-15/NV231
?Freedom is never more than one generation away from extinction? by Ronald Reagan.
Formerly of DFW/Gun Barrel City, TX - eventually to return...
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Take a look at the cross sectional area of typical straight pipe used in exhaust systems:
2" = 3.14 sq.in. Dual = 6.18
2.25" = 3.98 sq. in. Dual = 7.96
2.5" = 4.91 sq. in. Dual = 9.82
3" = 7.07 sq. in.
A dual 2.5" has greater cross section area than a single 3" and not by a wide margin. A single 2.5" is has a little more than half the cross sectional area of the 3".David
76 NT Cherokee
83 CJ7
05 Frontier CC 4x2
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