necking down after collecter?

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I have often wondered about the exhaust cooling and condensing as it travels back .
But I think 2” is a bit too small. I considered going to 2.5 .
 
I'm headed for bed. Thank you so much for confirming my concern... I will have a good talk with him in the am.
 
Not the popular opinion, but I don't think there is such a thing as too big in that distance from the merge to the mufflers. One 3" pipe is similar in area to two of 2"pipes, but 2 of 2" pipes has ~33% more pipe skin... so if you installed a PAIR of 2s on each side, you'd end up with a lot pipeskin,er radiating area, and your muffler would not have to work so hard. lol. But I'd run about a foot and a half of merge-sized pipes first.So then.............
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My 367 is running dual 3s just for those reasons. and that lil bugger went 93 in the Eighth. At 3467pounds at 900ft elevation, with a 230@.050cam, reving at 7000.
 
This is the guy you want doing your exhaust, another member on here has had work done by him on his duster.

Rowdy Flanagan's Muffler Shop

2850 fm1980
Marble Falls, Tx 78654
IN-HOUSE MANDREL BENDING
 
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I think 2 inch is to make it easier for him to bend and tweak around driveshaft and cross members. Better ground clearance too. I'd get a 3 inch aftermarket system that's had all the bugs worked out and do it yourself. Also Jegs and Summit price match.
 
The shop my Duster is in wants to neck down the exhaust from TCI headers to a 2 inch pipe. The collectors are 3", after the foot of 2" pipe they plan to use, the 2" extensions the headers came with, they plan on going to 3" out the back. Is this stupid or a good idea?

Thanks

Dam sure wouldn`t do it to mine !!
 
I think 2 inch is to make it easier for him to bend and tweak around driveshaft and cross members. Better ground clearance too. I'd get a 3 inch aftermarket system that's had all the bugs worked out and do it yourself. Also Jegs and Summit price match.
Plus a 10' stick of 2" pipe cost him a few bucks. Huge profit in 2" exhaust. Go at least 2 1/2" Stoker could use 3" with 2 1/2" tail pipes. With all the nice exhaust kits out there now days, why go with a crudely bent set up from a exhaust shop.
 
The shop is an all around mechanic shop, not an exhaust only shop. I kindly mentioned it to him today and the "TTI" not "TCI" headers came with 3/8" flanges for the extensions/collectors to mate up with a gasket between. So I got him to cut a 3" pipe and weld it to the flange that would have held the 3" to 2" extensions/collectors. The inlet side of the extension/collector is 3" then it tapered down to 2". I think ya'll are right, he may have been trying to save time/cut a corner on it, but I got it straight with him so it will be 3" all the way... Thanks for all of your input.

I have dyslexia, that is how I got "TCI" and "TTI" mixed up. Oops! They are TTI 3 step headers, very nice ones. About $800 if I remember right. That is why red flags went flying when I saw that 2" section on there.
 

Rowdy is 106 miles away from me. While I could tow it there, I will have to wait until they are needed again. There is no exhaust on it, the motor and trans are brand new, can't drive with open headers, but yeah, someone told me about Rowdy before. I talked to him and he was very intelligent, priced right, and does great work. Just a bit far for the build this time around, but the next time I need exhaust work, I'm drivin' to him, even if I need it towed!
 
Not the popular opinion, but I don't think there is such a thing as too big in that distance from the merge to the mufflers. One 3" pipe is similar in area to two of 2"pipes, but 2 of 2" pipes has ~33% more pipe skin... so if you installed a PAIR of 2s on each side, you'd end up with a lot pipeskin,er radiating area, and your muffler would not have to work so hard. lol. But I'd run about a foot and a half of merge-sized pipes first.So then.............
xxxxxxxxxxxxxx xxxxxxxxxxxxx xxxxxxxxxx
My 367 is running dual 3s just for those reasons. and that lil bugger went 93 in the Eighth. At 3467pounds at 900ft elevation, with a 230@.050cam, reving at 7000.

Thanks AJ, I do plan on givin' 'er a run at the track to see what my numbers are, I will post them, but it will probably be spring before I can. Please read above posts for the latest.
 
Both Summit and Jegs have the Pypes 3" to 3" and 3" to 2.5" collectors. 304 stainless, tig welded. Reasonable price. I see no possible explanation for necking down to 2" and even less reason to open back up to 3". Once you've necked down for more than 6-8", it's like putting a cork on the exhaust.

We've done countless dyno tests. If you have nice TTI headers and 500hp, we would recommend a 3" to 3" collector, 3" X pipe, 3" mufflers and 2.5" tailpipes. All mandrel bent which is a MAJOR factor in choosing this consideration. If a local shop, did this same configuration, you'd lose 30-50hp. :(
 
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