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Old 02-21-2010   #1
wilkink
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Expanding the Y-Pipe

Just had a quick question regarding the expansion of the Hedman Y-pipe. As of right now, it is 2.5" and from everything that I have been reading, it says how it would restrict flow of the exhaust going into a 3" pipe. People are saying that you can expand it and all, but they never say how. Just wondering what I have to do to get it expanded to the desired 3". Any help would be great.

Shawn
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Old 02-22-2010   #2
FearThisGTA
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GTA Year: 1991
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Re: Expanding the Y-Pipe

You can either get an adapter, or take it to a muffler shop(my recommendation), and have them expand the pipe for you.hth
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1991 GTA Trans Am
w/305,231 miles
on the original motor!!!!
Time of Death on motor, 4:07pm on 05/29/2010.
Hp:211.2@4200rpms/Tq.328.5@2700rpms
Best et: 13.959@97.05mph
Best mph: 98.3
Best 60' : 1.875 on BFG Comp TA's w/ 32 lbs of air in them
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Old 02-22-2010   #3
90 L98 TransAm
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Re: Expanding the Y-Pipe

Here's what I did when I installed my Magnaflow catback:

http://www.gtasourcepage.com/forum/s...ad.php?t=51761
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Vortech V-3 SC, ~7 psi max boost
0 - 60 in 5.40 Seconds
1/4 mile in 13.9 seconds @ 103 mph @ 5,000' elevation, 309 HP (per Escort GT-2 meter)
Shift kit, 9 clutch 3/4, Corvette servo
Magnaflow 16829 catback exhaust
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Old 02-22-2010   #4
wilkink
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Re: Expanding the Y-Pipe

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Originally Posted by FearThisGTA View Post
You can either get an adapter, or take it to a muffler shop(my recommendation), and have them expand the pipe for you.hth
Any idea how much it would cost? And would the cost be worth it when it comes to power or sound(not sure if it would effect it or not)?
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Old 02-22-2010   #5
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Re: Expanding the Y-Pipe

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Originally Posted by 90 L98 TransAm View Post
Here's what I did when I installed my Magnaflow catback:

http://www.gtasourcepage.com/forum/s...ad.php?t=51761
That was one of the reasons why I bought it. I have step by step instructions and even pictures to verify exactly what it looks like on the car before I buy it. Are you satisfied with everything? Sound good? WOT sound? Quality of the stainless? Much power increase? I just got a nice set of Hedman headers to match up with it too, so that should help out on the power and sound.
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Old 02-22-2010   #6
90 L98 TransAm
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Re: Expanding the Y-Pipe

So far i'm happy with the magnaflow but i've probably only driven 500 miles or so since I put it on.

I like the sound - no drone at highway speeds, a nice rumble when you start the car or get on the gas. Do a search for some sound clips online. I think there are some at the magnaflow site also.

Overall quality seems good especially for $315.

Haven't checked for a performance improvement yet - will do so in a couple of months when i take the car out of winter storage. You can take a look at magnaflows' dyno charts.

I decided to re-use the factory double-hinged clamp. Since you have an aftermarket Y-pipe you may need a different type of adapter that will allow you to connect your Y-pipe outlet to your cat-back inlet.

Exhaust shop charged me $10 for the adapter shown in my install thread. To tie into the outlet of a factory dual-cat just take in the front part of your old midpipe (back to the first curved pipe) and the cat-back pipe sections (back to the first curved pipe) to show them what you need and to make sure the length comes out right.

Hope this helps more than it confuses things.
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Old 02-22-2010   #7
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Re: Expanding the Y-Pipe

I'll have your thread up when doing the install, for direction and comfort. I have been checking out videos for some time now. Mr. Brisk from TGO has a few videos on youtube and his cars sound great, especially the IROC-Z. The videos on Magnaflow's site seem kind of quite, but then again it is on a duel cat car with no headers. The dyno charts off that car look good, considering after the install he gained something like 18 and 15. Just to clarify, you got yours from Bandit, right? Any recommendation on what to offer them? I am probably going to get the Magnaflow High-Flow cat (93441) off eBay because I have a few eBay gift cards laying around.
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Old 02-22-2010   #8
90 L98 TransAm
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Re: Expanding the Y-Pipe

Yes, I bought mine from banditexhaust.

I don't think it matters what you offer as long as it is less than their minimum price. Try offering $250. I think it will come back with a response showing the lowest offer they will accept. You can always make a higher offer later.
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Old 02-22-2010   #9
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Re: Expanding the Y-Pipe

Sounds good. Thanks again for the help. Any chance you would know what it costs to get y pipe expanded at an exhaust shop? Would it be worth it?
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Old 02-22-2010   #10
90 L98 TransAm
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Re: Expanding the Y-Pipe

Shouldn't cost much at all $10 or $20 at most.

There are several different ways to join exhaust tubing sections. Since I kept my factory dual cat assembly it seemed easiest to use a bellmouth adapter to connect the outlet of it to the straight tube inlet of the catback. The magnaflow kit uses one type of clamps. My Cobb exhaust uses flanges connected by two bolts.

If you have access to a decent exhaust shop I'd just explain to them what you want to do and show them the parts (Y-pipe, cat(s), catback) you are trying to assemble.
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Old 02-22-2010   #11
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Re: Expanding the Y-Pipe

I got ya. Doesn't sound difficult at all, just a matter of fitting all the pipes. Thanks a lot for all the info.
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Old 02-23-2010   #12
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GTA Year: 1991
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Re: Expanding the Y-Pipe

Quote:
Originally Posted by FearThisGTA View Post
You can either get an adapter, or take it to a muffler shop(my recommendation), and have them expand the pipe for you.hth

You will need to check with your local muffler shop, but I dont think it would cost that much...hth...
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Cliff Jones
1991 GTA Trans Am
w/305,231 miles
on the original motor!!!!
Time of Death on motor, 4:07pm on 05/29/2010.
Hp:211.2@4200rpms/Tq.328.5@2700rpms
Best et: 13.959@97.05mph
Best mph: 98.3
Best 60' : 1.875 on BFG Comp TA's w/ 32 lbs of air in them
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Old 02-23-2010   #13
wilkink
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Re: Expanding the Y-Pipe

Not sure why I skipped over this, but when they expand it, is it just the ends they enlarge to the 3" or is it the whole pipe?
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Old 02-23-2010   #14
FearThisGTA
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GTA Year: 1991
GTA Engine: 350 TPI Automatic
Re: Expanding the Y-Pipe

just the ends...
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Cliff Jones
1991 GTA Trans Am
w/305,231 miles
on the original motor!!!!
Time of Death on motor, 4:07pm on 05/29/2010.
Hp:211.2@4200rpms/Tq.328.5@2700rpms
Best et: 13.959@97.05mph
Best mph: 98.3
Best 60' : 1.875 on BFG Comp TA's w/ 32 lbs of air in them
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Old 02-24-2010   #15
gorin002
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Re: Expanding the Y-Pipe

sound is as this
http://www.youtube.com/watch?v=UCM2wqutXS8

and is it qwiet in the car ?
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Old 02-24-2010   #16
wilkink
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Re: Expanding the Y-Pipe

Quote:
Originally Posted by gorin002 View Post
sound is as this
http://www.youtube.com/watch?v=UCM2wqutXS8

and is it qwiet in the car ?
Is that what you think the 16829 will sound like? If so, it sounds pretty good to me. Plus its stainless for the durability. Perfect for these northeastern snow storms.
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Old 02-25-2010   #17
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Re: Expanding the Y-Pipe

Quote:
Originally Posted by wilkink View Post
Is that what you think the 16829 will sound like? If so, it sounds pretty good to me. Plus its stainless for the durability. Perfect for these northeastern snow storms.
i don t know am asking
if sounds good to you thats fine with me
i want the sielent mode
thats mi opnion you have yours
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