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Homemade 2 3/4in exhaust


Drwojo
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Well I will start with that I am not a professional welder. I was given some 2 3/4 custom sized exhaust pipe from a friend for helping pull the motor on his STi. There has always been the argument between 2 1/2in and 3in exhaust, so I guess I will have the best of both??? maybe?? I purchased a chop saw from Harbor Freight for 50 bucks. Why not? Now I can cut metal whenever I see fit. I was running the stock downpipe to a poorly bent pipe that a friend welded to the flex pipe. I decided to do pie cuts and weld together my own downpipe. It is noticeably lighter and dose not have 4 different size changes in it now. Flame suit on!

 

http://i160.photobucket.com/albums/t168/food28/DSC02830.jpg

 

http://i160.photobucket.com/albums/t168/food28/DSC02826.jpg

 

http://i160.photobucket.com/albums/t168/food28/DSC02822.jpg

 

http://i160.photobucket.com/albums/t168/food28/DSC02821.jpg

 

http://i160.photobucket.com/albums/t168/food28/DSC02829.jpg

 

http://i160.photobucket.com/albums/t168/food28/DSC02823.jpg

 

http://i160.photobucket.com/albums/t168/food28/DSC02828.jpg

 

http://i160.photobucket.com/albums/t168/food28/DSC02827.jpg

 

Not the worlds best welds but I learned a bit. I left my mask on way too dark and couldn't see what the hell I was doing for the first half of the welding. Once I adjusted the shade I started to lay out nice beads. What you see is the yuckier of the group. Now to drill a hole and install my Innovate wideband and be done with my garge project. O and yes it is 5:13 am and I am just getting done. I started around 1:30.

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Not as pretty as some, but much better than what I've got, and WAY worth the $50 and the little time you've got in it so far. One thing you'll absolutely need to add to the DP is a flex pipe. If you mount it solid like it is, even with a few hangers along the way, there won't be any flex off the manifold and you'll be ripping exhaust studs out of the head. I just did a quick search on Ebay and couldn't find 2 3/4, but you can get 3" and either space up or weld up the difference.

 

http://cgi.ebay.com/ebaymotors/3-X-8-Stainless-Steel-Exhaust-Muffler-Flex-Pipe_W0QQcmdZViewItemQQhashZitem439d88156dQQitemZ290405750125QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

 

You'll notice no actual flex in the stocker, but the flex is achieved by the two bolts after the precat with the springs on them. They allow the lower pipe to give while it moves on the donut between the pieces.

Edited by vbrad511
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You'll notice no actual flex in the stocker, but the flex is achieved by the two bolts after the precat with the springs on them. They allow the lower pipe to give while it moves on the donut between the pieces.

 

I may get one of these. I kept looking to see how I could mount something like the stock knuckle thing that was going on.

 

I had been running the open downpipe for a while and thought to just do it right. It did sound really good. I hope this one has a little more gurth to it! When it is mounted it hangs with about 1 1/2 of space form the framerail. With the motor rocking I THINK it will be clear. Will have to wait and see. Plus I shoot flames!

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It's not a clearance issue, it's a combination weight/movement issue. The soft aluminum of the head wn't take the movement of the motor tied to the exhaust and it's stability/weight. You'll develop exhaust leaks at the manifold and soon realize you the studs won't tighten anymore because the threads have been pulled out.
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Here is some exhaust welds for ya I did. ;) Turn the heat to 65 amps and you won't even need filler rod.

 

http://i156.photobucket.com/albums/t18/gr8white1/2JZ%20Project/DSC01231.jpg

Edited by Laodicea
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  • 2 weeks later...

not bad work, and im glad to see you do it yourself and save all that money.

 

 

as for the welding, my certification instructer told us that your not really a badarse welder untill, you can weld a straight bead and make it read f u c k y o u in the half moons. so far he said he hasnt seen anyone that could do it.

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I did exactly the same thing to my 1984 Maserati Quattroporte with dual exhaust and four cats (two each side). For pretty much the same reasons too, bad bends restricting flow and I thought it would be much easier adjusting the fit with welded segments than bends. Worked great, sounded great. Nice job!

 

Scott

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  • 2 weeks later...

So I never posted pics of my flex pipe. Here ya go. Again crappy welds. It was difficult to weld thin metal to the exhaust pipe. Used JB weld to make sure all the pinholes are filled. I'm sure someone will pipe in and tell me that was a bad idea. I will post a vid as soon as I get a thread repair kit fix the stud on the turbo. Also need to weld in the bung for the Innovate and calibrate it. My mind is distracted with body work and bumper shaving!

 

http://i160.photobucket.com/albums/t168/food28/0418002322.jpg

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  • 3 weeks later...

I finally installed the o2 bung and wrapped it. Was gonna install the wideband and calibrate it but the battery was completely dead. Wanted to make a short vid. Here is how she is looking.

 

http://i160.photobucket.com/albums/t168/food28/0506000219.jpg

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Wow that pic kinda sucks. I only seem to use my phone now.

 

http://i160.photobucket.com/albums/t168/food28/0505001536.jpg

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Oh man dude, I'm gonna have an identical setup on my car this weekend, except with 3" tubing. With such a short section, I can't imagine you'll be needing that flex section, but we'll see I guess.
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Oh man dude, I'm gonna have an identical setup on my car this weekend, except with 3" tubing. With such a short section, I can't imagine you'll be needing that flex section, but we'll see I guess.

 

Better to to have it and not need it, then to need it and not have it.

Edited by randyshaw81
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  • 2 weeks later...

Finally got a video. Sounds a lot like the old one or any other open dp starquest.

 

1. I warmed up the car before I made this video.

2. I know it is hanging low, I still need to weld on the hanger plus there is no fender on the car.

3. It is dirty and has dust and beer on it.

 

http://www.youtube.com/watch?v=tCLkGySEAb8

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