Can anyone help me out with this? I'm installing a turbo on a 1gen xB and the downpipe sits back further than the stock stock pipe. I will need to cut and then mount a new flange on the exhaust side, sized to mate the downpipe or the stock header w/ doughnut gasket. All I can find online are three-bolt for domestic headers. Any help is appreciated. I'm to the point where I'm about to start junkyard hunting with a hacksaw just to get the piece.

Basically, I need to find the mate for this:



The turbo down pipe is much longer so I will need the flange after cutting the stock exhaust to fit it. Here's the comparison to the stock header.

 

I found this offering from Vibrant. It would be perfect except it's too large.
J-SPEC Header Outlet Flange Kit (For Header w/ 2.5" Outlet)



Anyone know where I can find this for a 1.75" outlet?

 

the downpipe is 1.75''? It may be better to just use 2 normal 2 bolt flanges or v band and add a flex section. But if It were me....... i would chop off the doughnut flange on the downpipe, weld on a reducer to 3'',v band. mate to 3'' flex, 3'' exhaust. hehe

take advantage of that built motor my friend!

 

3" seems a bit excessive, I'm shooting for 150 at the wheels. Stock is 1.75" I.D. Cat-back right now is 2 1/4". No room for a flex pipe, I have only about 2" of pipe length between where the downpipe ends and the first O2 sensor is right before the cat, and aren't looking to shell out another $600 for a high flow cat. Kinda pointless to race an automatic, especially whit all the speaker, air ride, etc. weight in it. Really putting it on more for the torque, hence the small quick spool turbo. It was nice with the Greddy turbo to go up a hill fully loaded and watch the boost needle climb instead of the tach.

I may end up cutting the donut and using a flat 2-bolt flange, we'll see. Maybe I should just go full custom, no cat. Can the F/IC + stock ECU handle that with a spacer on the second O2 or do I need a cat? Keep in mind I'm, in redneck southern MD, our inspections are lifetime until it gets resold WOOT! Any suggestions on a good shop? Was thinking mandrel bend sol'ns or Insane Exhaust, does PTuning do in-house exhaust fab?

 

A little more info. Here's where I need to cut the stock exhaust to get this to fit. It doesn't leave much room for error.

 

So I got tired of searching online and went to the local custom exhaust shop. They ended up making me one by flaring out a 2 1/4" mild steel pipe and slipping a 2-bolt flange behind it. The flange isn't welded but with the spring bolts providing constant force and it wedging against the flare it should be alright. It ain't pretty, but unless I'm running you over the exhaust won't be visible. As long as it works, I'm happy.

FYI, the OEM pipe OD is 2 1/8" where I'm cutting, and the slip on ID was only 2 1/16, so on the back end I had them use a pipe expander to get it out to 2 1/8. Hopefully it fits without issues. Guess that's all I have for this thread.

 

Yo, B..............I have to ask, why you going that route? And why mild steel?

Thats not like you. You got nice stainless from the down pipe than it's right to that god awfull mild steel connection that looks like someone from the high school auto shop made.

Youv'e got so much time and money in this ride, I hate to see you use something so inferrior.

Why not a 2 1/2 Vibrant flex pipe to connect the two? Effective and practical.

Either way good luck,

XBG

 

At this point the main thing is to have something functional that can be put on in the short term. Does it look pretty, no. Will it work, I'm fairly certain yes, and with keeping the donut gasket alignment can be a hair off. This is a non-moving, non-wear surface part. I don't know why people get hung up on polished stainless unless you're putting mirrors under your car at shows. Also, mild I can weld up at home. Stainless is a PITA. I'm still stock between the header and muffler, so I would reather weld like to like than to mess with dissimilar metals and have a bead crack. It may also be aluminized, not mild steel, I need to confirm.

I honestly don't see this as inferior from a functional standpoint. Will I be losing a single HP on it? As long as it seals, then I'm happy.

That stainless flex coupling won't do squat unless I have a way to mate it up to the downpipe, which is the entire point of getting this coupling. 2 1/2 won't work, the stock pipe is 2 1/8 and the downpipe is 2 even, would leave WAY too much gap. Also keep in mind that I only have 2-3" of gap between where I need to cut and the front O2 sensor. There's not any more room than for just a flange. Maybe when I have some time I'll go back and get a proper turbo-back system, it will be a lot easier to get a shop to make something there if I can drive it in with a running turbo.

The other option would be to drive the xB to a shop n/a, and then pay them to do the entire turbo install so a v-band or other "clean" method could be used to mate up the exhaust. Sorry, I'm not paying for that labor, not to mention the car being stranded at the shop if something goes wrong on the turbo install. If you have a better solution that can be done at a home garage with an Ox/A welder, let me know. So far I'm only out $20 and haven't cut metal yet.

 

So you have this solved?