4" Exhaust Build

[KYNgsx]

I've been wanting to upgrade my exhaust for a while. I also wanted to get more practice on my welding skills. My original plan was to replace all the 2-bolt flanges on my existing exhaust with v-bands. Then I figured I might as well make a whole new exhaust. Then I figured if I was going to make a whole new exhaust, I might as well make something unique and challenging. All this leads to a 4" exhaust.

Started with a bunch of boxes of things. All stainless:

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Size comparison of 3" vs 4":

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Got started on the downpipe. These flex joints suck to weld:

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Butt weld:

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Took a while for me to get the angles on the downpipe correct. This was version 2, still needed some modification before the final version.

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Did start gettting some nice results on the v-bands:

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[KYNgsx]

Final version of the downpipe:

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Closeup:

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On car:

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Started on the rear section:

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[KYNgsx]

More progress:

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Fitment:

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Need more practice on the butt welds; not as nice as the v-bands, but not as easy.

That escalated quickly:

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There's about 10 feet of weld in this picture. Seems like I could have used a few less bends but oh well. Makes a bit more sense once it's on the car.

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[KYNgsx]

Was a little worried about how low the downpipe would be, but ground clearance ended up pretty decent:

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Still need to weld up a "race pipe" to swap out with the muffler but I need to order more v-bands.

 

[View Askew]

Looks awesome! Just watch for big speed bumps. Mine gets caught in the middle every time. Love the sound it makes though.

 

[NordicSaab]

Looks great. Good work.

What differences do you notice is sound and performance?

Any plan to dyno?

 

[oneslowwdsm]

X2^ Would also like to know how it sounds inx comparison to a 3inch and if it is "drony"

 

[1990dsmkid]

Looks really good. Curious to know where you purchase your supplies at?

 

[View Askew]

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Don't mean to thread jack but here is mine. Hopefully the video works. Not the best quality.

 

[El Cuervo]

Was a little worried about how low the downpipe would be, but ground clearance ended up pretty decent:

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Still need to weld up a "race pipe" to swap out with the muffler but I need to order more v-bands.

Very nice. I would also love to have a 4 inch exhaust. Maybe you should look into making a few of them for people that would like one.

 

[Dsmkauai]

Would be expensive to ship from Kauai to mainland! supplies came from ace race parts (acestainless) a vendor on here great work bro

 

[CODE4]

Good fit ups and welds. Did you back purge the tubing at all?

Did you weld the v band assemblies clamped together?

You will not have any flow issues with a 4" muffler I am sure.

 

[Cooper-97gst]

At what point is a 4" necessary over a 3" ?

 

[Archer Fabrications]

So this is on an fp black? Completely unnecessary. But it looks good, just know youll habe to cut and weld the o2 part when you upgrade turbos.

 

[EC17PSE]

At what point is a 4" necessary over a 3" ?

At around 700hp! Maybe slightly less. Its super overkill for his application!

 

[KYNgsx]

Thanks guys, I am still a noob at this.

Looks great. Good work.

What differences do you notice is sound and performance?

Any plan to dyno?

X2^ Would also like to know how it sounds inx comparison to a 3inch and if it is "drony"

So far I just have a video of it idling in the garage. I will try and upload it later. Didn't get a chance to go drive it yet. There is no awd dyno here I can run it on, but I will be running it on the track. It is actually quieter than I expected, but I am used to the car running extremely loud with no exhaust at all. It is definitely louder and deeper than the 3" exhaust.

 

[KYNgsx]

Looks really good. Curious to know where you purchase your supplies at?

The piping and bends are from Ace Stainless, the clamps and muffler are from Summit Racing.

Very nice. I would also love to have a 4 inch exhaust. Maybe you should look into making a few of them for people that would like one.

I would, but it would be ridiculous expensive, especially with shipping, like mentioned.

 

[KYNgsx]

Good fit ups and welds. Did you back purge the tubing at all?

Did you weld the v band assemblies clamped together?

You will not have any flow issues with a 4" muffler I am sure.

Didn't back purge. Don't have the regulator for it. (That and argon is super expensive here.) I did weld the v-bands while clamped together to prevent warping.

At what point is a 4" necessary over a 3" ?

So this is on an fp black? Completely unnecessary. But it looks good, just know youll habe to cut and weld the o2 part when you upgrade turbos.

At around 700hp! Maybe slightly less. Its super overkill for his application!

Yeah, the 4" is overkill and not absolutely necessary. It won't hurt either though. Overkill is pretty much the theme of my build anyway. I do have a full T3 setup with a billet 6262 on the side, but I had some issues with the manifold hitting my hood and the turbo sucking in my air filter. The FB Black came up on sale at just the right time, so it will do the job for now until I decide to go bigger. I do like cutting, welding, and building stuff so I won't mind making another downpipe.

 

[Archer Fabrications]

Fair enough. And as for back purge, for yourself it's probably not that bog a deal depending on how much sugar there is. It will hinder flow a little (turbulance) but the size makes up for it, if this was a manifold thouh or something pre turbo, i would say purge is a MUST unless you dont care about potentilly killing your turbo. In some cases it's good to buy the regulator and use extra argon because it's cheaper to buy those things than a new turbo.

 

[KYNgsx]

The pipes are 14ga so there's very little sugar. Tried to get the weld just on the verge of melting all the way though. The joints are smooth on the inside. I did cheat on a few bends that didn't have super tight fitment by using a backing sleeve on the inside of the joint to cover the gap while welding. I definitely would backpurge on a manifold.

 

[jakeachy]

Fair enough. And as for back purge, for yourself it's probably not that bog a deal depending on how much sugar there is. It will hinder flow a little (turbulance) but the size makes up for it, if this was a manifold thouh or something pre turbo, i would say purge is a MUST unless you dont care about potentilly killing your turbo. In some cases it's good to buy the regulator and use extra argon because it's cheaper to buy those things than a new turbo.

if you looked at the welds, you would see that they are barely in the 35 amp range, and they were done quickly. I would bet there isnt even full penetration, which is totally good and honestly the only logical way to make something this big that has no purpose for purge.

 

[KYNgsx]

That's a pretty good description of it. I tend to just leave my welder set at 95 amps and use the foot pedal somewhere in the middle. I don't really know how many amps it's actually at while doing the butt welds. I try to start the puddle quick and move fast to keep from blowing it out.

 

[Archer Fabrications]

if you looked at the welds, you would see that they are barely in the 35 amp range, and they were done quickly. I would bet there isnt even full penetration, which is totally good and honestly the only logical way to make something this big that has no purpose for purge.

I looked. The outer coverage is great, but ive worked woth 16g material on low amps no back purge and still has 1/4" sugar so i trashed it (long ago) filler amount has an effect as well, but like i said, doesnt matter really because its post turbo, and like o saod. Size makes up for the turbulance

I'll say it again, good fitup and good welds though.

 

[KYNgsx]

Thanks.

 

[GST with PSI]

This is one of my favorite builds on the site. The welds might not be perfect, but you can really appreciate the whole project since you did it all yourself. That's something money can't buy.

Great work.