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Old 05-23-2014, 03:59 PM   #1
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Default Exhaust Cutout Location Discussion

So, my turbo wasn't spooling because it fell apart. But I'm also aware that my current exhaust setup sucks for a FI setup. Like, a lot.

Because of this, and also because racecar, I am thinking about putting an electric cutout in.

I recently deleted my cat, but the biggest issue is that right now my DP is 2.75" and the rest of my exhaust is 2.25", and there's no gradual reduction there. Just lots of gas bumping into my flange and trying to get into a smaller hole.

Like this:



I'd like to dump the cutout immediately after the DP with a turndown. Because racecar. The cutout size I'm looking at is 3" because that would be awesome to have zero restriction there. Alternatively, I could go with a 2.75 to match the DP, but yolo.

The problem is, that my DP flange is slightly angled down. So if I just get a flange and put the cutout pipe on it, it'll be sticking downwards towards the ground. Like this:



The easiest solution would be to use the angle and flange of my current exhaust and replace where my cat used to be with the cutout. But this doesn't eliminate the problem of the 2.75 => 2.25 abrupt change.

Like this:



The BEST solution I can think of would be to get myself a small 3" mandrel, attach it to a flange on one end and then the cutout on the other, then get a gradual 3" => 2.25" pipe (either buy a pipe that does that, or pie cuts, or whatever) and attach that to the other end, and finally to the midpipe... but thats quite a few welds, and I like to KISS. Not to mention possible points of failure/not lining up, etc.

Like this:



What other options are there? Any other suggestions? I think I'd like to go with the final diagram as a rough sketch of how to do it, but it just seems so complicated and woudl either be a PIA to whomever helped me, or rather costly to myself if I took it to a shop.

Thoughts?
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Exhaust Cutout Location Discussion-exhaust-diagram.png   Exhaust Cutout Location Discussion-exhaust-diagram-2.png   Exhaust Cutout Location Discussion-exhaust-diagram-3.png   Exhaust Cutout Location Discussion-exhaust-diagram-4.png  
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Old 05-23-2014, 04:04 PM   #2
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The solution is an Enthuza 3" exhaust.
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Old 05-23-2014, 04:04 PM   #3
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Brain will be by shortly to tell you how retarded cutouts are and that you fail as a human being if you don't run full exhaust.




But seriously, search my threads you'll find one where I/we discuss something similar. Won't answer your question on placement but might give you some ideas. (I had a dream....once)....its something like "all the power with none of the noise" or something

Lastly, I've yet to see a electric cutout not leak after a while. No matter how high the quality of it is.
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Old 05-23-2014, 04:12 PM   #4
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Quote:
Originally Posted by 18psi View Post
Lastly, I've yet to see a electric cutout not leak after a while. No matter how high the quality of it is.
Noted, and thanks for the tip.

Concealer, I'm assuming you're referring to this?

NB Turbo midpipe 3" - Enthuza Car, Inc

Not to sound ricer, but I'd really like to avoid having a cat. If I'm 100% honest it's because fireballs. WI has no emissions testing, and I've really, really enjoyed getting a little pop on lift in the week or so before my turbo fell apart after deleting the cat.

I like the idea of a full exhaust a lot more.. but it's ~$900 vs ~$250..
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Old 05-23-2014, 04:15 PM   #5
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Quote:
Originally Posted by mlev View Post
Noted, and thanks for the tip.

Concealer, I'm assuming you're referring to this?

NB Turbo midpipe 3" - Enthuza Car, Inc

Not to sound ricer, but I'd really like to avoid having a cat. If I'm 100% honest it's because fireballs. WI has no emissions testing, and I've really, really enjoyed getting a little pop on lift in the week or so before my turbo fell apart after deleting the cat.

I like the idea of a full exhaust a lot more.. but it's ~$900 vs ~$250..

So delete the cat.

Our car has the Enthuza 3". No cats. Not verified for fireballs yet, but it does burble and pop and make loud bangs from time to time.
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Old 05-23-2014, 04:15 PM   #6
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didn't you say your friend can weld? in that case it should be more like 400
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Old 05-23-2014, 04:17 PM   #7
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you want a 3" catless midpipe? seriously, 30 bux + shipping and its yours. tapers to 2.5" at the very end, fits perfectly
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Old 05-23-2014, 04:18 PM   #8
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Yeah he can weld, and started teaching me on the cat delete (man, TIG welding is hard) but he's got lots of projects of his own, and I hate to pester him too often with **** that I want done.

I feel like if I got all the materials and went out there he would have no problem with me using the shop while he worked on his Datsun, but I'd end up just melting a bunch of holes in the mandrel and then burn myself.
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Old 05-23-2014, 04:19 PM   #9
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Quote:
Originally Posted by 18psi View Post
you want a 3" catless midpipe? seriously, 30 bux + shipping and its yours. tapers to 2.5" at the very end, fits perfectly
O.o from you? Or from ebay? or what? You have my interest sir.

I assume this will fit NB
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Old 05-23-2014, 04:24 PM   #10
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From me. Proper thickness steel not some ebay gaynes

I'll snap a pic when I get home.

Shipping might be a pain though. I could cut it in half to save shipping costs? I dunno.

Yes had it on my 2001 nb
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Old 05-23-2014, 04:26 PM   #11
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Quote:
Originally Posted by 18psi View Post
From me. Proper thickness steel not some ebay gaynes

I'll snap a pic when I get home.

Shipping might be a pain though. I could cut it in half to save shipping costs? I dunno.

Yes had it on my 2001 nb
Keep me updated. In the mean time, I'll slog through posts and look for other cutout discussion.

I did some searching, but all i found was a lot of people talking about using junkyard TBs as cutouts.
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Old 05-23-2014, 04:39 PM   #12
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Get us a picture of the dp/cat/midpipe area, so we can brainstorm our own solutions.
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Old 05-23-2014, 04:42 PM   #13
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Looks pretty much exactly like my paint sketches, obviously.

In all seriousness I can try to get pics when I get home, but it's just a BEGi downpipe and FM 2.25" exhaust, with a piece of pipe (2.5" with pie cuts down to 2.25" because that's all we had) in place of the cat.
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Old 05-23-2014, 04:43 PM   #14
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meh, don't do the cutout. your car is too nice to ghetto rig ****, plus any holes to the cabin and you will get some exhaust gas creeping into the cabin when stopped. not a big deal mostly, but it can take its toll if you spend a lot of time stopped in the car.
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Old 05-23-2014, 04:44 PM   #15
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So what you're all saying is I should buy 18psi's midpipe and this: Manzo Stainless Steel Axleback Exhaust Muffler Fits Mazda Miata MX5 99 05 1 8L | eBay and call it good.
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Old 05-23-2014, 04:44 PM   #16
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Actually it is a big deal, and it will choke the crap out of him when sitting in traffic or not driving over 10mph.
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Old 05-23-2014, 04:49 PM   #17
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vlad, is the midpipe mild or ss?
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Old 05-23-2014, 04:51 PM   #18
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16g aluminized mild steel iirc. its literally like 200 miles old
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Old 05-23-2014, 05:07 PM   #19
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Quote:
Originally Posted by 18psi View Post
16g aluminized mild steel iirc. its literally like 200 miles old
Well, I suppose I'll look at some pictures of it; but unless it's as crooked as my johnson, the taper is made of kinked up aluminum foil, or shipping is going to be $$$, I'll take it.

Chop her in half to ship, no problem at all. One quick weld around the outside is no problem, I just didn't want to pester my friend with like 10 different welds and measuring and cutting and pie cuts and bending etc.
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Old 05-23-2014, 09:14 PM   #20
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nah this bad boy is super duper strong. it aint the prettiest thing in the world, but the piping is thick, its smooth, no crazy bottlenecks, and the bend at the end fit perfectly on my 01. bolted up both to the stock muffler and my 3" enthuza XR

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