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Old 09-10-2009, 07:50 PM   #1
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Default Starting on exhaust

Ok so I've been reading a few threads with exhaust talk.
I've been running a stock exhaust this whole time and while its awesome in that the car is super quiet and I don't attract cops, I really can't leave all the power and flow on the table that I could be putting to use.

SOO, I just ordered one of these:
http://www.performancepeddler.com/de...CT_ID=MAG12577
part number MAG12577 (in case it doesn't show up).
MAGNAFLOW 6 x 12 Oval / 2.5 Offset Inlet / 2.5 Offset Outlet / 22 Body Length / 28 Overall Length

I want as quiet as possible while having decent flow. Since my downpipe is 2.5" I ordered the 2.5. I know I can have a tiny bit more power with 3" but this is my decision.

I will be using a resonator with this as well that I have laying around from a previous car. Resonator is about 6x3 and 14 long 2.5" straight through.

I'll be making the exhaust myself and using this as an example:
(the one on the left)



Any comments? Ideas? Criticism? Feel free to chime in here. I'll probably start on it as soon as the muffler comes in either monday or tuesday.

Last edited by 18psi; 09-10-2009 at 11:13 PM.
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Old 09-10-2009, 10:54 PM   #2
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Looks legit to me. I also went with 2.5" exhaust.. but no cat or muffler for me(its really loud). I figured with a 2.5" downpipe, no need to spend the extra money on minimal flow benefits, plus I have a 1.6.

You "example" isnt showing up for me. ??
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Old 09-11-2009, 02:13 AM   #3
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I just had my downpipe and midpipe redone in 2.5 for under $300, exiting through my HKS Super Drager muffler it is quieter than stock with no resonator.
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Old 09-11-2009, 11:11 AM   #4
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the one on the left will have the 22 inch muffler sticking out the right side of your car.

you're gonna need a gooseneck from the diff to the muffler inlet. mine's ok, but still too close to the right rear tow hook. See if fmowry will throw up a photo of his muffler install. it's pretty much ideal.

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Old 09-11-2009, 02:53 PM   #5
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Cat or no cat? Looks like a pretty solid plan, should be pretty damn quiet.
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Old 09-11-2009, 04:37 PM   #6
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Thanx for the tip y8s.

wayne there will be no cat. just resonator and muffler.
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Old 09-11-2009, 07:15 PM   #7
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isn't a cat required where you live?
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Old 09-11-2009, 07:28 PM   #8
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LOL if I played by the rules 99% of everything I had on the car would have to be taken off. No one really pays attention to a miata around here, so I don't get harassed. The evo/sti/honda crowd take all the heat. I just need to make sure I'm QUIET. I took off my exhaust a while ago for a few hours and just ran open downpipe. Holy crap I think I could hear my car from like 10 miles away. That is a no-no around here. I need max power with as little sound as possible. That is the winning combination in avoiding trouble with the po-po around here
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Old 09-11-2009, 07:48 PM   #9
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Well, when you get caught you can only blame yourself, there are high flow converters that will also quiet the exhaust. I'll try to get a video/sound clip of mine today or tomorrow.
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Old 09-11-2009, 07:52 PM   #10
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Quote:
Originally Posted by 18psi View Post
Any comments? Ideas? Criticism? Feel free to chime in here. I'll probably start on it as soon as the muffler comes in either monday or tuesday.
That exhaust on the left is the most awesomeest exhaust i've seen today. That's a 3" exhaust BTW.

Let me know if you need more pics of it. It's the first one I did on my back in my garage.

EDIT for Y8S: I think you could fit the 22" there now that I've done enough of these. You'd have to cut off the straight sections of the muffler though...but most likely possible. I wonder how much quieter it would be....hmm.
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Old 09-11-2009, 08:58 PM   #11
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Quote:
Originally Posted by zoomin View Post
Well, when you get caught you can only blame yourself, there are high flow converters that will also quiet the exhaust. I'll try to get a video/sound clip of mine today or tomorrow.
A high flow cat won't pass smog around here just like a catless exhaust. Cops that pull people over around here never look under the car to check for a cat. They usually issue a "modified exhaust" or "exhaust too loud" ticket that you have to go to ref for and if they decide to pop your hood and anything shiny or remotely resembling non-OEM stuff is under there, you get a "modified emissions" ticket as well. Basically if you're pulled over a high flow cat won't change a damn thing.

But feel free to post up a clip of what yours sounds like. I might just put one in just for sound purposes.
Quote:
Originally Posted by TurboTim View Post
That exhaust on the left is the most awesomeest exhaust i've seen today. That's a 3" exhaust BTW.

Let me know if you need more pics of it. It's the first one I did on my back in my garage.

EDIT for Y8S: I think you could fit the 22" there now that I've done enough of these. You'd have to cut off the straight sections of the muffler though...but most likely possible. I wonder how much quieter it would be....hmm.
That exhaust is utter beauty and I fell in love with it way back before I even turbo'd my miata

If you have more detailed pictures please feel free to post them up or send me a link to them: I will be very grateful.

I did a bit of measuring today and I THINK I will be able to get away with stuffing the 22" in there at an angle just like yours is. It would be tight, and the ends would DEFINITELY need to be cut off, but that's not a problem at all.
Worst case scenario I will just put it in just like y8s has his. No problems there.
Can't wait for this thing to come in so I can start on it already
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Old 09-11-2009, 09:02 PM   #12
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Be a real man and do this:

I'm redoing this with a muffler momentarilarialy
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Old 09-11-2009, 09:03 PM   #13
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Here's another question:

Do you guys think I need a flex section where the dp mates to the exhaust? My downpipe is bolted to the transmission via a very strong bracket and does not move AT ALL. So it moves with the engine/transmission. Is it a good Idea to have a flex section between exhaust/dp so that it doesn't put stress on the flanges when the engine/tranny moves or are the stock hangers flexible enough to absorb the movement?
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Old 09-11-2009, 09:04 PM   #14
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Quote:
Originally Posted by TurboTim View Post
Be a real man and do this:
[IMGhttp://www.inoneear.com/outtheother/paul/paulexhaust4.JPG[/IMG]
I'm redoing this with a muffler momentarilarialy
haha I definitely could and it would be a helluva lot easier than my planned routing, but I'm sure a 22" muffler won't fit there, and without a muffler I'll last all of 2 days
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Old 09-11-2009, 09:12 PM   #15
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Quote:
Originally Posted by 18psi View Post
If you have more detailed pictures please feel free to post them up or send me a link to them: I will be very grateful.
Pics...these are all 18" long cores (5x8 or 4x9), take off ~2" off each straight and you got your 22...HORRAY MATH again should be easily doable!

Beware of the older flanged halfshafts and resulting clearance requirements.

If no show, right click & "show pic" or hit refresh.

My car (the first exhaust I did like this):




EvanK's MSM:




artie's without muffler. this shows the bends real well, BUT is different than all the other's i've made, smoother bends. I didn't record how I did it:


with muffler:






Yeah I'm taking over your post with my own pics cause i'm an **** that whoo hoo.

Last edited by TurboTim; 09-11-2009 at 09:27 PM.
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Old 09-11-2009, 09:21 PM   #16
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Quote:
Originally Posted by 18psi View Post
Here's another question:

Do you guys think I need a flex section where the dp mates to the exhaust?
What's your application? Street? I haven't put a flex in a street exhaust/DP in years w/o issues. Track car, do a good long flex. Hippocrate? yep.

Quote:
My downpipe is bolted to the transmission via a very strong bracket and does not move AT ALL. So it moves with the engine/transmission. Is it a good Idea to have a flex section between exhaust/dp so that it doesn't put stress on the flanges when the engine/tranny moves or are the stock hangers flexible enough to absorb the movement?
Actually, my own car broke the thick bracket I made to the trans, on my first homemade setup (ramhorn bottom mount SS GT2560 1.6). I never run 'em anymore because of that. I make the downpipe very close to the trans because they move together, but DON'T connect them rigidly. If you are running an open downpipe or really really want to connect to the trans, I highly recommend making a brace from one of those stiff reinforced rubber "hangers" for truck exhausts, the ones with the series of holes and a steel arc piece at the end for use with a cheap-o U-clamp. It'd give the DP support up/down and side/side, but allow it to grow along the length of the car (parallel to driveshaft).
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Old 09-11-2009, 09:26 PM   #17
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SWEET. Thanx for the pictures/advice kind sir, I really appreciate it.

The car is 100% street. So I guess I won't use a flex section at all.




*edit: just checked tracking - it will be here on tuesday. YAY
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Old 09-11-2009, 09:49 PM   #18
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Quote:
Originally Posted by 18psi View Post
SWEET. Thanx for the pictures/advice kind sir, I really appreciate it.

The car is 100% street. So I guess I won't use a flex section at all.




*edit: just checked tracking - it will be here on tuesday. YAY
No problem! More Pics. These are on the server but not linked anymore on the site...odd.

Don't not use a flex because I don't.

Left is 2.25" Enthuza, Mine, My old midas crush bent 2.5"




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Old 09-12-2009, 11:22 AM   #19
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Quote:
Originally Posted by TurboTim View Post
EDIT for Y8S: I think you could fit the 22" there now that I've done enough of these. You'd have to cut off the straight sections of the muffler though...but most likely possible. I wonder how much quieter it would be....hmm.
tim, that IS the 22"... like i said, it's shoved really far over to the passenger side. Frank's implementation is better, if uses a little more pipe in the U bend area. my error was installing the tailpipe bend before hanging the muffler.
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Old 09-12-2009, 09:33 PM   #20
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Quote:
Originally Posted by y8s View Post
tim, that IS the 22"... like i said, it's shoved really far over to the passenger side. Frank's implementation is better, if uses a little more pipe in the U bend area. my error was installing the tailpipe bend before hanging the muffler.
Matt, i KNOW that is the 22 on your car, and it is oriented damn near perpendicular to the driveshaft. I am saying the 22 can most likely be used in the orientation I use.
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