Exhaust advice needed - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Prefabbed Turbo Kits A place to discuss prefabricated turbo kits on the market
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools
Old 02-14-2007, 02:03 AM   #1
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default Exhaust advice needed

Well this year I am doing an exhaust. I've done a TON of searching and have found many interesting setups. The sound quality on most of the videos is very poor, so I'm not sure what to run with yet.

It will be a home made exhaust as I have a lift, welder and a pipe bender. Problem is, I can't seem to get a strait system down.

The closest car to the sound I want is a WRX with that custom exhaust they all have. Loki's sounded really nice. Basically a deep tone. I don't want it too loud, but I wanna be heard. I'm not sure where to start, some have said 2 resonators with no muffler, others one of each, 2.25" pipe, 3" pipe....I dont know!!

I will be using the stock greddy downpipe and I do not have emissions testing so the cat will most likely be deleted. Also I want it to be in the factory exit. The budget is low, of course, but don't let that stop any suggestions. NO premade cat backs, I can't afford em. Thank you for anyone who can help me out, I just can't make up my mind.
miataspeed1point6 is offline   Reply With Quote
Old 02-14-2007, 03:31 AM   #2
Junior Member
 
Join Date: Oct 2006
Posts: 257
Total Cats: 0
Default

don't know if this will help, but i have a 2.5" fm turbo exhaust. i love the sound.

http://youtube.com/watch?v=I1HRnqyU8gA
shinobix is offline   Reply With Quote
Old 02-14-2007, 05:13 AM   #3
Senior Member
 
boostinsteve's Avatar
 
Join Date: Oct 2006
Location: Honolulu, HI
Posts: 563
Total Cats: 0
Default

I would personally run a 3 inch exhaust with 2 resonators. That would sound pretty good and should make up for the fact that it probably will not be mandrel bent. If you want one of the tuner mufflers on the end, I would just run 1 resonator, and put the muffler on the end (I would just look on ebay to get the muffler and the resonator. That should give you the sound that you want.
boostinsteve is offline   Reply With Quote
Old 02-14-2007, 06:11 AM   #4
Supporting Vendor
iTrader: (3)
 
Join Date: Jul 2006
Location: San Diego
Posts: 2,863
Total Cats: 485
Default

I've never had better success on making a car sound good than running 2.5" piping with one resonatr - I used a glasspack, and then a 'tuner muffler' on the end - which is straight through muffler with a resonator inside. I'd get em from ebay. maybe 3" dia would be better for your turbo setup.
Right now I have 2.25" piping, high flow cat, glasspack inline, and Magnaflow single tip muffler. I like it but when I switch to turbo I'll chop the Magnaflow out and run a tuner muffler straight out the back leaving the piping and glasspack. Should work well. Then later I may remake it all with larger diameter.
-Ryan
ThePass is offline   Reply With Quote
Old 02-14-2007, 01:51 PM   #5
Elite Member
iTrader: (2)
 
Join Date: Jun 2006
Location: ABQ, NM
Posts: 1,850
Total Cats: -8
Default

You'll never get the same exact sound of a WRX. They have a much bigger horizontally opposed motor. I've never heard an I4 that sounds like an H4.

That said I think the above recommendations would probably turn out a decent sounding exhaust.
BenR is offline   Reply With Quote
Old 02-14-2007, 04:06 PM   #6
Junior Member
iTrader: (2)
 
Join Date: Jul 2006
Posts: 482
Total Cats: 0
Default

I found a stock evo8 exhaust 2.5". Just needed to clock it at the flange. and make a couple hangers. No muffler. Sounds bad ***!!!
rappadan is offline   Reply With Quote
Old 02-14-2007, 04:13 PM   #7
Senior Member
 
Join Date: Dec 2004
Posts: 1,450
Total Cats: -1
Default

Quote:
Originally Posted by rappadan View Post
I found a stock evo8 exhaust 2.5". Just needed to clock it at the flange. and make a couple hangers. No muffler. Sounds bad ***!!!
Unless you're 17 yrs old, you'll get tired of it REAL fast.
bripab007 is offline   Reply With Quote
Old 02-14-2007, 04:36 PM   #8
Junior Member
 
Join Date: Oct 2006
Location: Detroit Area, MI
Posts: 227
Total Cats: 0
Default

sent you a pm
expensivehobby22 is offline   Reply With Quote
Old 02-14-2007, 05:06 PM   #9
Senior Member
 
Join Date: Dec 2004
Posts: 1,450
Total Cats: -1
Default

"I'd run the smallest exhaust possible to keep the exhaust gas velocity up, plus our small engines like a bit of backpressure."





WARNING: The statement above is meant for comedic purposes only.
bripab007 is offline   Reply With Quote
Old 02-14-2007, 06:32 PM   #10
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default

I know my miata won't sound like a WRX, just an example so you guys know what I'm going for. I want a deeper tone than that FM, not sure if its possible. My 3 options in my mind are...



1.Going with the stock greddy downpipe, 3" pipe to 2 resonators then out the back with a nice tip. Is this too loud for daily driving? I don't mind louder than stock, but if I can't hear my music at 50 mph its too loud.

2.Then what if I went with stock greddy downpipe, (any diameter exhaust pipe) to 1 resonator, then a "tuner" muffler or fart cannon. I'll admit I have heard those mufflers sound good before.

3.Lastly what if I went stock greddy downpipe, (any diameter exhaust pipe) to 1 resonator and a magnaflow muffler then a nice tip?

Thanks for the help. I'm leaning for option 1, but not sure if it will be defeaning at 50?
miataspeed1point6 is offline   Reply With Quote
Old 02-14-2007, 06:42 PM   #11
Senior Member
 
boostinsteve's Avatar
 
Join Date: Oct 2006
Location: Honolulu, HI
Posts: 563
Total Cats: 0
Default

One of the other reasons that the boxer motor sounds like that is because they idle at like 500 rpm, just a thought. All of those are good options, for the two resonators, if you want it to be softer, just use longer resonators. It really depends on what you want the exhaust to look like. I really like the way that Rusman's exhaust came out, so I might switch over to the fart can style muffler with one long resonator her very shortly. Really just depends on what you want it to look like. Good luck.
boostinsteve is offline   Reply With Quote
Old 02-14-2007, 08:28 PM   #12
Senior Member
 
Join Date: Dec 2004
Posts: 1,450
Total Cats: -1
Default

Quote:
Originally Posted by miataspeed1point6 View Post
1.Going with the stock greddy downpipe, 3" pipe to 2 resonators then out the back with a nice tip. Is this too loud for daily driving? I don't mind louder than stock, but if I can't hear my music at 50 mph its too loud.
I've read of folks that have tried that setup and decided it was far too loud, and there are folks running open downpipes that think it sounds great (I ran an open downpipe for about a week and my ears bled).

It's all up to personal taste (imagine that!).
bripab007 is offline   Reply With Quote
Old 02-14-2007, 09:08 PM   #13
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default

Well your right, I guess I won't know until I try. I've decided to try it, if its too loud I can just put the old one back on. I'm going to go with 2 resonators with no muffler. Where would you advise I put the resinators? I'm thinking one strait off the down pipe and then one right before the diff. How long? What brand? I'm no exhaust guru, so I'm not sure what brand will do what. Thanks for the help, I need it
miataspeed1point6 is offline   Reply With Quote
Old 02-14-2007, 09:13 PM   #14
Elite Member
iTrader: (24)
 
kotomile's Avatar
 
Join Date: Oct 2006
Location: Monterey, CA
Posts: 7,578
Total Cats: 40
Default

Magnaflow and the like are pretty popular, as for the size, I'd be curious what other people are running and how loud it is. Of course, the more resonator you use the quieter it'll be. [/captain obvious]
kotomile is offline   Reply With Quote
Old 02-14-2007, 09:52 PM   #15
Senior Member
 
boostinsteve's Avatar
 
Join Date: Oct 2006
Location: Honolulu, HI
Posts: 563
Total Cats: 0
Default

I would put the resonators as far from the tip/tailpipe as possible, that way if it is too loud, you have options. You can take the tip off and put a fart can muffler on, or you can still add the magnaflow.
Edit: Put them prior to the differential.
boostinsteve is offline   Reply With Quote
Old 02-15-2007, 12:32 PM   #16
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default

So heres the plan so far. I'm not sure how long of a resonator I can fit under the car, so just imagine for arguments sake that the two resoators fit.

Stock greddy downpipe > resonator > resonator > Tip in stock outlet

Is the the optimum layout for the given constraints? And what size pipe? I'm not sure 3" is all that needed seeing as I have the greddy downpipe. Will 3" mellow the tone out and make it deeper? If not, what size is recommended? Thanks.
miataspeed1point6 is offline   Reply With Quote
Old 02-15-2007, 01:07 PM   #17
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

if you want good prices on magnaflow units let me know. I was thinking of doing a similar setup with two inline mufflers.
Braineack is offline   Reply With Quote
Old 02-15-2007, 01:43 PM   #18
Junior Member
iTrader: (8)
 
Join Date: Jun 2005
Location: Lansdale, PA
Posts: 426
Total Cats: 0
Default

I run a full 2.5 inch exhaust with a magnaflow cat and a summit turbo muffler. It's just a tad louder than stock and has a nice mellow tone. It's perfect for my taste. I had a video floating around somewhere...I'll see if I can find it.
Stripes is offline   Reply With Quote
Old 02-15-2007, 03:24 PM   #19
Senior Member
Thread Starter
iTrader: (1)
 
miataspeed1point6's Avatar
 
Join Date: Feb 2006
Location: Detroit
Posts: 1,235
Total Cats: 0
Default

Does anyone suggest parts for me to use? I looked up Braineacks site and all I saw were the round mufflers. I'm not sure if those are the same as resonators? After reading all the posts I'm going 3". One day I hope to replace the Greddy downpipe, so I might as well build the exhaust the right way now.

From what I'm reading this should be louder than stock, but not enough to make me go deaf.

I have new questions! I noticed alot of people who are using some sort of band clamp to hold the exhaust together. Why is this better than welding? Seems like welding is a much better idea to me, but with the bands you could take it apart.
miataspeed1point6 is offline   Reply With Quote
Old 02-15-2007, 03:34 PM   #20
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

brainy can get you what you want. check out the dynomax bullet race mufflers (they are <$40) in whatever length you think you can fit. go with at least 12" long though for the forward one. the second one should be as big as possible. know that you WILL have drone with just a small rear muffler, it's unavoidable without a big fat muffler back there. The alternative is one of the magnaflow stainless LARGE mufflers but they're $120 or so... very quiet though and the same design as the straight thru race mufflers. Braineack can get those too since he's a magnaflow man.

The clamps are V-band clamps. We use them because it would be pretty impossible to get a turbo-back exhaust on or off a car without them! MUCH easier to split it up into a few segments and take off only what needs to come off, say, if you're doing the clutch or whatever. You can use 3-bolt flanges too or slip joints or just weld it and use a sawzall to remove it. The V-Bands are great because they seal well, have very little flow disruption, and allow you to align the pipes 360 degrees. building your own exhaust sometimes needs that kind of "oh crap I did it wrong" flexibility...

Matt
y8s is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
15x10 - 15x11 6UL @ 949 Racing emilio700 Wheels and Tires 151 06-02-2017 03:36 PM
Another Cast Manifold Corky Bell Prefabbed Turbo Kits 18 11-22-2016 10:01 PM
Need help - Stock Balancer and Fastforward overlay pulleys Frank_and_Beans Supercharger Discussion 13 09-12-2016 09:17 PM
BP-6D on CAS only aidandj MEGAsquirt 14 09-25-2015 06:26 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 08:48 PM.