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Old 01-17-2009, 08:54 AM   #1
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Default cutout vs exhaust

Finishing up my turbo mani and soon it will be time to start working on a downpipe. Searched around for threads with the word "cutout" in them and came up with nothing similar to my question so here goes:

electronic cutout on the downpipe bolted to stock exhaust

vs

3" exhaust system

Which do you think is better and why?
pros and cons of each as I see them would be:
cutout
Pro: unbeatable flow when open helping power/spool. Stock or quiet sound when closed for daily driving
Con: It might sound too loud/raspy? possibility to burn something on the underside of the car. What else?
3" exhaust
Pro: really nice deep sound and obviously good flow for turbo.
Con: always loud, attracts attention from the cops, more expensive.

I am looking around and trying to make up my mind. Kinda leaning towards cutout since I want the car to look/sound stock or near stock daily driving and enjoy a nice run through the gears every once in a while with as much power/good spool as I can get.

Lastly, if you were to go with a cutout, what do you think about these in this particular order (from cheapest to most expensive):
1) eBay Motors: Raceland Exhaust Cutout Switch-N-Blast Remote (item 110339069315 end time Jan-17-09 19:33:46 PST)

2) eBay Motors: BadlanzHPE Electric Exhaust Cutout Cutouts REFURBISH (item 170286920490 end time Feb-10-09 10:55:25 PST)

3) eBay Motors: QTP EXHAUST ELECTRIC VALVE 3" & SS CUTOUT CAMARO GT Z28 (item 200297456158 end time Jan-20-09 11:34:28 PST)

While I had exhausts on both my subies and never was a fan of cutouts, I have driven a few cars with them installed and must say I was really impressed. Definitely would have gone this route if I kept the subaru, but since I dont I want to try this in the miata.
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Old 01-17-2009, 10:40 AM   #2
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Different tuning for cutouts open vs. closed if getting in the boost maybe? Backpressure vs. open makes a big difference in the tune, doesn't it? Sometimes you may want to boost w/out all of the attention in the world on you, and sometimes it doesn't matter.
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Old 01-17-2009, 10:47 AM   #3
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You have a good point. I know it makes a big difference in the performance, but does it really affect the tune?
The way most subaru guys do it is tune with it open and just leave the same tune for when its closed. You get worse spool and less power, but the car is quiet. When you need the power/spool to take advantage of the map you just open the cutout....

That would be the case for me at least. With it closed I wouldnt even intend to push the car at all, and hope that afr and everything else doesnt get affected. Only the power/performance gets "muffled" so to speak.
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Old 01-17-2009, 10:56 AM   #4
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just go with the full exhaust i had the cut out on my evo and it just turned into a pain in the ***. tuning was hard and the electronic cut outs break they are all shitty. just go with full exhaust and you will be happy
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Old 01-17-2009, 11:00 AM   #5
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I wouldn't really worry about getting a cutout unless you plan on going to the strip with your car.

My dad had cutouts on his vette and to be honest it really much of a difference, same for my bro and his camaro ss.

I know it makes a huge difference on turbo cars but, I say go with the exhuast first and then decide whether or not you want the cutout.

I think that if you get the cutout and leave the stock exhuast on you will end up just having the cutout open all the time.

my .02

ps, congrats on the manifold man! Looks great!
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Old 01-17-2009, 11:06 AM   #6
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i got a 2.5" exhaust and a manual cut-out. Works like butta. Having the cut-out open makes a hugemongous difference.
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Old 01-17-2009, 11:42 AM   #7
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Quote:
Originally Posted by SloS13 View Post
i got a 2.5" exhaust and a manual cut-out. Works like butta. Having the cut-out open makes a hugemongous difference.
well thats nice to hear
Quote:
Originally Posted by viperormiata View Post
I wouldn't really worry about getting a cutout unless you plan on going to the strip with your car.

My dad had cutouts on his vette and to be honest it really much of a difference, same for my bro and his camaro ss.

I know it makes a huge difference on turbo cars but, I say go with the exhuast first and then decide whether or not you want the cutout.

I think that if you get the cutout and leave the stock exhuast on you will end up just having the cutout open all the time.

my .02

ps, congrats on the manifold man! Looks great!
thanx. see the whole deal with the cutout also is that I'd have to only fab up the downpipe and weld the cutout to it = less work/money...If I fab up a whole exhaust I obviously wont go back to a cutout since I've already put in all the work/money for the exhaust.

The other thing is that here in cali we get snipped for exhaust all the time. they send you to a ref, you have to resmog, pay hella fee's, etc etc etc....
I'm definitely considering both, so dont think I'm just defending the cutout, but unless someone gives me some good reasons why 3" exhaust is better I think I might lean towards the cutout.
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Old 01-17-2009, 12:17 PM   #8
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3" Enthuza from Jason and you'll be all set.

Vash-
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Old 01-17-2009, 12:18 PM   #9
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What I was trying to get at is with a 2.5 you don't have to have a loud *** exhaust but it still flows good and you've got the cut-out for the track, etc.

Building an exhaust from scratch is easy and cheap. I would never consider running a turbo on a stock exhaust. Mine is close to stock sounding with the cutout closed
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Old 01-17-2009, 12:58 PM   #10
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Here's what I would do given your circumstances. 3" exhaust all the way to the rear w/ a 2.5" tip. The tip will bring the noise down some and won't affect flow whatsoever. Drive it. If it's too loud, THEN consider a cutout. But you will have to either:

a) have the cutout always open at the exact same RPM/Load as to be able to run one tune
b)enable map switching so you can tune for both.

You should put a large glasspack in your exhaust too. It will help with reducing the volume. I have 3, but I"m retarded. But my exhaust be quiet!
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Old 01-17-2009, 01:41 PM   #11
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or get a 3" and fix up some sort of removable silencer that would have whatever diameter you choose
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Old 01-17-2009, 01:47 PM   #12
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Quote:
Originally Posted by akaryrye View Post
or get a 3" and fix up some sort of removable silencer that would have whatever diameter you choose
Yup, get a 16-18" straight thru muffler/resonator have it flanged. Take it off when need be. Its easy.

Even have it at the end with a V band clamp and take it off whenever..
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Old 01-17-2009, 02:13 PM   #13
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I was talking about something more like this:

A'PEXi 155A-008 - A'PEXi Super Silencers - summitracing.com

but I cant freaking find any for 3" pipes ... I would like one personally that brings it down to a 2" diameter for when I want it quiet.
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Old 01-17-2009, 02:17 PM   #14
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interesting....so majority of opinions are for exhaust. I'll have to start looking for piping and a nice muffler then.
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Old 01-17-2009, 03:02 PM   #15
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See post #9 in this thread by slos13 https://www.miataturbo.net/forum/t29571/, that's how I might do a cutout with just a hand cable in the cockpit and not worry about an electric cutout failing.

Last edited by zoomin; 01-17-2009 at 09:54 PM. Reason: forgot the link!!
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Old 01-17-2009, 04:17 PM   #16
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Default sorry for the threadjack

Why is this the only freaking silencer I can find for a 3"?? and these only come in pairs, so what gives ... then there are silencers like that for 3.5" on every corner on ebay, but nothing for 3

eBay Motors: Perrin Universal 3" Exhaust Dual Tip Silencer, Set of 2 (item 300236844617 end time Jan-21-09 21:04:18 PST)

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Old 01-17-2009, 04:28 PM   #17
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thread jack away lol
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Old 01-17-2009, 09:56 PM   #18
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I live in washington so i dont think the cali rules apply. I am going to be building a 2 1/2" -3" downpipe and full 3" exhaust. Downpipe is gonna be stainless and the rest is gonna be aluminized. I wish i woulda saw the price difference before i bought all the tubing its like 150% more expensive for the same thing. Also summit racing has a nice 3 in 3 out turbo muffler for pretty cheap

Summit SUM-630130 - Summit Performance® Turbo Mufflers - summitracing.com

all u need for the cat-back is some hangers, pipe and 2 180* see below link

Photo 1 of album Custom 2 1/2 Catback


some nice flowage
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Old 01-20-2009, 05:54 PM   #19
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my vote would be for a full. even if you go 3" it can still be made to be very quite. it'll cost you more up front, but you'll be so much happier with it.

you'll love the way the car runs with a cut out, but that is the problem. you'll want it to run that way all of the time.

believe me when I tell you that there are plenty of mufflers out there in 3" that will flow enough for your power goals and be quite enough. and don't let anybody tell you that there isn't enough room to tuck a full 3" exhaust tight enough under there to not be seen. you could allways spray it with some hightemp black to be extra stealthy.

side note if some of you need a silencer insert for the tail pipe. just get a short piece of pipe about 1/2" diameter less than your tip and have the end of it expanded at your local muffler shop to fit snuggly inside. drill a hole in the bottom and bolt it in there. or you may even be able to find one to fit in the adaptor section at pep boys.
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Old 01-20-2009, 07:45 PM   #20
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Quote:
Originally Posted by dynokiller90 View Post
side note if some of you need a silencer insert for the tail pipe. just get a short piece of pipe about 1/2" diameter less than your tip and have the end of it expanded at your local muffler shop to fit snuggly inside. drill a hole in the bottom and bolt it in there. or you may even be able to find one to fit in the adaptor section at pep boys.
i thought about that, and i will be making one when i get my turbo stuff installed.
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