Tunes and downpipe cutout?

That spinning thing that makes all of the cool noises. OE and Aftermarket.

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Hinano
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Tunes and downpipe cutout?

Post by Hinano »

I'm on a super tight budget and like having a quiet exhaust.

I'll be going with the stock wrx exhaust and maybe a bigger aftermarket down pipe for my ej20g and am considering to have a electric or perhaps some kind of manual cutout welded onto the down pipe at the same time the extensions to fit the wrx exhaust are made. Will there be boost creep?

I've read that you can set the tune up for open downpipe and just drive the car in that tune and loose some power with the cutout closed. Or you can have a two stage set up. Any ideas on how to set this up well?
James614
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Re: Tunes and downpipe cutout?

Post by James614 »

You won't be tuned specifically for an open DP, and I don't know how cutouts perform in general. I do know that running open down pipe hurts power compared to a full 3" turboback. But on a budget that may be one of your better options. I would definitely recommend running a 3" aftermarket down pipe if you aren't already planning to, that will open up flow a lot.

I've never set one up. But be advised that open downpipes are LOUD on these cars. A quick pull through 3rd gear would give me a headache when I ran that way.
93 Touring Wagon (EJ20G 5spd Swap) -- Finally back and running strong as ever!

05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.
Hinano
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Re: Tunes and downpipe cutout?

Post by Hinano »

Thanks for the input. Yeah I'm really hoping to help with the spool but also get some extra power. I was thinking of a 3 or even 4 inch down pipe with a cutout on a stock wrx exhaust. I didn't think it would be so loud that one pull through 3rd gear would cause a headache.. I've read something like 15whp gain for a cutout on a stock wrx exhaust. I'm just trying to make sure the turbo spools up quick, I am trying to do some autocross on a small track and its basically set up to run second gear. I noticed the gears in this car seemed much longer than my 6 speed miata so I am a little worried about the lag. Maybe I'll worry about it AFTER I have everything set up and running.
James614
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Re: Tunes and downpipe cutout?

Post by James614 »

Should definitely spool better than a stock exhaust, but on the 2.0 with the TD05 you'll still be spooling well over 3000rpm. Mine spools at like 3800, but there various factors that cab effect exact spool up. I have yet to autoX mine on the swap but I feel like a couple shifts to 1st would be warranted on really tight sections.

Turbo scoobs are by by far the loudest open exhaust 4 pots I've ever heard.
93 Touring Wagon (EJ20G 5spd Swap) -- Finally back and running strong as ever!

05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.
Hinano
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Re: Tunes and downpipe cutout?

Post by Hinano »

3800??! Wow, that's higher than I was expecting.. Hmm.. Maybe I can just stay in first on the track. It really is super small track. Second is needed for the Miata for traction reasons but maybe I can man handle it in first with the awd lol.
James614
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Re: Tunes and downpipe cutout?

Post by James614 »

Oh yeah, if a Miata only needsb2nd for traction a Subie caj probably keep it in first.
93 Touring Wagon (EJ20G 5spd Swap) -- Finally back and running strong as ever!

05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.
cj91legss
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Re: Tunes and downpipe cutout?

Post by cj91legss »

I have a V-Band clamp at the bottom of my 3" and every once in awhile I will undo it just to hear that whistle....
91 L-TW Wagon with a full Swap -RIP
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91 SS 4EAT Sold!
98 LGT 4EAT
98 LGT Wagon 4EAT
mike-tracy
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Re: Tunes and downpipe cutout?

Post by mike-tracy »

My td05 hit 18psi by 3500 (on an ej20g).. But they really rev quick, so its not as bad as it sounds.
1992 Legacy SS 5mt, build in progress
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Hinano
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Re: Tunes and downpipe cutout?

Post by Hinano »

Since it sounds like its going to be ears hurting loud, I'll just get it running on the wrx exhaust, then go for a 3 or 4 inch down pipe. If I need, I also have access to a 04 STI catback. Not sure what the extra 1/4 inch difference will do though.. :/
James614
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Re: Tunes and downpipe cutout?

Post by James614 »

From what I've read, the STI axle back is the same diameter as a stock turbo legacy exhaust. So I would get whatever you can, lol.
93 Touring Wagon (EJ20G 5spd Swap) -- Finally back and running strong as ever!

05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.
Hinano
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Re: Tunes and downpipe cutout?

Post by Hinano »

James614 wrote:From what I've read, the STI axle back is the same diameter as a stock turbo legacy exhaust. So I would get whatever you can, lol.
I actually read that the wrx exhaust is 2 1/4 while the STI is 2 1/2.

But yeah, WRX is free so I'll go for that first LOL!
James614
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Re: Tunes and downpipe cutout?

Post by James614 »

Yeah, I believe the stock turbo legacy (and likely the 93-96 JDM WRX) is 2 1/2.
93 Touring Wagon (EJ20G 5spd Swap) -- Finally back and running strong as ever!

05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.
Hinano
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Re: Tunes and downpipe cutout?

Post by Hinano »

James614 wrote:Yeah, I believe the stock turbo legacy (and likely the 93-96 JDM WRX) is 2 1/2.
Oh okay I see. I have the N/A witch I think is like half an inch! LOL! Nah nah

I'll be putting on 04 WRX exhaust so maybe that's what was 2 1/4?
cj91legss
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Re: Tunes and downpipe cutout?

Post by cj91legss »

The sti axleback is less restrictive and you get a bit more of the rumble. It was significantly louder than my 2006 wrx axleback.

Size, i cant comment on because its been awhile since i compared the 2. I do have the wrx axleback still.

Legacy turbo and wrx is 2 1/4, sti is 2 1/2 i believe.

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91 L-TW Wagon with a full Swap -RIP
92 SS Prefaced, GD dash swapped, 22T/205 Hybrid 20 psi - BEAST!
93 SS Bone Stock Gone!
94 TW Bone Stock Gone!
91 SS 4EAT Sold!
98 LGT 4EAT
98 LGT Wagon 4EAT
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