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How restrictive is the sti genome muffler?


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Long story short I have a second V7 Sti and the exhaust is a 3 inch catless turbo back with a sti genome tip (whole exhaust is one peice with no flanges). It sounds really good and wondering about putting it on my black V7 sedan.

My question is would the genome muffler be too restrictive as my black v7 is tuned to 210wkw. 

Potentially going for 240-250kw in future. Would it allow for those numbers?

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3 minutes ago, Loren said:

extremely unlikely to be too restrictive.

Ok sweet. I might go ahead and swap exhausts over.

The genomes are reasonably quiet but when you hit boost it wakes up and sounds pretty good with a 3 inch before it.

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I'm gonna be a pest and say it's probably too restrictive for 250wkw, from memory those Genomes aren't big mufflers, like.... 2.25" or something. I had a 2.5" Zerosports on mine and it became a limitation over about 230wkw.

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13 minutes ago, boon said:

I'm gonna be a pest and say it's probably too restrictive for 250wkw, from memory those Genomes aren't big mufflers, like.... 2.25" or something. I had a 2.5" Zerosports on mine and it became a limitation over about 230wkw.

 

So you couldn't make more than 230kw... and you swapped  the rear muffler only, and then you were able to make more than 230kw? 

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18 hours ago, Loren said:

 

So you couldn't make more than 230kw... and you swapped  the rear muffler only, and then you were able to make more than 230kw? 

 

Yes, exactly that, literally without removing the car from the dyno. Ran the car up and it made like... 236 or something, tuner was like "I suspect your exhaust", unbolted it at the mid-pipe and did a pull and it made 250-something.

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35 minutes ago, boon said:

 

Yes, exactly that, literally without removing the car from the dyno. Ran the car up and it made like... 236 or something, tuner was like "I suspect your exhaust", unbolted it at the mid-pipe and did a pull and it made 250-something.

 

What would be an acceptable loss for a not so restrictive set up though?

Surely just about any setup would perform a lot better with the axle back section removed, maybe not so bad on a relatively straight through single exit V7 setup but the overly convoluted later setups must surely add noticeable restriction even when pushed up a size. 

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Another question,

The exhaust from the donor car has the o2 sensor in the 'post cat' area of the downpipe (if there was a cat) but on my car the o2 sensor is at the very top of the downpipe. Will it matter if I move the o2 sensor from top of downpipe to underneath the car without screwing with the tune? I doubt it matters but wanna be sure.

Neither exhaust has a cat.

 

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6 hours ago, Andy_Mac said:

 

What would be an acceptable loss for a not so restrictive set up though?

Surely just about any setup would perform a lot better with the axle back section removed, maybe not so bad on a relatively straight through single exit V7 setup but the overly convoluted later setups must surely add noticeable restriction even when pushed up a size. 

 

Not sure really. I went to an obnoxiously loud 3" (not a straight pipe mind you, it has a muffler and resonator) and it made more power again, but we changed a couple of other things. Would it have made >230kw with the old exhaust and those things changed? Not sure. What I'm getting at is that a smaller (or at least, constricted design) exhaust is definitely a significant restriction at those power levels, whereas a freeflowing 3" didn't seem to be.

4 hours ago, Subru said:

Another question,

The exhaust from the donor car has the o2 sensor in the 'post cat' area of the downpipe (if there was a cat) but on my car the o2 sensor is at the very top of the downpipe. Will it matter if I move the o2 sensor from top of downpipe to underneath the car without screwing with the tune? I doubt it matters but wanna be sure.

Neither exhaust has a cat.

 

 

Nope, no difference. Make sure the loom is long enough. On a V7 the O2 sensor should be at the bottom, if it's at the top you probably have a GC/GF downpipe shoehorned in.

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27 minutes ago, boon said:

 

 

Nope, no difference. Make sure the loom is long enough. On a V7 the O2 sensor should be at the bottom, if it's at the top you probably have a GC/GF downpipe shoehorned in.

ok sweet, I found the original O2 sensor wire extension under my seat so its all good to go.

 

The exhaust is pretty straight and 3 inch all the way to about an inch before the genome muffler so it cuts out the bends and flanges so airflow should be okay even if it does have the restriction.

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