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whats the true answer (cutout question)

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Old 09-04-2006, 10:11 AM
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Default whats the true answer (cutout question)

i have done many searches but cant find the answer. what gain range does a open i pipe cutout gain on a otherwise stock car? the only numbers i seem to find is the gains on aftermarket VS cutouts
Old 09-04-2006, 10:12 AM
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i heard around 5whp, may be a little more.
Old 09-04-2006, 10:16 AM
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By-passing the stock muffler will allow better exhaust flow. This means more power. I would think in reality you would be looking at ~5-8rwhp at the most on a stock car. A modified car is a different ball game though. A good catback will flow as well as the piping so a cutout is pretty pointless on the correct setup. Stock piping is a restriction at 2.5", the cutout can not by-pass this.

If you plan on a decent catback or duals, a cut-out becomes quite redundant as a performance mod, although they can be quite good as a volume control device if you want a more stealthy everyday exhaust.
Old 09-04-2006, 10:37 AM
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thats exactlly why i got mine. im just wondering what the gains are when i open the cutout and if there is any loss of tq seeing that i still have the stock y-pipe and cats
Old 09-04-2006, 05:43 PM
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Originally Posted by 300bhp/ton
By-passing the stock muffler will allow better exhaust flow. This means more power. I would think in reality you would be looking at ~5-8rwhp at the most on a stock car. A modified car is a different ball game though. A good catback will flow as well as the piping so a cutout is pretty pointless on the correct setup. Stock piping is a restriction at 2.5", the cutout can not by-pass this.

If you plan on a decent catback or duals, a cut-out becomes quite redundant as a performance mod, although they can be quite good as a volume control device if you want a more stealthy everyday exhaust.
Hate to sound negative, but you couldnt be more wrong. People have gained 20+rwhp OVER the 4" mufflex setups with a cut-out added in the i-pipe. Regardless of how well a muffler flows, a cutout will always be better because it BY-PASSES IT. Don't believe it ? Do a search.
Old 09-04-2006, 05:56 PM
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A cutout alone is good for at least 100hp worth of High Sound Levels. HEHE. Yeah, I should be able to get an extra 15-20whp over my flowmaster with my cutout.
Old 09-04-2006, 06:07 PM
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Originally Posted by lilbuddy1587
Hate to sound negative, but you couldnt be more wrong. People have gained 20+rwhp OVER the 4" mufflex setups with a cut-out added in the i-pipe. Regardless of how well a muffler flows, a cutout will always be better because it BY-PASSES IT. Don't believe it ? Do a search.
Couldnt agree more!
Old 09-04-2006, 07:13 PM
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gained 13rwhp with my flowtech over the stock muffler
Old 09-05-2006, 02:22 AM
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Originally Posted by lilbuddy1587
Hate to sound negative, but you couldnt be more wrong. People have gained 20+rwhp OVER the 4" mufflex setups with a cut-out added in the i-pipe. Regardless of how well a muffler flows, a cutout will always be better because it BY-PASSES IT. Don't believe it ? Do a search.
Well considering the mufflex muffler is known not to flow too well it's hardly surprising. A good straight thru bullet style muffler is a different matter though.

Why not try a little research yourself. The sticky on induction/exhaust would be a good place to start, try post 13 onwards by David Vizard.

You also need to remember that on most setups a cutout will affect the exhaust pressure wave, this more likely the cause of gain on some setups as opposed to exhaust flow.

Also ther more highly tuned a vehicle is (i.e. HP level) the more affect it will likely have.




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