More pipe = less power?
More pipe = less power? Well as you can obviously see from my sig I have a borla cb, right now its wide open (because I dont' have any other plates) and I'm about to buy an electric motor from qtp for borla or just a cutout in the Y with a fully closed plate. Has anyone dyno and/or track tested against straight pipes vs. a cutout after the Y? I wouldn't normally stress over the very few extra hp I might get from it, but if I'm going to spend over $200 for less hp than what I would have with $30 I think I should be told 
TECH Addict
Joined: Jun 2005
Posts: 2,660
Likes: 14
From: England
read the sticky!!!!
It explains all you need to know about exhaust flow.
Basically, if there is a restriction in the exhaust system before the muffler, then adding a cut out after this point will net you ZERO hp gain, just one heck of a lot of noise.
If the muffler is the biggest restriction, then a cutout 'should' gain you some hp, but depending on how restrictive the muffler is, you will only see X gain.
Do you have CATS/LT's? What size Y pipe are you running, any other mods?
Personally, I'd say it's a waste of dollars, but without more info I can't be certain.
As a rule a cut is only any good if:
1. It's a stock exhaust.
2. The exhaust muffler is know to be restrctive that a cut out will by pass.
It explains all you need to know about exhaust flow.
Basically, if there is a restriction in the exhaust system before the muffler, then adding a cut out after this point will net you ZERO hp gain, just one heck of a lot of noise.
If the muffler is the biggest restriction, then a cutout 'should' gain you some hp, but depending on how restrictive the muffler is, you will only see X gain.
Do you have CATS/LT's? What size Y pipe are you running, any other mods?
Personally, I'd say it's a waste of dollars, but without more info I can't be certain.
As a rule a cut is only any good if:
1. It's a stock exhaust.
2. The exhaust muffler is know to be restrctive that a cut out will by pass.
Last edited by 300bhp/ton; Oct 14, 2005 at 07:22 AM.
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Joined: Apr 2003
Posts: 7,133
Likes: 2
From: Miami
Originally Posted by Silas2k
Well as you can obviously see from my sig I have a borla cb, right now its wide open (because I dont' have any other plates) and I'm about to buy an electric motor from qtp for borla or just a cutout in the Y with a fully closed plate. Has anyone dyno and/or track tested against straight pipes vs. a cutout after the Y? I wouldn't normally stress over the very few extra hp I might get from it, but if I'm going to spend over $200 for less hp than what I would have with $30 I think I should be told
Feels sluggish off the line, as the tq peak moves up in the rev range, yet the tq peak will improve. Down the 1/4, it makes for a faster setup, especially when leaving off the line at 3500+rpm.
I was wondering the same thing. I took out my cats and put in the FLP off-road pipes and run an open plate borla catback. The car is definately louder, but im not sure what kind of gains i got. Did i loose low end torque with the lack of back pressure and gain peak HP? or did it just make the car louder and thats it I just dont know
I just dont know 
