Exhaust sizes
09-10-2003, 03:04 PM
#1
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Exhaust sizes
The stock exhaust system had 2.25 coming off the manifold, then it goes into the single pipe, what size is this? Someone told me it's 3".
I have older SB manifolds on my LT1 swap, they're 2". Anyone run 2" full dual exhaust (like in a swap)? I don't know if this is too much of a restriction, an exhaust place told me that the way I have it now (changing to 2.5" after the engine) doesn't do anything for the engine (velocity), it only makes it like a megaphone, and I'm trying to find the quietest mufflers. Would it have any effect if I have 2" true duals, then change to 2.25" duals after the engine?
I have older SB manifolds on my LT1 swap, they're 2". Anyone run 2" full dual exhaust (like in a swap)? I don't know if this is too much of a restriction, an exhaust place told me that the way I have it now (changing to 2.5" after the engine) doesn't do anything for the engine (velocity), it only makes it like a megaphone, and I'm trying to find the quietest mufflers. Would it have any effect if I have 2" true duals, then change to 2.25" duals after the engine?
09-10-2003, 03:30 PM
#3
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I have to clear steering, I tried all kinds of headers but I only have about 2.5" of space before it gets to the steering, and headers come straight out and then make a bend which interfered with it. Even the original LT1 manifolds wouldn't work, so I'm using older SBC manifolds.
09-10-2003, 03:53 PM
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Ok, I talked with Flowmaster and here is what they say. 2" Pipe will handle about 250 HP w/ dual exhaust on street driven vehicles. Changing to a larger diameter further back in the system only makes it louder, slows down the exhaust but doesn't help the engine performance. They say I'll have monster low end torque though in the lower RPM range, so I'll leave it all 2" since I won't be racing, just want good street performance.
Just some info about pipe diameters...
Just some info about pipe diameters...
09-10-2003, 04:44 PM
#5
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Re: Exhaust sizes
Originally posted by kevmor99
The stock exhaust system had 2.25 coming off the manifold, then it goes into the single pipe, what size is this? Someone told me it's 3".
I have older SB manifolds on my LT1 swap, they're 2". Anyone run 2" full dual exhaust (like in a swap)? I don't know if this is too much of a restriction, an exhaust place told me that the way I have it now (changing to 2.5" after the engine) doesn't do anything for the engine (velocity), it only makes it like a megaphone, and I'm trying to find the quietest mufflers. Would it have any effect if I have 2" true duals, then change to 2.25" duals after the engine?
The stock exhaust system had 2.25 coming off the manifold, then it goes into the single pipe, what size is this? Someone told me it's 3".
I have older SB manifolds on my LT1 swap, they're 2". Anyone run 2" full dual exhaust (like in a swap)? I don't know if this is too much of a restriction, an exhaust place told me that the way I have it now (changing to 2.5" after the engine) doesn't do anything for the engine (velocity), it only makes it like a megaphone, and I'm trying to find the quietest mufflers. Would it have any effect if I have 2" true duals, then change to 2.25" duals after the engine?
09-10-2003, 07:48 PM
#6
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Originally posted by kevmor99
Ok, I talked with Flowmaster and here is what they say. 2" Pipe will handle about 250 HP w/ dual exhaust on street driven vehicles. Changing to a larger diameter further back in the system only makes it louder, slows down the exhaust but doesn't help the engine performance. They say I'll have monster low end torque though in the lower RPM range, so I'll leave it all 2" since I won't be racing, just want good street performance.
Just some info about pipe diameters...
Ok, I talked with Flowmaster and here is what they say. 2" Pipe will handle about 250 HP w/ dual exhaust on street driven vehicles. Changing to a larger diameter further back in the system only makes it louder, slows down the exhaust but doesn't help the engine performance. They say I'll have monster low end torque though in the lower RPM range, so I'll leave it all 2" since I won't be racing, just want good street performance.
Just some info about pipe diameters...
09-10-2003, 07:55 PM
#7
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Flowmaster said 250hp for two 2" dual (no Y) pipes for street driven (This is probably if you don't spend most your time near redline, on their website it says 2" is good for 100hp per pipe, 2.25 160/pipe, 2.5" 200/pipe) but he seemed to think for a daily driver it would be ok. Maybe the more torque at lower rpm will make it more fun on the street even w/ the loss of higher rpm power 
I don't know, I'll see how it turns out.
With the Y pipe on fbody's it's different though with them going into one. I would think the one pipe would need to be the size of both the front pipes in order to keep it the same, but maybe a smaller single pipe helps as the exhaust speeds up?
I don't know, I'll see how it turns out.With the Y pipe on fbody's it's different though with them going into one. I would think the one pipe would need to be the size of both the front pipes in order to keep it the same, but maybe a smaller single pipe helps as the exhaust speeds up?
09-10-2003, 08:47 PM
#10
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Originally posted by kevmor99
Flowmaster said 250hp for two 2" dual (no Y) pipes for street driven (This is probably if you don't spend most your time near redline, on their website it says 2" is good for 100hp per pipe, 2.25 160/pipe, 2.5" 200/pipe) but he seemed to think for a daily driver it would be ok. Maybe the more torque at lower rpm will make it more fun on the street even w/ the loss of higher rpm power I don't know, I'll see how it turns out.
With the Y pipe on fbody's it's different though with them going into one. I would think the one pipe would need to be the size of both the front pipes in order to keep it the same, but maybe a smaller single pipe helps as the exhaust speeds up?
Flowmaster said 250hp for two 2" dual (no Y) pipes for street driven (This is probably if you don't spend most your time near redline, on their website it says 2" is good for 100hp per pipe, 2.25 160/pipe, 2.5" 200/pipe) but he seemed to think for a daily driver it would be ok. Maybe the more torque at lower rpm will make it more fun on the street even w/ the loss of higher rpm power
I don't know, I'll see how it turns out.With the Y pipe on fbody's it's different though with them going into one. I would think the one pipe would need to be the size of both the front pipes in order to keep it the same, but maybe a smaller single pipe helps as the exhaust speeds up?
09-11-2003, 05:05 AM
#15
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Originally posted by kevmor99
Yeah I tried block huggers, do you mean the stock LT1 manifolds? Mine are really short so maybe that'll help some.
Yeah I tried block huggers, do you mean the stock LT1 manifolds? Mine are really short so maybe that'll help some.
It won't be cheap, but probably not much more than some of these header kits out there for the f-body (can we say FLP's at $1300 a set
)
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