Dual 2.25" exhaust too small for 450hp?
11-07-2004, 05:33 PM
#22
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And I know a guy that ran right over 900rwhp with a factory 75mm throttle body (F/I)...The ability isn't in question here. Hell, you could probably reap 600rw F/I pwr through a single 2" pipe, but it'd be a restriction to say in the least...
11-08-2004, 11:39 PM
#24
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Owned? Yeah... 
Since some of you geniuses pay $1300+ for the 20 or so rw you get from a FAST system, that's a damn big difference for what such a simple decision costs. Even though you're talking about an open single 3" system...If you're laying down 600rw through a single 3" pipe, chances are good there's a good bit of hp to be made there with a larger dual system. There's most definitely a fair amount of torque left on the table-especially under the curve. If this was all false info., I wouldn't have gained a thing stepping up from a 2.5" to a 3" dual system. Absolutely necessary? Of corse not, but the simple decision before paying for all the tubing was worth around 8rwhp and 11rwtq (N/A 346).
With a huge positive split in cam duration, sure, 'WAY too big' could be the case. It's all about system requirements...
Since some of you geniuses pay $1300+ for the 20 or so rw you get from a FAST system, that's a damn big difference for what such a simple decision costs. Even though you're talking about an open single 3" system...If you're laying down 600rw through a single 3" pipe, chances are good there's a good bit of hp to be made there with a larger dual system. There's most definitely a fair amount of torque left on the table-especially under the curve. If this was all false info., I wouldn't have gained a thing stepping up from a 2.5" to a 3" dual system. Absolutely necessary? Of corse not, but the simple decision before paying for all the tubing was worth around 8rwhp and 11rwtq (N/A 346).With a huge positive split in cam duration, sure, 'WAY too big' could be the case. It's all about system requirements...
Last edited by NoseUp; 11-08-2004 at 11:45 PM.
11-14-2004, 08:06 PM
#26
Originally Posted by NoseUp
Owned? Yeah... Since some of you geniuses pay $1300+ for the 20 or so rw you get from a FAST system, that's a damn big difference for what such a simple decision costs. Even though you're talking about an open single 3" system...If you're laying down 600rw through a single 3" pipe, chances are good there's a good bit of hp to be made there with a larger dual system. There's most definitely a fair amount of torque left on the table-especially under the curve. If this was all false info., I wouldn't have gained a thing stepping up from a 2.5" to a 3" dual system. Absolutely necessary? Of corse not, but the simple decision before paying for all the tubing was worth around 8rwhp and 11rwtq (N/A 346).
With a huge positive split in cam duration, sure, 'WAY too big' could be the case. It's all about system requirements...
Since some of you geniuses pay $1300+ for the 20 or so rw you get from a FAST system, that's a damn big difference for what such a simple decision costs. Even though you're talking about an open single 3" system...If you're laying down 600rw through a single 3" pipe, chances are good there's a good bit of hp to be made there with a larger dual system. There's most definitely a fair amount of torque left on the table-especially under the curve. If this was all false info., I wouldn't have gained a thing stepping up from a 2.5" to a 3" dual system. Absolutely necessary? Of corse not, but the simple decision before paying for all the tubing was worth around 8rwhp and 11rwtq (N/A 346).With a huge positive split in cam duration, sure, 'WAY too big' could be the case. It's all about system requirements...
01-29-2005, 10:07 AM
#27
Originally Posted by DMNSPD
So if i'm reading this right, you're saying 2.5 is all you'll need for a bolt on/cam 346?
01-29-2005, 02:53 PM
#28
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The general consensus among the people that actually know is that LT's with 2.5" X piped TD's is enough for 450rwhp. After that, it'll start to become a restriction where 3" will free up more hp AND torque. One of the people who's said this before is Lane on here, and I'm pretty sure his claims are valid. 
On a bolt on car I would guess a 3" TD like the one from TSP would make no more useable power than a 2.5" kit. So IMO, I would stick with 2.5 up to the point of heads/cam on the stock bottom end. I'd rather have the little extra ground clearance than maybe 5hp at 6000 rpm. But once you beef up the bottom end to support bigger heads and cam and or boost, you'll need bigger.
Jason
On a bolt on car I would guess a 3" TD like the one from TSP would make no more useable power than a 2.5" kit. So IMO, I would stick with 2.5 up to the point of heads/cam on the stock bottom end. I'd rather have the little extra ground clearance than maybe 5hp at 6000 rpm. But once you beef up the bottom end to support bigger heads and cam and or boost, you'll need bigger.Jason
