 Exhaust Size |
 Apr 7, 2004 - 8:46 AM
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 Enthusiast  Joined Jan 22, '04 From WA, Australia Currently Offline Reputation: 1 (100%)  |
I know I;'ve had a few posts about this before
 but yeah i'm finally getting it done, just making sure of some last minute things (big things), I'm getting a 2.5" cat back and I've had the celi checked that it will all fit, but will 2.5" give me less back pressure, enough to give a power loss? i need ideas fast 
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Apr 7, 2004 - 8:30 PM
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 Enthusiast Joined Aug 29, '02 From Dallas, Tx Currently Offline Reputation: 0 (0%) |
You're reading a little too much into it (or taking a little too much from it  ). I shouldn't have quoted the last part, its not totally correct. If you read on in the thread you'll find this guy (who is also right):
On a car with one cylinder bank (I4, I6) a single exhaust is always the way to go. On a car with multiple banks, packaging and cylinder firing order usualy dictate that a dual exhaust is better. In the case of the celica the 'best; power (most torque and best driveability, aka, fastest car) will be found with a well designed 4-2-1 header into a single exhaust. An extensive dyno session would be required to find the optimal length and diameter of the exhaust but it will be somewhere in the 2.25-2.75 range for 99% of street cars (our cars).
I think you're thinking about it wrong. Think of the exhaust flow as a single column of moving air. That column of air has inertia. That inertia can create negative pressure behind the moving column. That negative (relative) pressure creates the scavenging effect. There is no 'where' of the scavenging. It happens everywhere in the exhaust. The end goal is to get the exhaust out of the cylinders as quickly as possible (and as completely as possible, some exhaust always remains in the cylinders during each exhaust stroke, the less the better). Its a really hard concept for me to explain. Am I making sense? |
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Posts in this topic
ShadowFX Exhaust Size Apr 7, 2004 - 8:46 AM
playr158 i don't think 2.5" should hurt your power... Apr 7, 2004 - 9:34 AM ShadowFX okay thanks! does anyone have 2.5" on the... Apr 7, 2004 - 9:35 AM Supersprynt Well yeah u'll have less back pressure, but th... Apr 7, 2004 - 11:06 AM ghostdog assuming your SX is the 1.8l 7afe, I wouldn't ... Apr 7, 2004 - 11:27 AM Supersprynt I have a 3'' catback.
Stock ST185 exhaust... Apr 7, 2004 - 12:15 PM SpedToe169 2.5" should be just fine. Almost perfect for... Apr 7, 2004 - 5:35 PM shid After reading that- what you're saying is that... Apr 7, 2004 - 7:11 PM shid You are speedtoe, thanks to my HS and college phys... Apr 7, 2004 - 9:19 PM
ShadowFX QUOTE (gh0st_d0g @ Apr 7, 2004 - 4:27 PM) assuming... Apr 8, 2004 - 4:34 AM |
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