DIY - Custom Exhaust
05-25-2009, 09:25 PM
#32
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The car feels stronger in the higher RPMs, but I'm 99% sure I lost some low end torque. I'm going to add a high-flow catalytic converter in place of the one we removed to restore the torque.
Side note: Back in 05 we did a new 2005 eclipse for mitsu north america (sema). Dyno'd each part we made starting with a new car baseline, then after each mod. Started with headers +16HP (mostly just by removing pre-cats), cai (+8hp), y-pipe (+5hp).. We were so close to 300 (286hp). Figured we had it licked. Last up .. free-flowing exhaust, no cat ... +4 hp at peak, lost -8hp all the way across the band, -18-25 torque lost across the band. Car was acting funny. Back to the shop, tossed a high-flow cat on there. Re-dyno'd next day .. BAM. 294hp at the wheels. Food for thought.
Side note: Back in 05 we did a new 2005 eclipse for mitsu north america (sema). Dyno'd each part we made starting with a new car baseline, then after each mod. Started with headers +16HP (mostly just by removing pre-cats), cai (+8hp), y-pipe (+5hp).. We were so close to 300 (286hp). Figured we had it licked. Last up .. free-flowing exhaust, no cat ... +4 hp at peak, lost -8hp all the way across the band, -18-25 torque lost across the band. Car was acting funny. Back to the shop, tossed a high-flow cat on there. Re-dyno'd next day .. BAM. 294hp at the wheels. Food for thought.
05-26-2009, 07:07 AM
#33
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My Ride: BMW 535xi
Model Year: 2008
Originally Posted by crmb' post='890152' date='May 26 2009, 12:25 AM
The car feels stronger in the higher RPMs, but I'm 99% sure I lost some low end torque. I'm going to add a high-flow catalytic converter in place of the one we removed to restore the torque.
Side note: Back in 05 we did a new 2005 eclipse for mitsu north america (sema). Dyno'd each part we made starting with a new car baseline, then after each mod. Started with headers +16HP (mostly just by removing pre-cats), cai (+8hp), y-pipe (+5hp).. We were so close to 300 (286hp). Figured we had it licked. Last up .. free-flowing exhaust, no cat ... +4 hp at peak, lost -8hp all the way across the band, -18-25 torque lost across the band. Car was acting funny. Back to the shop, tossed a high-flow cat on there. Re-dyno'd next day .. BAM. 294hp at the wheels. Food for thought.
Side note: Back in 05 we did a new 2005 eclipse for mitsu north america (sema). Dyno'd each part we made starting with a new car baseline, then after each mod. Started with headers +16HP (mostly just by removing pre-cats), cai (+8hp), y-pipe (+5hp).. We were so close to 300 (286hp). Figured we had it licked. Last up .. free-flowing exhaust, no cat ... +4 hp at peak, lost -8hp all the way across the band, -18-25 torque lost across the band. Car was acting funny. Back to the shop, tossed a high-flow cat on there. Re-dyno'd next day .. BAM. 294hp at the wheels. Food for thought.
05-26-2009, 08:36 AM
#34
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Consider a design engineers situation - they have to balance cost, manufacturability, emissions, and performance. It's much easier to optimize just one then to optimize all of them.
Originally Posted by juris335' post='890450' date='May 26 2009, 07:07 AM
Very tough odds trying to beat millions of dollars of engineering...
05-28-2009, 11:06 AM
#38
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Revision 2 is done. Sound is impressive. Performance is there (now). That cat helped a LOT. We'll probably drive it around for awhile and decide if we want to change anything.
*EDIT: We're going to get a few vids of it later w/ sound clip. *
*EDIT: We're going to get a few vids of it later w/ sound clip. *
05-28-2009, 12:45 PM
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My Ride: 2004 SMG 545i
silver grey metallic / bamboo anthracite / black leather
CPO
sport package
premium sound
park distance control
cold weather package
Originally Posted by lorinzo' post='892455' date='May 27 2009, 08:41 PM
Impressive!
Looks intimidating.
Post some videos when you're done. I'm curious to see what it sounds like.