Exhaust Question - Toyota Nation Forum : Toyota Car and Truck Forums

clem · 11-11-2005, 10:09 AM

Hey what size exhaust should i go with i was sayin 3 inches and one of my friends was sayin 2.5 what do u guys think ? we dont have emissions laws or anything down here so what do u think i should do ?

chrwof8217 · 11-11-2005, 10:54 AM

Although it is not as important on turbo cars as it is NA, even turbo'd motors can suffer from too much exhaust flow (in my studies). If you are running near stock, go with the 2.5 inch. If you have mods that bring you over 300whp, deifnitely 3 inch. The reason for this is infact flow. If the pipe is too big, it can actually flow slower than a smaller pipe. When exhaust valves open and close...open and close....it causing pulsations in the air flow (thus the puff..puff.puff you feel when you walk by a tailpipe). Those pulsations have vacuum pressure between them. That vacuum pressure actually helps pull the exhaust gas out, creating higher flow. It's almost like sucking on a straw, you create vacuum pressure when you use a straw, thus drawing up the liquid. (kinda the same concept). Not sure how better to explain it, but get an exhaust that will help your current or near future application the most.