Rule of Exaust Set Up? Options

[jiranz5]

1210kg if I'm right?? Yes I suppose your right, it's on the heavier range of lightweight vehicles over here tho, and I bought one because I do around 600 miles traveling and needed a "heavier" car for better cruising. And It does just that, now I'm looking at ways of overtaking slow traffic a bit faster, i.e. get the cat taken out. As for the power thing...the japs are VERY heavy on the environment thingy that their cats are like trying to blow through a winter grade duvet

[Valo666]

with my 5S i did 2.5" from front to back, with a 3" outlet. Didnt want any thing big or gaudy, plus it has a nice low tone sound.

yea i know my back end is rusty, i got that all sandblasted and undercoated again. But yea, i got some lil apc muffler its only a 2.5" inlet with a 3" tip, and its only 6inchs long. Its really small muffler, but its quiter than a crappy rice pipe.

[jiranz5]

Yea, that's almost what I'm gonna do with my 3s, although, I'll only use 2.25 inch pipe as I need that added back pressure for cruising over the mountain range twice a week. (again, as per TRD recommendations for my particular circumstance)

[Kwanza26]

Yea, that's almost what I'm gonna do with my 3s, although, I'll only use 2.25 inch pipe as I need that added back pressure for cruising over the mountain range twice a week. (again, as per TRD recommendations for my particular circumstance)

LOL... backpressure. Backpressure = BAD BAD BAD no matter what. Exhaust travels in pulses and faster pulses = more power. Backpressure is when those pulses get crammed together, which equals bad performance (clogged cat anyone?). Torque loss with exhausts is because when engine load is reduced from free flowing exhausts, the exhaust velocity also slows down (at lower rpms). However at higher rpms, the exhaust velocity can speed up FASTER and create more power... but too big of piping on a small engine HURTS performance because the engine cannot spit enough exhaust to fill the extra space and speed up the flow. Make sense?

This post has been edited by Kwanza26: Feb 13, 2006 - 1:01 AM

[jiranz5]

So basically, by increasing the pipe size I'll get more torque and power at higher rpm and by keeping the standard pipe i will have less hp but better low down torque? Part way there? So if I'm limited to traveling at 60 m/h over a 145 mile trip and my revs are sitting at the 3k mark, what size piping should I have to give me good economy but still maintain enough torque to make it over the range?

[Cutrara]

I still don't believe you can get a 10% increase by removing a cat. They aren't that inefficient. I'll believe it when I see a dyno graph.

[jiranz5]

haha, I don't think you've ever seen a Japanese cat before...they're clogged before they're even used. Performance increase is anywhere from 5-15% depending on the vehicle. I'll try and get some dyno readings for ya. otherwise you'll have to wait till I get my exhaust done (no idean when I'll be able to afford that!)