Originally Posted by Astral

stock exhaust fits into the car thru the passthru, can in the back seat:




Though I would not recommend this. I recommend sawing off the intermediate pipe (where that pipe joint is), it'll make it easier to take out the stock exhaust and you won't have to pop out the plastic exhaust shrouds. It'll also make it easier to package it in your trunk if you wish to keep it.

I gave my stock exhaust w/ 5K away for free. If you ever want to go back to stock, just find someone w/ a stock exhaust who wants yours, swap and you're good to go.

Originally Posted by Outkast187

the cats are usually the major heat source, an open exhaust isnt going to generate as much heat. If the exhaust coming out underneath the floor was 1800 degrees, the rotor housings would be 2400 degrees.....metal doesnt hold up for long at 1800 degrees.

Originally Posted by MazdaManiac

A bunch of things:

1) The CAT temp is computed by measuring the resistance across the rear O2 sensor's heater circuit. There is no separate sensor.
2) This computed value (via CANScan) is way to slow to be useful for anything.
3) You can't tune using EGT. EGT is used as a baseline reference after you already know the proper A/F for peak torque. I've already written extensively on the subject, so do a search.
4) Leaning out the A/Fs will increase EGT up to a point before they go down again and that point is way past 16:1.
5) Retarding timing or having unusually slow combustion will also increase EGTs to a point.

Vlad - your temps seem just a tad high (maybe 200°F), but every car is different (see point #3) and I don't know where your sensor is positioned.
Mine is right at the inlet to the turbo, which is 2" from the rear exhaust port and I see 1200° - 1300° in off-boost cruise and 1600° - 1700° under boost at the torque peak.

Originally Posted by rotarygod

With my custom exhaust sleeves on a 13B, the very first engine they ever went in had a T-04 on it. The turbine wheel was not inconel. It melted within a few minutes and folded the turbine blades over. The stock 13B exhaust sleeves expand to over double their area within the span of about 2". My sleeves hold the exhaust port shape and area constant and the header pipes are formed to match. They are smaller and higher velocity. I've seen temps of 2000*F with them.

Originally Posted by rotarygod

Right at the exhaust ports at full throttle you may see 1800*F but 2000*F isn't unheard of. The temps sensor on the cat says much less (around 1650*F or so) but there is a lot of heat lost in the exhaust system over a very short distance.

Originally Posted by TrochoidMagic

at least on my '07, the pipe can be separated from the muffler from just one easy turn to unlock the notch...

when has it stopped being that way?