Engine back-pressure

[Dagolith]

is the 5MEG tuned to a specific back-pressure, or is it just going to run better with less. because i was considering removing my catalytic converter and installing headers. but i want to know if it's just going to crap out if i do.

[Dave A.]

The stock exhaust system on the MKII is pretty restrictive, especially the muffler. You can gain a few HP by upgrading to an aftermarket catback system. Check with the chimp. He should be able to set you up with a good catback system.

[Dagolith]

crap so if i was to just take off some of the back pressure it wouldn't run properly?

[scorpmatt]

how do you plan on taking off the back pressure??

Just running a set of headers on these cars will start to deafen most. Some have found that the engines come alive with a 2.5" manifold/header back system installed. If your area requires a cat there are hi-flow cats availiable to allow for having a cat. If not, a straight thru system will not harm these engines that much. They can finally breathe. :)

check these out for available exhaust setups for our cars. :)

RabidChimp Performance Exhausts:
http://www.rabidchimp.com/mk2sup_exhaust.htm

Raptor Racing Exhuasts:
http://forums.celicasupra.com/showthread.php?t=37028

[Dagolith]

when you say "that much" do you mean that it will damage the engine slightly over a long period of time. I just wanna know if i will see better performance out of the engine without a cat.

Because as you probably know, some engines are tuned to operate with a specific back-pressure, i'm just wondering if the 5MEG is one of them.

[CarFreek]

I heard the Raptor system on Junkies car before he went turbo. I think he has 3", which is HUGE for a N/A 5m. The sound was INCREDIBLE at full throttle. Sounded like the bastard child of a Ferrari and an F-15 at takeoff. I can think of no long term Ill effects from opening up exhaust. I wouldnt worry about "Back Pressure". Toyota uses a manifold, so obviously didnt tune the exhaust past pipe sizing.

[Dagolith]

awesome thanks

[StanS]

Also, get a flow thru muffler and not a turbo muffler which is not flo-thru (marketing to fool the unwary.) wrapping the catback should also give some additional gain.