Exhaust system

[Morton]

2 yrs ago I replaced the entire rear muffler that was damaged on a rock & torn open with some piping on my GU, at the time the pipe made to fit cost $60, today I took that off to fit another muffler on (second hand) & out of curiosty started the thing up without anything on the back section, there is no change in noise, not louder at all, why the hell is the muffler there? I was quoted some ungodly amount 2 yrs ago to replace the last section hence the section of pipe for $60, is it needed for back pressure, I cant for the life of me imagin that being the case, it is a 3L diesel

[threedogs]

Lots of turbo diesel 4x4 run straight through systems ,back pressure must be for non turbo and petrol maybe.
But can't have them too loud these days. Exhaust prices are up there around $1000 and up for some

[Morton]

true & this is the reason I swapped the rear section out for a length of pipe, absolutely no change in the note or the noise coming out of the car, I fitted the pipe back in as I would probably only damage the muffler anyways

[threedogs]

keep an eye on your boost and EGTs, they maybe affected by exhaust change

[mudski]

keep an eye on your boost and EGTs, they maybe affected by exhaust change

Funny about this. Everyone says that, but when I went from stock to 3inch Redback, boost and EGT's did not change at all. As for back pressure. You don't see race cars, even turbo charged one using mufflers, the quicker the gas gets out of the exhaust the better the engine will flow. IMO, back pressure is an old wifes tale.

[Winnie]

Funny about this. Everyone says that, but when I went from stock to 3inch Redback, boost and EGT's did not change at all. As for back pressure. You don't see race cars, even turbo charged one using mufflers, the quicker the gas gets out of the exhaust the better the engine will flow. IMO, back pressure is an old wifes tale.

Back pressure is necessary for sure. Not in the form of mufflers but say for example if you have no exhaust at all your car will run like absolute crap

[BigRAWesty]

Back pressure is necessary for sure. Not in the form of mufflers but say for example if you have no exhaust at all your car will run like absolute crap

But this is a tuning issue. Engines are tuned to run with shout to comply with noise and emissions controls. The easier an engine can breath the better they preform as the expel old gasses and draw new fresh gasses easier..

As for mufflers, well it depends on if its turbo or not? If its turbo drop all of your mufflers off and enjoy earlier boost and a bit more power..
If its a NA, you'll need some mufflers to kill the drone but you can still increase power by allowing it to breath with high flow mufflers..

Kallen Westbrook
Owner of
Westy's Accessories

[threedogs]

Don't too short an exhaust burn out valves on petrol, bear in mind I've just taken a handfull of meds, could kick in anytime ,might have already who knows, who cares yeah har , waffle, waffle ,waffle
Mudski a race car is designed to accept a straight through 3-4" system, talking here about changing from std to infinity and beyond ok that was the meds'
Your 4x4 must have shown some type of change with exhaust change, and agree 100% the quicker you get out the air the better, but gotta get it in as quick to suit ie match

[mudski]

What did you wash your meds down with tonight TD? I washed mine down last night with a glass of red. Man I slept good. Felt alright this morning too.

[Alitis007]

You need back pressure for low to mid range torque unless your motor sits at high rpm ie drag car so the air going out is the same speed going in. Your exhaust size meeds to match your motor capacity or driving style, on my rotary i have a single 3" turbo back to the hollowed out cat then it splits to twin 2.5" pipes thats tuned length that go into a pair of Varex mufflers (they are adjustable) when the mufflers are open (no back pressure) its gutless down low up untill 3500rpm and the turbo hits boost and it takes off, but when they're shut (back pressure) from idle to 4,000rpm it flys and then hits a brick wall. Thats when you feel the motor start to struggle to push the air out! ImageUploadedByTapatalk1358595717.668799.jpg this is my system before i made the turbo to cat section!