I want to have a go at building my own exhaust for my h20 v6 vitara from the headers back that flows better. While doing this i was thinking about a high flow cat to suit, I can get a catylitic converter off a brand new v8 commonwhore thats has done about 10k will this work in the same way?

What would be the most suitable diameter for this sized engine?

Ill be tig weldeing it using mandrel bends aswell.

cheers inbits

EDIT: power and quiet dont go together. and by upgrading the whole system and restricting it at the muffler you may as well not bother at all.

WTF?

Glass pack striaght through mufflers and heimholtz resonators work on absorbsion not restriction to lower noise levels. Can make a very quiet and effective exhaust system.

WTF?

Glass pack striaght through mufflers and heimholtz resonators work on absorbsion not restriction to lower noise levels. Can make a very quiet and effective exhaust system.

good im glad the glass pack on my ute is quiet not. Used to not be able to hear the thing before the straight through and headers were put in now its not super loud but it will set off alarms in carparks if reved.

sure you can make a nice system that isnt too loud but if you want better flow its going to be a bit noisier. and if you want everything you can get out of it its going to be loud.

noise does NOT equal power. well designed mufflers can quieten an exhaust while improving performance.

I want to have a go at building my own exhaust for my h20 v6 vitara from the headers back that flows better. While doing this i was thinking about a high flow cat to suit, I can get a catylitic converter off a brand new v8 commonwhore thats has done about 10k will this work in the same way?

What would be the most suitable diameter for this sized engine?

Ill be tig weldeing it using mandrel bends aswell.

cheers inbits

If you've ever heard a Highway Patrol Commo do a u-turn and floor it, you'll know this is true. All you'll hear is "Pffftt...."

If you've ever heard a Highway Patrol Commo do a u-turn and floor it, you'll know this is true. All you'll hear is "Pffftt...."

because the restriction type muffler on the hwy patrol cars are high tech. have you ever seen an Australian police car catch someone going really quick? No there are two reasons for this they arnt allowed to go really quick 140 is the limit and those hwy patrol cars are buckets of bolts.

There are three types of muffler in reality. the restrictive type which is used on most cars from factory, its cheap and nasty and works to keep the thing quiet but is rubbish for flow.

then there is the absorbing type like a glass pack straight through. much better for flow but louder than restrictive and louder than the third type

the third type is reflective and works on the principal of reflected sound waves cancelling like sound waves out problem is this is a complicated piece of physics and doesnt work for the whole range of sounds bouncing down an exhaust pipe as it has to be tuned to a certain range of frequencies, this makes them good for getting rid of drone and probably the best at killing the most noise they are still not as good performance wise as a straight through absorber.

Exactly, but people often think more noise = more power, and then go on to assume that therefore the noisier the better. That is not true. An excessively noisy vehicle usually points to an attention seeking plonker

so are ya gonna cross it over underneath to help with scavenging? or run both banks of cylinders down into one tail pipe? tuned length extractors and no bigger in diameter than 2 and a half inch id think too else you run into problems with the old backpressure vs velocity scenario.

and a couple of high flow mufflers at the back for a nice noise.

the biggest flow inhabiter in a standard exhaust system is the factory muffler.

and not exactly legal but grab a cat bash the center out and fit it like that highest flow cat you will ever get.

EDIT: power and quiet dont go together. and by upgrading the whole system and restricting it at the muffler you may as well not bother at all.

dont go 2 1/2 system you will regret it, you end up not having any low end but alot of top end and you get the wonderful sound of a crumydore

dont go 2 1/2 system you will regret it, you end up not having any low end but alot of top end and you get the wonderful sound of a crumydore

Do you know the brand of muffler and approx dimensions of it?

I was thinking about using 2 cats one for the left bank and one for the right then join into one after the transmission. Kind of hard to explain but illtake a pic and show how I plan to route it andget your opinions.

Thanks for that info a brand would be good. I measured standard vit one earlier tonight the inside diameter measures a touch under 50 mm about 48 so it already has 2 inch. I think I'll go 2.25 inch from the cat back and 2" from the headers to the cat.
I was thinking about using 2 cats one for the left bank and one for the right then join into one after the transmission. Kind of hard to explain but illtake a pic and show how I plan to route it andget your opinions.

Anyone who knocks the center out of a catylitic converter is a complete f*&k wit theres a reason they are on the car.

By noisy I meant I dont want a droning piece of shit that drives me crazy. I dont mind it having a nice note but when cruising on the highway etc I dont want to have to turn the radio up just to stop the exhaust pissing me off.

I think ill go down the path of a glass pack and a resonator and if its still to loud ill sort that out later. Whats a decent but cheapish brand of muffler