REPLACE CATALYTIC COVERTER

[peregrine]

Hi While the following will probably apply wholly or in part to all other models. My car is a 1999 V6 Vienta with approx 175000 Ks on the clock so considering changing Cat: As I believe this to be the biggest restriction in the exhaust system I am considering fitting a larger say 2.5 or 3 inch inlet, outlet Cat: either hi flow or normal, preferably mettle core. As a change is needed, should be a cheap way of reducing back pressure to gain a little better fuel economy and maybe a smidgen of power without any noticeable increase in exhaust noise. Any constructive suggestions or help appreciated. I expect cost to be around $200 to $300 approx.

[David the Viking]

The biggest restriction is the y pipe joint just before the cat converter on the 1mz engines. It would be best to change/modify both to get any sort of benefit and even then it will probably be only very small.

[peregrine]

[quote name='SupaTouring'

Thanks for your swift response, however I'm quite happy with the existing setup although it would be nice to get rid of the catastrophe you mention. My reason for considering a swap of the Cat is due to the existing Cat I feel having reached its used by date, after over 10 years and 175,000+Ks. So I feel if it has to be replaced, why not take advantage of an upgrade at very little extra cost,if its worthwhile. Might get a quote on that "Y" replacement. You've got me thinking, thanks again.

Edited March 7, 2010 by peregrine

[Rocketeer1]

Get it looked at. You can certainly 'knock' it and listen for anything loose as a first bushmans check, but then most muffler shops will have a laser thermometer and can tell within a few minutes if it is still effective. Something I am planning on doing with mine soon....

[topgun]

Hi While the following will probably apply wholly or in part to all other models. My car is a 1999 V6 Vienta with approx 175000 Ks on the clock so considering changing Cat: As I believe this to be the biggest restriction in the exhaust system I am considering fitting a larger say 2.5 or 3 inch inlet, outlet Cat: either hi flow or normal, preferably mettle core. As a change is needed, should be a cheap way of reducing back pressure to gain a little better fuel economy and maybe a smidgen of power without any noticeable increase in exhaust noise. Any constructive suggestions or help appreciated. I expect cost to be around $200 to $300 approx.

if you need to replace it, replace it with the same cat, i wouldnt modify it

[Whip Cracker]

If the cat's gone, either replace it with the same thing, or go a high-flow cat. Up to you at the end of the day.

SupaTouring's right as well - the Y pipe is the most restrictive piece of the exhaust on the 1MZs. Heaps of people in the States and a few here in Australia have changed theirs around with great results.

[STYLSH]

It isnt that much to get a custom y pipe made up. Mine was $220 which is actually less than the price to replace the stock cat with a high flow metal cat. While mine is the properly tuned to the same length, it is still better than what the stock setup is.

[peregrine]

Hi thanks for the replies all appreciated and helpful.