Outer Limits 4x4 Board

g'day all

i was just thinking why not put a high temp buterfly valve and a tee section before the cat. so when you want it you can bypass the cat and the rest of the restrictive part of the exaust.

you couldn't do this on road but, off road it would surely help people who have under powered motors...thats all us right?

i think some of the supercars use this, 360, 430, vantage, and so on but it's an electrionic activation where as this would be manual.

Matt

it's illegal like you said, but lots of people already do this for the 'track'

Its legal if you dont use it onroad, and you cant activate it from inside the cabin. Ie to be legal you should have to get out, lift the hood and flick switch or whatever.
You may also legally have to put a sticker on the dash reminding you to make sure its deactivated onroad.

These guys make it

Active Exhaust Systems Australia
0409 288 347
kevindavis@exemail.com.au


and you can get it here but it is not a cheap item.

http://www.hyperflow.com.au/techaes.htm

i thaught some one must have done it before, i knoe the hot rodders used a removable plate.

Matt

only the older cats are restrictive. the newer honey comb style are far less so. when i had the falcon tested it was 1psi difference across the entire system

For the cost of the bypass system you could go out and buy a big high flow cat.. then you have better performance on road and off.

HotFourOk wrote:For the cost of the bypass system you could go out and buy a big high flow cat.. then you have better performance on road and off.

you might be right there the right valve would be pritty pricy

Matt

I recall some years ago (probably close to 20), I saw something like this in an american performance mag. They were cast iron with a valve and cable that could actuate it from the cab. Obviously, mainly aimed at the street calss drag fraternity. They were'nt that horrendously expensive.

BUT

Why would you do it on a fourby? Doesn't unrestricting the exhaust to this degree unleash power at the high end of the rev range at hte expense of bottom end power? A drag racer can afford to make this sacrifice but when 4wd'ing, you mostly need bottom end grunt and want it at the lowest revs possible to keep speed to an absolute minimum.

If you want it loud, go for it, but if you were wheeling with me, by the end of the day I'd want to belt you in the head!!


Regards

bigbluemav wrote:
If you want it loud, go for it, but if you were wheeling with me, by the end of the day I'd want to belt you in the head!!


Regards

I think u will find that most 4x4ers will feel the same way

ok so it is easy to open the pipes - just like running open headers!

but what about the time it takes to change to colder plugs and larger jets, to now make the most of the open headers ( and also stop burning out valves and limit detonation)



But hey it'll sound cool!

at least untill someone tells you to "SHUT THAT F**KEN THING UP!!!!"