Quickest way to remove a cat I want to remove cut off from manifold and put...

Quickest way to remove a cat I want to remove cut off from manifold, and put downpipe there, with no welds (for the moment) but don't want warning light to come on.

This is for a special stage rally car no don't worry about it will fail MOT etc

On a 1.6 exhaust manifold is at the back of the engine

%d comments
  • That help?

  • Cars
  • Ha ha well its on a high air flow intake so yeh it does gain i presume.. ill post a pic of what u can see of mine Jake Harry Oatham

  • It's only gonna take in as much air as the map will allow so you could run it with no air intake and no exhaust, hypothetically (as it actually wouldn't run like that) it still wouldn't use more air.

    N/A engines take in the air they need, turbo engines have it rammed down their throats which is why they are far easier to tune, you can make it use more air by upping the boost.

    It's all a fad, the engine will only do the usual till you map it to do otherwise.

  • 1.4/1.6 exhaust manifold at the back.

    1.8/2.0/ST170/RS exhaust manifold at the front.

    That's for all mk1 Focus.

  • Brilliant :) cheers didn't know if it was a mani-cat or normal, does anyone know the dimensions? Like circumference of the downpipe? And how long it need to be to join the downpipe to the manifold?

  • I didn't have a clue either to be fair fella, had a quick Google search for dimension too but can't find anything

  • Same cheers anyways if anyone knows this Id really appreciate the information

  • Just changed mine to a 4-2-1 manifold and straight threw on a 2.0ltr :) no eml light on

  • Naturally aspirated rely on exhaust velocity not back pressur for power, the quicker the gas leaves the exhaust the more fresh mix it will pull from the intake giving a better volumetric efficiency. (Scavenging) Removing the cat will give gains, you will loose the gains if you increase the exhaust diameter. The more of a restriction in the exhaust will kill top end power but increase low end tourqe, if you go too large of a diameter exhaust it will lower power all round

  • Cars
  • I'm keeping it standard size, but thanks for the info you explained it better than most! Aha, I just need to circumference so I can see if the downpipe we got will fit or if I gotta order some