Guys,

My Manifold and Cat are knackered, I would like to replace with uprated items eg stainless+ sports cat. I was tempted to decat and get a Mill box to fool the Lambdas.
Any particular brands I should be looking for?
Thanks

My FRP had a full Milltek system but was very pricey, dont want to fork out that much as the ST170 is being replaced with a Cossie or FRS in the near future.

Any advice would be appreciated.

 

I thought the st170 manifold was meant be ok, it was just the cat that was restrictive??

Apparently if you go for sports cat you can have problems on emissions test unless you really warm car up first.

From wot iv herd with focus's and other fords the milteks are meant be quite good. Best bet is just look out for 2nd hand ones as they will be jus as gud but at fraction of price. Iv managed to get all my parts for my car that way and all together they prob cost same price as buyin one item new lol

Matt

 

The ST170 standard 4-2-1 Manifold is stainless steel and very efficient, there is no need to change this its very good as it is. Miltek is the best though but as you say expensive. I would go for a CFM Sports cat if i was you but dont expect it to pass an emmisions test. Dont bother with a complete decat this will make the cat sound awful and VERY loud

 

The ST170 manifold is NOT stainless steel - it's mild steel but it's a Cosworth designed item and is VERY good so you will gain nothing but pub bragging rights by changing it. It's the upgrade of choice for pretty much all 4 pot Zetec-E engines.

The Milltek sports cat/decat and flexi are meant to be good upgrades but there are questions about one of the mounting brackets on the flexi (I think) and, as you say, they are very pricey (Will Pedley was selling one recently, he might still have them for sale).

For reference the ONLY bit of an ST170 standard exhaust system that is made of stainless steel is the tailpipe tip.

 

Never heard of having to change a ST170 manifold as said before they are designed by Cosworth to get the very best out of the engine. The olny thing i have heard but don't know if it was true was that if yoiu heat wrap them then they are more likely to fail ????

 

yea iv got the st170 manifold/cat/flexi on my 1.8 and made a noticeable difference!!

I was lookin at the decat/flexi combo from miltek and wondered if it made much difference over std cat/flexi. Was also interested in the 200 cell sports cats, but not sure of any performance gains (and bin told u av really work car up for it to pass emissions test). The miltek combo you were on about has bin sold now a think. I wud be interested no peoples opinions on gains from decat/flexi combo and sports cat over stock bits?

Thanks

 

Thanks for the replies, didnt make myself clear, the manifold is knackered split, so your saying replace with a standard item?

The cat is breaking up inside and rattles to high heaven at 2k revs, its not the heat shield because ive taken it off already. If you give the Cat a tap from under the car the noise can be emulated. As yet no warning lights on the dash, ive got paperwork regarding the changing of at least one lambda sensor by a previous owner.

As for passing MOT's you just need a sympathetic and knowledgable tester, they will rev the car to 3.5k for the emissions test instead of 2.5k. Did that with the FRP which is also prone to failing MOTs on emissions.

 

I would replace with standard manifold mate just waistin your hard earned on anything less. Are you sure it's the cat itself that's rattling and not the heat shield? Remember the heat shields are an issue with every ST170, i took mine off and threw it to fuck. Check the heat shield and the bracket at the back of the block because this fucker breaks aswell.

 

Its the cat mate, took the heatshield off first because thats what I thought the rattle was, spent ages farting around until I banged on the cat from under the car and it was breaking up inside. Think I will replace the manifold with standard as suggested.

Thanks