exhaust manifold

[stevej 0]

Hi

 

my exhuast manifold is cracking and heat sheild on down pipe is rusting and rattling on my 2l 16 v. i was thinking of upgrading to a stainless steel manifold and was wondering what any other valver guys would recommend. i had a look at the wiki and read that TSR manifold was a popular choice. from what i understand this removes the cat as well, although a boss for the lamba probe is welded to pipe so it can be retained. i was under the impression that as my valver is 1994 that the cat would need to retained for emissions etc ??. sorry but bit confused. thoughts and any other recommendations appreciated. :?

 

cheers

[ProdigalSon 1]

Hi Steve,

 

Was thinking about something similar for my '92 G60 as I thought I had a dodgy cat - from reading elsewhere on the Forum, it appears that it is illegal for a manufacturer to build a post-August 1992 car without a cat, but not for an owner to de-cat their car. As long as it passes the emissions tests without a cat (and most will), then you're fine :)

 

But don't take my word for it, ask your friendly neighbourhood MOT technician or do a search on here for who originally said that! :wink:

[Crasher 3]

It should be there for the MOT and I can't see it passing without one. Personally I really don't like tubular exhaust manifolds for many reasons. The manifold used on the KR and 9A is prone to cracking and finding a used one without at least some internal cracking is difficult. Fitting a tubular manifold and de-cat is unlikely to gain you more than 3 or 4 PS on a 9A in my experience.

[davidwort 0]

glad to see someone talking sense about manifold/downpipes

 

I'm pretty sure that the exagerated claims for 4 branches stem mainly from the 8v GTI days, the mk1 and 2's definately improved from the fitting of all in one manifolds and downpipes, I know for a fact that many of the GTI Engineering conversions showed 10bhp gain on the engine dyno (not a rolling road, a proper controlled engine dyno) but the 16v never really had much of a problem with the standard system (9A CAT excluded).

The VAG cast iron manifold doesn't harm to be internally cleaned up though.

[ProdigalSon 1]

I get the impression that MOT testers will probably be suspicious of a post-'92 car without a cat, and could make life awkward.

 

I'm not going to de-cat mine as the blowing was from a loose joint, not from the cat itself (and emissions from last MOT were spectacularly low thanks mainly to a new lambda probe).

 

IIRC, doesn't a 4-2-1 exhaust system spread the power band so that the torque is shallower and wider (rather than having a very 'peaky' response)? Looks like the PG, KR and 9A engines all have that arrangement (from vagcat.com), or are the drawings incorrect? I'm no expert, so enlighten me! :wink: :)

[stevej 0]

cheers for the info. certainly some stuff to think on :?

[dubcharger 0]

Flow aside, the stock mani being cast it actually draws the gas out of the alloy head as it holds the heat better than s/steel, get a new one and port it 8)