de-cating help!

[Diamond Hell]

my ED1 had one as standard

but it was a german car where it was legal from 1988

now removed with a 4 branch and a stainless system

Continental Europe got a lot of things we didn't get in the UK - Golf2 G60 GTI and G60 Syncro for example.  Normally on VW motors of that era there was a different, low-compression unit fitted for the cat version as unleaded was 2* not 4* so wasn't a 'performance' fuel.

As far as I am aware there were no UK market catted Golf2 models, Jetta2 might be different as I think it staggered on slightly longer than the Golf2.

The reason I'm asking is that it's possible either the OP is being strung along by a garage or he's seeing the first silencer box and presuming it's a cat.

If there IS a cat then it won't be as simple as just 'chopping it out' as it'll have a lambda sensor in the cat, which you can't just delete.

[jamie_pyrite]

Definately got a cat mate Even says on the reg. documents "1.6 TX CAT"

Underneath the car it goes downpipe>cat> long straight pipe > middle box > backbox.

So what would have to happen with the lambda if it had one? Would it still have a lambda probe with it being a carb? (pierburg 2e2)

[rubjonny]

cat was an option in the UK on MK2s, but very rarely fitted since as you can imagine it was very expensive and made the car slower.  I have seen one or 2 over the years but hardly common.

jamie is it definitly a bog std 2e2?  I've seen VW documents for a special conversion kit for the 2e2 which basically turns it into an SPI, supposedly to make it work with a cat.  I'm pretty sure all cars with a cat have a lambda but not 100% positive.  Easy to spot tho look for a metal thing with wires hangin out the zaust

'normal' 1.6 has a smaller diameter zaust to the 1.8 8v carb/gti models (16v/G60 is bigger still). Not sure if a larger diameter zaust would have been fitted to CAT models though.  If it helps 1.8 8v zaust is 2", 16v is 2.25". Not sure what 1.6 is, my wild guess is 1.75" 

[Diamond Hell]

Definately got a cat mate

I think we need pictures, please.  What you think is a cat could be a resonator box.

I'm still not convinced a)that it's a carb and b) that it's got a cat.

If it's a carb then it doesn't have the key feedback loop or the electronic control required to manage the mixture to stop it grenading the cat with excess fuel.

If it's got a cat then it won't be running a carb because a carb can't control the fueling and emissions effectively enough to protect the cat.

I stand waiting to be corrected, but I've never seen a cat on a carb engine in a manufacturer's pricebooks and I was a proper car anorak back when the car in question was manufactured.

[jamie_pyrite]

Thanks for the info you two, I'm taking the car to get the carb tuned tomorrow afternoon so I'll get some pics, etc. there. although I'm sure the garage will be able to tell me what I have! 


EDIT: According to some info I found, details of my engine/carb are:

Jetta 1.6 Cat. RF 86-92 Pierburg 28/30 2E2 32/34 DMTL

Found here: http://www.clubgti.com/forum/showthread.php?t=441

[sidecarphil]

metros had a cat with carb

the cat lasted about 1 year before it was chocolate inside

my car runs just as good without the lambda probe disconnected as it does with it connected

the 4 branch has a lambda boss welded in so i left it in (new)

but no cat and it is loads better through the gears and believe it or not better on fuel 

[Diamond Hell]

Without the cat of course your car runs better.  You've removed a major restriction in the exhaust!  Plus the cat might well be partially blocked after many years in service - my T4 actually span the cat round and was blowing it across the exit to the can - it took the AA man some time to figure that one out.

Although the car would run better without a knackered lambda connected.  It will likely use more fuel on part throttle as that's when the lambda is trimming the mixture.

This also means it's also going to be putting out rather more unburned hydrocarbon emissions.  A lambda does not damage performance if it is working correctly.

If the Jetta is a carb with a cat the best thing you can do is to cut it out - an 18 year old cat won't be doing performance any favours at all.

[danny_p]

that cat is dead anyway, cut it out ipe past it or just smash the insides out,  it wont be doing anything usefull anyway

[rubjonny]

etka doesnt offer much though it does say theres a different 2e2 upper half for models with retrofitted emmissions regulation, matches up to what i remember reading in that VW document a while ago.  EZ_Pete dug it out, I'll see if I can find it.
Once you get pics we can see if its a boggo 2e2 or if its something a little more special

[jamie_pyrite]

Well I took it to a garage today to get the carb tuned, said the cat is completely knackered which explains why the car isn't running too great. They're going to get rid of it and re-tune it next week.

I'll get some pictures of it on Sunday for you jonny