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Discussion Starter #1
Hi All,

I have now booked my car in to have a full system fitted at one of the Powerflow dealer networks this coming Friday.

I intend to have the catalytic converter removed from the car, although something the guy said on the phone kind of baffled me a bit....

I know my car is a 2.5 V6 CF2 model = I have no idea how many lambda sensors it has. The guy from Powerflow told me on the phone if I had four lambda sensors (and no cat), the engine management light would come on. If I had 2 lambda sensors (and no cat), I would be OK.

I intend to give the dealer a call on Tuesday to question this, but wondered what anyone on the forum thought of this. I know for a fact that Powerflow can make a decat' system - but another thing I thought of was if they could "rethread" the lambda probe back into the new exhaust system (which is before the cat). I know the Supersprint decat pipes are around £120, but are made from mild steel, so I don't know whether it would be easier to buy one of these (which already come threaded for a lambda probe) or just to get the Powerflow dealer to do it! Either way I don't want that bloody light back on again!

Any help appreciated!

Tony.
 

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You have one lambda sensor and one cat converter, the lambda sensor is in the main exhaust just in front of the cat. Get it decatted, there'll be no issues :thumbs:
 

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I have 2001 model CF2 2.5 V6 without the cat and no problems, dont know how you get on in the UK with the MOT though without running a cat.

Do you plan to swap the cat back in when its time for the MOT?
 

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I have 2001 model CF2 2.5 V6 without the cat and no problems, dont know how you get on in the UK with the MOT though without running a cat.

Do you plan to swap the cat back in when its time for the MOT?
Thats the way to go...I'm partway through it now (I welded a stainless pipe between the flanges on my old cat)
 

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just had a full stainless system fitted at mij performance, new downpipe with lambda probe, high flow sports cat so it'll go through mot without changing.... well impressed with noise and performance.
 

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Discussion Starter #6
You have one lambda sensor and one cat converter, the lambda sensor is in the main exhaust just in front of the cat. Get it decatted, there'll be no issues :thumbs:
OK thanks for the help. Do I just leave the probe unplugged then, or do I have to actually have it rethreaded back into the exhaust?

I wasn't sure if I had post cat sensors as well?

Cheers,
Tony.
 

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You dont have to do anything with the probe, it is located just after the exhaust manifolds and before the cat.

You just remove the cat and fit de-cat pipe or sports cat :)
 

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Fitted my de-cat this morning, it makes a lot more noise (and it was effing loud already) only done a couple of miles with it, it'll have to make a big performance difference for me to keep it.
The spanking new cat I took off is a much less substantial item than the original, I can even see daylight through it, couldn't do that with the old one, I felt the car went better with the new cat than before too, but only slightly.....
I'll keep you all posted.
 

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Mines not overly loud with decat and straight through centre piece Jason.. Maybe its something to do with the different backboxes we are using.

Top man eldo - you don't have any post-cat sensors, I assumed you meant a cat-back system you were getting but if you are getting new manifolds and downpipes you will need to get the lambda probe plugged into the downpipe. You can't leave it unplugged as the engine needs it for mixture control. Removing the cat doesn't affect its readings though so no worries.
 

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I didnt think mine was too loud but when I recently heard an Audi RS6 with fancy exhaust, I asked my wife if my car was as loud as that................... she said mine was louder :lol:

Must do a sound clip some time...........it does seem to pop on the overrun
 

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Discussion Starter #11
Mines not overly loud with decat and straight through centre piece Jason.. Maybe its something to do with the different backboxes we are using.

Top man eldo - you don't have any post-cat sensors, I assumed you meant a cat-back system you were getting but if you are getting new manifolds and downpipes you will need to get the lambda probe plugged into the downpipe. You can't leave it unplugged as the engine needs it for mixture control. Removing the cat doesn't affect its readings though so no worries.

Thanks for the help. To be honest, I am still a little unsure of the exhaust setup on this car! All I know is that I have a blow on the front, centre (after the cat) and the back box - hence a new exhaust is due! As far as I know, and someone please correct me if I am wrong, is that the exhaust setup goes as follows:

(1) Exhaust Manifolds
(2) Front Pipes
(3) Cat'
(4) Middle Section
(5) Rear Section

I have asked the Powerflow dealer if they can make everything except for the manifolds, and instead of using the original cat converter, if they could make a decat pipe. This is why I wondered where the lambda probe was. If it is before the cat, does this mean it is on the front pipes or actually on the cat-section itself?

Tony.
 

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I didnt think mine was too loud but when I recently heard an Audi RS6 with fancy exhaust, I asked my wife if my car was as loud as that................... she said mine was louder :lol:

Must do a sound clip some time...........it does seem to pop on the overrun
Yeah and mine now, and I've barely done another 2 miles:lol:
Sound clips'd be right on.
Mine is now a more "treble" sound rather than a bass boom, a little bit nastier (in an evil, Christine kinda way-not unpleasant nasty)
I will try and see my terminal speed on my usual 1/2mile private road I know what it did when I got it, and where it is now.... (I've got 3mph more than when I got it) Only the cat back exhaust and service items (plugs maf coil pack etc.)
 

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Thanks for the help. To be honest, I am still a little unsure of the exhaust setup on this car! All I know is that I have a blow on the front, centre (after the cat) and the back box - hence a new exhaust is due! As far as I know, and someone please correct me if I am wrong, is that the exhaust setup goes as follows:

(1) Exhaust Manifolds
(2) Front Pipes
(3) Cat'
(4) Middle Section
(5) Rear Section

I have asked the Powerflow dealer if they can make everything except for the manifolds, and instead of using the original cat converter, if they could make a decat pipe. This is why I wondered where the lambda probe was. If it is before the cat, does this mean it is on the front pipes or actually on the cat-section itself?

Tony.
Tony, the lambda is on the short section between the manifolds and the car, from memory..The manifolds do join though, and remember it could be a gasket making the exhaust blow.
This section also has a flex section on it...
There's a lot to be said for getting down under the car and having a look, if you got no ramps or jack and axle stands (a must) then have a look when its on the ramp at the garage, and discuss with the guys there.
 
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Tony, am gonna fit my de-cat pipe tomorrow (weather permitting :rolleyes:) - will take pics when I'm under the car :thumbs:
 

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Tony, am gonna fit my de-cat pipe tomorrow (weather permitting :rolleyes:) - will take pics when I'm under the car :thumbs:
That smells like tech help to me:cheese: :cheese: :cheese:
I'm interested in your thoughts after the de-cat Jon.
 
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That smells like tech help to me:cheese: :cheese: :cheese:
I'm interested in your thoughts after the de-cat Jon.
Eek, just read my post back - should have said while I'm under the car (that is safely supported) ;) :lol: :thumbs:



Will deffo give feedback :D
 

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I didnt think mine was too loud but when I recently heard an Audi RS6 with fancy exhaust, I asked my wife if my car was as loud as that................... she said mine was louder :lol:

Must do a sound clip some time...........it does seem to pop on the overrun
I just did the same test! I didn't think mine was THAT loud, just asked my wife - she assures me it is.

(Raggazon straight through cat and centre section - Standard Back Box)
 
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I reckon am gonna have vid to myself doing a drive by, since I fitted the CDA ages ago my friends & family assure me they know when I am in the vicinity :lol:
 

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Discussion Starter #19
Tony, the lambda is on the short section between the manifolds and the car, from memory..The manifolds do join though, and remember it could be a gasket making the exhaust blow.
This section also has a flex section on it...
There's a lot to be said for getting down under the car and having a look, if you got no ramps or jack and axle stands (a must) then have a look when its on the ramp at the garage, and discuss with the guys there.
Excellent stuff, thanks. I've had a look on Alfaworkshop.co.uk under the parts > exhausts link and I can see exactly where the lambda probe goes. Powerflow are claiming that they can make this section as well, although I am still not sure if they can "rethread" the lambda probe into the new stainless section they are making! I will have to make a phone call and question that !

Thanks for your help,
Tony.
 

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just let you know
my 2.5 v6 jan 2001 has 4 cats 4 lambda so check your cars out, you might be surprised
if it has replace them with early ie 99 headers then decat pipe otherwise having work done youll end up with an un mot able car!
 
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