Decat pipe for 3.2?
- Thread starter AudiiduA
- Start date
Wouldn't it fail mot? What about getting a custom pipe to replace the centre silencer, gives a nice noise (but doubt it would give any more powers)
Why would you want to lose the cat ??. you need that to give you back pressure to clear the cylinders. It might work better at high revs but would kill low down performance IMHO.
the thing you have to remember with any mod like that is the manufacturer spent millions over the years developing a package that works and the idea that you can chop a bit off and it will be better is not really realistic. The 3.2 lump has developed from the 2.8 8 valve into a 3.2 16 valve (3.6 vw) over 20 years and is probably as far as it will reasonably go performance wise. Its most likely that the cat already flows more than enough gas to cope with the stock engine so unless you plan to turbo or increase bore etc i doubt anything would be gained from just chopping the cat.
the thing you have to remember with any mod like that is the manufacturer spent millions over the years developing a package that works and the idea that you can chop a bit off and it will be better is not really realistic. The 3.2 lump has developed from the 2.8 8 valve into a 3.2 16 valve (3.6 vw) over 20 years and is probably as far as it will reasonably go performance wise. Its most likely that the cat already flows more than enough gas to cope with the stock engine so unless you plan to turbo or increase bore etc i doubt anything would be gained from just chopping the cat.
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marknjayne
Registered User
wrong,they work to a budget and regulations,you CAN always better what they have done.
you do need the backpressure though unless its mapped to suit you wont see much if any gains,on some turbo cars the ecu actually starts to pull timing and runs rich so you actually loose power unless you have the map tweaked to suit the extra flow
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A/ So what are you going to chop off that Audi didnt thats going to make your 3.2 quicker ??
B/ So how are you going to map an engine to suit the lack of back pressure ?? If you can do that then sell the idea to the companies that spend a fortune developing exhausts on flow rigs...to produce back pressures when all they needed was a remap.........
I thought the 3.2 has 24 valves(4 per cylinder) and the 2.8 has 12v (2 per cylinder)??
marknjayne
Registered User
a/the cats for one and many other things that make it heavier such as air con if you are only interested in speed and not comfort .
b/have you got a degree in engine management ?,no,neither have i but i can tell you that decatting and mapping to suit WILL gain power,i have done it myself on my own cars and seen it done on many others
marknjayne
Registered User
remember,they have to build a car to A/a budget and B/regulations(hence the catalytic converter),also add creature comforts such as air con,stereo etc etc...
you can also change pannels such as bonnet and wings for carbon fibre to make the car lighter and get a lighter flywheel to gain a bit of acceleration but thats taking it to the extreme,there are so many things that can be done,why do you think audi have not done them,well because they cost more and you take that cost over thousands of cars,itll be millions of £ in parts
you can also change pannels such as bonnet and wings for carbon fibre to make the car lighter and get a lighter flywheel to gain a bit of acceleration but thats taking it to the extreme,there are so many things that can be done,why do you think audi have not done them,well because they cost more and you take that cost over thousands of cars,itll be millions of £ in parts
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No cat where one was factory-fitted = fail from Jan 1st 2012!
http://www.dft.gov.uk/vosa/repository/MOT%20Inspection%20Manual.pdf
http://www.dft.gov.uk/vosa/repository/MOT%20Inspection%20Manual.pdf
marknjayne
Registered User
No cat where one was factory-fitted = fail from Jan 1st 2012!
http://www.dft.gov.uk/vosa/repository/MOT Inspection Manual.pdf
lol,there are ways around that
Sorry but i think you are talking total rubbish for the sake of an argument. The guy wants to know if he can chop his cat out...I told him it serves a purpose in giving back pressure to the cylinders to clear exhaust so be careful.
There is no point in chopping the cat if you then have to fit a custom map to make up for it, you might as well map the std car unless you can prove the twin high flow cats fitted are restricting the power. I have been there with the 3.2 and got the t shirt, spent hours on dyno's and come to the conclusion the 3.2 is running pretty well as good as it ever will. You can increase the Torque on that lump by about 20lb/ft in the lower range but you will lose it again if you de cat.
The guy doesn't want to lighten his car by dumping the aircon.lol, you dont buy a 3.2 and then set about lightening it !! if you do you bought the wrong car and you'r about to devalue it big time.
As for money spent.. Audi have spent a small fortune on fuel systems, exhaust systems, 24 valve heads, VVT systems ,uprated cranks and engine management systems to suit and been developing and improving that engine and set up for 20+ years with changes of just about every part. Its gone from 170bhp to 245bhp...if you can succeed where Audi have failed by getting a meaningful amount more out of it then good luck.
There is no point in chopping the cat if you then have to fit a custom map to make up for it, you might as well map the std car unless you can prove the twin high flow cats fitted are restricting the power. I have been there with the 3.2 and got the t shirt, spent hours on dyno's and come to the conclusion the 3.2 is running pretty well as good as it ever will. You can increase the Torque on that lump by about 20lb/ft in the lower range but you will lose it again if you de cat.
The guy doesn't want to lighten his car by dumping the aircon.lol, you dont buy a 3.2 and then set about lightening it !! if you do you bought the wrong car and you'r about to devalue it big time.
As for money spent.. Audi have spent a small fortune on fuel systems, exhaust systems, 24 valve heads, VVT systems ,uprated cranks and engine management systems to suit and been developing and improving that engine and set up for 20+ years with changes of just about every part. Its gone from 170bhp to 245bhp...if you can succeed where Audi have failed by getting a meaningful amount more out of it then good luck.
marknjayne
Registered User
wickyianr1
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i agree with paddy on this one i have a custom exhaust cat back the guy who did it has a r32 he did it and its a right pig to do
Apologies for hijacking the thread, but I guess it wouldn't be worth doing a decat on my 140 TDi then?
marknjayne
Registered User
yes it would and you will see more gains as its a turbo'd car ,it would be more worth while having it re-mapped though
My cars already mapped, a little more go would be nice, i plan to have a stainless system asap! cat back anyway! i just love the sound!
It would fail MOT but would bolt it back in for that! now thinking CAT is staying and maybe loose a silencer?? are there any cams for the 3.2?
It would fail MOT but would bolt it back in for that! now thinking CAT is staying and maybe loose a silencer?? are there any cams for the 3.2?
Yes you can get cams but you already have VVT so the timing of the cams is already variable. Changing cams is another way of altering the open shut time but the only advantage you might see on/over VVT is a longer opening time but that will only benefit you if the opening time of the std cam is not adequate already.... which it might not be.
The only way to get power out of that lump is a Turbo. To do that you need to be very very sure all other components are absolutely spot on and preferably change the pistons exhaust manifold and down pipes etc. I dont want to pee on your fire works but as i say that engine has already gone as far as its cost effective to take it. You could possibly go the old route and skim the heads and gas flow the thing but its a lot of work. I have flowed a lot of heads in my time and it can be rewarding but the chances are on a modern engine like yours, flow is not a real issue anyway. Lighten the crank, balance the whole thing, blue print it.....Its all possible but as i found you can trade it for an S3 far cheaper than increase its power.
The only way to get power out of that lump is a Turbo. To do that you need to be very very sure all other components are absolutely spot on and preferably change the pistons exhaust manifold and down pipes etc. I dont want to pee on your fire works but as i say that engine has already gone as far as its cost effective to take it. You could possibly go the old route and skim the heads and gas flow the thing but its a lot of work. I have flowed a lot of heads in my time and it can be rewarding but the chances are on a modern engine like yours, flow is not a real issue anyway. Lighten the crank, balance the whole thing, blue print it.....Its all possible but as i found you can trade it for an S3 far cheaper than increase its power.
