Milltek downpipe

[Ryan Cox]

Morning All,

Does anyone have any experience with the milltek downpipe, or any other aftermarket? Will I need to remap and will it cause warning lights to stay on?

Thanks

 

[samuelh_888]

Not sure about Milltek, assuming it’s the same as BCS if you have a sports cat then you shouldn’t get ECL. You’ll be fine on stock map but obviously a map would give the full benefit.

 

[-Ju-]

Adding a sports cat is taking the efficiency levels down to the point where the lambda can flag up as a fault, not always straight away but after some time.
This can be alleviated by fitting a spacer to the lambda which removes it out of the flow tricking it into thinking the cat is more efficient.
Obviously a map would be the best option as you are using the downpipe to it's best and would code out the post lambda sensor.
On a side note, when I bought my previous 8P S3 from the main dealer, it had a full turbo back milltek and never gave a cel. I had it mapped back to 2/2+ and when I took the map off for dealer work the cel came on!

 

[Ryan Cox]

Interesting, thanks both.

 

[Ryan Cox]

Does it make a difference if u have a de Cat or a sports Cat? Or will u get warning light with both?

 

[samuelh_888]

With the BCS and a cat, most don’t report an ECL however a couple have. I even confirmed this with BCS prior to purchase. I’m not sure about the Milltek sorry.

After a while (I’m not sure what the cycle is, on my R32 it was 4 engine starts but I’m not sure if this is official) the CEL will come on with a decat.

The cat is a 200 cell sports-cat so it is high flowing- in hindsight I’d have gone decat but was always worried about the MOT fail.

 

[Ryan Cox]

Thanks for this. I’ll prob go b***s out and get the decat