100cl or 200cl CAT?

[T9 man]

Am having a 3" downpipe and sports CAT fitted on saturday, and have a choice of 100cl or a 200cl CAT! I have been advised to go for the 100cl sports CAT for my Saab 9-3 as it will be less likely to fail the emissions test on the MOT than a 200cl would. Is this true? then why make a 200cl?

As always, your guidance and help is always appreciated! :bigsmile:

 

[HDi fun]

Am having a 3" downpipe and sports CAT fitted on saturday, and have a choice of 100cl or a 200cl CAT! I have been advised to go for the 100cl sports CAT for my Saab 9-3 as it will be less likely to fail the emissions test on the MOT than a 200cl would. Is this true? then why make a 200cl?

As always, your guidance and help is always appreciated! :bigsmile:

Possibly it's to do with warm up time if they have to test the car when it's not at full operating temperature. The smaller one will heat up faster.

I've had my eyes opened to this recently, having bought the 2nd user E39 (petrol) which is a straight 6. The exhaust is very odd, there's two 3 into 1 manifolds, each serving 3 of the six cylinders. These feed two separate catalytic converters,n and they're both tiny. Each about the size of a wine bottle. It's only further back that the pipes amalgamate into one fairly large one and go to the two rear boxes which are in series. There is only one tailpipe.

I questioned the 2 cats thing with a specialist and was told that it's done for fast warm up - there's also apparently a couple of secondary air pumps to force air into the exhaust upstream of the cats during warmup. This, too, is simply done for emissions reasons.

But if they test your car when it's just been driven swiftly the 200 centilitre cat will perform equally well. The 200cl should flow better as well.

 

[T9 man]

Possibly it's to do with warm up time if they have to test the car when it's not at full operating temperature. The smaller one will heat up faster.

I've had my eyes opened to this recently, having bought the 2nd user E39 (petrol) which is a straight 6. The exhaust is very odd, there's two 3 into 1 manifolds, each serving 3 of the six cylinders. These feed two separate catalytic converters,n and they're both tiny. Each about the size of a wine bottle. It's only further back that the pipes amalgamate into one fairly large one and go to the two rear boxes which are in series. There is only one tailpipe.

I questioned the 2 cats thing with a specialist and was told that it's done for fast warm up - there's also apparently a couple of secondary air pumps to force air into the exhaust upstream of the cats during warmup. This, too, is simply done for emissions reasons.

But if they test your car when it's just been driven swiftly the 200 centilitre cat will perform equally well. The 200cl should flow better as well.

Many thanks for the heads up! HDi, for the few extra pounds that they are asking for the 200cl, its nothing money! will have them fit this on the car saturday, cheers!

 

[T9 man]

Possibly it's to do with warm up time if they have to test the car when it's not at full operating temperature. The smaller one will heat up faster.

I've had my eyes opened to this recently, having bought the 2nd user E39 (petrol) which is a straight 6. The exhaust is very odd, there's two 3 into 1 manifolds, each serving 3 of the six cylinders. These feed two separate catalytic converters,n and they're both tiny. Each about the size of a wine bottle. It's only further back that the pipes amalgamate into one fairly large one and go to the two rear boxes which are in series. There is only one tailpipe.

I questioned the 2 cats thing with a specialist and was told that it's done for fast warm up - there's also apparently a couple of secondary air pumps to force air into the exhaust upstream of the cats during warmup. This, too, is simply done for emissions reasons.

But if they test your car when it's just been driven swiftly the 200 centilitre cat will perform equally well. The 200cl should flow better as well.

Well I had the 200cl CAT and 3" downpipe fitted yesterday HDi, what a difference it has made to the turbo! have noticed much less lag when I put my foot down now, also noticed the car has taken on a more throaty rumble to it, but it I can live with it. Also had fitted on Friday a BSR cold induction kit with a heat shield at long last! a remap has been booked in for next Thursday at Viezu in Bromsgrove to knit everything together, so hopefully I will finally crack the 300bhp barrier!

Cheers for the help HDi :bigsmile:

 

[HDi fun]

Good to hear that the performance cat is worth having.

Does the exhaust sound any different as a result?

 

[T9 man]

The exhaust does indeed sound different, much less harsher note than it had before, definately a deeper rumble on tickover, but no more noise coming inside the car at normal town speeds which is good! will be on the motorway tomorrow, so will see if there is any more noise at higher speeds and if it is still manageable! :blink1:

 

[HDi fun]

It's something I would consider if I have to replace the cats on the BMW provided the noise is not intrusive. Or the cost, come to that. Looking around BMW OEM parts are actually incredibly reasonably priced. Hopefully won't be needing many though, all the same.