8bit

Active Member
Feb 11, 2010
3,380
3
Aberdeen
Anyone got an aftermarket downpipe and sports cat mated up to the standard cat back section and kept the center silencer/resonator?

My stock exhaust is leaking around the flexi section so thought about getting an uprated downpipe and sports cat if they can be mated to the stock mid and back section, maybe Cobra or Blueflame. Guess if I got a 3" pipe I'd need a reducer in between the cat and the center resonator, will there be room for that?
 
I think jamjay ran with a 3" downpipe and decat mated to std cat back, it is possible however I think it caused surge with the map it had
 
OK so I went for the Cobra 2.5" DP and cat. The reasoning is that this should mate up to the stock cat-back and not be any louder.

Can anyone confirm whether the join between the cat section and the center resonator section is a flange or a sleeve? If it is a flange, has anyone got a part number for a gasket for that?
 
OK so I went for the Cobra 2.5" DP and cat. The reasoning is that this should mate up to the stock cat-back and not be any louder.

Can anyone confirm whether the join between the cat section and the center resonator section is a flange or a sleeve? If it is a flange, has anyone got a part number for a gasket for that?
They should mate perfectly with mirror flanges. Cobra normally supply gaskets with thier cat backs if not standard exhaust paste will be fine but most fitters use high temp silicon at the catback.
 
OK, so you're saying the stock LCR resonator section has a flange where it joins to the cat section? It's not the cat-back section I'm buying, it's the DP and cat. I did ask Cobra if they supplied gaskets with that item and they said no; I guess they would for bigger than standard systems.
 
OK, so you're saying the stock LCR resonator section has a flange where it joins to the cat section? It's not the cat-back section I'm buying, it's the DP and cat. I did ask Cobra if they supplied gaskets with that item and they said no; I guess they would for bigger than standard systems.

Yes mate the standard LCR cat back is 63mm and has a flat flange with two fixing bolt holes that should be a perfect match up to the 63mm cobra cat and DP.
 
Thanks Willy, appreciate it.

DP and cat is here, as are new gaskets and some fresh RBF 660 brake fluid, car getting that lot done on Tuesday, in time for Knockhill next weekend :)
 
Hi guys. I come back now and again and see who's been speaking my name :D

My issue with my car was simply the Stage 1 tune that I had could not effectively deal with the DP & Sports Cat. It was mapped for a standard exhaust/cooling system which would provide a certain amount of boost pressure in order to supply the combustion chambers with the air that was required to increase the performance at that level of tune and that the standard hardware was capable of supporting. However, the DP and Sports Cat opened up the tap considerably and allowed the turbo to work far easier than the map anticipated hence the turbo was sucking in far too much air causing it to bottleneck in the system because A) the standard FMIC's and piping where clogging it up and B) the engine just wasn't ready to consume that much air.

I partly resolved this by installing a much more efficient FMIC and pipework but the flaw in the map remained. It swiftly went for another custom map to support the exhaust and more efficient IC where fuelling, timing and boost pressure were harmonised and hey presto, issue sorted.

Note: Turbo surge is where excess air is built up in the turbo housing (cause by a build up due to a bottleneck or some sort), causing the turbine to literally chop the air as it spins. This makes an audible and rapid 'chuff, chuff, chuff' sound.
 
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Note: Turbo surge is where excess air is built up in the turbo housing (cause by a build up due to a bottleneck or some sort), causing the turbine to literally chop the air as it spins. This makes an audible and rapid 'chuff, chuff, chuff' sound.

not being a pedant or anything, but for others who may read this, the compressor is what chuffs from surge for the reasons you say. (turbines in hotside driving the comp wheel)