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Author Topic: BCS CAT BACK MATED TO A MILTEK?  (Read 2239 times)

Offline MrJT247

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BCS CAT BACK MATED TO A MILTEK?
« on: January 02, 2016, 10:12:31 am »
I have a ko3 rtech stage 2+ gti with a full MILTEK sports cat res fitted. I'd like to improve exhaust flow by changing the cat back section to something more direct, like the BCS rear section perhaps?
The MILTEK is great but  the extra spaghetti bends at the rear is a restriction i'd rather not have.
Probably a stupid question for some but can I couple a BCS rear section to my MILTEK? Any other ideas would be welcome..
Thanks in advance for any input guys..

Offline AJP

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Re: BCS CAT BACK MATED TO A MILTEK?
« Reply #1 on: January 02, 2016, 10:29:20 am »
You probably could, but I wouldn't hold your breath for any power gains - the restriction is in the cat/dp.

Offline r5gtt

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Re: BCS CAT BACK MATED TO A MILTEK?
« Reply #2 on: January 02, 2016, 06:29:12 pm »
Just remove the sports cat and resonator.  :happy2:

Offline flashp

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Re: BCS CAT BACK MATED TO A MILTEK?
« Reply #3 on: January 02, 2016, 08:51:39 pm »
I have a ko3 rtech stage 2+ gti with a full MILTEK sports cat res fitted. I'd like to improve exhaust flow by changing the cat back section to something more direct, like the BCS rear section perhaps?
The MILTEK is great but  the extra spaghetti bends at the rear is a restriction i'd rather not have.
Probably a stupid question for some but can I couple a BCS rear section to my MILTEK? Any other ideas would be welcome..
Thanks in advance for any input guys..
I'm a bit confused over your thread title and the first sentence in your thread. One says BCS cat-back and the other indicates that you have a Milltek cat-back system fitted already and you talk of adding parts from one brand to another? Are you thinking of replacing the Milltek cat-back system with the BCS equivalent? Either way it appears that you don't have a replacement downpipe with the pre-cat deleted, is this correct?

If you have a Milltek system I would add the downpipe to aid gas flow and heat dissipation at the turbo since you seem to have recognised at least one of these considerations as a requirement, especially at stage 2+. In fact, I'm surprised that you weren't advised to fit one when you got your vehicle mapped. The heat developed by the turbo is significant at these levels of tune. Getting rid of the pre-cat lightens the thermal load on the turbo thus helping to prolong its life.

Presumably you've analysed the gas flow characteristics and thermal dynamics of Millteks original design? You claim to have identified design weaknesses.

Could you also have said I want something louder?  :happy2:
« Last Edit: January 02, 2016, 09:14:52 pm by flashp »

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Offline MrJT247

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Re: BCS CAT BACK MATED TO A MILTEK?
« Reply #4 on: January 02, 2016, 09:58:18 pm »
Oh okay I guess I didn't make myself very clear earlier on Flashp.
Let me clarify the situation for you.
I have a complete turbo back Miltek system currently fitted on the car. Thats the down pipe, high flow sports cat, resonated centre section, rear silencer and jet trims. With all other hardware the car is stage 2+ tuned by Rtech and on their road achieved pub talk headline figures of 276bhp and 327ftlbs for what it is worth.

I was just asking about whether there would be any gains to be had at this level of tune by swapping out the Miltek rear silencer section, which snakes around the back of the car for a more direct rear section like the BCS which just swerves around the rear arm and out. In stage 2+ tune the little K03 turbo is pretty much maxed out and apart from perhaps fitting a stronger actuator the only way of getting more performance as far as I can see would be to look at improving the flow in and out of the engine.

Mappers will no doubt notice that they are able to squeeze more out from certain hardware designs, between CAI's for example. Some will allow for more gains than others. As exhaust design requires the careful balancing of flow capacity with velocity I am interested to learn if at this level of tune a more direct rear section would preform better and if so can I mix and match rear sections between the two manufactures?

There must have been a reason for both companies choosing to settle on their end design. Has any body A,B tested any zorts?
« Last Edit: January 02, 2016, 10:14:09 pm by MrJT247 »

Offline flashp

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Re: BCS CAT BACK MATED TO A MILTEK?
« Reply #5 on: January 03, 2016, 06:41:16 am »
Oh okay I guess I didn't make myself very clear earlier on Flashp.
Let me clarify the situation for you.
I have a complete turbo back Miltek system currently fitted on the car. Thats the down pipe, high flow sports cat, resonated centre section, rear silencer and jet trims. With all other hardware the car is stage 2+ tuned by Rtech and on their road achieved pub talk headline figures of 276bhp and 327ftlbs for what it is worth.

I was just asking about whether there would be any gains to be had at this level of tune by swapping out the Miltek rear silencer section, which snakes around the back of the car for a more direct rear section like the BCS which just swerves around the rear arm and out. In stage 2+ tune the little K03 turbo is pretty much maxed out and apart from perhaps fitting a stronger actuator the only way of getting more performance as far as I can see would be to look at improving the flow in and out of the engine.

Mappers will no doubt notice that they are able to squeeze more out from certain hardware designs, between CAI's for example. Some will allow for more gains than others. As exhaust design requires the careful balancing of flow capacity with velocity I am interested to learn if at this level of tune a more direct rear section would preform better and if so can I mix and match rear sections between the two manufactures?

There must have been a reason for both companies choosing to settle on their end design. Has any body A,B tested any zorts?

Thanks for clarifying this, I'm with you now!  :laugh:
I think you already have an excellent system that will be doing all an exhaust can for your car in it's current tune.

I also think different manufacturers have responded to different market demands, and that is after all good business sense. Some have focussed on the customer requirement for a different exhaust note and others less so by going for an OE replacement that might be more discreet. I'm not qualified to say so, but I imagine that one may not perform any differently from the other in terms of engine benefits and technical function. I think that most, if not all of the premium brands have achieved correct technical function and good build quality but have added  different appealing features. Aesthetically I think they can vary hugely.

In short, I think you'll add nothing to the car by changing from a technical perspective. If however you wanted a different exhaust note then going by reviews I would say a BCS system would give it to you. If by adding a BCS system to Milltek downpipe there's a change in pipe diameter it may be considered beneficial to maintain the same diameter throughout.

I bought my Milltek new and so I have excellent warranty support as the original purchaser, maybe you have the same benefit? I also know that my system will get through the tightest of static noise tests at a circuit. This may or may not be an issue for you. I've no idea where a BCS system is on this front.

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