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si-g

E39 M5 Exhaust Manifold

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Hi all,

 

I want to buy new performance exhaust manifolds for my E39 M5 but undecided whether to go for replacement cats. A part of me would like to retain the original cats but im worried as to how the new manifolds would attach to them, I wouldn't want a single piece exhaust from the engine back to the cans, would want to be able to unbolt the cats from the new manifolds as you can do today. Has anyone fitted them like this? Do the original cats cause a performance concern over the sports cats?

 

The option is there to go for 200 cell sports cats but im worried that it might make the system too loud, im not really after the noise, i want the performance gains that come from the headers, although a slight little bit more noise that stock would be nice :)

 

Do you have to get the car remapped to take advantage of the new manifolds, or are there gains there straight away? 

 

Thanks

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On 9/16/2018 at 12:39 AM, sayanthan said:

100 cells. DMS did the mapping 

Is that the 4-2-1 manifolds, cats and remap but with standard air intake?

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On 9/15/2018 at 7:22 AM, si-g said:

Hi all,

 

I want to buy new performance exhaust manifolds for my E39 M5 but undecided whether to go for replacement cats. A part of me would like to retain the original cats but im worried as to how the new manifolds would attach to them, I wouldn't want a single piece exhaust from the engine back to the cans, would want to be able to unbolt the cats from the new manifolds as you can do today. Has anyone fitted them like this? Do the original cats cause a performance concern over the sports cats?

 

The option is there to go for 200 cell sports cats but im worried that it might make the system too loud, im not really after the noise, i want the performance gains that come from the headers, although a slight little bit more noise that stock would be nice :)

 

Do you have to get the car remapped to take advantage of the new manifolds, or are there gains there straight away? 

 

Thanks

You could get a V band attachment between the headers and cats which would make swapping them about very easy. I have a set ready to go on which have this arrangement.

 

It would be interesting see if anyone has tested the sports cats over standard as I am having the same dilemma st the moment. Apparently sports cats can be difficult come MOT time and I don't believe they have much bearing on power, its the headers where the restriction lies.

 

There are gains to be had pre-mapping for sure, in fact most of the dyno results originally provided by Evolve and others were on standard mapping. Its definitely worth having it done though to realise maximum potential and improve throttle response. 

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4 hours ago, Jameswsb said:

Is that the 4-2-1 manifolds, cats and remap but with standard air intake?

Yes

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17 hours ago, sayanthan said:

Yes

Brilliant results there. An additional 10+bhp should be easily possible with an intake system too.

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