Exhaust modifications?

Technical Area Motorsport & Trackday Preparation
21

Cool!! :thinking:

22

turns out that the header on the NC is the most restrictive part of the whole power system.

if you replace the stock header with the high flow you do get a power gain and if you remap aswell you can bump the cars power by about 20hp going up to 25/26 if you also change the center pipe or about 30/32 if you change the whole exhaust system.

23

Thanks Thibor!

1 Like
24

Hi Drewby

I thought this had been done to death but seemingly not😂
I think everything said on this post has been said already several times so did you really research/search this topic properly before posting?

Essentially your car will be fine so long as it is modified and mapped properly the second cat will do it’s job. My car is a de-cat manifold and sits well under the emissions limits. Yes it’s technically “a fail” but the tester doesn’t notice/care. It’s more a question of whether your comfortable with slightly more risk or not?

There are no cheap ways to add significantly more horsepower to an NC but the remap and manifold is the first step and I don’t think anybody on this forum ever regretted doing it.

The end.

25

I am going for the BBR catted manifold but has anyone mixed this with a MX5parts centre section?? The BBR centre section is very expensive!!

26

Does the centre section have a catalytic converter in it?

27

Yes it does.

28

Hmmm, just an opinion but I thought you said you wanted a bit more “power and noise” from the exhaust system.
Looks like you are just replacing like for like to me, (albeit in SS) and a nice bit of kit. :man_shrugging:
Anyway, good luck with your choices.

1 Like
29

Sorry, but how can you compare an OEM header (the most restrictive part of the system) and a BBR header? :thinking:

30

I think he’s referring to the centre section. That would also achieve slightly more power and noise anyway though in my opinion.

31

If that is the case, then I apologise to Scarletpimpernel! Ok, next question then, how restrictive is the OEM centre section?? Would leaving it dissipate any gains made with the BBR header?

32

I had the IL Motorsport catless exhaust manifold, standard centre section with cat, Cobalt backbox and an ECUTek remap and it achieved 184BHP on an NC1. I had no issue with the MOT or emissions and in my opinion it sounded great (pops on upshifts, not too loud, but loud enough not to sound like your driving a hair dryer!).

33

Thanks Craig, I am going to stick with the BBR catted header only because I don’t really want to mess with the sensors. So for now, I could leave the OEM centre section and get a back box of some sort. Cannot get Cobalts for NC anymore I don’t think. Sounds like a compromise! Can always come back and update the centre section when I have more money! :smiley:

2 Likes
34

No problem. Are you going to get it remapped after the installation of the new catted header? If not you won’t see maximum gains, but if you are planning to then they will map the sensors out anyway if you went down the catless header route.

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35

Yep, definitely getting it remapped. Got me thinking again now!!!

36

Ha, sorry. I had the same dilemma at the time. My main concern at the time was if it would pass an MOT if I had a catless header both from an inspection point of view and emission point of view. But I haven’t had any problems in the 4 years post installation. But the decision is down to each individual owner of course.

1 Like
37

Just giving opinions as to what I have done.
Everything has compromises and if you want maximum power (normally aspirated) then you have to go down the route of a de-catted header, proper remap, intake modifications, (cams and whatever else) etc.
Always passed the MOT and never known anyone that has had a car failed by removing the front one.
Mistakes happen, as I didn’t anticipate the extra amount of loud annoying noise (now sorted).
Be careful with your choices.
I’ll leave now and let others debate with you all, good luck. :slightly_smiling_face: :+1:

1 Like
38

Thanks all!! one last thought that influenced me…The BBR website has a dyno comparison between the catted and non-catted headers for the NC and there was only about 2bhp difference!!

39

Was that with a standard centre section though?

40

With the Super 200 conversion…

1 Like