Exhaust Manifold Question (and a few others)

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AdyDurn
Joined: Wed 22 Jan, 2014 16:13
Posts: 16

  Z3 roadster 2.0

Exhaust Manifold Question (and a few others)

Post by AdyDurn » Tue 29 Aug, 2017 14:08

Hi Guys,

I know it's been a while since I last posted (long story in real life, involved pain, blood and someone leaving the country) I haven't forgotten about here.

I've been thinking more and more about the Z and what I feel it has, and what I feel it lacks I'd also like to reflect on a few rumours and a few options I have available to me in the next few months. The main question I want to raise is around exhaust systems and getting that little bit more from the car.

So looking at the 2.0l engine and the exhaust manifold seems to have a quite aggressive 90 degree bend as it leaves the cylinder head. I am quite surprised at just how aggressive it is, is this the same across the range? I also heard that swapping the manifold for the one off a 2.8 gives better flow, a deeper and more growly note and noticeable power increase. Is it possible to just change the manifold or would it be a complete system change? I had a quick search through the history but I couldn't find anyone specifically raising this issue so I don't know if this is true. I don't really want to change the backbox and especially don't want to change the tips (I like that the car is quicker than it appears).

(If this has been answered before I can delete this if anyone knows where it has been answered.)

I'm also considering some strut braces, they had no real effect on my old Honda, so I've been putting them off but I have been that they are possibly the single best handling upgrade you can make for the Z. Finally, has anyone used magnetic chip guards before? I'm giving serious consideration of getting some for the rear arches. The office recently moved to Basingstoke and the new route in has a lot of loose gravel around it. I'm sick of looking at chipped paintwork.

Thanks guys,

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Devon Z
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Joined: Thu 20 Nov, 2003 21:39
Posts: 650

  Z3 roadster 2.0
Location: Brixham, Devon

Re: Exhaust Manifold Question (and a few others)

Post by Devon Z » Tue 29 Aug, 2017 18:21

The exhaust system and manifolds are the same on the 2.0 and 2.8 M52tu engines, they changed on the M54 engines when they fitted the cats in the manifolds! they've got some tight bends in them!
If your looking for improvements in your 2.0 six then you should look at the inlet side as that's where the restrictions are. I've just fitted an M54 inlet manifold from the 2.2/2.5 engines, it's a straightforward swop..ish, just need a manifold plus DISA and a thottle body adaptor available on eBay, all in cost me £110.
It's made a dramatic difference to my car, here's a link to my posts on the other forum.
https://zroadster.org/threads/m54-manif ... ion.19360/

Strut brace, yes definitely, same for the magnetic arch guards, I have them both.
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AdyDurn
Joined: Wed 22 Jan, 2014 16:13
Posts: 16

  Z3 roadster 2.0

Re: Exhaust Manifold Question (and a few others)

Post by AdyDurn » Wed 30 Aug, 2017 10:01

Thanks Devon, definitely looking into that. Just looking over the parts available on ebay, and yeah, £120 seems to be enough to line up the parts. I'm on for that. Looks like a straightforward swap as you say.

Just quickly, as it's not entirely clear elsewhere but is there any difference between the M54 2.5 and M54 3.0 manifold/DISA? Bimmerforums suggest that there's no difference.

Thanks,

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BladeRunner919
Joined: Fri 17 Feb, 2012 20:18
Posts: 2221

  Z3 roadster 1.9

Re: Exhaust Manifold Question (and a few others)

Post by BladeRunner919 » Wed 30 Aug, 2017 17:13

AdyDurn wrote:
Wed 30 Aug, 2017 10:01

Just quickly, as it's not entirely clear elsewhere but is there any difference between the M54 2.5 and M54 3.0 manifold/DISA? Bimmerforums suggest that there's no difference.
The easiest way to answer any compatibility questions is to make your way to Realoem.com and find the part - it will then tell you all the cars that the same part was used on.

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Devon Z
Z Register member
Joined: Thu 20 Nov, 2003 21:39
Posts: 650

  Z3 roadster 2.0
Location: Brixham, Devon

Re: Exhaust Manifold Question (and a few others)

Post by Devon Z » Wed 30 Aug, 2017 23:32

Not sure on that, the M54 DISA's are same and maybe the 3.0 manifold has larger inlet tubes? The manifold gaskets are the same part number so the overall size of the ports are the same so from my observations the 2.5 manifold I used with the D shaped ports were as big as the gasket would allow.
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AdyDurn
Joined: Wed 22 Jan, 2014 16:13
Posts: 16

  Z3 roadster 2.0

Re: Exhaust Manifold Question (and a few others)

Post by AdyDurn » Thu 31 Aug, 2017 09:40

Thanks Devon, I've now ordered the parts. Hoping they all arrive next week so that I can fit them over the weekend. I've been looking at the power increase others have been getting from this switch and it's not insignificant.

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Devon Z
Z Register member
Joined: Thu 20 Nov, 2003 21:39
Posts: 650

  Z3 roadster 2.0
Location: Brixham, Devon

Re: Exhaust Manifold Question (and a few others)

Post by Devon Z » Thu 31 Aug, 2017 22:55

AdyDurn wrote:
Thu 31 Aug, 2017 09:40
Thanks Devon, I've now ordered the parts. Hoping they all arrive next week so that I can fit them over the weekend. I've been looking at the power increase others have been getting from this switch and it's not insignificant.
Your right but for me the way the car drives now is chork and cheese, it just feels so much more eager and unrestricted compared to before. Just a shame she'll be coming off the road for the winter at the end of September, still that's weeks away!

Let us know how you get on?
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AdyDurn
Joined: Wed 22 Jan, 2014 16:13
Posts: 16

  Z3 roadster 2.0

Re: Exhaust Manifold Question (and a few others)

Post by AdyDurn » Fri 01 Sep, 2017 10:59

Yeah, everyone I've seen who has made this change, even on the e46, is claiming big power increase and better response, so I'm excited. The intake body and DISA have just arrived in the office right now. The adapter is due to arrive early next week so fitting will be next weekend, instead of this one.

I don't retire mine for the winter, I keep her going, she handles snow and ice surprisingly well (not that I expect either this year).

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