ARMA Speed 130i exhaust manifold fitted to 125i

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///MBan
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Re: ARMA Speed 130i exhaust manifold fitted to 125i

Post by ///MBan » Sun Jul 19, 2015 1:38 am

jonwilli wrote:
///MBan wrote: I wouldn't mind so much about only gaining 6 hp if I saw gains right across the rev range like the SS chart shows, but my gain is pretty much only above 6,000 rpm.
I think that's pretty normal for an exhaust upgrade on an NA engine. I guess you only see the gains once the exhaust gas volume reaches a flow where the OEM design is a limiting factor. Have a look at the Supersprint E46 M3 dynos, 10bhp for the race exhaust and cats with OEM headers, an extra 9bhp on top with their headers....the power curve only really exceeds the OEM exhaust from 6,000 rpm. The Supersprint M3 set up is €7,000 for 15 to 20bhp and considered one of the best aftermarket exhausts out there.
Thanks for the perspective - much appreciated.

As you say, it looks like the volume and velocity of exhaust gas doesn't exceed the stock manifold's capacity until about 175hp (6,000 RPM on my dyno chart). Hopefully with a tune, I'll hit 175hp a bit earlier and the manifold will have a wider rev range in which it's providing benefit. That's kind of what I was expecting, I just thought the improvement might be greater before the tune.

Looking back, I wouldn't have done anything differently - I was always going to get a set of exhaust manifolds - so the initial disappointment is fading. The gain I got is the gain I got and so I move onto the next stage, which is a tune.

By the way, how loud is your exhaust with a full Supersprint system? I'm still not quite convinced that I don't want my exhaust to be a bit louder.

jonwilli
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Re: ARMA Speed 130i exhaust manifold fitted to 125i

Post by jonwilli » Sun Jul 19, 2015 7:09 am

Its hard for me to say if it is the headers or the Supersprint exhaust that has changed the exhaust note on my car. They all essentially got fitted together. My guess is that the ARMA headers don't add that much volume to the car (I think that was a consideration in their design from what ARMA said to me). It is a different sound to the OEM exhaust/headers and BMWP back box, not a louder note by much (and I don't have the mid section resonator). I really like it but it is a subtle change from the BMWP set up. Sorry the above isn't that much help, it is all so subjective and a lot down to personal taste. I tried to do a video from start up yesterday on my phone...managed to video about 10 seconds of me getting into the car!! I will try again maybe with the help of my girlfriend who will think I'm being a geek!
E81 BMW 130i
http://babybmw.net/viewtopic.php?f=19&t=75502" onclick="window.open(this.href);return false;

///MBan
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Re: ARMA Speed 130i exhaust manifold fitted to 125i

Post by ///MBan » Mon Jul 20, 2015 6:03 am

I like how mine sounds now, particularly below 5,000rpm but a more aggressive note above that might be nice. However, I've heard some sound clips of 125i with just the PE and they sound loud and clattery, almost like they have a broken exhaust manifold gasket. But in other clips they sound great.

On the weekend I asked my girlfriend to drive around the block, going up and down the rev range, while I stood on the side of the road. She said I was nuts and it was raining at the time so I'll have to try again next weekend.

In any event, my next purchase will be tune so a new muffler isn't on the cards for a while.

awhc
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Re: ARMA Speed 130i exhaust manifold fitted to 125i

Post by awhc » Tue Feb 13, 2018 7:04 am

I am also from Australia and searching if there are any RHD N52 headers available for my 130i.

But with those gains, I don't know if I will get it.

Have you considered removing the cats on the header to see if there will be any improvement?

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