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New 2x 2 inch exhaust system - 325i
Posted: Sun Sep 16, 2007 7:39 pm
by BMracing
Some pics here of my new custom made system, all the way up to the manifold. I'm pretty happy with it, the pipework is very good, it makes a lovely smooth noise up to around 4000 rpm and then a racey rasp after.
I can't decide whether its too loud or not though.
As you can see the tailpipe is like a scorpion/mongoose, I couldn't really see anything else that I liked or would suit it.

Re: New 2x 2 inch exhaust system - 325i
Posted: Sun Sep 16, 2007 7:53 pm
by agreen
looks good fella i like dtm on e30s but thats my opinion
Re: New 2x 2 inch exhaust system - 325i
Posted: Sun Sep 16, 2007 7:55 pm
by agreen
looks good fella i like dtm on e30s but thats my opinion
Re: New 2x 2 inch exhaust system - 325i
Posted: Sun Sep 16, 2007 7:56 pm
by Jhonno
who made it? mandrel bent?
2x2" is a little big for a 325i.. Ok for top end tho
Re: New 2x 2 inch exhaust system - 325i
Posted: Sun Sep 16, 2007 8:01 pm
by oze30
i don't think they're mandrel.. they close in abit on the insides, so I'm guessing just a normal bender.
nice system, but I wouldn't use mongrouse or shlorpian.. Too loud imo.
Re: New 2x 2 inch exhaust system - 325i
Posted: Sun Sep 16, 2007 8:02 pm
by Jhonno
yeah was gonna say after looking closer doesnt look mandrel..
Re: New 2x 2 inch exhaust system - 325i
Posted: Sun Sep 16, 2007 8:03 pm
by zaust
The louder the better...

Posted: Sun Sep 16, 2007 8:14 pm
by BMracing
Thanks agreen,

i'm not so keen on dtm's generally, although they do look nice on e30's.
Jhonno its a powerflow exhaust, not mandrel bent unfortunately. To be honest I wouldnt usually go there but I paid a mates rate for it. I wasn't sure whether to stick with the standard 2x1.75 or not, someone on here said the alpina system was 2x2 so I thought with the few engine mods i have planned i'll probably benifit eventually, yes it is at the top end i've noticed an improvement.
I do like it loud but I don't always like drawing attention to myself! I keep getting eviled by pedestrians who think i'm driving flat out!
Re:
Posted: Sun Sep 16, 2007 8:16 pm
by Jhonno
i dont think the alpina system is 2x2".. Player6 uses 2x1.75" on his 260bhp m20 iirc..
Re:
Posted: Sun Sep 16, 2007 8:19 pm
by maxfield
Alpina is 50mm IIRC.
Re:
Posted: Sun Sep 16, 2007 8:20 pm
by Jhonno
Re:
Posted: Sun Sep 16, 2007 11:23 pm
by snoops
50mm is roughly 2 inches? can't beat scorpions, nice smooth sound at low rpms then comes a throaty roar
Re:
Posted: Sun Sep 16, 2007 11:24 pm
by Simon13
alpina system is indeed 50mm over the stock 44mm pipes
Re:
Posted: Sun Sep 16, 2007 11:32 pm
by gareth
what's with the wierd (restrictive) tailpipe?
if i were you' i'd get more hangers on there. there should be a bracket on the gearbox and a hanger on the rear subframe (can't see one anyway). with it the way it is, it's likely to crack as the SS is more brittle and thinner than a mild steel system.
Posted: Mon Sep 17, 2007 1:11 pm
by BMracing
Thanks for your points and info guys.
Gareth do you mean the back box is restrictive, because it starts with 2 pipes and ends in 1? And then the tailpipe brings it to 2 again! I noticed it wasn't the best shape for gas flow. I commented on this when they were fitting it but they said thats the only type they supplied. I guess they mainly deal with saxos and escorts so 95% of the systems they make will have a single pipe.
Do you think i'm losing out there then?
Re:
Posted: Mon Sep 17, 2007 6:38 pm
by gareth
i suspect you are losing out, by how much, i'm not sure.
that backbox is probably designed to be used in reverse, where a single saxo peashooter needs splitting into 2 V8 style exhausts!
it just seems very wrong and not how the system is designed to work
Re:
Posted: Mon Sep 17, 2007 6:40 pm
by Jhonno
depends on the dia of the outlet tbh.. Some e36 systems use weird setups like that and make 192bhp
Re:
Posted: Mon Sep 17, 2007 6:51 pm
by gareth
not just that, there's the backpressure, turbulence induced drag, and that 'Y' (or near 'T') split that will be pulsing back up the system
Re:
Posted: Mon Sep 17, 2007 6:55 pm
by Jhonno
true, but we are talking m20 here, not highly tuned S14, i think it will be minimal..
Plus to be fair, the non mandrel bends will make more of diff imo
Re:
Posted: Mon Sep 17, 2007 7:13 pm
by gareth
the non mandrel bends compared to a bunch of sharp edged 90° bends?!!! hardly!
Re:
Posted: Mon Sep 17, 2007 7:23 pm
by StuBeeDoo
Jhonno wrote:depends on the dia of the outlet tbh.. Some e36 systems use weird setups like that and make 192bhp
As long as the Y (ie the single outlet from the silencer) is more than 2.75in diameter, it won't cause a restriction, as its area will be greater than the combined area of the 2 2in pipes.
I like the style of the tail pipes. 
Re:
Posted: Mon Sep 17, 2007 7:27 pm
by Dan320is
Jhonno wrote:i dont think the alpina system is 2x2".. Player6 uses 2x1.75" on his 260bhp m20 iirc..
I think thats correct. He's got a BTB mild steel six branch manifold with a standard bmw centre section and a powerflow back box.
Re:
Posted: Mon Sep 17, 2007 7:43 pm
by Jhonno
gareth wrote:the non mandrel bends compared to a bunch of sharp edged 90° bends?!!! hardly!
sharp edged 90 deg bends? where? that y piece isnt ideal, but at least has curve to it, its not a T
Re:
Posted: Mon Sep 17, 2007 7:45 pm
by gareth
StuBeeDoo wrote:Jhonno wrote:depends on the dia of the outlet tbh.. Some e36 systems use weird setups like that and make 192bhp
As long as the Y (ie the single outlet from the silencer) is more than 2.75in diameter, it won't cause a restriction, as its area will be greater than the combined area of the 2 2in pipes.
I like the style of the tail pipes. 
it's not that simple folks!
Re:
Posted: Mon Sep 17, 2007 7:57 pm
by gareth
oh, just look at it...!
the gas hits a flat face and has to split to flow either way. there will be so much turbulence it's unreal.
i'm sure it's ok-ish but it's supposed to be an upgrade and imho, it isn't!
this is going off topic and i apologise!
Re:
Posted: Mon Sep 17, 2007 8:34 pm
by StuBeeDoo
StuBeeDoo wrote:I like the style of the tail pipes. 
By that, I meant the style of the twin tips, not the fact that it's a single pipe coming out of the box. TBH, I don't think that part of the design is all that good either. Looks a bit "cheap", but if BMracing is happy with it, that's all that matters. He's obviously thrown quite a few sovs at it.
The design of a Scorpion or Mongoose (for example) just looks more "right".
But then, normally all you can see of the system is the tips.
Re:
Posted: Mon Sep 17, 2007 10:21 pm
by hubble
One of the nicest double-barrels I've seen for a long time.
Re:
Posted: Tue Sep 18, 2007 12:37 am
by Kos
its powerflow, you can see the stamp on the rear silencer.
depending on which branch you go to they are generaly very good, and price is a hell of a lot cheaper compared to other custom systems.
always used them and probably always will.
looks good though mate !

Re:
Posted: Tue Sep 18, 2007 12:49 am
by Steve-E30
Think my system is 2 1/4 inch piping ?? my backbox is the same , Single exit into 2 as well

Re:
Posted: Tue Sep 18, 2007 12:50 am
by phil-ray
looks lovely mate, I'll be changing mine some time to this style!
Posted: Tue Sep 25, 2007 8:29 pm
by BMracing
Thanks for all your comments guys, glad to hear a lot of you like it, and that its influencing!
I enjoying the sound and the top end gains, I am a little bit concerned though about what Gareth says about the flow not being smooth, i'm really fussy about things like that and it bugs me. The guys at my local powerflow said they could change the backbox if i thought it was too loud, but they definitely don't have a 2 in 2 out box. I could go for a single tailpipe but that would spoil it i think, or fork out for a scorpion/goose backbox, which is hassle and costly

Posted: Tue Sep 25, 2007 8:36 pm
by StuBeeDoo
BMracing wrote:fork out for a scorpion/goose backbox, which is hassle and costly
..... And is only 45mm!
Posted: Tue Sep 25, 2007 9:03 pm
by BMracing
Good point!