New 2x 2 inch exhaust system - 325i

[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.

[agreen]

looks good fella i like dtm on e30s but thats my opinion

[agreen]

looks good fella i like dtm on e30s but thats my opinion

[Jhonno]

who made it? mandrel bent?

2x2" is a little big for a 325i.. Ok for top end tho

[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.

[Jhonno]

yeah was gonna say after looking closer doesnt look mandrel..

[zaust]

The louder the better...

[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!

[Jhonno]

i dont think the alpina system is 2x2".. Player6 uses 2x1.75" on his 260bhp m20 iirc..

[maxfield]

Alpina is 50mm IIRC.

[Jhonno]

[snoops]

50mm is roughly 2 inches? can't beat scorpions, nice smooth sound at low rpms then comes a throaty roar

[Simon13]

alpina system is indeed 50mm over the stock 44mm pipes

[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.

[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?

[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

[Jhonno]

depends on the dia of the outlet tbh.. Some e36 systems use weird setups like that and make 192bhp

[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

[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

[gareth]

the non mandrel bends compared to a bunch of sharp edged 90° bends?!!! hardly!

[StuBeeDoo]

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.

[Dan320is]

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.

[Jhonno]

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

[gareth]

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!

[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!

[StuBeeDoo]

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.

[hubble]

One of the nicest double-barrels I've seen for a long time.

[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 !

[Steve-E30]

Think my system is 2 1/4 inch piping ?? my backbox is the same , Single exit into 2 as well

[phil-ray]

looks lovely mate, I'll be changing mine some time to this style!

[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

[StuBeeDoo]

fork out for a scorpion/goose backbox, which is hassle and costly

..... And is only 45mm!

[BMracing]

Good point!