Jay m A

iTrader: (2)

Hi all

I have a MY95 WRX which I believe has the older,larger and laggier turbo.
Its time for my decat downpipe, I'd like more torque rather than bhp but ultimately I'd like the turbo to spool up quicker.

I assume any decat dp will have this effect, but my question's is what one is more suited to the bigger turbo?

I read that 3" is for bhp and 2.5" is for torque (generalisation I know) but I'm a tad confused on the differences between twin dump and the non-twin types.

Any ideas? I have a Scooymania straight thru centre section (3") and a STi back box at present mated to the OE dp.

Any comments appreciated

Cheers

Justin

Graham Stocker

Same situation myself Justin 95 wrx tanabe mid setion and back box . But which downpipe to go for ?. Graham.

Leigh

I have the scoobysport downpipe on my 95 wrx, the turbo seems to spool up much quicker than before, and I've had 259bhp (powerstation) or 272bhp (well lane) depending on which rollers you believe. My only other mods are a blitz induction kit and fujitsubo legalis R exhaust...and octane booster, of course!
The scoobymania downpipe is a very nice piece of kit also. (it wasn't available when I was looking for a downpipe)

[This message has been edited by Leigh (edited 12 March 2001).]

ChristianR

iTrader: (1)

i would go for a bpm downpipe - as it will handle the bigger turbo.

get it from brdevelopments.

Jay m A

iTrader: (2)

Thanks for the repies, keep em coming!!

The BPM, is it twin dump? 3"? Made from stainless? I heard when they first came over they were made from MS....is this still the case?

After doing a search I'm kind of favouring the Scooymania dp, any comments on these?

Cheers

Justin

steve McCulloch

Yes BPM was MS - and then they went to SS after receiving a fair bit of abuse

As far as the BPM system goes - I visited Longlife Exhausts the other day.

I showed them the BPM twin dump and the rear GT Silencer that BPM have given me

Longlife would probably be able to replicate the full BPM system for probably half the price! - plus they can give u whatever noise your after! by changing the baffles in the sliencer

They are based in Cardiff and Bristol

If you dont want the hassle I stronly recommend a BPM full system - its the best one I've heard... so far - much meatier than HKS, Scoobsport, and the quieter Scoobymania

Give BR Developments a call if you want to source one

BR should be able to answer your question about torque and bhp


Steve

Trout

iTrader: (1)

I can also endorse BPM.

It enables the turbo to spool up very quickly.

It is also HPC coated - so any copy needs to include this into the price (£50-150).

R

PS I also got mine from BRD.

mattski

My 2p's worth...

I have an MY94 WRX and opted for a full scoobymania exhaust inc downpipe.

The car pulls much harder than it did before and the turbo spools up earlier too. To top it all off it sounds superb and the turbo now sounds like a whistling beast from some dark horrible cave

ta,
Matt

Jay m A

iTrader: (2)

Brilliant stuff.

OK, looks like BPM are worth further investigation, although if the Scoobymania is the more quieter version it could influence my desicion.

I'm more concerned with the cabin noise - i.e. consider the missus but stuff the nieghbours!

Mattski, I've listened to your sound files but I don't suppose I can listen to your car in person sometime?
Same goes for the BPM brigade..I get to most SE meets

Cheers all

Justin

firefox

Is the BPM downpipe Stainless ?

I thought it was mildsteel?

J.

Trout

iTrader: (1)

I thought it was aluminised plastic...

Jay m a - I am happy to let you play in my car, STI (so noisy anyway), BPM, HKS Hiper, both with and without baffle.

It all depends on set-up - Firefox has SS backbox and BPM d/p and I could hear him from three miles away!

I am in Fleet, let me know if you want to hook up.

Rannoch

[This message has been edited by Rannoch (edited 14 March 2001).]

Jay m A

iTrader: (2)

Thanks Rannoch, maybe at the next re-venued Quays meet? I'll mail you next time I'm in your area

Justin

mattski

Justin,

No prob, of course you can have a listen some time... as for when I dunno!

ta,
Matt

Howie

Steve, If longlife produced a replica of the BPM system would that not infringe copyright law. I was under the impression that to be legal there had to be a 10% difference in design, hence - the Scoobymania system, the turbo dump pipe joins the main section further up the main pipe compared with the BPM - does it not?

BPM GT Full system on its way over to me right now - cannot wait , by far the best sounding system for the Scooby! and what a suberb piece of quality Engineering.

Cheers
Howie

[This message has been edited by Howie (edited 15 March 2001).]

steve McCulloch

Barge

Try 192

Ask for Longlife exhausts in Cardiff (they have a site in Falfield - N Bristol as well)

Steve

steve McCulloch

Howie

Dont be an arseh*le! - It does not have to be an exact copy... Jesus....

My bpm downpipe is MS with HPC coating - so it has not rusted thru like rest of the system - that said they sorted that and its all now SS with hpc

If you want a quiet exhaust with similar power for a cheaper price without HPC try Scoobymania (cant say I'd want a non-hpc under my bonnet - for obvious reasons!)
Scoobysport is the meatier option a bit dearer - not much though

But if you wants the sound then the BPM is the one.....soooooooo much louder than any HKS system I've heard. lovely and meaty....

Much as I wanted to change my bpm system I just cant do it... I'd be near suicide... I love it too much... I've got a new rear silencer from BPM... shame they did'nt provide a full rear pipe .. so I have to get Longlife to do some pipe making and welding.. At least I can get rid of the Cat at the same time!

barge

Who are Longlife ??

Where are they ??

Anyone got a WWW address or Phone Number ??

Mac's Power

As a BPM agent I have a full BPM system on my car and it is top notch.

Be warned it is loud!!! I had a sigle dump downpipe on before the twin one and there is a difference. The cars holds it's boost better with the twin dump pipe.

I have the GT Muffler and it's not for the faint harted. I decided to take it off recently as the noise is quite intrusive on motorways etc. I put on the other system we sell which is similar to the SS option and I took it off after a week. I'm back to the good old deep note of the GT. I'll probably have a deafness claim against Greg soon

Paul.

Howie

Steve,

Correct me if I am wrong may be I miss understood your word "replicate". No hard feelings m8, just go a bit easier on the abuse next time

Cheers
H

steve McCulloch

Howie

Sorry

Jeezzzz its like being at work - so many serious folk

nmyeti

Sorry to drag this post out of the grave, but I have a few questions, and have tried to get a straight answer from the search engine, but with little luck and lots of confusion I have found this thread.

First... I have a US spec WRX, and love this car. It is a very nice change from my last ride (a celica GT-S or would be a 190 in the UK I think). I love the extra torque, the AWD, and the way this car is so easy to live with.

Now however, I am in a quest for a bit more power. On my celica I had a TRD exhaust and a pipe and filter kit. The thing was VERY loud. Really too loud when the Cam switch came into play, and I quickly grew tired of the noise for the less than stellar performance increase.

With the WRX... call me strange, but man I kind of love how this car is so quiet, but still manages pretty good power. I already have a pretty good idea as to the power path I will take in the future, and hope to get slightly over STI levels to like 280ft/lbs and 300hp. The problem comes in that I hope to not sacrifice the relative quiet of the car IN the cabin.

I sent a note to BPM and they seemed to think their GT setup with removable silencer, full downpipe and mid section was their quiet exhaust, but after reading some of the comments here I get the impression that this is by no means quiet.

So here are my questions
1. Is anyone running the full BPM setup with the GT muffler and the silencer?
2. If so, how loud is it compared to the stock WRX?
3. I know that loud does not always = performance, but can a quiet system get the job done as well?
4. If so what would your recommendations be along these lines?

Thanks for the help! You have no idea how glad we are to have this car on our side of the pond.

-Nathan
02 WRX

Adam M

Right people,

Hope no one minds if I add a a few bits as for once people have stepped into my arena.

As a patent agent, I am also qualified in matters of design registration, copyright law and also unregistered design rights, which is what you are talking about here.

It would be wrong for me to offer definitive advice on a public forum, but people spurting crap about 10% difference annoys me.

How do you quantify 10% of a design? you can't.

The fact is, it is irrelevant to all intents and purposes, as designs for spare parts for vehicles are rarely protected under the provision that they must fit or must match. Eg. aftermaret door panels must fit the car for which they are made, therefore they do not attract any protection.

In this case, the hangers must be located in specific places, and the exhaust must take the same route from front to back of car as there is not a lot of choice in the matter, so it must fit. Hence no protection.

There is freedom of design regarding the twin or single dump issue, so with this section in mind there might be some consideration but there are a number of twin dump exhausts out there and there is nothing stopping you from creating two pipes at the turbo and joining to one pipe at the mid section, you have to ask how many ways there are of doing this? not many. Unregistered design and copyright sgive you protection from copying only, you cannot be prevented from individually creating the same or a similar design.

Right now that the law is out of the way.

Rannoch is correct regarding the HPC of the mild steel. That is a crucial part of the BPM design. The DP is MS not stainless and must be hpc'd for this reason. Mild steel has different resonance characteristics and as such will change the sound.

It is interesting to note that greg reckons on the DP being actually 6db quieter than similar after markets. Not sure if figure is true, but I know several people who have fitted it who can confirm the dp is actually quieter.

Being a 2.2 my car is different in the first place, but it has been common to my exhausts, so should be okay for comparison.

Car came with Scoobysport system with which I was happy. nice sound, not too loud, not intrusive, plus turbo spooled up fairly low, then again 2.2 helps massively here.

I wanted a change only because the car is being used at weekends now and not so much for getting to work so noise wasnt a big consideration. Also, wanted a touch of originality as ss is the norm wherever I go. I knew bpm was supposed to be loud, but that was no longer an issue, plus I did like the idea of twin dump especially on a larger turbo such as the vf23.

Trusted friends had mentioned reports of the bpm downpipe flowing better towards the top, some had said at the expense of low down torque. I felt the car was strong enough at the bottom getting weaker towards the redline, so made up my mind.

Downpipe decided.

just a note that both sm and bpm are three inch twin dump, BPM dunp pipe joins main pipe much further down whereas SM joins very close to turbo end.

SS dp is also three inch but single dump, opening in one big hole over wastegate and exhaust exit, tapers to 2.5 inch before joining centre section. This designed is lifted straight from group A.

Trouble was remainder of system is 2.5 inch and dp is 3. Fluid dynamics has taught me this is a bad thing, as pressure wave reflections will occur at the join, so a three inch system had to go on.

Options are full bpm or mike at scoobymania.
Also HKS but for some reason I didnt even look at this.

Was tempting but in the end ordering the dp from australia, postage is already paid so I thought full bpm.

Now remaining choice is gt or twister.

The twister doesnt have a silencer in the bb, but splits into three pipes then rejoins before the tail pipe (on the mark 3). The rejoining of these pipes is supposed to effectively suck out the exhaust more so than it being driven out by the piston. I am sceptical about this and have asked greg for the patent number so that I can read how it works, but have received nothing as yet.

The twister was the top of the range and had been proven to be more effective on dynos in australia against other exhausts so I thought, bollocks! why not? I feel the car deserve top of the range stuff so I went for the twister mk3.

Ordered from greg in aus, but dont advise this as it is less convenient and phone calls add to bill. Did arrive very quickly though.

Centre section and bb are full polished stainless, tail pipe is not great looking on the twister, has letters BPM wleded on top.

Tail pipe has a corkscrew (bung) in the middle of it which is removable for more noise and supposedly power.

Full system comes with sports cat in the centre section. I asked greg if he could supply a straight through centre, but the difference in price would have been £33 so I went for the cat, knowing I could insert a scoobymania pipe if necessary.

Fitting.

Pat fitted the system for me, in stages. Thanks

First bb mated to ss dp and ss straight through centre. The result was raucous as Pat Moray and R19KET will confirm. Bloody loud, and it barked kind of like blipping a ferrari, but much more angry.

Turned many heads and set off alarms. I was happy with it, but it would have become tiring, was quiet on cruise though! Sounded like there is a whirlwind underneath the back box. Interesting

Removed bung. Bad idea. Sounded like it had no exhaust, very very loud. Painfully so, all the time. Very embarssing

Then fitted BPM dp and BPM catted centre follownmg week. Cat should soften things, plus reported effects of quiet dp should have effect .

All in and fittede. Finish is lovely.
Car is pleasant and almost as quiet as scoobysport when the cat and bung are present. Doubt it could match SS for volume with cat and/or bung out.

Steve's system is the quieter of the two bpms prob. cos he doesnt have a centre cat, I am guessing. Also the twister system without the bung when mated to bpm centre and dp is still phenominally loud. deep powerful sound would be tolerable but unfortunately too boomy at cruise, good for track days if under emissions levels.

Answer is to leave the bung in , which creates a whoosh sound. Not pleasant through tunnels though too high pitched, sounds like a loud gas leak. Sounds great out of tunnels though which is most of the time!

Worth noting it is quieter than any other system I know (barring standard), when actually boosting, just not when driving normally.


So, I am happy with fit and volume is loudish but certainly not much louder than other systems. I also have the benefit of a cat which when warm may get me through an mot, although emissions strictly speaking should not be tested on my car, but it should also pass road side stops should they become more common!

Performance is the key issue.

Wow is all I can say. The car does almost exactly what i was expecting. It pulls like a train on the standard ecu, from boost to redline with no hint of tailing off. I have no signs of leaning out on lambda link, and knocklink shows bottom green light at worst.

This is running super and millers which is advisable on a jecs'd 22B.

The crucial point is I have not really noticed any significant change in spool up point. No more lag than previously. I was prepared for a drop but there has been nothing really to report. Originally I thought there was a slight difference, but the more I make a point of looking, the less I can perceive.

In all I am very happy with the exhaust. The car is faster than it has ever been.

Only problem was knocking when going over bumps, which was associated with the difficulties of fitting it with only a trolley jack and drive on ramps.

With the car on proper ramps this was sorted within ten minutes by a competant exhaust specialist .

Sorry if I have rambled but I hope any one looking will find it useful.

Can't do sound files, but if anyone is in north london, they are welcome to have a listen.

Adam




[This message has been edited by Adam M (edited 14 May 2001).]

Pete Croney

Adam

just a quick point, your Scoobysport DP would not have created a pressure wave reflection, the taper has been carefully designed and positioned. The location is also well within the temperature/pressure range for going to 2.5".

Incidentally, BR was using a Scoobysport downpipe when he recently got 347bhp at the PE Rolling Road day. Bob had returned to a Scoobysport downpipe, finding that the twin dump systems were detrimentally affecting boost control, meaning that mapping could not be as accurate/aggresive.

I'm confused about one thing... If I have read correctly, you seem to now have a 3" system that has a bung in the end?? And is unbearable with the bung removed???

Adam M

Pete you are correct about the tapering, I should have made it clear. A reduction from 3 to 2.5 inches in an abrupt step causes a discontinuity which will creat pressure wave reflections. A smoothly tapering pipe such as your dp will not create this effect if if maintains lamina flow, which having seen it I am certain it does.

Bob Rawle would udoubtedly be able to confirm this as I belive he does fluid dynamics for a living.

Bob had mentioned the affects of boost control to me, when approaching the top end of the rev range, and from what I have learned, it does create a problem, by making it more difficult for the mappable ecu to control.

I do not have a mappable ecu running my car at the moment, but the jecs is adaptable and hopefully would be able to cope.

I am not a mapper, so all I can do is concentrate on the lambdalink and look for anything untoward. So far it seems fine and the boost towards the top end is maintained for any length of time taht I am noticing oddities.

It is odd to buy a freee flowing three inch system then block it up with a bung, but this serves to distort the flow of air enough to silence the thing a bit. Which is does well. The point is, it enables raised performance on the track without excessive noise on the road.

The car is noisy without it, so in this respect I would avoid it if you don't like noise.

If a pleasant sound that doesnt make a feature of the noise of your car is what you are after then gop for a scoobysport or SM (which I have less experience of).

I have to note the look of the scoobysport is without doubt my favourite, as it fited perfectly into the recess on the 22B spoiler, and also the whole system sits 2 inches higher than the bpm.

I also forgot to mention prices!