exhausting...

ok other than westi, as i hope he posts in here too, who else has made their own exhaust pipes?
going to have a crack at fab'ing my own up for my subie conversion
any tips for merge collectors, my sadistic side says i should do it myself 😂
also whats the go with cats, ill need one to save red tape etc later but im limited on space as we all know with conversions, so whats the requirement to make it legal emmissions wise say a guide on sizing or something?
same with whats my best chance muffler wise of having it at legal sound levels?

so far ive got the heads to the merge mostly sorted out but the merge design/cat/muffler/available space combo im struggling with...
now straight pipes i could do just fine, but i think ill take a few attempts at the merge to get it right 🙂

eagerly awaiting advice suggestions, other than pay an exhaust shop to do it, im doing it myself ok

Well, given that you're using a Subaru engine, the choice of catalytic convertor is obvious. Either use a stock WRX or STi cat, or use any of the aftermarket replacements recommended for this motor.

As far as mufflers go, try fitting the biggest one that will fit, volume usually helps you out a lot. I'm no expert on the selection of mufflers, but there are books and online sources out there with plenty of detail about choosing a muffler. I would buy a merge collector and weld it in, but if you feel like giving it a go then do it! Good luck, and please post up plenty of pictures of the results!

mine are hand made. not by me though richard at vforce did mine.

Your welding is better than mine and you've seen how all my home made headers and mufflers turned out.

You need FA muffler on a turbo engine, you know how tiny that new one of mine is and it's quiet enough a turbo will be quieter again.

Just get a highflow aftermarket cat like that one of mine, stock arent worth shit, too restrictive and passed used by anyway.

Holzl did mine as well - stepped merged system

best off to just pay some one to make it.
I just got the local muffler guy to do mine a think my cat is a small steel cat???
and get them to make sure the 3inch pipe coming down from the turbo clears the drive shaft etc when the suspension travels up and down.😂😂
and still be able to work on your motor eg to take the spark plugs out etc with out taking the exhaust off.
No emissions test in NSW.

Just one pet hate: How often do you see the outlet pipe on a collector funnel, welded INSIDE the collector, instead of being belled and welded outside - which doesn't LOOK nearly as cool.

MOST retail extractors, without proper merging, if you cut open the collector area, the secondary pipe protrudes well into the "extraction" area, causing huge restrictions.
These pipes look good on the outside "for sales purposes" but don't do much to "extract" exhaust gases.

There is one brand on the market (Melbourne) that does it properly - but they tend to use use smaller cross-section tubing, which doesn't help in high performance applications.

waveman -stock cat too long
Barls & Bizzare, what did the, what appears to be ceramic coating? cost you ontop of the system? - ballpark figure would be awesome
Ian - i didnt buy a tig welder for home for nothing 😂
joel - jump on msn sometime & ill nut it out with ya so far

i have only got one path to go through that will fit 3" pipe from turbo to outlet, up over the kafer brace, around the axle & IRS arm, squeezing between the torsion tube, sway bar and IRS, going under that, then kicking out slightly to go around the up pipe section from the 2-1 merge, hugging the pipe coming from the drivers side head/sitting just below the plugs/cover & exiting just below the remanufactured bumper bracket, if thats not quiet enough ill have to go down in size & go around the engine sitting JUST behind the rear valance & exiting out the section of the aero guard that kicks up a little bit at the rear, but thats a hefty amount of piping if i have to go that far, oh, NOTHING will be hanging below floorpan height 😀 - or at least VERY close to that height
despite the challenge im enjoying this, wait till im finished though haha

magnaflow do some nice cats and many muffs on ebay

if you look back through some of westi's very early posts he shows just how to do merge collectors properly with a "jig"

my ceramic coating cost close to $350

remember tho, nothing wrong with the subie system and a re invented wheel will still be , well , umm ROUND 😀

i'm sure you have seen Steves dump system

sounds like the path mine goes. out of the heads down and forward through the heater boxes, into the headers merged over the gearbox then up and in to a glass packed muffler under the left hand rear guard.
as for the ceramic coating, cant remember what it cost but it wasnt that much more compared to what the exhaust cost me. around 2-300 dollars i think for the coating. richard knows for sure.

Joel,

FA?

Cheers

Newt

correction, ahead of the IRS arm, between forks & sway bar, thankfully theres clearance for both styles of swaybar, didnt think that sounded right how I typed it out before its funny how exhaust design affects coolant & oil systems too 😂
any objections to an unmuffled section to exit out the guard just behind the rear tyre hehe
cheers for the tip on magnaflow gear daimo 👍 still gotta make a trip thru that way but its looking like nationals at the earliest

trying to avoid having it go back across the car again as that will mean hanging lower than id like unfortunately - can anyone tell ive been using odd bits of bend & a tape measure the last few hours?

Newt wrote:Joel,

FA?

Cheers

Newt

F**k all 😉

My new muffler is tiny, 12" long mercury turbo muffler and the 2.5" hi flow catco cat with mandrel bends.

Not what you call whisper quiet, I still get mistaken coming up the road for the neighbors STi WRX but it doesnt set off car alarms anymore like it used to and idles quieter than a stock VW engine.

The trick to shutting them up is in the tailpipe length

it was recommended to me to buy a sidewinder exhaust for my 1600Tp what about phatboy?

some ideas

westis merge.......🥷😎
http://forums.aussieveedubbers.com/viewtopic.php?tid=60666&page=4

Lots of ideas, lots of talk, no dyno charts...

Hi Dave

Are you going to replace the stock header with a merged set? From all the reading I've done you only need to do this when chasing the last bit of hp.

Hold off doing anything until the Nats, your quiet welcome to have a look at mine, shame that Brad is so far away form you.

Steve

making my own from the heads to tip, i cant run stock setup as my engine/box sits lower & further backwards compared to yours so im aiming to reclaim maximum clearance, rethinking my setup to go over the gearbox now otherwise id have to compromise on the merge on the turbo side but that causes problems for intercooler, oil filter relocation & coolant lines 😂
nutting it out slowly while im off sick from work 👍

heres mine

ok guys i just picked the car up. sounds great with the new exhaust. its well worth the money spent as its a one off custom system to match the heaterboxes
so here is the rest of the pics.









and here it is installed after being ceramic coated





ive currently got a single muffler fitted to it.

cb john wrote:Lots of ideas, lots of talk, no dyno charts...

I made a 4-1 for my 1987 Vmax, coz you can only buy a 4-2-1, and they cost $1200. I made up a merge collector for it, I'd put up photo's but I'm at work. Anyway, I made the centre "pyramid" 1/2 the length of the collector to reduce internal volume, and the outlet diameter was one step up from the 4 inlet pipes (1.5" in, 1.5/8" oulet), then into a meg up to 2.1/4" and 16" long and straight into a 2.1/2" muffler 12" long. The inlet pipes were 1.3/8" by 16" long, then stepped to 1.1/2". The total length from valve to collector ranged from 30" to 36" (uneven-fire motor, needs staggered lengths to pulse-tune evenly on cylinders).
I'm writing all this crap because I tuned my system to work at 6000RPM, and it makes 125hp @ wheel, in other words the same revs and horsepower as your average VW hotrod.

On the only dyno that matters, I picked up 3 tenths and 3.5mph (into a 10mph stronger headwind and 4*C hotter), compared with a good quality 4-2-1, changed them on the same day an hour apart.

I reckon build it yourself, what's it going to cost? A bit of pipe and endless hours of swearing in the shed!
It's all good. 😎

http://forums.aussieveedubbers.com/viewtopic.php?tid=58055&page=3

begins 7/5/2007

DUUUUUUDE i had no idea that you made your own exhaust! thats awesome 👍 im still yet to find a 2-1 merge which is what i need to make, but i think its sorted & im going up over the gearbox & exiting out the RHS so i have room for a neat merge on the LHS, damn turbos make life difficult for making things fit 😂