L-series - ideal exhaust setup

[subalex]

This is a thread that seems to have disappeared from the forum listing here so I thought I'd re-ask the old question and see how we go for suggestions and pricing.

I'm right now about to buy a new exhaust system for my '91 L-series wagon. I've called three locations for their pricing based on the following system requirements:
Cat back - 2.25" piping, hotdog (resonator) in the mid-section, main muffler, chrome tip of my choice.

All of the suppliers said that they would swap over the hotdog and/or muffler to achieve the sound that I liked and all would use mild steel items.

They all told me that the main muffler brand would not make much of a difference as the materials were all the same and they all make a variety of designs - straight through, two bends, three bends etc. and it is mostly in these differences internally that the different sounds were achieved, along with the length of the hotdog.

All also agreed that Subarus all have a low 'boxer' sound that can be boomy inside the car and that if I wanted that louder, rumbling exhaust tone then it would also be louder inside the car.... you can't avoid the booming sound in the car if the pipes are bigger and more open in design.

So, the three different quotes so far are: including Redback products $280 fitted; the second supplier uses Lukey products and quoted $400 and the third supplier uses their own brand "Swift" that they make themselves and they initially quoted $570... they've brought it down to $340 after telling them the competitions' quotes. The cheapest supplier will weld everything together and not use flanges at the joins. The other two will. All the piping will be custom made to suit my needs re: lift kit and tucking it up out of harms way.

Personally, I'm really stuck as to the pick of these three. The only thing left to decide is what kind of main muffler design and what size hotdog to use to achieve the best sound I can live with on a daily basis as well as really enjoy.

Any ideas? Post them up.

[subalex]

If anyone is interested, I had a system fitted today and, so far, it seems pretty much what I wanted: the nice burble from the exhaust on the outside, a little more boomy inside when accelerating but when cruising or off the throttle it's pretty much the same as the standard exhaust except with a tiny bit more of the burble there to remind you it's there.
Key to getting rid of the drone, apparently, is using a spiral internal design of the hotdog.

[beastofburden]

Well I,ve never done this to a soobie b4 but i,ve found if u put extra clamps from exhaust pipe to body, you will stop droning or resonance.. Could be a cheap fix? just my 2c cheers Steve

[CPOCSM]

Gday - I recently got the L series done with a cat-back 2 inch, retained the hotdog, and a supertone muffler with a 2.5 outlet. Has a very nice drummy tone and really sounds great. No droning in the cabin due to the hotdog muffler(personally it is a necessity!!!) and all the mounts in the world wont stop it - all to do with the shock wave travelling down the pipes.

All up it cost me $160 fitted at a local Queanbeyan muffler shop - great service and the fellow that did the instal loved it so much, he is on the look-out for a soob to do the same thing...lol:p

Whatever your choice - enjoy it. Dont go silly and put a 3 inch system or bigger on - you will suffer from bad fuel economy and the ridicule of your peers...tongue in cheek of course:D

Hooroo

[subalex]

True CPOCSM, there's so many young fellas getting around with those enormous pipes on small engines and it's ruining any chance of having torque down low in return for those extra 3% (at maximum) kilowatts at the top end when revving the proverbial out of it... it's laughable.

That said, I feel totally conspicuous at the moment since I don't have any better engine in my L-series than the stock EA82 so far but it makes a good sound, a really good crackle from the tip when you take the foot off. The exhaust was fitted with a 3" tip... looks good... just fits nicely between the bumper and tow bar. It would be better with a smaller set of pipes (2" would be fine) but I decided to get the exhaust suitable for the EJ engine coming up. As for your system cost... holy Moses that's cheap!

[subyleone]

I have a 1984 MY Leone with an EA71. Exhaust is already 2 inch and has hotdog on it from what im sure is standard, different from every other leone I have seen. Only thing holding it back is the stock muffler wich was removed in favour of a straight pipe. will be getting some kind of cannon muffler for it soon but havnt decided yet.

[CPOCSM]

Yep I think the resonators were standard to stop the drumming of the boxer engine - if you have ever owned a VW beetle - try driving it 600km on a aftermarket exhaust...my ears were bleeding - Subarus are the same - if you remove that resonator(hotdog)you will be tone deaf within a week...

Really nice sound though - I have a mini with a lukey 2 inch but the perforations go right to the tip of the tailpipe - the little A series noise and the 3 port exhaust make a horn sound:twisted:

I will get some pics up of my setup for you all...

Hooroo

[discopotato03]

Yes a real Cooper S (no not 1100 S 1275) sounds nice , even better with a works 648 cam / long center branch extractors and a 48mm side draught Weber on the long 7" inlet manifold which required a box mounted back through the fire wall . Ah and 38mm chokes in the barrels .

As I keep saying , in my experience what helps shut exhausts up is soft points like those braided wire covered concertina joints .
Virtually all transverse mounted engines have them because the engines torque reaction is fore and aft rather than side to side so to prevent the engine pipes breaking the flex joint is needed to allow the engine to be only restricted by its engine mounts - the exhauste doesn't try and act as a long engine steady bar ...

A lot of the boom/resonation poeple get is because a lot of the engines vibration (remember sound is vibration) can be transmitted down the pipe - mainly because this pipe is hard bolted to the cylinder heads and is quite rigid - unless it has flex joints placed in it .
Blind freddy can see that the engine and gearbox are hard bolted together so the soft joint needs to be behind the gearboxes exhaust mount/hanger .

Big bore exhausts make exellent echo chambers and the very nature of their larger cross section makes them more rigid and capable of acting as a bloody great engine steady bar/vibration transmission pipe .

I reckon beyond 2" on any N/A EA is a waste of money and adds weight for no real performance gain .
The state of tune of EA82s is soft soft soft , they were aimed at making some torque at lowish reves and beyond that their aint a whole lot happening . They are predominantly a front wheel drive car engine .
If you look at the factory WSM's you can see that the cams are pretty tame / the compression ratio nothing special / heads with smallish pre historic ports and really woeful inlet manifolds - and thats the twin inlet port MPFI ones .
The carburetted ones are worse with the tiny venturies and half the inlet port area - and even softer cam profiles .

This is why there is not a lot of point in fitting large exhausts to them , the state of tune won't allow the engine to breathe and rev so taking a lot of the restriction out of the exhaust often just makes more noise and the engine can actually run worse .
The reason why thats the case is that everything in an engine that see's gas flow is part of an integrated system - it's a matching set of systems all tried and tested by the manufacturer .
If they'd wanted more power from a higher state of tune they would have altered a series of things not just one ie the exhaust - behind the cat .

Do as you will but don't expect great gains fom just the exhauste . There ARE 2" bore mufflers that do silence and flow well enough , maybe not super cheap but work better than a cheap nasty 2.25 inch system .

Another largely unknown fact . Exhaust gas cools and contracts in its way along the exhaust so you can start slightly larger at the front of the system and reduce towards the back . Maybe 2.25 to the resonators outlet and 2" beyond .
There would be a tuned length and size for the header pipes but given the engines realistic rev range and state of tune I wouldn't think they'd be real big - or long in the primaries . If you can make sensibly sized secondaries equal length that may help as would replacing that pathetic excuse for a std cat - they really are restrictive because of the lack of smarts with cats in those days (mid late 80's wasn't yesterday) .

A .

[subalex]

This sort of information is what I was after. No, not necessarily the Mini info but it all contributes to the point. I had a 2.25" system fitted based on what I had read on these forums over years and that size was best recommended for a good sound on the EA82 and since I'm looking to go for a bigger engine soon then I asked around the workshops and they agreed that the 2.25 would work well for the bigger EJ engines. If that was poor advice then I'll be paying for it... but that's my choice to take the advice in the first place. Interesting about the smaller piping toward the back that Discopotato detailed. The muffler installer suggested that if I did go EJ20 turbo then I could go a 2.5 system in the middle section and keep the 2.25" parts I've already had fitted at the rear.

[CPOCSM]

Yeppp - I would be doing that right there. 2.5 is plenty big enough and you get a good note and a good return of power.

As for the mini stuff - the twin box setup on them actually makes 4 more horses than the single box one. The RC40 is a funny thing - trust the poms to invent it! There is nothing like a nice exhaust note though - on any car...especially when the angry pedal is flattened.

Have fun - I am trying to youtube my exhaust for you to no avail...

Off to Shidanee - see you all when i get back:D

Hooroo

[chubby37]

i spoke with a pommy exhuast guy a couple of years back and he said the HUGE exhuast was a want thing.(his words not mine)..he raced cars...turbo and n/a and said that even on a worked turbo car it would be not worth going over 3"...i mentioned subaru and he said that anything over 2" you starting to loose benifits....back pressure...unless you have had headwork....he strongly advised againt anything over 3" on turbo car as it will just run out of puff...all i ever do now following what he told me is keep close to standard...even on EJ....and open up the rear muller and open up the air intake...get it to suck in as much air as you can and get it out the back as straight as you can..upping the size of the pipe work to greatly will couse sort of like pooling...instead of the motor pushing the spent gass out under pressure it will bee more like a drible.....turn on your hose and put you finger over the end little by little and it gets a stronger stream...take your finger off and it just flows.bigger the hose the bigger the effect..same thing...the pipe acts like your finger on the hose...if you dont have some sort of restrictive behavier you loose preesure..

hope that makes sense

[discopotato03]

I'm not in agreeance with the backpressure bit but it seems to be something people can grasp and unhook the I need a downpipe sized exhaust system .

It's really about having adequate gas speed in the exhaust system to keep the gasses moving in the outwards direction .
Exhaust like any gas has mass and therefore when it moves at any speed (velocity) it has momentum .

When you take a properly designed (for the manufactures purposes) std exhaust and replace it with a larger one it changes the whole world the engine "see's" . Because it's larger and has more volume the gas speeds beyond the start of the larger exhaust will be lower , gasses moving at lower speeds have less momentum and given the chance it can momentarily stop or even leak backwards into the cylinders in the engines scavange or valve overlap phase (inlet valves starting to open before exhaust valves are fully closed) . What you do is lose the scavange effect of the exhaust gas velocity (creating area of lower pressure downstream of the exhaust valves to "pull" if you like the last dregs of spent gasses with them) .

Now to learn what makes an engine potentially grunty - it's called TORQUE
and its important to run an engine somewhere around its torque peak if you want it to pull the car along in style .
The old saying used to be torque wins races and horsepower/ kilowatts sells cars - marketing departments LOVE Kw numbers because they are generally higher that torque numbers and moores law sells - bigger number bigger manhood extention . Some wag mentioned recently that women have less to start with so a greater extention to achieve perceived equality ?
Sorry folks - have to dodge far too many fairer piloted Cruiser/Patrols round here .

Take this to the grave - virtually ALL production engines make their TORQUE peak a lot lower in the engines rev range than their Hp/Kw peak .
It is the torque we are trying to boost to make the heap pull harder so the bit to enhance is around the torque peak and that's not going to be high up in the rev range . Now , because its not up there the gas flow won't be either so the system doesnt need to huge to complement whats going on at peak torque revs .
Most people realize that big sysyems usually cost engine torque - they attemp to move the torque peak upwards . The trouble is that the ports/valve sizes/cam profiles/AFM + filter parameters are not suited to the higher state of tune . You've killed the low end torque and the engine can't breathe well enough to make anything worthwhile higher up .

These are the reasons I wouldn't go beyond 2" on an NA EA82 , I also wouldn't fit an "EJ" sized exhaust to an EA powered L series - I'd skip down the wreckers and fit a cheap temporary or put up with what I already had if it was servicable .
I think you're better off using the money on the conversion if thats what you want .

Hint , I layed the exhaust off an early Lib sedan over an L series one at a wrecker and they are quite similar - possibly similar enough to cut weld and jury rig quite a reasonable temporary together . The Lib one looked like proper 2" where the L one was a little smaller .

Keys rattling worse than 291K old EA lifters , spud out .