EA81 Exhausts

Brumby Kid · Post by **Brumby Kid** » Sun Feb 19, 2012 8:59 pm

Hey All,
Dad has agreed to a new exhaust.
2 Problems.
1st, What is the best way to go / best parts.
2nd I have to meet gay guidlines for my L's and P's. But the car is registered in Dad's name.
We want the best noise/performance asap.
So we were thinking of getting a "standard" Lukey exhaust from the headers back.
2.5" I think is what i have been told is best? Would this be legal?
Then once i can i would like to swap some parts like the tip, muffler etc.
Or am I allowed to have everything performanceized now?

Thoughts, knowledge and a tool to pick your brainz would be Awsome

Cheers Cam

alx92 · Post by **alx92** » Sun Feb 19, 2012 9:13 pm

check youre states mod rules... doubt youll have issues with the performance aspect for your licence

noise would be the only kicker (attracting cops), but that shouldnt affect your licence restrictions

stenno · Post by **stenno** » Mon Feb 20, 2012 6:44 am

Extend the headers to 28 inches long both sides into a shallow angle merge then a 2.5 inch cat then 2.5 pipework to a muffler at the rear. 2.5 is standard commodore size if you want to use 2nd hand cat etc to save some coin.
At least thats what I've seen thrown around on here and usmb as "best"

steptoe · Post by **steptoe** » Mon Feb 20, 2012 7:41 am

2.5 will push the budget, 2 inch is more than enough and go resonator then muffler keep it quiet to avoid the ears of the cops. My quiet EA81 std exhaust goes just as well as my noisy 2" no resonator EA81. A doodle head I know that should have known better, cut the guts out of his bommodore utes rear muffler, tore through a small town on the way back from a B&S, low gears and got the wrong attention, copped defect for muffler, non compliant Xmas tree lights and a bad attitude. Go for induction roar as it sounds better and is more controllable !

Brumby Kid · Post by **Brumby Kid** » Mon Feb 20, 2012 1:34 pm

Ok, so,
Where are the Mod rules, I can't seem to find any,
What is a resonater? As opposed to a muffler?
How do I get induction roar? Sounds good.

Cheers Cam

steptoe · Post by **steptoe** » Mon Feb 20, 2012 4:46 pm

google ? You'll find the standard exhaust has a small muffler first after any cat, that can be your resonator cuts out raspiness getting to the muffler at the rear.
I opted for no resontor or hot dog just went sports muffler 12 years ago and been promising self to quieten it down - gets awfully drummy on long hauls, so much I wear ear plugs, then it all feels and sounds weird until I adjust once plugs out after 300km. Just been waiting to EA82T my ute past six years before I get new quiet zaust !

Silverbullet · Post by **Silverbullet** » Mon Feb 20, 2012 5:23 pm

I've been googling it for about a year and I still can't find the .pdf with a list of allowed/not allowed mods for P platers...why oh why did I delete it in the first place?

I would have thought 2 1/2 inch would be overkill, I'm going for 2" from the Y pipe back with a hot dog and Lukey turbo muffler...then again my new Y pipe is not your bog standard EA81 Y pipe

Oh should have said, My brother's 04' WRX has a non-factory 2 1/4 inch system, and you can hear it coming from about half a k away when you're inside the house.

subaruby · Post by **subaruby** » Mon Feb 20, 2012 7:18 pm

2 1/4 exhaust

resonator

muffler

sounds good, not too droney and slight improvement in performance:)

Brumby Kid · Post by **Brumby Kid** » Mon Feb 20, 2012 7:34 pm

Ok, So is the resonater/hotdog another name for the catalytic converter?
Or is it instead of?
Kinda confused, but i do know what a muffler is yay:rolleyes:

Cheers Cam

subaruby · Post by **subaruby** » Mon Feb 20, 2012 7:58 pm

Catalytic converter would be at the engine end where the two pipes join into one. Mine does not have a catalytic converter as it was not required in 1984, the year of my car. Yours should have one though, resonator is the one in the middle.

mud_king91 · Post by **mud_king91** » Mon Feb 20, 2012 8:12 pm

i have a huge ass book of compliance and road rules and unfortunately cam under new "high power" restrictions it must be a stock exhaust... the good news is 90% of cops wouldnt know what they were looking for if it bit them in the face iv got 2.5 with a smashed cat into 3 inch tip with high flow intake and i havn,t gotten in trouble so far

Brumby Kid · Post by **Brumby Kid** » Mon Feb 20, 2012 8:52 pm

Ok,
Thanks guys for the current info.
If you have more i would love it!

Cheers Cam

coxy · Post by **coxy** » Mon Feb 20, 2012 8:59 pm

OK who decided 2.5 " is the go for a rather ordinary breathing pushrod engine,seriously that is nothing but wank factor and will lose performance.

I build performance engines and exhaust systems including headers for a living and have done since the early seventies so I believe I know more than most.

Giving you an example of one of my own,I rallied a Nissan Stanza during the early eighties with some pretty nice Ex Works gear,I initially ran group 2 specification without the Factory FIA Cylinder head and when this engine 10.5CR twin 48mm Webers with 40mm chokes works 76 Degree Cam big valve fully ported head CDI ignition etc.

The Exhaust was a works spec 4 into 1 header and a good 2" system,I changed this to a 2.25" exhaust and lost power especially torque and throttle response.

What I had to do just to regain the lost torque involved a Barry Seton designed 4 into 2 into 1 header an increase in Compression ratio to 11.3 to 1 and more Dyno time.

This was a pretty efficient high performance Rally engine with some 190HP and it could barely use a 2.25" exhaust,therefore don't go telling young guys with no experience that a 2.5" system is the go for an EA 81 as it sure as hell is not.

If you want a good system for an EA81 look no bigger than 2.0",use good quality mufflers and remember noise only equates to look at me.and then it is usually only the Cops or some Twit laughing at you.

A mate over from New Zealand totally cracked up when he saw young fools were Modifying Hyundai Excels in this country,so know the good points and limitations of what vehicle you have and act appropriately.

For an EA81 a good sensible Exhaust,maybe a Weber conversion though not an overpriced Ebay conversion,homework here will give the results for minimal cost especially trawling wrecking yards looking at other models ie Fiat,English based small Fords etc.

The information is out there and a good example to look at is the Competition Cams website in the USA,whilst not early Subaru specific they have calculators online that will change your mind on just how much exhaust,Camshaft and Carburetor size actually works and is recommended by professionals,generally much smaller than you think unless it is for a full competition spec application.

sven '2' · Post by **sven '2'** » Mon Feb 20, 2012 9:08 pm

^^^ like he said.

See Dave a Gepps X Exhaust.

He will sort something spot on (he has done a few Subes - incl my MV back in the day), meets all the regs, and importantly will not drone (something I have never understood why anyone would tolerate on a road car).

Good price too.

YouTube · Post by **El_Freddo** » Mon Feb 20, 2012 11:16 pm

stenno wrote:Extend the headers to 28 inches long both sides into a shallow angle merge then a 2.5 inch cat then 2.5 pipework to a muffler at the rear. 2.5 is standard commodore size if you want to use 2nd hand cat etc to save some coin.
At least thats what I've seen thrown around on here and usmb as "best"

I've not read that on here for an EA81! TOO big! I've got an EJ22 and it's a 2 1/4 inch cat back system that goes well. That's a 2.2 litre and a smaller diametre exhaust than a 2.5 inch system. Put that on a 1.8 litre and you'll have all sorts of pooformance issues.

steptoe wrote:2 inch is more than enough and go resonator then muffler keep it quiet to avoid the ears of the cops.

This is what you want. And if you've got a good exhaust shop and some time to spend with them they *might* even let you try out different mufflers to hear what they sound like to get exactly what you want.

The resonator is generally what stops the rhythmic "thrumming" when cruising. It also will effect the note of the engine but is not really as restrictive in noise as the last muffler from what I've been told.

steptoe wrote:You'll find the standard exhaust has a small muffler first after any cat, that can be your resonator cuts out raspiness getting to the muffler at the rear.

Yep, definitely get a resonator, you're just wasting money if you don't!

Brumby Kid wrote:Ok, So is the resonater/hotdog another name for the catalytic converter?

Nope, two entirely different parts of the exhaust system. I've seen an EJ22 exhaust system that just had two hot dogs in it, one in the centre and one in the rear where you'd normally have the rear muffler.

sven '2' wrote:He will sort something spot on (he has done a few Subes - incl my MV back in the day), meets all the regs, and importantly will not drone (something I have never understood why anyone would tolerate on a road car).

Yeah a good exhaust shop will know what they're doing. I was lucky with mine - as I walked in to discuss my exhaust with them a modified WRX was on the hoist having it's exhaust done so I figured they must have been doing something right.

For a cat back system about 3 years ago it cost me $450 cat back, mild steel and most likely bottom line resonator (I wanted the hot dog style, got a square one

but didn't specify) and rear muffler. Good subi note but not as refined as some WRX's or NA foresters that I've heard...

If you get the extractors (Y pipe) built and you want the subi "beat" you need to keep one pipe longer than the other, if you make them equal length you'll lose the beat

The other thing to remember is that with exhausts, as the diametre of the pipe increases linearly, the area of that pipe increases exponentially.

Cheers

Bennie

Edit: Subaruby's exhaust has a great note for an EA81

Brumby Kid · Post by **Brumby Kid** » Tue Feb 21, 2012 9:05 am

Ok,
I think i only have a cat and a muffler currently.
Will check tonight.
Yeah i'm after that nice suby beat, not too loud but louder than stock.

Cheers Cam

Silverbullet · Post by **Silverbullet** » Tue Feb 21, 2012 5:58 pm

Brumby Kid wrote: Yeah i'm after that nice suby beat, not too loud but louder than stock.

Cheers Cam

Me too, I think the word here is subtle. Looking forward to seeing what yours will sound like so I can choose mine

mud_king91 · Post by **mud_king91** » Tue Feb 21, 2012 8:10 pm

and dont get a droner my skyline drones... its only amusing the first few drives

Brumby Kid · Post by **Brumby Kid** » Wed Feb 22, 2012 7:26 am

^^^ Yeah I noticed it does do that a bit.
Certain that I currently only have a cat, and then a muffler.

Oh, and the coke bottle.
What about this induction roar? And how to achieve it?

Cheers Cam

Silverbullet · Post by **Silverbullet** » Wed Feb 22, 2012 5:45 pm

Same as my exhaust, no cat but a hot dog! at least that's what I think it is...I know I don't have a cat