EA81 Unequal Length Headers

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El_Freddo
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Post by El_Freddo » Wed Mar 04, 2015 9:33 pm

Nice piece of kit Bantum!

Might have to add them to the birthday list!

Cheers

Bennie
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El_Freddo
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Post by El_Freddo » Thu Apr 09, 2015 2:42 am

After hanging out with a bunch of streeter subi's with wicked exhausts my inner subaru nut REALLY REALLY wants a set of these extractors!

I might have to ask a mate if he'll help me out - then find some funds to hide from the minister of fun and finance to pay for it...

Keen to know Willy, with your coupe running this extractor set, what are the specs for the rest of the exhaust - pipe diametre/resonators/rear muffer etc?

Cheers

Bennie
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Willy Fisterbottom
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Post by Willy Fisterbottom » Thu Apr 09, 2015 9:32 am

Currently running 2" system with a strait through muffler about halfway down and 2" to the end.
I don't really like the muffler I have as it isn't as deep as what I have on tyhe hardtop. I'd prefer to run a 2 1/4" system with a hot dog in the middle and a straight through muffler at the back.

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El_Freddo
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Post by El_Freddo » Fri Apr 10, 2015 4:54 pm

2.25 inch diametre is a bit much for a 1.8ltr isn't it?? I've got 2.25 inch with the ej22 and that's a good setup IMO.

Do you think the note with this same exhaust would be different between a hydro lifter EA81 and a solid lifter EA81?

Also what sort of distance is the pipe from the LHS port to the collector?

Cheers

Bennie
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Silverbullet
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Post by Silverbullet » Fri Apr 10, 2015 6:07 pm

El_Freddo wrote:2.25 inch diametre is a bit much for a 1.8ltr isn't it?? I've got 2.25 inch with the ej22 and that's a good setup IMO.

The battered factory Y pipe I have for the EA81S is bigger than 2" where both pipes come together, I think 2 1/4" or even 2.5" !!
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El_Freddo
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Post by El_Freddo » Mon Apr 13, 2015 10:44 am

I don't know how much research they put into exhausts back in the day of the EA81, but I'd guess it's a lot less than what manufacturers have these days, and I'd go as far as saying that a lot of decent exhaust builders will know a pot load more now than they did back then...

You really can't measure an exhaust at the collectors - If I measured a set of extractors I have for a Holden 186 we'd be looking at near 3 inch diametre - I can tell you now the exhaust isn't anywhere near that big down the line!! I'm 99% sure that's also the "old thinking" with extractors is to make the collector area larger for "ALL" the exhaust gas to meet up at. Max power is about making the exhaust gas move down the pipe the easiest way possible - the exhaust pipe needs to work like a chimney, help draw the gasses out.

What we're doing is making them collide for that "thump-thump" sound. I'm hoping it's all in the extractors for 90% of that subi beat - My thoughts are to build a set of these extractors and keep the 2 inch "cat back" (really it's a "Y pipe back") system that's already there. If that's not sounding decent then start playing with mufflers. Of course this is unless my exhaust builder says he knows something that'll be heaps better for the note ;)

Also was meant to ask you Willy, has the not changed at all since the initial build? Exhausts seem to have a tendency to kind of bed in/change note as they wear a little bit. I know Ruby's exhaust is different to how she sounded when they were first fitted...

Cheers

Bennie
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Willy Fisterbottom
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Post by Willy Fisterbottom » Mon Apr 13, 2015 12:16 pm

May be just in my head but, but I think the exhaust sounds better and better each day.

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sublime
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Post by sublime » Mon Apr 13, 2015 4:05 pm

Definitely your head willy! :p
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Willy Fisterbottom
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Post by Willy Fisterbottom » Mon Apr 13, 2015 7:48 pm

El_Freddo wrote: My thoughts are to build a set of these extractors and keep the 2 inch "cat back" (really it's a "Y pipe back") system that's already there. If that's not sounding decent then start playing with mufflers. Of course this is unless my exhaust builder says he knows something that'll be heaps better for the note ;)
Is this for your Brumby? I dont think comercial vehicles needed Cat converters, are you confusing your Resonator with a Cat?

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steptoe
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Post by steptoe » Tue Apr 14, 2015 10:41 am

Commercials had to have cats, may be condfused with O2 sensor control ??

"that's not a pushrod boxer engine in there" said the man in the WRX hearing the willY Pipe

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Willy Fisterbottom
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Post by Willy Fisterbottom » Tue Apr 14, 2015 4:05 pm

steptoe wrote:Commercials had to have cats, may be condfused with O2 sensor control ??
That's not what I learnt at TAFE in the late 90s.
No doubt this rule has changed now.

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