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EA81 Exhaust Question?
Posted 23 October 2003 - 05:50 PM
I searched the "Older Sube" forum for "header" and related terms and saw one reference to a custom header or y-pipe. It looks like most people are running the stock y-pipe/catalytic converter combination. It looks like a few people have cut the cat of the stock y-pipe and replaced the cat with pipe. A few people have made up dual exhausts, but I understand the y-pipe helps torque...
Are these all the options for the normally aspirated ea81?
Is there any compelling reason to replace the stock y-pipe with a custom header/y-pipe?
Or, is it best to cut the front cat off the stock y-pipe and replace the back cat with a better flowing 3-way (which I understand is legal everywhere except california)?
Thanks in advance for any info you can give me.
Posted 23 October 2003 - 08:45 PM
Posted 23 October 2003 - 09:44 PM
Posted 24 October 2003 - 11:59 AM
Sounds like rewelding the stock y-pipe like you two did and replacing both cats with a better flowing 3-way cat and muffler(I'm in an emissions testing arrea) might be the way to go for me.
Posted 28 October 2003 - 12:49 PM
"Header primary length is critical to this engine, you need 1.625 od tubing (1.5 id) off the head 28" long into a collector from there on your 2" will work."
Posted 28 October 2003 - 12:55 PM
Posted 28 October 2003 - 01:08 PM
Remember, the 1.5" ID is for the primaries. The 2" from there back was my idea based on other stuff I had read. I am way out of my depth here, but a lot of the stuff I have read says not to go too big too soon or you hurt scavenging. those sources say to run 1 7/8" or 2" to the muffler (a better one) and 2" or larger from there back.
OTOH, I've read the stock exhaust is so poor it really doesn't scavenge very well at all anyway, so maybe better designed larger primaries would work better on a built car.
I'm looking for answers, not answering them... :cornfuzz:
Posted 28 October 2003 - 01:19 PM
Posted 28 October 2003 - 01:38 PM
my new GRizzly Brat has 1 7/8" at heads to 90 deg 'Y' and then 2.25" to same Magnaflow muffler. a bit quieter as well, as a little better low end...
Jerry (Bratrus1) had the dual exhaust on his 86 Brat. better for higher RPM's
The place I go to is a 1 owner shop that specializes in exhaust for all kinds of vehicles (mostly American muscle cars) but the do all kinds of work as well... they did a real nice job on this last y pipe. tucked up nicely for less chance of getting knocked off while off-roading (plus I put a big skid plate on it that covers the exhaust....)
Posted 04 November 2003 - 04:41 PM
Now all I need to do is find a good shop near Seattle to design and fabricate the system
Posted 04 November 2003 - 06:28 PM
Posted 04 November 2003 - 07:12 PM
more low end and more top end
have a Weber 32/36 feeding it
offered to make complete (minus "Y" pipe) systems for 200 green backs, no one was interested so I quenched the project sorry
Am working on turbo down pipes now
Posted 04 November 2003 - 10:11 PM
Posted 05 November 2003 - 01:02 PM
Can anyone recommend a person or shop in the Seattle area?
They need to be able to design the header or y-pipe mods for my purposes (maximize towards low-end torque while preserving ability to do the speed limit on the freeway), fabricate the header or do the y-pipe mods and do the rest of the system.
Posted 05 November 2003 - 08:15 PM
Posted 06 November 2003 - 04:23 PM
Stage 1: Intake, ignition and exhaust cat back.
Stage 2: Port heads, regrind cam, deck block and the rest of the exhaust (header/y-pipe, collector and single three-way cat). If I have to re-do the whole exhaust when I get around to the internal engine mods, so be it...
Posted 20 November 2003 - 06:39 PM
Posted 20 November 2003 - 11:47 PM
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