djbroadus Posted January 18, 2004 Share Posted January 18, 2004 Ok so today went my budddies shop an got my exhaust put on- 2" Y headers to magnaflow muffler 2 1/4 out to tail pipe. Sounds sweet when at high Rpms or down shifting but idling and lower rpms it sounds like a frickin jesse james chopper I dunno its a little scary Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 18, 2004 Share Posted January 18, 2004 Too big - you've lost all your scavenging effect! Probably a neighborhood nuisance too. LOL GD Quote Link to comment Share on other sites More sharing options...
djbroadus Posted January 18, 2004 Author Share Posted January 18, 2004 Scavenging? Quote Link to comment Share on other sites More sharing options...
Qman Posted January 18, 2004 Share Posted January 18, 2004 How's the power now? Seems a bit big for stock set up. Quote Link to comment Share on other sites More sharing options...
Subarutex Posted January 18, 2004 Share Posted January 18, 2004 Its smaller than mine... although I do have a weber. Also, i kept the stock y-pipe... after that its opened up to 2.5" to a FlowPro muffler. Sounds pretty healthy. Atleast it drowns out the tick of the hydrolic lifters! Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 18, 2004 Share Posted January 18, 2004 Scavenging is important on these small engines. What it refers to is the tendancy for air to speed up when it enters a restriction in a pipe - this is known as the "venturi" effect. The smaller diameter of the first section of pipe in the exhaust causes a speed-up of the exhaust gasses, and this along with the overlap of the intake and exhuast valves, helps to "pull" more air/fuel mixture into the cylinder for the next engine cycle. Too big of an exhuast - especially at the heads, will lose all of your scavenging, and you'll actually lose power, due to less air/fuel being pulled into the cylinder. A lot of people use the stock y pipe, and just go with a bigger exhaust from there out to the tail - this removes the restictive muffler and small pipe from the end, but keeps the scavenging effect.... Not that this is much consolation after you spent time and money building it.... sorry. GD Quote Link to comment Share on other sites More sharing options...
djbroadus Posted January 19, 2004 Author Share Posted January 19, 2004 Power seems a bit better up hills and stuff, gas mileage is way better. I am going back down tommorow and we are gonna try to quiet it down a bit. What is the stock y pipe diameter like 1.5"? i think i will just make smaller headers because the ticking is just out rageous. I guess I am not subu guru enough bigger is usually better but in this case no. Quote Link to comment Share on other sites More sharing options...
PHATBRAT Posted January 19, 2004 Share Posted January 19, 2004 I used either 2 or 2 1/4 (Can't remember) on my old BRAT and had no power problems, That thing ran GREAT! Quote Link to comment Share on other sites More sharing options...
Rooinater Posted January 19, 2004 Share Posted January 19, 2004 mine is straight duel 1 and 7/8inch to 2" mufflers and 2" tips i have no problem but it's a built motor. mine sounds really beastie idling. i like it that way. sounds like a bigger engine then it really has. ticking sound?? like valve or just something else?? Quote Link to comment Share on other sites More sharing options...
djbroadus Posted January 19, 2004 Author Share Posted January 19, 2004 Just the valves Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 19, 2004 Share Posted January 19, 2004 Your slight power increase may have come from the removal of your very restictive stock muffler. Likely you would have even more power if you had at least a little smaller pipe off the heads. But if it's working for you, then go with it. GD Quote Link to comment Share on other sites More sharing options...
djbroadus Posted January 19, 2004 Author Share Posted January 19, 2004 What size is the stock y pipe? Quote Link to comment Share on other sites More sharing options...
MilesFox Posted January 19, 2004 Share Posted January 19, 2004 smaller pipes will give better pull, lower rpm torque, wheras bigger pipes will have better highway mileage and open throttle response at higher rpm my rule to pipes is, use a stock size pipe, 1 3/4 inch from the heads for dual exhaust to a muffler (cherry bomb) and then 2 1/2 to 4 in pipe, for sound single exhausts i run a cherry bomb rught behind the y pipe, and fat rump roast pipe after the muffler Quote Link to comment Share on other sites More sharing options...
djbroadus Posted January 19, 2004 Author Share Posted January 19, 2004 Mine is 2 inch to dual inlet magnaflow exhaust and single 2 1/4 out Quote Link to comment Share on other sites More sharing options...
torxxx Posted January 19, 2004 Share Posted January 19, 2004 Gonna have to hijack this.... For you guys that replaced the exhaust, did it require a lot of bending for the new ones? I was thinking about cutting off everything from the Cat back and putting 1 7/8" to a glasspack and then 2 or 2 1/4" from the glasspack to the back where the stock muffler was.. How complicated of a project is this? Quote Link to comment Share on other sites More sharing options...
archemitis Posted January 19, 2004 Share Posted January 19, 2004 morganm had an exhuast on his spfi wagon that was 2inch pipes, back to dual 2, or 2.5 inch inlet cherry bombs, and no crossover pipe, and it sucked alot. no power till you hit 4 grand. it pulled like crazy, after that, but only good for airplanes. i think i saw one skip did that had some kind of xpipe that looked good. i got a stock y pipe, welded to a 2 inch pipe, going to a supertrapp. the ones with the adjustable back pressure. no bends. sounds nice Quote Link to comment Share on other sites More sharing options...
Mike W Posted January 19, 2004 Share Posted January 19, 2004 My trial and error so far: On a stock EA81 I did 1-7/8" from the cat back and gained high end but lost low end torque. It was like having a fifth gear on the freeway and I didn't have to downshift climbing freeway hills where I used to. But from a dead stop, it didn't pull as hard until rpms got up to 2grand or so then it pulled great. Now on my my offroad car with stock EA81 block, big weber and intake plus hot coil, I did 2" from the cat back and felt a huge improvement at all rpms...it didn't seem to lose low end torque at all. They say the intake and carburation need to be matched and tuned to the exhaust so maybe that's what was going on. Then I installed a custom 2" from the head y-pipe I found at the junkyard. It was fairly well made, had almost equal length tubes and a decent merge. Well it sucks. I got a big loss of torque and overall horsepower. I blame that on losing the scavenging effect but I'm not giving up on it until I try rejetting the carb first since they say carbs often need retuning to match exhaust. Has anyone tried using a quick-mount restrictive tailpipe for better torque on the trail? You know like run free flowing exhaust on the highway and then cork it up a bit when you get to the trailhead. Doesn't the H6 outback have a restrictor gadget in the muffler to reduce flow at low rpms? Quote Link to comment Share on other sites More sharing options...
MilesFox Posted January 19, 2004 Share Posted January 19, 2004 as far as complicated bends, the only place for that is the rear axle. from the ypipe tp the diff, straight pipe will do. i would end the exhaust right before the diff, or curve it out before the back wheel Dual x pipe on the sedan: http://www.warpthree.com/milesfox/88sedan/xpipesedan.jpg Toms dual exhaust made from electrical conduit: http://www.warpthree.com/milesfox/82brat/tomexhaust.jpg homemade doit yerself make from scrap dual exhaust: http://www.warpthree.com/milesfox/trashwagon5/dualdooktubulars.jpg cherry bomb and straight piupe on single exhaust: http://www.warpthree.com/milesfox/trashwagon5/cherrybomb.jpg Quote Link to comment Share on other sites More sharing options...
djbroadus Posted January 19, 2004 Author Share Posted January 19, 2004 last night dug around a little on the car and I think the gaskets on the head are leaking, making things a little louder. Quote Link to comment Share on other sites More sharing options...
torxxx Posted January 19, 2004 Share Posted January 19, 2004 thanks guys for the advice.. I think I'ma run 1 7/8' to the carrier bearing and then the glasspack startign right there and then just leave it with the glass pack right before the diff Quote Link to comment Share on other sites More sharing options...
Meeky Moose Posted January 19, 2004 Share Posted January 19, 2004 yeah skip brat has the custom x-pipe and dual out the back.. saw it this last sat. sounds like a freekin v8.. has the rumble and the looks.. i gotta do somethin with my hatch.. just had a new centerpipe/cat put on it, but the muffler is shot.. i want something a little louder and less restrictive in its place.. Quote Link to comment Share on other sites More sharing options...
torxxx Posted January 19, 2004 Share Posted January 19, 2004 can I run my ea82 with 118k miles on it without a Cat? if so, I realize its goin to make it lots louder and the exhaust dirtier (screw the IM testing) but is it going to hurt anything to go with something say leave the stock y pipe, gut or remove the cat and then just run straight pipe to a turbo mufler in the same stock place? Quote Link to comment Share on other sites More sharing options...
Snowman Posted January 19, 2004 Share Posted January 19, 2004 Hey Torxxx, Cat gutting: Well, I gutted my cat last fall because I thought it was plugged. Turns out that wasn't the case, but it did result in a bit louder exhaust and I think some more power overall. It will probably help more after I get my new motor in w/ bigger cams. I don't think it hurts anything to gut the cat, but I have no actual proof of that. My motor was screwed up before, and it was still screwed up after. Only scientists working for the tobacco industry could conclude anything from that... Replacing the back half of your exhaust: You might wanna take a look at mine at the lift party, but I can describe it pretty well here. As I said, I've got a guttet cat, and the stock pipe all the way back to a thrush 3-chamber muffler. This setup is ridiculously easy and cheap to set up, as you can just cut off the stock muffler clamp this one on, and hang it. The stock midpipe looks pretty good for flow characteristics to me, at least for a stock or near-stock engine. And it's a heck of a lot stronger and rust-resistant than most pipe that you would put in its place. Quote Link to comment Share on other sites More sharing options...
torxxx Posted January 19, 2004 Share Posted January 19, 2004 yeah.. the thing that worries me the most about redoin my exhaust is having to bend something to make it it... But yea what you said about yours, that sounds like a better plan I wonder if a flowmaster will clamp on with out welding or wending, 87flowmasterGL any comments? Quote Link to comment Share on other sites More sharing options...
Erik R Posted January 20, 2004 Share Posted January 20, 2004 Don't forget: Heat!! This is a major problem on V8's......keeping the headers H O T.........They can be wrapped with a fiberglass cloth or you can buy them with a ceramic coating. It's like a stove pipe.....when cold, it won't draw; smoking into the room until the flue heats up............heat draws air in. If you think you over did it on your pipes, try insulating them wth something, like the "header wrap" I mentioned above. GD is correct about the size of the main head pipe......should be smaller...........anything larger than the port size is a waste......... If using a carb., it should act like it's been jetted UP........... Short-stroke engines are VERY sensitive to changes in intake or exhaust....... I noticed the factory pipes are covered in sheetmetal............if not to prevent brush fires, it sure looks like it keeps the head pipes out of the cool breeze............... Sorry, I'm applying V8 knowledge where it doesn't belong, but flow dynamics are.....well, there are similarities. Quote Link to comment Share on other sites More sharing options...
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