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how do i get a nice+smooth exhaust on an ej18 brat?


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i just got a nice magnaflow front exhaust <from the heads to the Y and cat, and then another 24" after the Y>. i paid a lot, at least by my financial standards. it was great, i was happy, proud of my nice exhaust, then i took my ea81 apart for various reasons. <spfi pistons, port+polish, head decking, new gaskets, clean crud+sedinment out>. so i never got it back together, lame, pathetic, whatever, i know, i suck, shame on me. but WHATEVER.

now i have a very nice ej18 THANKS SUBERDAVE!! its not in yet but soon will be. got a trans adapter lined up for tomorrow. which gets me to my point:

all i need now is a nice exhaust for my ej18.

what have people done in the past? i know for sure a few of you guys have ej18s in your brat. jerry does. not sure if ej22 has the same exhaust set-up.

 

but either way, can someone tell me what they would do about that? is there a good shop with a mandrel bender, and reasonable prices? i got mine done at a small local shop in maple valley. it has the pinches at every bend, i had planned to eventually get the back half redone nicer. the front half, as i said, had the magnaflow, which had VERY nice smooth bends. sounded better, looked better, WORKED better. i got that part on ebay for maybe like 185+shipping. it was specifically for a stock brat with ea81.

they have the same thing right now for a 95 impreza. but its almost $100 more than the ea81 part, even though they are identical except for the dual port head design. also i have no clue if it would actually FIT my brat, where the one a bought was designed for my exact car, this is for an mid-90s impreza.....

 

http://cgi.ebay.com/ebaymotors/MagnaFlow-Direct-Fit-Catalytic-Converter-23875-/370522932331?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3ASubaru|Model%3AImpreza|Year%3A1995&hash=item5644e3446b

 

so i guess i should just cut off the first 12", or so, of the y-pipes, and get a whole new custom exhaust back from there?

any advice or previous experience would be UBER-appreciated.

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EJ18 exhuast is the same as the EJ22. I for one had an EJ18 in my brat when I first did my EJ swap. Now it has a built EJ22. I have a magnaflow cat to a mangaflow single in dual out. I do belive I ran 2" exhuast. I also tipped the tips to the outside corners under the bed.

DSC01825.jpg

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hey mr. brat. i just today saw a clip of you at wcss 11 doing donuts in the mud, on youtube. sounded great. then again, computers really dont do car exhaust sound much justice. im not sure why youtube has so many short clips trying to show off their fancy exhaust sounds, because its never impressive. a 1967 426 Hemi sounds pretty bad on a youtube video. but whatever. what im trying to say is, your brat sounded at least as good, if not better, than any other nice performance car ive ever heard on a computer. lol...

 

p.s. that wa smeant to be a compliment, but came out confusing.....

whatever

Edited by Qman
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all i need now is a nice exhaust for my ej18.

what have people done in the past? i know for sure a few of you guys have ej18s in your brat. jerry does. not sure if ej22 has the same exhaust set-up.

 

but either way, can someone tell me what they would do about that? is there a good shop with a mandrel bender, and reasonable prices? i got mine done at a small local shop in maple valley. it has the pinches at every bend, i had planned to eventually get the back half redone nicer. the front half, as i said, had the magnaflow, which had VERY nice smooth bends. sounded better, looked better, WORKED better..

 

 

You don't need mandrel bent exhaust. Mandrel bent exhaust is a big buzzword at the moment, and alot of magazine articles have alot of people thinking that it is necessary. A compression die bent exhaust system will work just fine. Although from the description of the job you had done before, I would go elsewhere. You can find an experienced, good muffler shop that has a compression die bender, and they can do a great job. Pinches, dimples, flattening, and other deformation of tubing that has been bent with a die bender is a sign of improper hydraulic pressure settings on the machine, and the dies being out of alignment. Aligning the dies, and setting the machines back pressure properly takes experience, and knowledge, but it is very doable. Especially considering you are using such small tubing. Compression die benders are often used to bend 4" exhaust tubing, and I can tell you first hand that they can be properly adjusted to do so without dimples, or flattening of the tubing. The quality of the tubing used on your system may also be suspect. I use 14ga aluminized exhaust tubing on all my systems, and can routinely bend 2 3/4" tubing 180* with very little flattening in the deepest part of the bend. No dimpling, no pinches. None of that. My advice would be to find an experienced tubing bender, and have them make whatever you want. If you want to mate it to your old system, that would be very simple.

 

Now, as far as the thought of mandrel bending, the entire purpose of mandrel bending is for the smoothest bends possible to decrease backpressure. A 2" system on a 1.8L engine is already plenty enough to kill any idea of backpressure. It is even plenty for a 2.2L engine. Unless this car is highly tuned, and seeing constant high RPMs you are way overthinking this. The 2" system will support more flow than is needed with a moderately built flat four. To give perspective, I recently bent a full length dual 2.5" system for a 401 ci (6.6L, exactly 3 times more displacement than an ej22) v8 running through super 44 series Flowmasters, and over a rear diff. That engine is tuned to 450+ HP, and the dual 2.5" die bent system will flow it easily.

 

Mandrel bending is great in a perfect world, and I don't want anyone thinkning that I am badmouthing it, BUT, THE REALITY is that 99.999999% of enthusiasts just don't need to spend the extra money on it. Unless your car is highly tuned, and needs every bit of flow it can get, or you are working with incredibly tight spaces and need extremely smooth bends on the smallest tubing that will work for the application, you just won't notice ANY difference for the money spent.

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a 401, eh? is that on a wildcat, or a riviera? i dontthink skylarks came with those from the factory. or GS's. skylarjs, iirc, only came with 300s or 340s.

 

my riviera has the 430, and it had no engine options in 67. one possible engine, one possible tranny.

 

that 401 is a 4 barrel? or a 4x2?

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yeah duh, my bad.....

 

i had that file in my hard drive, the processor just wasnt accessing it.

or, another metaphor would be:

 

i knew that floor was on my building, my elevator just didnt stop at that floor.

 

i guess AMC is kind of a little known and little understood make of cars.

no disrespect meant to the amx or javelin though. they are bad rump roast cars.

ambassadors are kind of an ugly turd though.

 

buick had a 401 nailhead in the early and mid 60s. i think up until like 64. then there was the 425 nailhead after that. im a buick man so my mind automatically went to buick.

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thank you for the detailed response, by the way. i appreciate that.

 

my understanding of exhaust and backpressure was that you could get the best low and mid power, and quicker throttle response, by using the smallest possible tubing, with the smoothest run, front to back. i know for sure that a long straight narrow passage creates the highest velocity and smoothest escape. thats bernoullis principle.

 

thres been a lot of car craft articles knocking the trend toward 3 inch exhaust on chevy 350s and such. i know because of my buick, that, as you said, a big bad boy like a 60s big block iron beast can get plenty of fart out of a 2 inch pipe, as long as your mufflers are decent.

my brat has a 2.25" inch cherry bomb. but not the stereotype "cherry bomb" glasspacks. its the turbo type, like flowmaster uses, but WAAAAy cheaper. boggles my mind how some guys will throw away 2 hundred cash for a damn muffler. just shows that the hot rod crowd often has more dollars than it has sense. i think the subaru crowd in particular tends to think things through, and make a habit of UNDERSTANDING how and why things work. and not being so quick to jump to the biggest is better philosophy.

 

some might even take the freudian view that subaru owners, as a general group, may have bigger than average ummmm.... tools. and so we dont feel the needs, unlike the Hummer and escalade crowd, to prove anything to total strangers. we like subarus, and subarus are a well-designed, and efficient machine. excuse that tirade, lol, just thinking thru my keyboard again.

 

but yea....

sounds like you personally do exhaust for a profession, 3eyes. i would send the work to you, but the name of your town isnt familiar, so i assume its far away, and i dont want to deal with shipping all that ************e. and anyhow, id prefer to get it built ON my brat, turns out better that way. any chance that you know any specific shop in seattle/bellevue/tacoma area?

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also, in my previously chosen exhaust shops defense, they work on real nice cars, and i basically showed him a relatively small amount of cash, and asked him if he could make it happen. the welds are goods, and he lined it up nicely, and tucked it away, up higher, with more clearance than Fuji/subaru built it in the first place.

 

my guess is that, correct me if im way off track here, but i think maybe that if you have like 4 or 5 feet of good, smooth, high flow exhaust, from the engine, to the Y, thru the Cat, and 2 more feet after the cat, if the last 5 feet are less than perfect, maybe the exhaust has already cooled and slowed enough by that distance from the engine, that a few pinches arent even a measurable factor???

 

just my pet theory.

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You have the right idea that tight bends are the enemy. That is where mandrel bending really shines, but, you have to realize the expense of a mandrel bend machine. They often run upwards of $30,000 new, and can climb far higher depending on the range of pipe they will bend. In turn, that expense is passed on to the customer. There is nothing at all wrong with that, it's just that alot of people these days hear that new craze, and think that a tried, and true system like compression bending is no longer acceptable. I've even had people go as far to tell me that a competetive exhaust system cannot be made on a compression die bender. Most people don't realize how many 11 second cars out there have 2.5" - 3" compression die bent exhaust systems. Another problem is that due to the buzz about mandrel bending, many very talented exhaust people have closed shop. You can now order a mandrel bent system for most cars through the mail, and have it to your doorstep. The real laugh is that many people will order these systems for upwards of $500, and then take them to the exhaust shop, and have them installed. I have to laugh, because these people are paying twice for the same labor. They often end up having well over $1000 into a system when they could have had a very similar system bent, by a pro, for around $600-$800. I will give you the straight scoop lowdown. The AMX previously mentioned had long tube headers that end under the drivers seat, making exhaust jobs butter. I had just under $300 into materials on that job including a very nice set of Flowmaster Super 44s, and about 20 feet of 14ga aluminized pipe. That means $300 in 6 hrs of labor totalling a VERY NICE exhaust system for $600. As you can imagine, a longer car will cost more, and there isn't much shorter than an AMX. If you are going to have a custom job bent, I cannot say enough to go ahead and get the good pipe. The heavy walled 14ga aluminized pipe sounds far better, gives that mellow throaty reverb, and most importantly bends really well. I've bent the cheaper pipe, and it is really hard to get it to bend nicely. It's thinner, and sometimes harder making it dimple, flatten, and do other strange crap. Aluminization will also last a lot longer making it a far more sound long term investment. I've seen aluminized systems here in Washington last 15 years or more without leaking. That's a great return on your money VS. having a setup rot in 5 years.

 

You are dead on about Bernoulli's principle. What most people don't think about when it comes to exhaust is that any time you are flowing exhaust into an area larger than the valve opening, you are creating stagnant exhaust flow. A little stagnation isn't the end of the world, but, when you are running 3" exhaust on a head with 2" exhaust valves you are creating a problem. You are only emptying one cylinder at a time, unless something is terribly wrong:lol:. I won't argue about the sound, as I can understand the desire for that deeper rumble, but, if you are interested in function over form, you are wasting alot of potential. As you said; oversized exhaust tubing will cause a loss of "tip in" power. Most of the time, that is what people are after, but, they end up setting themselves back with their exhaust choices. I guess it is all a happy medium depending on what sound you want. It sounds like you have a good grasp on this, so, I won't bother preaching to you about that any more.

 

I am not a professional exhaust guy. I'm just a muscle car enthusiast who bought a WAY overkill tubing bender to do work on my own vehicles, and those of my friends. I will not pretend I am an expert, but, I am learning alot every time I do another job. To me it is an excercise in being more self reliant, and basically a free education. Exhaust work, like most other things mechanical, is all about your patience, and attention to detail. The same exact machine used by two different people can result in vastly different exhaust systems. It's all about the standards of the person using it.

 

I'm located near Mt Vernon Washington. I wish we were closer, as I'd be glad to give you a hand. Unfortunately, I don't know any exhaust people that far south, but, I'm sure you can find someone. It sounds like your shop is capable, but, that they may have used pre-existing, or store bought bends to do your system. I know alot of times the wrinkle bends you see are store bought from places like NAPA. I don't think any good shop would have a hard time mating your existing system to the new motor. They'd probably end up cutting it about under the passenger seat, and just make what they need to from there forward. Even with good pipe I couldn't see it costing more than $200 or so.

Edited by 3eyedwagon
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awesome, thanks for the extensive advice.

thats a lot to respond to in an organized way, but first off, i must say, you may have misunderstood what i meant about the exhaust i had done. it is shrunk at the bends by maybe 10%. not the krinkle "accordian", just a smooth but restricted "pinch" sort of. as far as mt vernon, YEA thats far for me. but im gonna need to go up to Bham to see scott soon anyhow. only problem is, id nee dto bring my actual brat to you, in order to do that. but the catch is, it would be most convenient and "efficient", time and gas -wise, to combine a trip to mt vernon with a trip to Bellham. but my reason to go to scoot in Bham is my trans plate, to actually physically install my engine. until i do that, i cant drive the car, and so you see what im getting at, yea? lol.....

 

dang..... life is hard.

 

couldnt agree more on getting a GOOD quality exhaust. i love my brat. ive gone thru a fair number and VARIETY of cars. and of all of them, my brat is my favorite. brats are a great combination of FUN, PRACTICAL, PRODUCTIVE, FUNCTIONAL, AFFORDABLE, RELIABLE, and SPORTY. yea, they are not a 2 hundred mile per hour car. hell, a brat isnt even a ONE hundred mile per hour car. with the ea81, i was working it fairly hard just to see 75mph, lol.....

 

but it FEELS fast. its quick at REAAAAASONABLE speeds. so what if your car can do 256mph, bugatti, you never will, that situation just doesnt exist. my brat is about as fast as i feel a need or desire to ever go.

truth be told, im a big believer in survivalism, self-reliance, producing your own food supply and potentially your own power, living simple. and along that line of lifestyle, a Brat seems to me, one of the best tools/vehicles a person could ever own. more so with the original ea81, because of simplicity and weight, ease of repair and maintenence. but whatever, these days, i dont think many small-town mechanics would have any problems fixing an EJ18, be it Tibet or Peru or a remote fishing village in newfoundland. whatever.

 

im working on maybe hping SKR scott will trust me on advancing me the trans adapt plate ahead of time, so i can then drive up to him to pay him back. not sure how that will go, and i have no right to DEMAND it, or whine if he isnt willing to do that. im just hoping, because it would streamline my effort to get this brat back on the highway, including to you, for example, to get my exhaust in order. im thinking that i can cut off the impreza exhaust, maybe a foot on each side, just so i have SOMETHING to bolt on there, for that minimal backpressure. ive heard the ZERO backpressure can damage your valves, and recess the exhaust valve seats.

 

we shall see how scott feels about all that hope of mine. i want to be clear, i have no DEMANDS or pressure against him, and if any friends of his, or himself reads this, please dont think i am aiming to manipulate or guilt-trip or ANYTHING like that. its like the lottery. i HOPE i win it, but im not gonna talk smack, and badmouth or spite the lottery if i DONT win.

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awesome, thanks for the extensive advice.

thats a lot to respond to in an organized way, but first off, i must say, you may have misunderstood what i meant about the exhaust i had done. it is shrunk at the bends by maybe 10%. not the krinkle "accordian", just a smooth but restricted "pinch" sort of.

 

 

im thinking that i can cut off the impreza exhaust, maybe a foot on each side, just so i have SOMETHING to bolt on there, for that minimal backpressure. ive heard the ZERO backpressure can damage your valves, and recess the exhaust valve seats.

 

 

The biggest problem with running a very high loss of backpressure is the chance for expelled exhaust gasses rapidly heating the exhaust valves. You need, on minimum, about 12" or so of tubing away from the heads. 18" is far better. Running straight out the head is ok for just starting it up to see if it runs, but, I would suggest not running for long. It will cook the valves, and seats. In most cases it ends up burning an exhaust valve, but, I am talking about v8s as that's what I know more about.

 

I understand now what you're talking about in the bends of the tubing. It is very difficult to prevent flattening in the bends when using a compression die bender. There will always be a little bit, but, there are measures to prevent much. You're just asking alot of the tubing when effectively crushing and reshaping it. Lubing the dies, and tubing goes a long ways to preventing flattening. I have extensively compared mandrel bent tubing bends, and that of my machine. I even went as far as to do a measurement of volume in CCs on two pieces of 2 1/2" 14ga tubing bent on a mandrel machine VS bent on my fairly well tuned die machine. They were both 18" in length before bending, and the loss was under 10ccs on a 180* bend. It ended up being about a 4-5% loss of volume. I did alot of research on all of this when I first got started. I understand your concern, and it is good that you're paying attention to things like this in hopes of achieving maximum efficiency. Another thing to think about with the flattening of the pipe is that while it may be slightly flattened (usually on the outside of the bend) it has expanded to the sides resulting in a somewhat ovular section of pipe. The dies fit just a hair loosely allowing for expansion to anywhere the tubing can escape to, and while bending really sharp bends, you can witness the expansion in that direction. So, yes, some flow is lost, but, I've learned that on a well tuned machine it is usually negligible. Especially for what most of us are up to.

 

Another thing I'd like to share is the fact that the smaller the tubing, the less distortion/deformation you will get when bending it. Once you get up to about 2 3/4" tubing you start to realize how important it is to have a machine set properly as any flaws will begin to show. The smaller stuff will often be a breeze after that.

 

Good luck, and I hope you find what you're looking for.

Edited by 3eyedwagon
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What mandrel bends would you like I can get aluminum mild stainless alumanized and 409 stainless. Pm me I work at a mandrel bending company. I'm not a spammer. I won't give the name for advertising but ill help you out

Edited by sube101
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