EJ22 exhaust mods???

[Beegeer]

Been searching, have not found much on exhaust mods. There is a ton of stuff for the ‘old gen’ cars but not much from ‘new gen’. Might be the fact that your exhaust systems cost more than a lot of the ‘old gen’ cars?

I have a 98 imp ob, with an ej22. I’m thinking about building an exhaust just like my EA81. Gutted cat, into a 2.25 pipe, glass pack about two feet back from cat, then 2.25 all the way back. I realize that I would need to weld O2 fittings into the system. Also lack of back pressure might be problem. Would the lack of back pressure and lack of cat cause a check engine light? Would I gain anything? Or would it just sound like my old ea81?

[rugbyben]

I'm pretty sure the lack of a cat would cause a CEL, not to mention an inspection failure (if yours area requires). When my CATS went bad it caused a cel, so i assume a gutted one would do the same.

[Beegeer]

No inspections here, plus I would keep the old exhaust just in case.

 

 

 

 

 

 

 

I'm pretty sure the lack of a cat would cause a CEL, not to mention an inspection failure (if yours area requires). When my CATS went bad it caused a cel, so i assume a gutted one would do the same.

[idosubaru]

i've run all sorts of exhausts on the older subaru's with no CEL or O2 sensor issues. i wouldn't worry about that.

 

the XT6, 6 cyilnder, runs nice with 2.25" exhaust. xt6.net has dyno plots and stuff about this thanks to myxphlyx (also a member here).

 

on the EJ22 i don't know, it's different. the XT6 gets 1-3mpg better on all highway driving and i believe a 4-7 hp and torque increase going to 2.25" according to his dyno plots.

 

EJ22 is a different beast, but i'd expect some small gains if it's not too large. i've had straight pipe on my XT6 and it definitely looses power and mileage. maybe it has more power REALLY high...like 5,000 rpms, i don't know, but it's not where i normally drive so it did me no good.

[Beegeer]

Thanks this good info. I'm not so concerned about CELs either. My primary concern before i get too far along is: will lack of back pressure cause any damage to my motor?

 

I'm surprized with all teh EA-EJ swaps there is not more info on this...

 

 

 

i've run all sorts of exhausts on the older subaru's with no CEL or O2 sensor issues. i wouldn't worry about that.

 

the XT6, 6 cyilnder, runs nice with 2.25" exhaust. xt6.net has dyno plots and stuff about this thanks to myxphlyx (also a member here).

 

on the EJ22 i don't know, it's different. the XT6 gets 1-3mpg better on all highway driving and i believe a 4-7 hp and torque increase going to 2.25" according to his dyno plots.

 

EJ22 is a different beast, but i'd expect some small gains if it's not too large. i've had straight pipe on my XT6 and it definitely looses power and mileage. maybe it has more power REALLY high...like 5,000 rpms, i don't know, but it's not where i normally drive so it did me no good.

[1 Lucky Texan]

There are resistor fixes for the CEL - that way if another item sets a code it would get noticed.

You may lose a little low end torque from what I've read. But the important thing is keepin the inside diameter the same as much as possible. Necking down or expanding causes a lot of turbulence and impedes flow. And mufflers with 'ridges' inside are worse that straight with just swiss cheese type holes or slots.

 

I'd read and search the NA forum at http://www.nasioc.com in addition to info here.

 

Also, consider lighter wheels (less rotating mass and less unsprung mass) lighter flywheel (some folks report problems under 11 pounds though - stay with 13 pounds) and maybe lighter pulleys.

 

Carl

[strat]

95+ is obdII so you have a 2nd o2 sensor that will throw a CEL without a cat in there...

 

backpressure is restriction... restriction is bad... lack of backpressure will not do damage... you want to maintain exhaust flow velocity. 2.25" piping should be fine for an ej22.

 

you should consider a header while you're doing your exhaust and maybe a high flow cat instead of no cat... hi flow's can be had for $50 or less on ebay and shouldn't throw a code. if you go with a glasspack, make sure it's a perforated core... louvered cores cause turbulence and will decrease performance.

 

my gf has a borla header, 2.25" piping, catco cat, and a borla muffler. it sounds mean and made a nice difference in performance

[idosubaru]

too little exhaust in place is a bad thing - it can damage your exhaust valves. but no worries there, large exhaust won't cause that. a lack of one or very radical changes would cause that.

 

if the exhaust is too large i would suspect a loss of low end power. on the various exhausts i've tried on the XT6, anything too open, no cat and large pipe is sluggish at low RPM's and wants to downshift all the time going up hills. not my cup of tea. i would expect similar results on the EJ22.

 

2.5" seems like the upper limit for normal use. my experience is minimal, but i'd probably stick with 2" or 2.25" unless you find yourself driving in the high RPM range often. if you're staying under 4,000 rpm's most of the time going over 2.25" might not offer you much.

 

looking forward to some results on this as well, post back what you try and what you get.

[Beegeer]

This is great info, thanks.

 

I guess my first step will be to record some good numbers. Mileage is easy; power is a bit more difficult. Unfortunatly my dynamometer is broken, LOL... So any power numbers will be 'seat of pants' measured only. I'll take picks and report on what I come up with.

 

Also any further info on the resistor fixes for the CEL? I need to search that as well.

 

Think I'll just build and see what happens, if I a CEL comes up, I worry about it at that point...

 

-brady:burnout:

[1 Lucky Texan]

This is great info, thanks.

 

I guess my first step will be to record some good numbers. Mileage is easy; power is a bit more difficult. Unfortunatly my dynamometer is broken, LOL... So any power numbers will be 'seat of pants' measured only. I'll take picks and report on what I come up with.

 

Also any further info on the resistor fixes for the CEL? I need to search that as well.

 

Think I'll just build and see what happens, if I a CEL comes up, I worry about it at that point...

 

-brady:burnout:

 

D@ng! what's that deal called? There IS a not expensive device you can put in your car that can measure acceleration/hp based on vehicle weight and maybe other inputs. G something? anybody? they are available at some car parts places, ebay, etc. Mught be fun to have, better to borrow if anyone here has one or maybe a used one? If no one here knows ask at www.nasioc.com

 

man...wait...yeah G-tech here's an example;

 

http://cgi.ebay.com/ebaymotors/G-TECH-Performance-Meter-Pro_W0QQcmdZViewItemQQcategoryZ107062QQitemZ4625463630QQrdZ1

 

If you were very careful to make measuremnts before and after a mod under consistent conditions (fuel load, adjusting for weight gain/loss after a mod, weather temp tire pressurs,etc) it might work as an indicator of performance changes.

 

also, found a thread here about it - maybe try a search (or email one of those guys) for more info;

http://www.ultimatesubaru.org/forum/showthread.php?t=27733&highlight=gtech

 

fyi

 

Carl

[NoahDL88]

Its come up before, but i thought i'd re clarify again anyway.

 

Backpressure is bad, but its not necessary, you don't need backpressure for proper operation of your engine. What is important is flow velocity, you want your exhaust to flow between 240-260 FPS anything less and you get wind shear, which we see as backpressure, and anything more and the air becomes stagnant and looses its velocity.

[Beegeer]

Sounds like an accelerometer... I used them at my last job testing suspension systems. Teh G-tech might be a bit different, I'll look into it.

 

brady

 

 

 

D@ng! what's that deal called? There IS a not expensive device you can put in your car that can measure acceleration/hp based on vehicle weight and maybe other inputs. G something? anybody? they are available at some car parts places, ebay, etc. Mught be fun to have, better to borrow if anyone here has one or maybe a used one? If no one here knows ask at www.nasioc.com

 

man...wait...yeah G-tech here's an example;

 

http://cgi.ebay.com/ebaymotors/G-TECH-Performance-Meter-Pro_W0QQcmdZViewItemQQcategoryZ107062QQitemZ4625463630QQrdZ1

 

If you were very careful to make measuremnts before and after a mod under consistent conditions (fuel load, adjusting for weight gain/loss after a mod, weather temp tire pressurs,etc) it might work as an indicator of performance changes.

 

also, found a thread here about it - maybe try a search (or email one of those guys) for more info;

http://www.ultimatesubaru.org/forum/showthread.php?t=27733&highlight=gtech

 

fyi

 

Carl

[superu]

I've got a '95 legacy 2.2. I cut the cats off and had the O2 sensor (from the cat) ported into the stright pipe. I replaced stock pipe with 2.25 all the way back removing BOTH cats, and piped through a magnaflow. Outcome?

STUPID, WICKED LOUD!!

 

I lost all low-end power and nearly stalled around corners, downshifting into second, trying to goose out of traffic ALL THE TIME. I wanted low end torque for my application, so I had the cats reinstalled and am now on 2.25 pipe from the second cat out the rear, through a small cherry bonb as a resonator, finishing thorugh a magnaflow. It sounds Great, I have a low mellow, NOT loud exhaust signature, the cherry bomb helps with noise, the cats keep the backpressure early in the system, keeping the low end, but the larger pipe thorugh the magna flow, dumps the exhaust out the rear fast. I have gained power and kept the low end.

 

I would't recommend 2.5 of larger, 2.25 is a step above stock and all the wider you want. High flow muffler (magnaflow preferred over flowmaster), and keep the cats. I'm not sure on Imps but if you have 2 you might get away with ditching the rear and keeping the fore, but I'd just stick with both and do a cat back system.

 

The engine will not be harmed w/o backpressure, but it actually needs some. If you deleate the cats, plug theOs snesor(s) into the new pipe at their approximate locations (e.g same distance from the manifold and same side of the pipe, etc.). Your exhaust shop will be able to weld them into a new. If you deleate the cat(s) you will lose low end. I'm not sure of the Imps, but my legacy has 2 cats. The second could be deleated keeping some backpressure, but they also muffle sound too... There's no need to go larger than 2.5 in fact I wouldn't recommend larger than 2.25, especially on a 2.2... They're not tuner motors, and you won't gain anything by that large of pipe. The 2.25 is a step up from stock and allows the exhaust to flow faster and escape better. Keeping the cat(s) keepe the initial backpressure in the engine, but wider pipe cat back allows it to escape better and faster...

 

 

Good luck and hope this helps, as the other posts are doing.

 

 

Been searching, have not found much on exhaust mods. There is a ton of stuff for the ‘old gen’ cars but not much from ‘new gen’. Might be the fact that your exhaust systems cost more than a lot of the ‘old gen’ cars?

 

I have a 98 imp ob, with an ej22. I’m thinking about building an exhaust just like my EA81. Gutted cat, into a 2.25 pipe, glass pack about two feet back from cat, then 2.25 all the way back. I realize that I would need to weld O2 fittings into the system. Also lack of back pressure might be problem. Would the lack of back pressure and lack of cat cause a check engine light? Would I gain anything? Or would it just sound like my old ea81?

[strat]

I've got a '95 legacy 2.2. I cut the cats off and had the O2 sensor (from the cat) ported into the stright pipe. I replaced stock pipe with 2.25 all the way back removing BOTH cats, and piped through a magnaflow. Outcome?

STUPID, WICKED LOUD!!

 

I lost all low-end power and nearly stalled around corners, downshifting into second, trying to goose out of traffic ALL THE TIME. I wanted low end torque for my application, so I had the cats reinstalled and am now on 2.25 pipe from the second cat out the rear, through a small cherry bonb as a resonator, finishing thorugh a magnaflow. It sounds Great, I have a low mellow, NOT loud exhaust signature, the cherry bomb helps with noise, the cats keep the backpressure early in the system, keeping the low end, but the larger pipe thorugh the magna flow, dumps the exhaust out the rear fast. I have gained power and kept the low end.

 

I would't recommend 2.5 of larger, 2.25 is a step above stock and all the wider you want. High flow muffler (magnaflow preferred over flowmaster), and keep the cats. I'm not sure on Imps but if you have 2 you might get away with ditching the rear and keeping the fore, but I'd just stick with both and do a cat back system.

 

The engine will not be harmed w/o backpressure, but it actually needs some. If you deleate the cats, plug theOs snesor(s) into the new pipe at their approximate locations (e.g same distance from the manifold and same side of the pipe, etc.). Your exhaust shop will be able to weld them into a new. If you deleate the cat(s) you will lose low end. I'm not sure of the Imps, but my legacy has 2 cats. The second could be deleated keeping some backpressure, but they also muffle sound too... There's no need to go larger than 2.5 in fact I wouldn't recommend larger than 2.25, especially on a 2.2... They're not tuner motors, and you won't gain anything by that large of pipe. The 2.25 is a step up from stock and allows the exhaust to flow faster and escape better. Keeping the cat(s) keepe the initial backpressure in the engine, but wider pipe cat back allows it to escape better and faster...

 

 

Good luck and hope this helps, as the other posts are doing.

 

your engine does NOT need backpressure... you lost low end power because you lost exhaust flow velocity in the lower rpms...

 

again... backpressure is restriction... restriction is bad. think of an engine as a giant air pump. you want to evacuate the air as quickly and efficiently as possible. too small a diameter piping, you will have great exhaust flow velocity down low but not flow enough up top. too large a diameter piping, the air experiences turbulence and does not flow well in the lower rpms. once you reach the upper rpms though, you'll gain more power from larger piping. you want to find the optimum where you flow decently all across the rpm range to maintain low end and gain top end. 2.25" would be my recommendation for the ej22...

[JonOfScio]

lest we not forget that an EJ22 in a '98 has single port exhaust. ('97 up to be correct)

 

So the performance factor of putting an exhaust on those heads is not as great as a dual port head would benefit from a header setup. someone should definately make an equal length header for that head though, see if that works neatly or not.

 

my suggestion would be 1 3/4" internal from the heads, to a 1 3/4" to 2.25" Y, to a highflow cat, 2.25" catback with resonator, and 2.25" muffler. (although, be choosy enough not to get a straight through design.)

 

The RIGHT sizes of tubing for a particular motor is really important to retain the right velocity. on really costly high hp n/a builds, people have noticed 2.5" is good, but it takes ALOT of work to get to a point where a 2.5" catback would not suffer the low end.

 

also, it's not that you can't find headers for newer EJ cars, it's that you can only really find one header (borla) for a single port exhaust for the EJ22.

 

You know what is interesting about that head? it uses EJ25 valves, and the whole cam system is like that of an EJ25. It's really basically an early SOHC EJ25 head with the combustion chamber suited for an EJ22 block and a single exhaust port.

[JonOfScio]

forgot to post this:

 

it has been mentioned. yes, you do have two sensors. the second, you could put a fitting in to take it out of the stream of the exhaust flow, or you could put a resistor inline to change the signal to a point where the ecu doesn't care. sometimes the latter doesn't work as well as it should. if you could afford a highflow cat, you wouldn't need to gut it or play with your o2 sensor.

 

although, some highflow cats are really barely even a cat at all, and throw a cel anyway lol. so know what you would want.

[Beegeer]

Again thanks for all the good info...

 

I need to visit the local yard for an extra 'y' pipe and cat the start with. I'll post up what I find.

 

-brady:burnout:

[rugbyben]

I have one point to make. Take it however you want. But the cats are there for a reason. and its not to limit the performance of your car. that is just an unfortunate side affect. However, they serve a much better purpose, which is to limit the toxic chemicals in your exhaust. Have an ounce of responsibility! you dont have the right to pollute the air i have to breathe and our children will have to breathe to gain 3HP on a car the functions just fine as it is. You dont need to take the cats off. it doesnt have that much of an affect anyway.

 

Immagine if everyone bypassed their emissions controll systems. (I take it you have never been to Mexico city). the world is just more noisy and dirty.

[superu]

I have one point to make. Take it however you want. But the cats are there for a reason. and its not to limit the performance of your car. that is just an unfortunate side affect. However, they serve a much better purpose, which is to limit the toxic chemicals in your exhaust. Have an ounce of responsibility! you dont have the right to pollute the air i have to breathe and our children will have to breathe to gain 3HP on a car the functions just fine as it is. You dont need to take the cats off. it doesnt have that much of an affect anyway.

 

Immagine if everyone bypassed their emissions controll systems. (I take it you have never been to Mexico city). the world is just more noisy and dirty.

 

I SECOND!