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Unless you are running turbo.....I would be very careful what you do to them.

 

Best advice is to deburr any casting ridges inside the intake, and port match the intake/heads to the gasket.  Otherwise leave the intake alone.  You want a rough inside wall and will lose velocity if you open it up too much.

 

Exhaust you can do the same and also polish a bit and round off corners.

 

Really port work is more effective on Turbos because airflow is a major limitation for them.....N/A not so much.

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I honestly wouldn't bother with these. Unless you are planning to up the rev limit to 8k or something ridiculous, you won't see much of anything with improvements and will probably hurt your performance unless you plan on sticking a custom cam in and upping compression to 10.5:1 or something. Porting is more beneficial in an engine with 1 intake and 1 exhaust valve. Since these have 2 in/ex each cylinder, it's already flowing better.

 

Like Gloyale said, you can remove any flashing or ugly casting marks, but I STRONGLY advise NOT touching the port diameters. I'd also suggest porting the exhaust header INLET to be a touch larger than the exhaust port in the head, and leave the intake alone. Aluminum is a RPITFA to grind, and reworking the steel header is more safer and more practical. From there, I suggest a cold air intake, sticking a SINGLE high flow cat in, and running a 2.25" exhaust from cat-back. Although, since you are in CA., I suggest getting an approved cat like a 3" in/out and getting a welder to adapt that to a 2.25" diameter after the cat and matching it to fit the factory headers. A 225 HP 302W Ford would typically get dual 2.5" exhaust as an upgrade, which split in half is 2.5L per exhaust and the cars ran super strong with it. Being a 2.2L, 2.25" exhaust will match nicely. Doing the math, the old 302 was making 112.5 HP per 4 cylinders, as opposed to the 2.2L making around 132 HP. My old 96' Mark VIII with the 4.6L DOHC engine with 290 hp (2.3L and 145 HP per 4 cylinders) only had 2.25" and it ran fine with that too. Doing your exhaust and intake will be the most bang for butt with 4-6hp roughly from the intake and maybe another 10-15 hp for the exhaust depending how restrictive your entire set up is. Assuming you were a PRO at blending and working the heads (just cleaning up the ugly castings if they exist and removing burrs), you'd be HARD PRESSED to pick up 1-2 hp, although the engine might "feel" smoother when you step on it. 

 

Here's an example of how a restrictive exhaust steals HP. My Saab's factory turbo died right after I sold the Mark VIII. Needing a car to drive until a rebuild could be done on the turbo, I removed the CHRA but left the exhaust housing attached, and bolted on a home made "cover" to block the hole off, so the exhaust was just flowing through the hollow turbo exhaust housing. With a 5 speed, the car was barely making 90hp NA (might have been less). It was about as a quick as my old 84' Diesel Rabbit that had 50 hp. I ported the empty exhaust housing inlet (basically the same as a header inlet) as the rebuild was getting a MUCH larger compressor wheel and compressor housing, and the factory A/R was like 48, which is VERY small, it's like 4 cyl. trying to breath through 1 exhaust runner on a NA header. After porting that, the car picked up something like 15-25hp NA. I did a video before and after with just the exhaust housing ported and car running NA with no turbo. It was night and day. Dropping your factory 1 7/8" exhaust for a more performance friendly 2.25", should give you some HP numbers you can actually feel and back up with a stop watch.

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Im running a pair of EL headers that I believe are 2.25" already. Plus a cai. My front cat is a magnaflow and the rear cat is stock. Then the resonator, 12" I believe. At the end is a Magnaflow muffler. The headers and Magnaflow cat I put on at the same time. Made a difference I could feel. My thought on the heads subject was that I see a lot of posts saying the single port heads dont flow as well as the dual. Im not really sure that is true, but I thought a little port matching on both ends wouldnt hurt, especially when adding some delta cams. I would like to gain a higher rev as well, maybe not 8k, but close. Thanks for the input. Reducing my power is not my goal.

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Unless your engine is carb'd, you're electronically limited with the revs, so the cam won't make a difference with the redline as it's electrically limited. If the cam favors top-end, then you'd need to find a way to get a tune to raise the limit assuming the valve springs can tolerate it. CA. is a little too strict with regards to their inspections and all the "CA Approved" BS. Anywhere else you could just run a universal single cat. Your rear cat being factory, is still very restrictive and I think oddly shaped. Ideally you want them round with coarse honeycomb and short. The factory ones have a fine honeycomb and are rather long, which means more backpressure and more effort to get the gases through them. 

 

 

There really isn't a lot you can do to get a 2.2L NA making serious power as the aftermarket isn't really there for it like that. About the most you can do NA is install 10:1 pistons, have the heads professionally worked over (valve job, back cut, maybe increase the intake valve size), balance the engine, add nitrous.

Edited by Bushwick
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I honestly wouldn't bother with these. Unless you are planning to up the rev limit to 8k or something ridiculous, you won't see much of anything with improvements and will probably hurt your performance unless you plan on sticking a custom cam in and upping compression to 10.5:1 or something. Porting is more beneficial in an engine with 1 intake and 1 exhaust valve. Since these have 2 in/ex each cylinder, it's already flowing better.

 

Like Gloyale said, you can remove any flashing or ugly casting marks, but I STRONGLY advise NOT touching the port diameters. I'd also suggest porting the exhaust header INLET to be a touch larger than the exhaust port in the head, and leave the intake alone. Aluminum is a RPITFA to grind, and reworking the steel header is more safer and more practical. From there, I suggest a cold air intake, sticking a SINGLE high flow cat in, and running a 2.25" exhaust from cat-back. Although, since you are in CA., I suggest getting an approved cat like a 3" in/out and getting a welder to adapt that to a 2.25" diameter after the cat and matching it to fit the factory headers. A 225 HP 302W Ford would typically get dual 2.5" exhaust as an upgrade, which split in half is 2.5L per exhaust and the cars ran super strong with it. Being a 2.2L, 2.25" exhaust will match nicely. Doing the math, the old 302 was making 112.5 HP per 4 cylinders, as opposed to the 2.2L making around 132 HP. My old 96' Mark VIII with the 4.6L DOHC engine with 290 hp (2.3L and 145 HP per 4 cylinders) only had 2.25" and it ran fine with that too. Doing your exhaust and intake will be the most bang for butt with 4-6hp roughly from the intake and maybe another 10-15 hp for the exhaust depending how restrictive your entire set up is. Assuming you were a PRO at blending and working the heads (just cleaning up the ugly castings if they exist and removing burrs), you'd be HARD PRESSED to pick up 1-2 hp, although the engine might "feel" smoother when you step on it. 

 

Here's an example of how a restrictive exhaust steals HP. My Saab's factory turbo died right after I sold the Mark VIII. Needing a car to drive until a rebuild could be done on the turbo, I removed the CHRA but left the exhaust housing attached, and bolted on a home made "cover" to block the hole off, so the exhaust was just flowing through the hollow turbo exhaust housing. With a 5 speed, the car was barely making 90hp NA (might have been less). It was about as a quick as my old 84' Diesel Rabbit that had 50 hp. I ported the empty exhaust housing inlet (basically the same as a header inlet) as the rebuild was getting a MUCH larger compressor wheel and compressor housing, and the factory A/R was like 48, which is VERY small, it's like 4 cyl. trying to breath through 1 exhaust runner on a NA header. After porting that, the car picked up something like 15-25hp NA. I did a video before and after with just the exhaust housing ported and car running NA with no turbo. It was night and day. Dropping your factory 1 7/8" exhaust for a more performance friendly 2.25", should give you some HP numbers you can actually feel and back up with a stop watch.

Bushwick as you said in your post about using a "single" cat, Im wondering, what do you do with the rear cats o2 sensor? Do you just get a bung welded in there? My front cat, which is a Magnaflow, has two places for an o2 sensor. One bung before the wide middle part and one bung after the wide middle part. What would happen if I screwed both o2 sensors into the one cat?

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So, is there any difference in power or efficiency on the same application between an unequal length header and an equal length one? The difference in the sound of the engine is night and day. The equal length header makes the engine sound pretty much like any other inline 4 cylinder. The unequal length one gives the engine that tractor or harley sound that everyone within a city block knows is a Subaru engine.

Edited by Crazyeights
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As far as I know the EL headers produce more usable power and torque. Made a big difference power wise when I installed mine. Even though Im running EL headers I still have a great sound, most likely due to my Magnaflow muffler. My car does not have that jacked up lawnmower sound like a honda. The tone is deep and it is rumbly, although a touch raspy due to the 12" resonator. Maybe Ill post a vid of the sound, and the instrument cluster during acceleration. Then follow up with another vid after the head porting and deltas.

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Yeah, equal length are just that. They are essentially "tuned" and power from each cylinder is more consistent, i.e. each cylinder is closer to making the same hp/tq. With unequal length, there can be slight variations across each cylinder. 

 

 

If you run a single cat, make SURE it does what both cats do. I haven't looked at cats recently, but they are actually named differently depending on design. Some cars run a single cat, that does all the work. Other cars run dual cats, where the front one is slightly different than the rear if I understand it correctly.

 

To be safe, you can "only" replace a cat if it's failed or defective, so remember that if the question pops up, as your cats need to be "bad". Running too rich or lean for too long can ruin them, as does some fuel additives. The fuel additives can clog and overheat them, which causes them to melt the honeycomb. Melted honeycomb looks like melted glass  FYI.

 

If you switch to a single, hi-flow universal cat (Summit Racing is a great place to snag them, $80-120). Since you are NA, you probably don't have to worry about the material telescoping at your power level. Otherwise, they make a staggered honeycomb that prevents this, but those cost more. Hi-flow cats have wider holes in the honeycomb. think of factory cats as being the type of screen that faucets have, and high-flow cats as having the widest holes available fore a screen door that won't stop gnats, but will stop flies. The short, round cats that are advertised as "high-flow" are what we use in turbo'd cars to reduce back pressure at the turbo. You'll loose some torque early on, but it should pick up HP and tq throughout the powerband. It should also respond quicker to sudden pedal mashes. Being a CA. car, get a CA compliant cat to avoid BS. Better yet, keep your factory cat for inspections, then keep the "race cat" for "races" ;)

 

As far as the bungs go, you need the first O2 directly ahead of the cat. Use the factory cat and O2 location to put a new bung on the other pipe, avoid installing in a bend. The rear O2, needs to be directly after the cat, the closer the better. Use a touch of anti-seize on the threads and it'll be easy to remove in the future. Basically, get a straight pipe exhaust and add the cat to it and both O2 bungs. Fit everything before tacking into place. Add an extra flex pipe (those braided $25 section will work, and will limit any stress, though it shouldn't be as bad a transverse mounted engine in a true FWD car). Reset the battery and start the car. Give the cat a break in period. After 50 miles, if you CEL comes on, find out which O2 sensor has the issue. If it's the rear O2, buy 2 anti-fouler spark plug caps. They can be threaded into one another, and the O2 can be threaded into that. The bottom anti-fouler that get's threaded directly into the exhaust, needs it's hole drilled out. The top one I forget if it needs a slight drilling or not. Anyways, this pulls the rear O2 up and away from the direct stream of flow, BUT it allows it to sample the exhaust enough that it won't throw a bad O2 CEL. Mustang guys and even the Honda guys have to do this. I did it in my Saab before I had the tuning software and the car was cat-less briefly, and it worked and never threw a code despite no cat being there. I doubt you'll have the issue though if you install a correct "all in one" universal cat, but the option is there and it's easier than adding more bungs trying to find an optimum spot, and as you can infer, if you ever want to run "cat-less", this trick will stop the CEL for the rear O2 from popping up. Google "CEL eliminator for rear O2" to find threads about hole drilling size. Can but the cheapo anti-foulers at Auto Zone, which has 2 to a pack for like $6. Can buy aftermarket, which has the extra length in one unit, but they are nearly $20. Wherever you add the rear O2 bung, make SURE you have about 4" of clearance for the O2, and a spacer if you ever decide to run one, so obviously can't add bung to bottom of pipe or up top if it's going to hit the trans tunnel or firewall, etc.

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So even though I live in Ca. I live in one of the only counties that dont require smog checks every year or two. Only smog check is when the vehicle title gets transferred. Ill contact Magnaflow and find out if the rear bung on the front cat can be used for the rear cat o2 sensor. I dont know why else the front cat would come equipped with a front a and rear bung. If it works out like this then I could do a 2.25 cat back exhaust and be incognito :ph34r: Ill post back when I hear form Magnaflow.

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Bung sizes are the same front/rear. If you do away with a 2nd cat and have a straight pipe in it's spot, you can move the rear O2 directly AFTER the main/1st cat. It's main function is to just monitor that thew cat is doing it's job.  Some universal cats will have the rear bung incorporated into the cat. I have a Magnaflow "universal" cat as well as my emissions cat in the Saab. It's got the rear bung directly in the casing after the honeycomb. Front O2 is way up by the turbo. For best flow, get a small, round cat like turbo downpipes have. They are maybe 6" to 8" long, and look like a 1/4 of a glass pack. Your universal is long, and has lots of honeycomb. In my car, it's killing power, but I'm way out there with hp. 

 

Either way, dropping the rear cat will net you some lost power. Here's the type of cat I suggest:

http://www.summitracing.com/parts/flo-2230130/overview/

That's a 3" cat. Make sure yours is OBDII variant. Buy that in 2.25" and adapt to your header, then run 2.25" cat-back. Along with an open airfilter, or cold air, etc. it'll net most power w/o loosing too much down low. If you can, keep your existing pipe with cat, and use a fresh one for the new cat so if you run into issues, you can swap back. It's "illegal" to sell as car w/o a cat or an incorrect one, and the buyer can actually sue you over it. So if time does come to sell, it'll be less of a headache. 

 

@Fairtax  I beat to you it few lines up ;)

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You don't need one if it's not throwing codes for the rear O2. As long as the rear O2 is as as close as possible, you should be OK. All the extender does is "trick" the the ECM into thinking everything is OK for guys that run cat-less, or have a CEL after exhaust mods.

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  • 2 weeks later...

You can do the pipe now if you want. Personally, I'd go that route now because you have more backpressure between the front and rear cat, which the rear O2 is now sampling. The car has NO clue the rear cat exists, and it might be altering the mixture to compensate. Normally, the rear O2 doesn't get subjected to the backpressure. Being between 2 cats, the amount of exhaust might pool up or something. Point is, go ahead and cut the rear kitty out and install a slip-fit pipe, or buy 2 band clamps and connect the straight section that way. It'll allow you to revert easily if needed. I'd just hate for the car to run wrong now and clog the rear cat prematurely. Besides, the couple HP it's stealing would be more fun to have now ;)

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Muffler shop won't touch it. ONLY thing a muffler shop is allowed to do is replace with OEM, or an aftermarket cat meant for the car or they risk a serious fine as it's a Federal law and fine. A downpipe is a pipe that attaches directly to the turbo's exhaust port, usually with a cat attached, and feeds down to the main exhaust section. When you hear about people putting a down pipe on, it's usually in reference to adding an over-sized pipe (typically a 3") immediately after the turbo with a high flow cat. That helps decrease back pressure, which helps increase turbo spool up, which is reducing lag, and on higher HP turbos it's a must as it can actually restrict hp by running a stock diameter. 

 

I was referring to this:  (If the link isn't working, right-click it, select "copy", then paste directly into an address bar)

http://www.amazon.com/Dynomax-33226-Stainless-Steel-Hardware/dp/B000CQHUYG 

 

Buy 2 of those that match your exhaust diameter. Then cut a section of straight pipe that's the same length as the removed cat section. Stick the straight pipe up, then use those clamps on each end. Torque them as tight as they'll go with a 1/2 ratchet. Can even crank them a little more with a breaker bar, but don't over do it. The spot welds are fairly robust. That'll seal the exhaust and will be strong enough to keep the pipe in place. If you ever need to drop the exhaust or that section, the clamps can be reused. They are stainless steel, so they won't rust. I suggest a dab of anti-seize on the threads for easy removal in the future. 

Edited by Bushwick
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Hmmm the link wont work either way. Ill search amazon and see what i come up with. Thanks!! I was thinking about unbolting the second cat pipe, cause its direct fit, taking that in to the muffler shop and see if they can make me a pipe with flanges to bolt into place. Tell them its for my "track car" :ph34r:

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Yeah, that'd work. If you go to a muffler chain shop, they'll probably refuse to do it, say it can't be done, or some other nonsense.

 

Best advice I can give from experience is to go to a "custom" exhaust shop. The guys that bend pipes and do custom fabrication. OR call around and find a local welder and explain you are "replacing a section of rotted pipe". Wouldn't mention anything about a previous cat as some people can be really damn weird about it. Just make sure to mark everything well after the cuts. If the angles are odd or you are working with a bend, mark the pipe to flanges, have them tack the pipe to the sections, then test fit on the car  B)

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