Saving some MPG. Header/Cat/Computer Question

[LunchBox04V]

OK, I have hit a little bit of a wall on this one. I have a second Gen. 2.2L('99 BK 30th Ann.) with the single port. I am in the process of trying to get a little more gas mileage out of the 2.2L. It does not have the MAF sensor, it has the other type (MAP if I remember right). It cuttently has a 2.25" exhaust from the second Cat back, through a MagnaFlow.

The car is a single port exhaust. It them flows into a collector, with the first O2 sensor, then through two Cats, followed by a second O2 sensor. Then the custom exhaust.

Here is the plan: I would like to remove both Cats. I understand that I would not pass an emission test, but I would like the additional MPG. I believe this will relieve a little restriction and free up some range.


Real question: Technically, this is kinda easy, chop, and swap. However......I am 99% positive that the ECU will get pissy and through a code from the 2nd O2 sensor (Probably "Cat. Effectiveness"). Will this put the car into "Safe Mode" this redarding timing, loosing power, and negating any benifit I would gain? Like I said, I am sure that it will, SO..... is there anyway that I can convince the ECU that all is well?

Airgne, I think you posted for someone else on something like this, but I can't find the post.

Thanks for any insight that you guys and gals can give me.

[decke48]

you can put a resitor in the rear o2 so it wont CEL. so it will think there is a cat.

[LunchBox04V]

That is kinda what I thought. I know that Boxer4Racing has one for like $20. Has anyone done this? I am just looking for a little guidance. I will talk it over with my buddy Jerry, and see what he thinks. (Runs "Subaru Guys" of Traverse City.) I will see what information I can come up with. Currently I am getting 28 city, and 35.5 highway.

[MoclovFlop]

Do not, i repeat, do NOT remove both cats, that's just stupid to screw over the environment like that because you want maybe 2mpg more in efficiency. Put in a high flow metal substrate single cat at least, they flow amazingly (there are NUMEROUS articles out there stating that a good high flow cat flows almost as well as cat-less) and will reduce your noxious output by considerable amounts. And if you go the catted route, you'll be able to just put in an O2 mechanical spacer, saving you money and it's easier to install. For a N/A motor with minimal mods, going cat-less will have a minimal effect on your MPGs. Inflate your tires to 35psi, and accelerate gently and you'll get more miles per gallon than you ever would fucking over the ozone.

Sorry for the rant, but you'll thank me in 30 years when carbon reaches a perilous 480 ppm.

[LunchBox04V]

No worries dude! Honestly, i kinda knew that I was going to get that rant at some point. Like I said, I was kind at the technical wall, and didn't know where to proceed. I totally forgot about a high-flow cat! However, what did you mean by a "mechnical" way of fooling the rear O2?
I am thinking you mean something like this refering to the exhaust routing.......

Original

Exahust-----Cat.---Cat.--O2-------Exit

"Mechnical Spacer" Mode
O2
l
l
l
Exhaust-----H.F. Cat.------+-------Exit

Essencially spacing the O2 sensor out of the main exhaust flow? I think I have heard of this. If you can, try to explain it a little more, and educate me! lol

Again, don't worry about the rant, I can take a different point of view. Especiall an educated one. :cool: It is the ignorant ranting that I can't stand! :evil:

Oh, and the tires are at 42psi (Summer tires different psi max) and my friends will tell you that even the grannys out there flick me off when I cruise along at 45mph. :lol:

[LunchBox04V]

Well that didn't post the way I wanted. The "mechanical" one should have the "O2" sensor connecting after the "H.F. Cat" at the "+" sign. Sorry folks. Ok, I have to go play pilot for a few hours.

[Wiscon_Mark]

I'd like to see a shot of your engine bay, I'm pretty sure you don't have a MAP sensor.

[LunchBox04V]

Hey Mark, sorry I can't upload the picture here, the company put me in a hotel that does NOT have a working Wifi network. I had to barrow this computer.......lol. Anyway, there is a picture of the engine bay on the 4th page of my cardomain site, and there is a link to that from my signature. I did "make" a custom intake from a '93 Subaru intake tube. However, please correct me if I am wrong, but I am about 90% sure that I do not have a Mass Air Flow (door with a sensor) sensor on my car. The manual says the engine is "California Spec"........ From the shop I go to, they say that it only cam in the '99 model year Legacy, again, I could be totally wrong there though too. Thanks for the interest though folks! Always fun to learn. I just wish I could post from my smart phone!

Ok a little work, but here is a direct link to the page, it should be the top picture. Thanks for the help!
http://www.cardomain.com/ride/2581248/4

[MoclovFlop]

Yea, Sorry again for the rant, and yes, you are right. A mechanical O2 fix would be a spacer to remove it from the exhaust flow. You can actually go to any car parts store and buy the "OH NO" anti foulers, and just drill one out and then use two of them to pull it out of the flow. They are like 5 bucks for two so you can't go wrong.

And yea, it does look like your car is MAP because you definitely don't have the MAF in line with the intake. Crazy because it still has the offset coil pack, probably the same engine from 98+ Imprezas.

But yea, HFC= tH3 b1g w1nnar


EDIT: You have got one hell of a mish-mash engine.... single port exhaust? MAP? Hmm, I can almost bet you don't have single port exhaust, but you'd have to check for us.

[Huffer]

This is the 3rd sandstone metallic 30th ann. wagon I've seen with the MAP intake. Which is sweet...

[DLC]

MAP on a 2.2 is...weird, but cool. MAP FTW!

[LunchBox04V]

Hey guys, sorry it has been a while, but here is the crapy proof.
http://memimage.cardomain.com/member_images/1/web/2581000-2581999/2581248_47_full.jpg
Sorry about the bad image quality, but it is a
2.2L, Single Port Exhaust, MAP, 30th Ann. Eddition.
I know, it is a freak of nature. In the manual, it says that it is a "California Eddition" engine. So far nothing has been done as of yet. I have been too busy working, and too short of money, who would have thought! I will be doing something more with gas at the $4.20 mark.

[Huffer]

California spec is simply EPA regs that meet the CARB standard.

[shizznats]

Do not, i repeat, do NOT remove both cats, that's just stupid to screw over the environment like that because you want maybe 2mpg more in efficiency. ... Inflate your tires to 35psi, and accelerate gently and you'll get more miles per gallon than you ever would fucking over the ozone.

Sorry for the rant, but you'll thank me in 30 years when carbon reaches a perilous 480 ppm.

:lol: :lol: :lol: ... you're joking, right?...

[MoclovFlop]

Nope, no joke, the carbon numbers were wrong, but removing the cats from a n/a car is going to give very little benefit over a HFC and some basic things like tire pressure and better driving.

to quote WIRED mag's article:

"...[E]ven if the US, Europe, and Japan turned off every power plant and mothballed every car today, atmospheric CO2 would still climb from the current 380 PPM to a perilous 450 PPM by 2070...(do nothing and we'll get there by 2040.)"

Page 164. Volume 16 issue 06, June 2008.

[shizznats]

Based on what information? we don't even have enough historical data to make projections like that... i think its absolutely sick what the greenies are doing and the national attention and resources that are wasted on things like 'global warming' ... in the 1970s the big scare was global cooling; funny how we forgot so soon. its called climate cycles.

maybe we should all just stop breathing... can you imagine the carbon emissions coming from us humans.. unthinkable!

[MoclovFlop]

Based on research done by The Electric Power Research Institute in Palo Alto, California. But I'm not saying there's no such thing as cycles, I completely agree that there are numerous factors leading to a very large change in the Earth's climate, greenhouse gases and carbon are only parts of what is causing a change. We are due for bad times.

But don't be a _____ and patronize me, all I'm saying is that we don't need to fuck things up MORE by removing something so simple as a catalytic converter.

We'll adapt and survive, after all, the medieval times were a small ice age, so next on the list is a small tropical age.

edit: we do actually have historical data. Drilled and extracted core samples from the polar icecaps show the big variances in CO2 and carbon from as far back as pre-Jurassic period.

[shizznats]

im sorry if i came off like an asshole... it just infuriates me to see national resources being wasted on a fear inducing machine like global warming. and it really upsets me to see how well that machine works as a political platform. thats really all it is.

i mean, look at what has just happened in new zealand. an anti-flatulent drug was developed for the goats there (apparantly they have a lot of goats) to hinder global warming. they made anti-fart pills to reduce global warming... i mean that is just insane. but people will support things like this if politicians and the media push this myth of global warming enough. no evidence necessary; all the left wing needs is control of your tv and they have control of your mind. it scares me. but once again, sorry for being a bit of a dick.

[MoclovFlop]

No worries :smile: I know I cause global warming after eating Chipotle :shock:

[makipsee]

what if u remove the cats and installed a spacer and the CEL still comes on. does that mean it needs another spacer?

[Huffer]

Depends entirely on what the CEL is.

[birukun]

I also have a CA model BK (1999) that is MAP. (4EAT)

I am curious as to if your mileage increased after changing the catback exhaust since I only get 23 MPG mixed driving.

I have gone through all the MPG saving tips, new plug wires, plugs, air filter, PCV, tranny fluid, diff fluids, new wheel bearings.....

CA does use a 10% ethanol blend, does MI?

P.S. I am jealous - the Sandstone Metallic was the first choice, the dealer counld not find any except Brightons that had that color. Let me know if you want to trade... :-)

[track8]

Ok, so my spacers don't help. I even went so far as to weld the end of the spacers shut so the sensor only sees a thimble full of clean air at all times, leading me to believe that it wants to sense a wee bit of exhaust. Who knows the resistor values needed clear the code? You may PM the answer if you'd like to avoid the publik lynching.

FWIW, most ECU's won't go into "limp home" on a rear O2 code. That would be emission-stupid to go open loop over a weak cat, no?

P.S. I'm paying Al Gore "carbon credits" for my deleted cats. NOT! Who even listens to that >failed politician... hello!< anymore?

[Grafton]

That is kinda what I thought. I know that Boxer4Racing has one for like $20. Has anyone done this? I am just looking for a little guidance. I will talk it over with my buddy Jerry, and see what he thinks. (Runs "Subaru Guys" of Traverse City.) I will see what information I can come up with. Currently I am getting 28 city, and 35.5 highway.

wish mine was getting that 21 city 25-29 hwy

[ajfsgrl08]

My 1999 Legacy L (2.2L 5 speed) also has a MAP. :smile: