Catalytic converter bypass ???

[Mr.Balupalupe]

BTW global warming is hippie bullshit? The earth's sea level has been rising at almost 3 times its rate since the early 1900's. I'd say that's a pretty good indication the climate getting a bit hotter.

yeah he is right. i find myself a conservitive on most of the political stuff but im pretty sure global warming is fact. and besides. i didn't have cats on my custom magnaflow setup but 1. it sounds too raspy with only the muffler. 2. it smells like shit. and 3. it IS bad for the enviroment.

i just threw a high flow cat on from magnaflow on. it was like 60 bucks so its not very expensive.

[kabal]

BTW global warming is hippie bullshit? The earth's sea level has been rising at almost 3 times its rate since the early 1900's. I'd say that's a pretty good indication the climate getting a bit hotter.

generally when people talk about global warming they mean human accelerated global warming due to CO2 emissions, not the natural heating and cooling of the planet as has happened over millions of years


I just like to fight

[kabal]

wow ive never seen someone misread something as badly as you. i agree with ditching the cats, and i also agree that global warming is hippy bs. removing resonators = civic. i have no cats on my e36, but the resonators are still in place.

I have re-read, and I concede


you must have seen very little, if that is the worst

[OptionlessM]

I have re-read, and I concede


you must have seen very little, if that is the worst

sorry if i was harsh, and i think we are on the same sides of these issues so we may have to team up

[Mr.Balupalupe]

hey kabal what is that on the back of your bumper?

[OptionlessM]

hey kabal what is that on the back of your bumper?

+1 it looks like a tow hitch. you dont see too many yachts attached to E36's.

[Mr.Balupalupe]

i thought it was a tow hook but if it was wouldn't it be lower under the bumper cover?

[DiScoTeknix]

generally when people talk about global warming they mean human accelerated global warming due to CO2 emissions, not the natural heating and cooling of the planet as has happened over millions of years


I just like to fight

CO2 emissions and green house gases do contribute to the climate change IMO every bit of help counts. If that means sacrificing a couple horsepower to have cats.

I guess we Californian tree-huggers are a little concerned about our state being submerged by the Pacific.

[kabal]

damn, I should really change my sig pic, maybe a front view, people always ask

got it like that, and yeah, seems they did a crap job, cause the "diffuser" is cut in the middle.

was going to remove it, then got my dirtbike, and needed to tow my trailer.

FatJohn325:

[Mr.Balupalupe]

yeah when i first saw it i thought it was a penis. then i thought better of it.

[tonyg12]

OK here is the fix!! I got a 97 328is with a Full AA exhaust headers back and i have not Cats and im running regular o2 sensors with NO CEL. What you need to do is got to autozone and pick up 2 spark plug anti foulers. they run i think like $5.50 for the pair. Because the thread sizes of the spark plugs and the O2 sensors are the same they screw right in to the fouler, thus effectively raising the sniffer part of your O2 sensor out of the main exhaust stream. Have your CEL reset if its on and it should remain off for good. My buddy has it done on his M3 as well and we have not got any in 8 months CELs. Just make sure thats you put the O2 sensors in their correct plugs and do not mix them around or else there will be a CEL later on down the road. Its soo easy and saves you a lot of money that you would spend on the simulators!!! Good luck

Did you use both foulers? I thought you only needed one on the last downstream O2 sensor...

[ed323i]

Early M52 E36's might have had only one pre-cat oxygen sensor in the exhaust, just before the CAT, and one post-cat oxygen sensor, after the CAT.
Most of them (and in the US probably virtually all of them) have two pre-cat sensors (in the exhaust manifold, one for each bank), and two post-cat sensors (after the CAT, again, one for each bank/pipe).
So to prevent CEL I think you'd night two anti foulers for both post-cat oxygen sensors.. Or, if you have only one post-cat sensor, then you'd need only one.

It's an old thread, but here's some interesting info. A lot of people think a catalytic converter reduces torque and HP quite a bit. True, it reduces it a little, but what really caused the major drop in torque during the eighties in many BMW's is not the fact that it had a catalytic converter, but the fact that BMW had to lower compression in the cylinders quite a bit because catalytic converters die quickly when you use leaded fuel. And the lead was used to lower the risk of self-detonation. As there were no lead-free high-octane fuels available like nowadays, BMW had no choice than to lower compression substantially.

So, for example a model 1 E30 325i (1986) in Europe didn't have a catalytic converter and used a high compression CR=10.0 CR if I'm correct (might have been 9.7 perhaps).
Then came model 2 E30 325i (1988) in Europe and it came with catalytic converter and BMW had to lower the compression to CR=8.8 if I'm correct.
That compression drop caused a major drop in torque down-below, and combined with the increased weight, the model 2 325i felt a lot slower, and was slower.
Same for the very early 1986 E32 735i. It came without CAT and the M30B35 delivered 220HP (CR=10.0). Then, the later models did have a CAT and HP dropped to 211HP (CR=9.0) and the torque curve worsened quite a bit. It was primarily caused by the lowered compression, and not by just including the catalytic converter in the exhaust..
With the earlier M30B34 it was even worse.. HP dropped from 210HP (CR=10.0) to 188HP (CR=8.0) in the CAT version.

When the M50 came to the market, fuel quality had already improved, and knock sensors were used, and better engine design also prevented problems with pre-detonation. So compression ratio's were up again. CR=10.0 - 11.0 in common M50/M52 models. Within same generation (i.e. M50 vs M52), the lower the displacement, the higher the CR;
M52B20 = CR11, M50B20=CR10.5, M52B25 = CR10.5, M52B28 = CR10.2, M50B25=CR10.0, even while a CAT was installed.

So, don't expect miracles by just removing the CAT. It will help a little, but nothing as spectacular as a substantial increase in CR.