Removing Pollution Controls

Discussion in 'Fuel Economy' started by ssssmashing, Jun 4, 2008.

  1. ChenZhen

    ChenZhen Dreaded Car Salesman

    I honestly came here more out of protest than saving the money. I yanked out the passenger seat, the spare, and my sub box, all the while saying "TAKE THAT OIL MAN!"

    But that's just me. I'm kinda weird that way.
  2. Kevin108

    Kevin108 Well-Known Member

    I'm all for it. All the pollution control does is steal power, add weight and hurt your fuel economy. None of that junk should have ever been put on our cars in the first place. It is a band-aid for the fact that burning oil as a fuel pollutes the air. If these band-aids had never been invented, we'd all be riding around in cleaner, more efficient and alternatively-powered vehicles.

    But since you have to pass a smog test, I seriously doubt it's worth the investment of time and parts or the risk of driving an illegally-modified vehicle. Better stick to the more common practices mentioned here.
  3. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    As I said earlier, one of the Hotrod magazines (don't remember which) did a test a few years ago, with a Camaro. It actually had MORE power with the cats in place than without.
  4. Kevin108

    Kevin108 Well-Known Member

    Depends on the engine. Likely the Camaro engine needed back pressure which it got from the cats.
  5. some_other_dave

    some_other_dave Well-Known Member

    I believe you are wrong--unless you're talking about late-60s through mid-70s emissions equipment, which can be of questionable value.

    Modern cars generally work better (or just as well) with their "pollution control" equipment installed than without it, with very few exceptions.

  6. Kevin108

    Kevin108 Well-Known Member

    I may need to add that all of my performance mod experience has been with domestics. I could well be wrong about imports as I've never been under the hood of one longer than to pour in a few quarts of oil or a gallon of wiper fluid. But the vehicles I've owned and worked on, models well into the 90s, have all benefited by disabling the aforementioned band-aids. YMMV.
  7. kwj

    kwj I hypermiled this

    I'm assuming you posted this thread because you want to get better MPGs. Honest, I'm trying to assist, so bear with me please.

    So, I can assume you've not been Hypermiling for very long ("several months"). Although you've not logged your mileage, you've "tracked" it, and guess that it was around 28 MPG, combined mileage prior to trying some Hypermiling techniques. You like to travel at 75 MPH, for most of your annual 30,000 miles of driving in "relatively flat" territory. You drive "fast" but not "overly aggressively."

    You use "synthetic" oil, have reduced your speeds "significantly," "over" inflated your tires, use your foot rather than cruise control, stopped "riding" your brakes, and just "started" using neutral on the few hills you encounter. Those are all very subjective, and don't give me a clear idea of what might help.

    We know you drive a 2.3 Liter, in-line 4 cylinder Honda Accord, automatic. and that you are trying to curb a speed addiction (welcome to the club).

    I've got more questions. Over how long did you track your average MPG? Did you check it at each fill-up? And that 28 MPG is more than a guesstimate?

    Over what distance/time period have you tracked it since Hypermiling? Is 30 your new average, or is it something close?

    Will you consider logging your progress (or lack thereof) in the Mileage Logs?

    What exactly do you mean that you are a fast driver, but not overly aggressive? Can you describe what makes you consider yourself "fast" and "not overly aggressive?

    How "significantly" have you decreased your speeds? Like from what to what?

    How "over" inflated are your tires? Same pressure front and rear?

    Use of neutral on the few hills you have will probably help out. Have you tried the Pulse and Glide technique? It can work pretty good on flat terrain, and can make your "hills" last longer.

    Since you pull so many annual miles, have you tried driving with only a sock on your accelerator foot? It helps you feel unnecessary pedal modulations that you subconsciously make. I just used that on my recent 150 mile trip, and got 46.9 MPG.

    What grade of synthetic oil are you using? Are you using any oil or fuel additives? Do you ever "warm" up your engine? Do you idle your engine at long lights, or at drive thru lanes?

    Your Honda Accord has a lot of promise, for very little work. We on this site would be pleased to help you realize the possibilities, but you've got to work with us on this. I know it is frustrating to do "things" that don't seem to help, but that's part of the learning process. Practice makes perfect. What begins as "a lot of work," becomes second nature after awhile. People can get frustrated by expecting too much too fast, from themselves. This should be a steady process. You are already an accomplished driver. You put on lots of miles each year, giving you tons of experience. So, you are proven capable, and I think you'd be a stellar Hypermiler.

    So, do you want to try some more?
  8. jcp123

    jcp123 Caliente!

    FWIW, my Focus got about 4mpg extra when the rear O2 sensor went there may be something to it. But modern engines are designed to run WITH all that crap on it, so you're typically better off leaving it all intact. It's the older engines where this stuff was tacked on after the engine was designed that you'd see much more of a gain.
  9. trackermpg

    trackermpg Well-Known Member

    My advice would be to sincerely take the time to provide as explicit answers as possible to kwj's thoughtful questions. The more detailed information you can provide, the more likely it is he (and others here) can help identify those areas where you can receive the greatest benefits. The time you take to do this will be rewarded to an extent that you may not think possible yet, but trust him...

    IMHO, it would not be prudent for functional and ecological reasons to arbitrarily remove the Cat. The engineering that goes into making any car any more is incredibly complex and the systems/components function in such an integrated way (hence computers to manage and monitor it all), that it wouldn't be wise to think a single component in the engine/exhaust system or its function can be arbitrarily altered or removed without consequences (typically negative). An engineer will take into account the exhaust system as designed, and integrate engine design, operation, and control to work at its very best possible with those systems in place.

    Maybe someone can help me out here, but since most O2 sensor failures will result in an Open Loop condition (maximum fuel flow), would removing a Cat lead to issues with sensor readings and possibly end up forcing Open Loop?
  10. Chuck

    Chuck just the messenger

    Typical Beiing...remains to be seen if it's this way during the Summer Olympics

    T. Boone Pickens said it was worse than LA during the 60's. (for LA - it was auto emissions)
    This is what you get by removing pollution controls - any questions?
    Last edited: Jun 6, 2008
  11. HemiSync

    HemiSync Well-Known Member

    See I had the exact opposite result, 2 of my O2 sensors were failing to the point of triggering the check engine light and after they were replaced my mpg went up about 4 mpg. This can be seen clearly on my mileage logs as I documented the repair there.
  12. ssssmashing

    ssssmashing Member

    On my most recent tank I was very, very aggressive with these techniques. I turned off the motor at lights. Pulse Glide. Neutural on hills. Drafted off trucks. I got 26.2MPG, so clearly I am "doing it wrong", as this is the worst mileage I've gotten on the car in the 2 years I have owned it. I am sure you are right that I need practice and patience. The first will not be a problem, the latter has always been a struggle :eek:.

    Oh as an aside part of the reason I asked this is, this is the second car of this kind I have owned. Same year, same model. Same engine. One was a ULEV, this one is a LEV and it gets substantially better mileage, this is what prompted me to investigate what pollution control does to mileage. I am not, I repeat, not an environmental terrorist. I've never dumped motor oil in my back yard. I don't use hairspray. I recycle. I carpool. I love my wife. I don't kick my dog. etc. etc. etc.

    So as my next steps I am going to keep a spreadsheet of my mileage and order a scan guage. Honestly I was so faithful to these practices that these latest results are a real discouragement.
  13. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Thanks for taking the time to join us -- and to respond to all those questions!

    First, please be aware that many of these techniques take some work to get right -- even with a ScanGauge. Without one it is quite easy to apply them incorrectly and never know until you fill your tank and see disappointing results. The SG can tell you what works and what doesn't on a moment by moment basis -- the instant feedback really is a tremendous help in determining how to get the most out of your vehicle in any given situation.

    Second, I strongly suspect your tires have a max sidewall pressure of 44psi -- please use this as it is substantially better than even 38psi. I've only seen a max sidewall rating of 35 on lower quality tires. Even if that is what you have, though I can't legally recommend it I can tell you that the tires will handle that higher pressure just fine if they are in good shape. Tire burst pressure is something over 200psi for a modern radial in good shape.

    Third, those high speeds are killing your mileage. If you have to go 60mph, do that but don't go higher. There is a very steep fall off as you get to 65mph and higher due to the sharp increase in wind resistance. Your car will be most efficient in the 40-45mph range... higher speeds will be worse on an exponential curve with 65mph marking the start of a really steep fall off in efficiency. 75mph is really bad in this respect.

    Do order the SG and don't give up!! Once you have the gauge in hand you'll be able to see what effects your efforts are having -- with a little determined effort and paying attention to what the gauge tells you that mileage number will rapidly improve!
  14. kwj

    kwj I hypermiled this

    ssssmashing, I really appreciate that you took the time to respond. It sounds like you are doing so many of the right things. I'm sure things will begin to look up as you get more proficient, still, you sound like you are pretty knowledgeable of the techniques.

    You don't have a ski rack or anything like that do you? Do you drive with a sun roof open? Some of them can really put out a drag. I'm not sure if it helped me, but when I had a sun roof, and I opened it, I also cracked both front windows a bit to get some air flow. If I'd had a ScanGauge, I might have been able to test it.

    Perhaps you read a few of my questions wrong. Warming up your vehicle is a waste of gas, assuming you are idling. Start it, then after about 30 seconds, drive it gently. Allow it to warm up as you drive (but don't go ripping out on the interstate - let it warm up first).

    Don't idle at long lights. If you know you will be stopped anywhere for a minute or more, shut er down. Don't use the drive through unless you are the only one in line. Otherwise, park and go inside. Too much stopping and starting and idling. Wastes gas.

    I'm not sure how much the injector cleaner is doing for you. I used it once. Could be a waste of money, unless you are getting symptoms of a dirty injector.

    On my trip home tonight, something was preventing me from doing better than 43.5 MPG. Everytime I got a little above that, it wouldn't last. Now go figure, I drove up to NJ on a fairly full tank, and I drove back on about a half tank (and still have a lot left), so I should have been lighter. Yet I got 46.9 on the trip up and only 43.4 on the trip back. I can't explain why. I thought I was doing essentially the same things. It was quite hot on the return trip, and I hoped I could do a repeat or even better. But NO.

    See, sometimes you are just at the mercy of physics, thermodynamics and the laws of Mechanics, and there is nothing you can do but accept it. Don't get frustrated. Any savings you can get now, is an improvement over previous tanks. Every little bit helps.
  15. ssssmashing

    ssssmashing Member

    Well I promised to bring you all up to date. I have been carpooling so it's taken me a while to actually use a tank of gas, but I managed 32.8MPG. On the latest tank I had a few things going for me. Lots of highway miles, warm weather, a road trip where I had a strong tailwind in one direction and no wind at all on the return.

    Nonetheless a very encouraging development.
  16. Chuck

    Chuck just the messenger

    Carpooling is the most effective way to save money! :)
  17. ssssmashing

    ssssmashing Member

    I started pooling about 3 months with another guy - everybody thought we were nuts, now we have 5 in our party. Now its really paying off.

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