Where do you draw the line?

[dkjones96]

This is really because of another post I saw:

Originally Posted by maxxgraphix

Disconnect the EGR. Get a high flow CAT and muffler.

The EGR actually won't even increase mileage when disconnected and if it was working properly this will decrease mileage, FYI, but getting a high-flow cat (or none at all) will leave more pollutants in the exhaust and will pollute more than if the car in question leaves it on and suffers a bit of economy loss.

I guess it really depends on what your mods are for, pure MPG or more earth friendly. While you might think those are synonymous, they aren't, and I'm just wondering where people start to say 'This will give me better mileage, but will pollute more'.

I tend to leave my mods to ones that will pollute less and/or the same while increasing mileage. The mods I do to my car most of the time don't even use new parts, they are off junkyard cars so I'm not paying a company to pollute making me a new electric fan assembly when an automaker already has for the used one that might end up thrown away needlessly if I don't use it.

[Improbcat]

I don't just consider the "pollute more vs higher MPG" choice, I also consider the "improve my mpg vs decrease someone elses' mpg" choice.

Unfortunately there are a (probably relatively small) chunk of the hypermiling techniques that only work if either you are the only one doing it, or you don't care that you hurt someone elses' mpg. Drafting, pulse & glide (if the road is crowded), some forms of coasting, etc.

So I guess what I'm trying to say is that I consider my vehicle mods and driving technique for what will help the most without hurting someone else.

[VetteOwner]

my theory is if it breaks and doesn't affect mpg or performance then its gone/disabled...

liek the chevette has no cat and disabled the EGR

truck has a cat only because i suffered performance loss (not enough backpressure) but its EGR has been taken completely off because a new one is $80 and we don't have emissions testing

[McPatrick]

improve my mpg vs decrease someone elses...drafting

I don't really see how drafting would hurt someone elses mpg. If anything it will also improve the mpg of the truck you ar using for your drafting...

Otherwise I agree that if you could win some mpg's by using irregular speeds on busy highway (pulse and glide) that that wouldn't be very nice for your fellow drivers.

I have the impression though after having been on this forum for a while, that the people that are into hypermiling are not selfish drivers and if anything are safer drivers that look further ahead of what's coming and are considerate of others.

[Improbcat]

Originally Posted by McPatrick

I don't really see how drafting would hurt someone elses mpg. If anything it will also improve the mpg of the truck you ar using for your drafting...

Depends what you are drafting. Yes drafting a big rig won't hurt its mpg, but drafting something smaller can and will hurt the other driver's mpg. I can *feel* my xB slow down when someone drafts me in certain ways. Also drafting too close to a rig is just plain dangerous.

Originally Posted by McPatrick

I have the impression though after having been on this forum for a while, that the people that are into hypermiling are not selfish drivers and if anything are safer drivers that look further ahead of what's coming and are considerate of others.

Oh don't get me wrong, I don't think all or even many hypermiliers are dangerous or selfish. It is like anything else, most people are polite and considerate, but there are always a few in any group who take it to extremes and are so concerned with their own benefit they don't think if their actions are negatively impacting others.
Not out of malice or anything, just because they get so caught up in the gains they don't think enough about the downsides.

[dieselbenz]

Originally Posted by dkjones96

The EGR actually won't even increase mileage when disconnected and if it was working properly this will decrease mileage, FYI, but getting a high-flow cat (or none at all) will leave more pollutants in the exhaust and will pollute more than if the car in question leaves it on and suffers a bit of economy loss.

Disabling the EGR improved mileage for me and it was working properly prior to the modification. In 1989 Volvo installed EGR on California cars while 49 state cars didn't have it. The EPA numbers back this up.

EGR
http://www.fueleconomy.gov/feg/2008c...ef.jsp?id=5651

No EGR
http://www.fueleconomy.gov/feg/2008c...ef.jsp?id=5650

[theholycow]

Originally Posted by tjts1

Disabling the EGR improved mileage for me and it was working properly prior to the modification. In 1989 Volvo installed EGR on California cars while 49 state cars didn't have it. The EPA numbers back this up.

Any idea which other emissions systems decrease or at least don't increase fuel economy?

[dieselbenz]

My point is we shouldn't generalize like the originator of this thread. Modern emissions equipment has come a long way from the 80s and early 90s. Very few spark ignition engines use EGR anymore and most emissions equipment does not hurt fuel economy. Older systems are another story.

[theholycow]

Originally Posted by tjts1

My point is we shouldn't generalize like the originator of this thread. Modern emissions equipment has come a long way from the 80s and early 90s. Very few spark ignition engines use EGR anymore and most emissions equipment does not hurt fuel economy. Older systems are another story.

So...in such other stories, what might I remove from my 1980 Buick to increase MPG at the possible cost of emissions? It's exempt from emissions requirements in my state. I already intend to sell the cat and possibly remove the EGR.

How about the evaporative emissions system? Does that canister and all those tangled hoses help or hinder FE on a 1980 carbureted v6?

[rgathright]

I have always been a clean air freak. When I had my 4.7L Dakota, I put a true dual exhaust system on and included the cats.

Currently, I am debating whether upgrading the muffler on my Hybrid Jeep to Flowmaster 50 series will affect air emissions. Any ideas?