I have a really good problem! Great MPG - Page 5 - PeachParts Mercedes-Benz Forum

leathermang · #61 04-04-2008, 10:10 PM

Quote:

Originally Posted by Knightrider966

For the record! Evirosafe or anyother type of Hydrocarbon refrigerant will catch fire and could possibly explode if your smoking or doing anything else dumb while using it! An exploding metal can of anything will send flying shrapnel and could be deadly!

http://www.epa.gov/ozone/title6/609/saeepawarning.html

Knightrider966 · #62 04-04-2008, 10:25 PM

I read it. I see no logic in claiming that the Army uses HFC's because it doesn't want to endanger soldiers lives because HC's can catch fire and HFC will sure cause permanent brain damage. There is nothing here but the "good" benefits of HFC's and non of the drawbacks.

I would rather repair my system and retrofit properly and recharge with Envirosafe and risk fire in a crash instead of permanent brain damage from a chemical that has no warning and no odor known to eat through aluminum in older systems.

leathermang · #63 04-04-2008, 10:27 PM

OK, we have found your problem... you read the wrong paragarphs... LOL

t walgamuth · #64 04-05-2008, 12:25 AM

Quote:

Originally Posted by Skid Row Joe

38.472727 mpg is believable. If any diesel-Benz will do it, your model will.

It's a lot better than the 23.35 mpg I got on my last tank fill-up. Mostly City, w/o AC.

It might get 38 if driven at 42 mph, highway with no stops.

Tom W

Knightrider966 · #65 04-05-2008, 12:02 PM

Quote:

Originally Posted by t walgamuth

It might get 38 if driven at 42 mph, highway with no stops.

Tom W

Well, we did slow down to about 45 for half the trip on the way back to see the scenery! I forgot about that! If anyone comes to Arizona, I highly recommend travelling 93. 89A, and highway 87! This state is unbelievable for it's beauty. I feel lucky when I see this to live here, even if it does get hot!

2.5Turbo · #66 04-05-2008, 08:53 PM

Quote:

Originally Posted by Knightrider966

I read it. I see no logic in claiming that the Army uses HFC's because it doesn't want to endanger soldiers lives because HC's can catch fire and HFC will sure cause permanent brain damage. There is nothing here but the "good" benefits of HFC's and non of the drawbacks.

I would rather repair my system and retrofit properly and recharge with Envirosafe and risk fire in a crash instead of permanent brain damage from a chemical that has no warning and no odor known to eat through aluminum in older systems.

Even though we are horribly off topic...

I still have yet to find any evidence that states that 1, 1, 1, 2-tetrafluoroethane will cause brain damage with the quantities present (and concentrations if released) in a typical automotive air conditioning system. Sure, you might get hurt if you get a can of the stuff and inhale it directly, but if you vented the system under the hood (or got into an accident and ruptured the condenser), the concentrations present do not pose a significant hazard. Again I'll bring up my point about computer dusters. Most use 134a as the "air." How come nobody keels over with brain damage when using them?

I agree with the points made earlier. Putting pressurized flammable hydrocarbon gases in the first thing behind the front bumper isn't very smart, in my opinion. The reason we don't see CNG/LNG vehicles exploding every time they crash is that the tanks and lines are shielded from damage and don't live right up front on the car.

If the condenser was located somewhere else, then hydrocarbon refrigerants would make more sense in an automotive application.

And now back to your regularly scheduled MPG debate.

GREASY_BEAST · #67 04-05-2008, 09:47 PM

Despite its lower energy content, I have heard truckers claim a mileage increase with biodiesel of varying concentrations... I can only suspect that has something to do with the higher cetane value and increased lubricity (if you look for some data on the fluid you will find that it is far superior to diesel, and even most diesel additives in this respect). If you drive carefully, accelerate slowly, never accelerate up a hill, coast down hills (find the optimal balance between fuel input and maintaining constant, steady forward speed, and drive with an extremely light, but more importantly steady foot, huge mileage gains can be realized. Another important thing to achieving the best mileage possible is to drive slow. Other things that can be done are advanced injection timing, EGR removal, changed gearing to run the engine at a lower RPM, and anything to remove exhaust restriction and intake restriction, as well as ensuring the engine gets cold air, will all yield MPG increases. Another important one is to make sure that your tires are inflated to the max rated pressure, and to get tires that can take lots of pressure. This will make the car a little slipperier on the road, so more car will have to be taken while driving, but it will decrease your rolling resistance. Another factor in minimizing rolling friction is picking tires with a harder rubber compound. Also, road surface is another important factor. One can drive on the parts of the road that are less traveled (the "ridge" regions formed near the centerline, and in the middle of the lane, or conversely, on the white line and in the middle of the lane to ensure that one is driving on a smoother, more even, and less "sticky" surface. However, air resistance is the #1 impedence to forward motion (and therefore the primary cause of friction). Under about 35mph, air resistance does not affect the car very much, but it does increase as the square of the velocity of the airflow. Possibly, if you drive with a style similar to the one I described, have a well-maintained vehicle with hard tires, and don't exceed 55mph on the highway, large mileage gains can be realized. I think I might try an experiment and drive like a hypermiler for a tank one of these days and see what benefits it nets, but I so very much love blowing black clouds of smoke at traffic in the rear-view and cruising at ~90mph with the 2.47 rear end that I don't know as though I ever will...

On a side note, anything to lower the drag coefficient of the automobile will realize large measurable gains in fuel economy in the same manner that reducing airflow velocity will, but to a greater extent. Removal of the mirrors, and fairings in strategic places, combined with efforts to clean up the underside and reduce airflow through the engine compartment have realized tremendous gains, both in production vehicles (READ: Prius Cd = ~0.27), as well as various home-brew projects.

Another note: pretty much anything that can be done to the turbodiesel mercedes' that makes them more efficient, also makes them more powerful and increases performance, so restraint is required to realize the benefits.

I don't have any problem at all believing a 7-10mpg increase given a fairly steady tailwind of at least 15-20mph, an impeccably maintained vehicle with very little parasitic losses, gearing losses, hard tires, good calipers and rotors that don't drag, good wheel bearings, an engine/fuel combination that is getting good, complete combustion at cruising speed, and most importantly a careful driver.

And whats this paranoia about running some propane for refrigerant all about? How much volume of gas is in the system anyway? Also, please, don't be ridiculous about the oil cooler. I have dunked many a bar of yellow/orange-hot tool steel in buckets of used motor oil and there is usually a flame or two, but they go right out. It is amazingly difficult to get the stuff to burn. Also, I didn't see one part of that EPA document that mentioned anything dangerous or detrimental about using propane, just that it hadn't been exposed to the same testing regimen that other refrigerants have, and therefore is not endorsed and not legal. Says nothing about safety.. It really seems like there is some selective reading of the information here.....

Knightrider966 · #68 04-05-2008, 10:15 PM

Quote:

Originally Posted by 2.5Turbo

Even though we are horribly off topic...

I still have yet to find any evidence that states that 1, 1, 1, 2-tetrafluoroethane will cause brain damage with the quantities present (and concentrations if released) in a typical automotive air conditioning system. Sure, you might get hurt if you get a can of the stuff and inhale it directly, but if you vented the system under the hood (or got into an accident and ruptured the condenser), the concentrations present do not pose a significant hazard. Again I'll bring up my point about computer dusters. Most use 134a as the "air." How come nobody keels over with brain damage when using them?

I agree with the points made earlier. Putting pressurized flammable hydrocarbon gases in the first thing behind the front bumper isn't very smart, in my opinion. The reason we don't see CNG/LNG vehicles exploding every time they crash is that the tanks and lines are shielded from damage and don't live right up front on the car.

If the condenser was located somewhere else, then hydrocarbon refrigerants would make more sense in an automotive application.

And now back to your regularly scheduled MPG debate.

This is from Australia where HC's are preferred over R134A. Note the problems with corrosion and aluminum.
https://pgw100.portal.gases.boc.com/boc_sp/au/safety/material_safety_data_sheets/133.pdf

Another report about Envirosafe.http://autorefrigerants.com/Envirotechnical.htm

MSDS for R134A.http://www.afrox.com/templ-files/Safety/182_R134a.pdf

Arizona servicemen using Envirosafe.http://www.dndtransportrefrigeration.com/

Time to decide for yourself. I'm not going to argue.

Knightrider966 · #69 04-05-2008, 10:23 PM

Quote:

Originally Posted by GREASY_BEAST

Despite its lower energy content, I have heard truckers claim a mileage increase with biodiesel of varying concentrations... I can only suspect that has something to do with the higher cetane value and increased lubricity (if you look for some data on the fluid you will find that it is far superior to diesel, and even most diesel additives in this respect). If you drive carefully, accelerate slowly, never accelerate up a hill, coast down hills (find the optimal balance between fuel input and maintaining constant, steady forward speed, and drive with an extremely light, but more importantly steady foot, huge mileage gains can be realized. Another important thing to achieving the best mileage possible is to drive slow. Other things that can be done are advanced injection timing, EGR removal, changed gearing to run the engine at a lower RPM, and anything to remove exhaust restriction and intake restriction, as well as ensuring the engine gets cold air, will all yield MPG increases. Another important one is to make sure that your tires are inflated to the max rated pressure, and to get tires that can take lots of pressure. This will make the car a little slipperier on the road, so more car will have to be taken while driving, but it will decrease your rolling resistance. Another factor in minimizing rolling friction is picking tires with a harder rubber compound. Also, road surface is another important factor. One can drive on the parts of the road that are less traveled (the "ridge" regions formed near the centerline, and in the middle of the lane, or conversely, on the white line and in the middle of the lane to ensure that one is driving on a smoother, more even, and less "sticky" surface. However, air resistance is the #1 impedence to forward motion (and therefore the primary cause of friction). Under about 35mph, air resistance does not affect the car very much, but it does increase as the square of the velocity of the airflow. Possibly, if you drive with a style similar to the one I described, have a well-maintained vehicle with hard tires, and don't exceed 55mph on the highway, large mileage gains can be realized. I think I might try an experiment and drive like a hypermiler for a tank one of these days and see what benefits it nets, but I so very much love blowing black clouds of smoke at traffic in the rear-view and cruising at ~90mph with the 2.47 rear end that I don't know as though I ever will...

On a side note, anything to lower the drag coefficient of the automobile will realize large measurable gains in fuel economy in the same manner that reducing airflow velocity will, but to a greater extent. Removal of the mirrors, and fairings in strategic places, combined with efforts to clean up the underside and reduce airflow through the engine compartment have realized tremendous gains, both in production vehicles (READ: Prius Cd = ~0.27), as well as various home-brew projects.

Another note: pretty much anything that can be done to the turbodiesel mercedes' that makes them more efficient, also makes them more powerful and increases performance, so restraint is required to realize the benefits.

I don't have any problem at all believing a 7-10mpg increase given a fairly steady tailwind of at least 15-20mph, an impeccably maintained vehicle with very little parasitic losses, gearing losses, hard tires, good calipers and rotors that don't drag, good wheel bearings, an engine/fuel combination that is getting good, complete combustion at cruising speed, and most importantly a careful driver.

And whats this paranoia about running some propane for refrigerant all about? How much volume of gas is in the system anyway? Also, please, don't be ridiculous about the oil cooler. I have dunked many a bar of yellow/orange-hot tool steel in buckets of used motor oil and there is usually a flame or two, but they go right out. It is amazingly difficult to get the stuff to burn. Also, I didn't see one part of that EPA document that mentioned anything dangerous or detrimental about using propane, just that it hadn't been exposed to the same testing regimen that other refrigerants have, and therefore is not endorsed and not legal. Says nothing about safety.. It really seems like there is some selective reading of the information here.....

If you note the differences between Envirosafe and R134A, the latter has a lower ignition point.

Back to the fuel economy post!

I am running my tires at about 40 PSI whereas their max is 44 PSI. It's not a good idea to run tires at full pressure here in Arizona during the summer because the risk of blowouts is pretty good! I've seen plenty of them!

Don't want to see one of my own!

leathermang · #70 04-05-2008, 11:13 PM

Quote:

Originally Posted by Knightrider966

Back to the fuel economy post!

I am running my tires at about 40 PSI whereas their max is 44 PSI. It's not a good idea to run tires at full pressure here in Arizona during the summer because the risk of blowouts is pretty good! I've seen plenty of them!

Don't want to see one of my own!

OK, more bad physics evident.

Most of the heat which builds up in your tires ( with concomitant increase in air pressure ) comes from sidewall flex... so the 44 , if that is the listed max on the tire, should be the safer option ...

That IS assuming that you put that air into your tire with the tire COLD... if you are driving and check it hot and it is over your max and you take out air then you will have too little air in it when it cools and risk excessive heat build up the next time you start driving due to the sidewall flex...

Knightrider966 · #71 04-06-2008, 12:06 AM

Quote:

Originally Posted by leathermang

OK, more bad physics evident.

Most of the heat which builds up in your tires ( with concomitant increase in air pressure ) comes from sidewall flex... so the 44 , if that is the listed max on the tire, should be the safer option ...

That IS assuming that you put that air into your tire with the tire COLD... if you are driving and check it hot and it is over your max and you take out air then you will have too little air in it when it cools and risk excessive heat build up the next time you start driving due to the sidewall flex...

Yeah, but then it rides like it has solid wheels!

You feel every little pothole there is. 44 PSI is the absolute max on the sidewall, 35 to 40 is what is recommended.

2.5Turbo · #72 04-06-2008, 12:16 AM

That's true...I've witnessed this first hand, not on my car but on my friend's GMC Yukon. Last summer we took a trip to eastern WA to do some rail photography. This weekend was hot with 100+ degree temps. East of Wenatchee, there's a neat place on the rail line called the Trinidad Loop, which requires off-roading to get above. I parked the Benz at the bottom of the hill and we headed up in the Yukon. After getting our shots, we headed back down and started back to Wenatchee for lunch. While following the Yukon, I noticed that the right front tire was starting to look odd. I just dismissed it as being a weird shadow, and didn't think of calling him. A few minutes later, he slams on the brakes and pulls off onto a side road, his right front tire flopping about the wheel. After putting on the spare we headed to the tire shop. The general consensus was that the tire developed a leak while off-road. The tire leaked enough to excessively flex the sidewall, which created heat, which increased the pressure to the point of blowout. The tire was very hot when we changed it out.

Photo of the tire just after stopping...with one of the guys kicking it to make more smoke come out

I have a really good problem! Great MPG-_mg_9107.jpg

Knightrider966 · #73 04-06-2008, 12:27 AM

Most areas of the country cannot compare to Phoenix because of our temperatures!

If it is 120* in the shade, it's 150 or more in direct sunlight and I have seen the blacktop asphalt hot enough to melt the rubber off your tennis shoes. Sky Harbour Airport shut down at 124* because the air had no lift in it and tires would pop when the aircraft hit the runway!

I would find it hard to believe that any other city has pavement hot enough to cook an egg on it! The evening news did this one night and it was fascinating! Channel 12 dropped an egg on the pavement at 4:00 PM and had a smaller picture in picture while the news was on so we could watch the egg cook and a little clock timed it!

pgringo · #74 04-06-2008, 01:06 AM

in my 300sd, on wvo, i have gotten 34 mpg as witnessed by my girlfriend/ebay-parts-model. we didn't believe it ourselves and we did the math a few times to make sure we didn't hit a wrong button on the calculator. having traveled the same route several times, i know the exact miles traveled. we have only gotten _near_ that mpg a couple of times since.

Bio300TDTdriver · #75 04-06-2008, 01:07 AM

Quote:

Originally Posted by pgringo

in my 300sd, on wvo, i have gotten 34 mpg as witnessed by my girlfriend/ebay-parts-model. we didn't believe it ourselves and we did the math a few times to make sure we didn't hit a wrong button on the calculator. having traveled the same route several times, i know the exact miles traveled. we have only gotten _near_ that mpg a couple of times since.

So, what parts do you have for sale on EBay?