Fuel additives - Page 4 - PeachParts Mercedes-Benz Forum

#46 05-09-2008, 05:28 PM

Quote:

Originally Posted by DieselAddict

Cetane has nothing to do with mileage and everything to do with ignition delay which should be minimized to lessen the pressure spikes in the combustion chambers.

Cetane does effect mileage because it affects the efficiency at which it burns.

aklim · #47 05-09-2008, 05:37 PM

Quote:

Originally Posted by ForcedInduction

Cetane does effect mileage because it affects the efficiency at which it burns.

Bio has higher cetane but yet they tell you that it gets slightly less mileage. How does that come together?

Phil · #48 05-09-2008, 05:45 PM

I use
Power Service
ATF
Marval Mistery Oil

#49 05-09-2008, 06:10 PM

Quote:

Originally Posted by aklim

Bio has higher cetane but yet they tell you that it gets slightly less mileage. How does that come together?

The primary parameter that controls mileage is the energy content of the fuel and BD has less energy content. All things being equal, fuel also needs adequate cetane to combust completely. If you are not getting efficient combustion due to low cetane, an additive to boost cetane might help your mileage.

rcounts · #50 05-09-2008, 06:52 PM

Quote:

Originally Posted by Craig

The primary parameter that controls mileage is the energy content of the fuel and BD has less energy content. All things being equal, fuel also needs adequate cetane to combust completely. If you are not getting efficient combustion due to low cetane, an additive to boost cetane might help your mileage.

EXACTLY, and though I haven't read a bunch of studies on the subject, I have read a lot of threads and posts.
Some people seem to get a little better mileage, some seem to get a little worse, and a lot seem to get about the same - at least with bio blends below B50. The general sense and consensus I've gathered from my reading is that the slight decrease in BTUs is offset by the increase in cetane value.

todieselornot · #51 05-09-2008, 06:53 PM

Lucas oil.

rcounts · #52 05-09-2008, 07:10 PM

Quote:

Originally Posted by aklim

Think about this. While you think the fuel companies don't want to spend $$ to add more lubricity, it is the TERMINAL LEVEL where the lubricity agents are added not at the fuel company levels. You want ULSD, they send it to you. It is at the Terminal Level where it is done not up there.

What exactly is the difference whether it is done at the manufacturing or at the terminal level? The oil companies own most of the distribution network - including the terminals - don't they?

Quote:

Originally Posted by aklim

While you are mulling on it, think about this. To you it might not matter but to the manufacturer, every mile they can get out of your engine, is another mile closer to the warranty being over. The kicker? The life MIGHT or MIGHT NOT be extended ON YOUR DIME. So yes, their motives are not that pure either. Sure, they can advocate a 300 HFFR score. Why? If you get 101000 miles instead of 99000 miles, they are off the hook (assuming 100K is the warranty). Now, to add all the lubricity agents to get that 300 score, it might cost YOU $2000. OTOH, it cost them NOTHING. If it gives you 2000 miles more, they are home free. Whether that 2000 miles is worth the $2000 you spent is another story. Again, it is ON YOUR DIME, not theirs.

True - if warranties on these 80's vintage cars went to 100k, but they didn't. Some warranties are much shorter than that even to this day. Also, the vehicles we're talking about are almost all WAY, WAY past the 100k mark you're using as an example - 2 or 3 times past the 100k in most cases - and 5-10 times past the original warranty mileage limit. What we are working towards is extending their life even further.

If you want to look at it from the manufacturer's perspective think about this. The longer your car lasts the longer it will be before you buy another one. They have an incentive for it to last only a few thousand miles past the warranty period, and/or long enough for you to decide to trade it in, and then go KABOOM - so you have to buy another one. Are you familiar with the idea of "planned obsolecence"?

aklim · #53 05-09-2008, 08:56 PM

Quote:

Originally Posted by rcounts

If you want to look at it from the manufacturer's perspective think about this. The longer your car lasts the longer it will be before you buy another one. They have an incentive for it to last only a few thousand miles past the warranty period, and/or long enough for you to decide to trade it in, and then go KABOOM - so you have to buy another one. Are you familiar with the idea of "planned obsolecence"?

Yes, I agree the incentive is for it to make it a little past warranty to put them off the hook then the planned obsolescence comes in. My point is that the manufacturers want more lubricity because there is a chance that more might make it to that line and a little over before it fails. Best of all, it is on our dime not their's.

rcounts · #54 05-09-2008, 10:03 PM

Quote:

Originally Posted by aklim

Yes, I agree the incentive is for it to make it a little past warranty to put them off the hook then the planned obsolescence comes in. My point is that the manufacturers want more lubricity because there is a chance that more might make it to that line and a little over before it fails. Best of all, it is on our dime not their's.

Ya' seem to have missed a big part of my point partner.

What was the warranty on a new 300D in the early 80's? Maybe 50K? Unless you started adding 50% RUG to your tank, EVERY new pump was going to make it that far. Therefore there was no incentive for the manufacturer to promote anything that would increase its longevity.

aklim · #55 05-09-2008, 10:12 PM

Quote:

Originally Posted by rcounts

Ya' seem to have missed a big part of my point partner.

What was the warranty on a new 300D in the early 80's? Maybe 50K? Unless you started adding 50% RUG to your tank, EVERY new pump was going to make it that far. Therefore there was no incentive for the manufacturer to promote anything that would increase its longevity.

I thought the HFFR score that was accepted was 520 and the manufacturers wanted 460. This concerned ULSD and so I surmise it was only lately not the 80s