Biomass based diesel vs biodiesel - Page 6 - PeachParts Mercedes-Benz Forum

mrfeb14 · #76 04-12-2015, 06:50 PM

I've gone 400 miles (14 gallons) on my first fillup of HPR.. I have a CDI with the I6 OM648 so maybe it is different for the newer engines. I noticed at startup it is instantly quiet compared to d2 at 4am when i leave for work and when i romp on the accelerator i get no puff of smoke like on d2 (or at least it's not as visible). I am going to try and keep using it to see if i see any leakage or filter clogging problems but unfortunately I have to go out of my way to either oakland/berkeley or to sacramento to get it.

renaissanceman · #77 04-12-2015, 08:44 PM

I'm going to get my second tank of HPR tomorrow before heading out to Oregon. I'm planning to mix in 2-stroke oil again for lubricity, as I saw little to no smoke even with the the oil whereas D2 gives me noticeable haze on hard acceleration.

renaissanceman · #78 04-14-2015, 02:07 PM

I ran two full tanks of HPR during my time in CA. My idle seems to be smooth on the stuff, but a little more lopey.

I got 28mpg on the first which was a mix of hot Highway runs at 75mph (25%) and 55mph country roads (50%) and Fresno/Visalia city roads (25%)

The second was all highway at 70-75mph with ambient temperature consistently around 85F and the air conditioner on for 80% of the drive. This tank netted 29.3 mpg.

Not bad all in all, and with the other benifits, I'd run it full time given the chance. When I switched back to D2 in Yreka, I noticed an increase in engine noise level. I also seemed to have more power, but then I realized that the temperature was 40 degrees cooler. (85 in CA, 45 in OR).

sleepstar · #79 04-14-2015, 11:32 PM

pretty much my experience... quieter but a more "shakey" idle.. less power but i'm used to that running biodiesel..exhaust has no odor

renaissanceman · #80 04-15-2015, 12:15 AM

I cold started with D2 later in the afternoon, and was greeted by coughing, smoking and shaking of my dead glow plug (that I almost forgot I had).

Two tanks of HPR, and I got spoiled.

tjts1 · #81 04-15-2015, 12:24 AM

Quote:

Originally Posted by sleepstar

pretty much my experience... quieter but a more "shakey" idle.. less power but i'm used to that running biodiesel..exhaust has no odor

I think part of the "less power" problem is that our older engines can't automatically adapt to the lower energy density HPR by adding more fuel for a given throttle input. Newer EFI engines can do this.

tjts1 · #82 04-20-2015, 12:42 PM

After 3000ish miles on HPR I'm sad to report that I found a fuel leak on my OM603. It was leaking from the suction side connection to the lift pump. I replaced these hoses a couple of years ago after I bought the car. The hose wasn't visibly damaged but I had the wrong type of hose clamp on there for the job and it was over tightened. I cut off about an inch of hose and reconnected. I'm not sure HPR causes leaks as much as it finds the any weak points in your fuel system. This fuel leak would explain why my low fuel light came on at just 550 miles, about 100 miles short of my normal range.

BTW whats the correct fuel line diameter? I have 5/16" hose but I suspect I should be using 1/4".

otto huber · #83 04-20-2015, 02:33 PM

The rubber hose doesn't look swollen the way it usually does when biodiesel has had a chance to soften it up. Like the case with my aluminum washer, I think that this stuff is thin enough to seep through anything that isn't perfect.

tjts1 · #84 04-21-2015, 03:00 PM

Nevermind, the fuel line wasn't leaking after all. It was the delivery valve seales which I've been meaning to replace for a while now.

renaissanceman · #85 04-21-2015, 03:19 PM

We should get the mods to edit all these false alarms out, for posterity sake.

I'd hate to see HPR get bad press for creating leaks when someone only skims the thread.

BillGrissom · #86 04-21-2015, 03:44 PM

Quote:

Originally Posted by tjts1

I think part of the "less power" problem is that our older engines can't automatically adapt to the lower energy density HPR by adding more fuel for a given throttle input. Newer EFI engines can do this.

Not likely. There is no throttle plate, at least in 1985- M-B diesels. The "fuel pedal" simply controls the volume of fuel sprayed. Thus, there is no need to compensate for different fuels. The latest M-B diesels do have a throttle plate. However, not sure it is intended to control air flow rather than impart swirl to the air stream at low rpm for better burning (better mileage, lower emissions).

I am on about my 4th tank of Diesel HPR now and still happy with it. The price is holding 10c/gal less than reg unleaded. The engine runs noticeably quieter, which was my wife's main complaint. She would be embarassed driving a car with the normal diesel sound. She even talked about driving it now.

otto huber · #87 04-21-2015, 04:22 PM

Quote:

Originally Posted by renaissanceman

We should get the mods to edit all these false alarms out, for posterity sake.

I'd hate to see HPR get bad press for creating leaks when someone only skims the thread.

I don't think that my leaking washer was a false alarm. 70,000 miles without a problem running biodiesel and D2, then after 1 fill up with HPR and I've got a puddle of fuel under my car. I've replaced both washers on that line and am running B20 without any problems right now. When I run the tank clear of biodiesel, I'll try 20% HPR and see how it goes.

renaissanceman · #88 04-21-2015, 04:24 PM

If you had to press the pedal an additional 10%, that would be a perceived loss of power.

tjts1 · #89 04-21-2015, 05:03 PM

Quote:

Originally Posted by renaissanceman

If you had to press the pedal an additional 10%, that would be a perceived loss of power.

Bingo. HPR has 5% less BTU/gal than #2 diesel therefore without any other changes (more advanced timing for example) you will need to press the pedal that much further for the same amount of power. Simple as that.

renaissanceman · #90 04-21-2015, 05:34 PM

Which means theoretically you'll have 5% reduction in power on the power at the top end.