Two-stroke engine-oil is the most cost-effective additive. Added lube protection is measure in micron-improvement over ultra low sulfur diesel.
Super Tech Outboard 2-cycle oil from Walmart added with a 200 to 1 ratio scores very high in wear-tests in fuel injection pumps with a 162 micron improvement.
Used motor-oil, e.g. Shell Rotella 15W-40 only tested with a 2 micron improvement.
ATF at 200 to 1 showed just about no measurable gain in lube.
Here's a chart of test results. Disregard any prices shown since they change so much.
In Order Of Performance with controlled tests:
1) 2% REG SoyPower biodiesel
HFRR 221, 415 micron improvement.
50:1 ratio of baseline fuel to 100% biodiesel
66.56 oz. of 100% biodiesel per 26 gallons of diesel fuel
Price: market value
2)Opti-Lube XPD
Multi-purpose + anti-gel
cetane improver, demulsifier
HFRR 317, 319 micron improvement.
256:1 ratio
13 oz/tank
$4.35/tank
3)FPPF RV, Bus, SUV Diesel/Gas fuel treatment
Gas and Diesel
cetane improver, emulsifier
HFRR 439, 197 micron improvement
640:1 ratio
5.2 oz/tank
$2.60/tank
4)Opti-Lube Summer Blend
Multi-purpose
demulsifier
HFRR 447, 189 micron improvement
3000:1 ratio
1.11 oz/tank
$0.68/tank
5)Opti-Lube Winter Blend
Muti-purpose + anti-gel
cetane improver
HFRR 461, 175 micron improvement
512:1 ratio
6.5 oz/tank
$3.65/tank
6)Schaeffer Diesel Treat 2000
Multi-purpose + anti-gel
cetane improver, emulsifier, bio-diesel compatible
HFRR 470, 166 micron improvement
1000:1 ratio
3.32 oz/tank
$1.87/tank
7)Super Tech Outboard 2-cycle TC-W3 engine oil
Unconventional (Not ULSD compliant, may damage 2007 or newer systems)
HFRR 474, 162 micron improvement
200:1 ratio
16.64 oz/tank
$1.09/tank
8)Stanadyne Lubricity Formula
Lubricity Only
demulsifier, 5% bio-diesel compatible, alcohol free
HFRR 479, 157 micron improvement
1000:1 ratio
3.32 oz/tank
$1.00/tank
9)Amsoil Diesel Concentrate
Multi-purpose
demulsifier, bio-diesel compatible, alcohol free
HFRR 488, 148 micron improvement
640:1 ratio
5.2 oz/tank
$2.16/tank
10)Power Service Diesel Kleen + Cetane Boost
Multi-purpose
Cetane improver, bio-diesel compatible, alcohol free
HFRR 575, 61 micron improvement
400:1 ratio
8.32 oz/tank
$1.58/tank
11)Howe’s Meaner Power Kleaner
Multi-purpose
Alcohol free
HFRR 586, 50 micron improvement
1000:1 ratio
3.32 oz/tank
$1.36/tank
12)Stanadyne Performance Formula
Multi-purpose + anti-gel
cetane improver, demulsifier, 5% bio-diesel compatible, alcohol free
HFRR 603, 33 micron improvement
480:1 ratio
6.9 oz/tank
$4.35/tank
13)Used Motor Oil, Shell Rotella T 15w40, 5,000 miles used.
Unconventional (Not ULSD compliant, may damage systems)
HFRR 634, 2 micron improvement
200:1 ratio
16.64 oz/tank
price: market value
14)Lucas Upper Cylinder Lubricant
Gas or diesel
HFRR 641, 5 microns worse than baseline (statistically insignificant change)
427:1 ratio
7.8 oz/tank
$2.65/tank
15)B1000 Diesel Fuel Conditioner by Milligan Biotech
Multi-purpose, canola oil based additive
HFRR 644, 8 microns worse than baseline (statistically insignificant change)
1000:1 ratio
3.32 oz/tank
$2.67/tank
16)FPPF Lubricity Plus Fuel Power
Multi-purpose + anti-gel
Emulsifier, alcohol free
HFRR 675, 39 microns worse than baseline fuel
1000:1 ratio
3.32 oz/tank
$1.12/tank
17)Marvel Mystery Oil
Gas, oil and Diesel fuel additive (NOT ULSD compliant, may damage 2007 and newer
systems)
HFRR 678, 42 microns worse than baseline fuel.
320:1 ratio
10.4 oz/tank
$3.22/tank
18)ValvTect Diesel Guard Heavy Duty/Marine Diesel Fuel Additive
Multi-purpose
Cetane improver, emulsifier, alcohol free
HFRR 696, 60 microns worse than baseline fuel
1000:1 ratio
3.32 oz/tank
$2.38/tank
19)Primrose Power Blend 2003
Multi-purpose
Cetane boost, bio-diesel compatible, emulsifier
HFRR 711, 75 microns worse than baseline
1066:1 ratio
3.12 oz/tank
$1.39/tank