ACEA A3/B4 oils are Upper Mainline lubricants. They are designed for a use in high performance gasoline and light duty diesel engines and are typically used in newer vehicles as they provide the minimum performance demanded by many OEM specifications.
ACEA A3/B4 oils are probably seen in the widest range of viscosity grades. The most common being:
The main physical and chemical requirements for ACEA A3/B4 are shown below:
|HTHS viscosity||CEC L-36-A-90||cP||≥ 3.5|
|Sulphated Ash||ASTM D874||%wt||≤ 1.6|
|Evaporation loss (NOACK)||CEC L-40-A-93||%||≤ 13|
|Total Base Number||ASTM D2896||mgKOH/g||≥ 10.0|
Depending upon the viscosity grade blended, ACEA A3/B4 is usually coupled with a range of OEM specifications including:
ACEA A3/B4 was first introduced into the ACEA Oil Sequences in 2004, however, it is based upon the original ACEA A3 and ACEA B4 sequences that were introduced in 1996 and 1998 respectively.
For ACEA 2010 a number of changes to the requirements for ACEA A3/B4 have been made which raise the performance required to meet ACEA A3/B4-08. These include raising the level of diesel piston cleanliness performance in the VW TDI engine test and the inclusion of the new OM646LA engine test, as a replacement for the OM602A, along with increases in sludge handling.
The changes for ACEA 2010 are summarised below:
|Test||Change for ACEA 2010|
|Total Base Number||A new limit of ≥ 8.0 mgKOH/g has been added|
|VW TDI||Piston cleanliness increased from ≥ RL206 -3 points to ≥ RL206.|
|OM646LA||New test added|
|M111SL||Average engine sludge to requirement to increase from ≥ RL140 to ≥ RL140 +4 standard deviations or ≥ 9.0%|
The introduction of a minimum Total Base Number (TBN) of 8.0 mgKOH/g affects the number of ACEA sequences that can be combined with ACEA A3/B4-08. Prior to ACEA 2008, depending upon the performance of the engine oil, it was possible to combine ACEA A3/B4 with a number of other sequences including ACEA C3. However, as engine oils meeting the ACEA C Sequences are formulated to a lower sulphated ash level they tend to deliver a TBN of less than 8.0 mgKOH/g. Therefore, with the introduction of ACEA 2010 it is unlikely that engine oils meeting the ACEA C sequences will also be able to meet ACEA A3/B4.
The limits for an acceptable level of direct injection diesel piston cleanliness in the VW TDI engine test have been raised to the highest level seen within ACEA, aligning performance with ACEA A5/B5 and all of the ACEA C Sequences. Some existing ACEA A3/B4 engine oils will be unable to deliver this performance without being reformulated.
The limits for an acceptable level of sludge handling in the M111SL engine test have been raised to the highest level seen within ACEA, with every sequences now required to provide the same level of performance. Some existing ACEA A3/B4 engine oils will be unable to deliver this performance without being reformulated.
The inclusion of the new OM646LA engine test raises the diesel wear protection performance demanded from ACEA A3/B4 oils.
The relative performance diagrams presented below compare Lubrizol's interpretation of the performance of requirements of the existing ACEA 2007 A3/B4-04 oil sequence with the ACEA 2010 version. As shown, ACEA 2010 A3/B4-08 represents an upgrade in piston cleanliness, wear protection and sludge handling.