ACEA A1/B1-08

Overview

ACEA A1/B1 oils are Mainline lubricants. They are designed for use in gasoline and light duty diesel engines that have been specifically designed to use a low viscosity oil. ACEA A1/B1 oils are typically used in older vehicles as they do not provide the minimum performance demanded by the latest OEM specifications. These oils may be unsuitable for use in some engines.

ACEA A1/B1 oils are typically low HTHS (≤3.5cP) SAE 5W-30 based on API Group III base oils. The main physical and chemical requirements for ACEA A1/B1 are shown below:

The low HTHS (≤3.5cP) required by ACEA A1/B1 limits the number of additional performance claims that can be coupled with ACEA A1/B1.

Prior to ACEA 2008, ACEA A1/B1 was usually coupled with the Ford specification, WSS-M2C913-B. However, a new edition of this specification has been introduced by Ford which requires a higher minimum ACEA performance level of ACEA A5/B5-08. This will further reduce the range of applications for which ACEA A1/B1-08 oils are suitable.

Changes

ACEA A1/B1 was first introduced into the ACEA Oil Sequences in 2004, however, it is based upon the original ACEA A1 and ACEA B1 sequences that were introduced in 1996.

For ACEA 2008 a number of changes to the requirements for ACEA A1/B1 have been made which fundamentally change the performance required to meet ACEA A1/B1-08. These include the inclusion of the VW TDI engine test, as a replacement for the VW ICTD 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 2008 are summarised below:

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 A1/B1-08. Prior to ACEA 2008, depending upon the performance of the engine oil, it was possible to combine ACEA A1/B1 with a number of other sequences including ACEA C1 and C2. 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 2008 it is unlikely that engine oils meeting the ACEA C sequences will also be able to meet ACEA A1/B1.

The inclusion of the VW TDI engine test, which evaluates direct injection diesel piston cleanliness and ring sticking, changes ACEA A1/B1 the most. Previously ACEA A1/B1 oils were only evaluated for diesel piston cleanliness and ring sticking in an indirect injection engine test (VW ICTD). By introducing a requirement to provide a high level of protection for direct injection diesel engines ACEA have significantly raised the diesel piston cleanliness performance demanded from ACEA A1/B1 oils. Some existing ACEA A1/B1 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 sequence now required to provide the same level of performance. Some existing ACEA A1/B1 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 A1/B1 oils.

Relative Performance

The relative performance diagrams presented below compare Lubrizol's interpretation of the performance of requirements of the existing ACEA 2007 A1/B1-04 oil sequence with the ACEA 2008 version. As shown, ACEA 2008 A1/B1-08 represents an upgrade in piston cleanliness, wear protection and sludge handling.

Disclaimer
The relative performance diagrams represent an interpretation made by The Lubrizol Corporation ("Lubrizol") of various rules and specifications. They are not a literal translation of a performance specification and should not be used as a replacement for evaluating engine oil performance in accordance with the relevant vehicle manufacturer's requirements. They are presented to assist the reader in visualizing some of the parameters that need to be considered and balanced when formulating a lubricant. Lubrizol accepts no liability for any losses or damages incurred by the user as a result of them relying on the interpretation made by Lubrizol. Readers are advised to consult the specific rules for greater detail with regard to meeting the requirements as set forth in any specification.