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Cetane Booster - What is the Best?

by Andy Published on Friday, May 2nd, 2014

The overall quality of diesel fuel is dependent on a number of factors. These include BTU value, viscosity, pour flow point, aromatic and paraffinic content, and resistance to contaminant buildup such as water and bacteria. A diesel fuel’s quality also is very dependent on its cetane number.

The cetane number (CN) is an index of the ignition point or combustion quality of diesel fuel and is measured using an ASTM D613 test. Standard European BS EN590 diesel from the pump normally has a minimum cetane number of around 51, with premium pump diesel a little higher. Depending on engine design, driving conditions, and so on, the optimum cetane value for most vehicles is around the mid to high 50s. Any value greater than 60 will not achieve any additional benefits and in most cases will alter ignition timing to the degree that power is lost.

Matching cetane to the engine is important in order to maximise the engine’s performance. Biodiesel fuels in particular, especially the homemade brews, usually start with a much lower cetane number so cetane improvement for these fuels is essential.

A fuel with too low of a cetane number for a particular engine will result in reduced cold-start ability, rough running, excess engine noise/vibration and reduced combustion quality. This leads to reduced performance, excess emissions, and carbon buildup throughout the engine and emission system components (intake, EGR, DPF, etc.)

A higher cetane fuel that is a proper match for the engine will reduce ignition delay, improve overall combustion quality, liberate more BTU (energy) from the fuel, and improve performance and MPG. It also will reduce engine noise, deposit buildup, and exhaust emissions.

What should I look for in a cetane booster?

Contrary to some propaganda, alkyl nitrates still offer the greatest improvement in cetane number, with measured increases of up to eight points. When it comes to alkyl nitrates, 2-ethylhexyl nitrate (2-EHN) is the most popular and most respected. It offers more consistent ignition quality whilst reducing unwanted and negative combustion conditions.

Fuel additive manufacturers recognise both the benefits of boosting the cetane number and using 2-EHN so much now that most offer cetane improvers. The question in this case is what are you getting for your money?

From close examination it appears many cetane boosters contain useless fillers. To maximise profits most manufacturers still insist on the single bottle per tank philosophy. Some 200-300ml bottles that treat a single tank of fuel have as little as 20% active ingredients. This is lucrative for the manufacturer but not a good value for the consumer. Therefore, it is important to understand what you are getting for your money.

The optimum amount of 2-EHN is around 20-100ml per tank of fuel, depending on the engine and base cetane level. As 2-EHN can reduce lubricity it is important that a lubricant is also blended in. To ensure you are getting the best value, make sure the product contains 2-EHN as its base and a reasonable proportion of the remainder contains useful ingredients, such as lubricant, detergent, etc.

So what do we recommend and why?

Active cetane improvers are essentially a form of fuel modification, or more accurately, combustion modification. However, when combined with the correct fuel catalyst technology, latest nano detergents, and lubricity additives, they can turn the most mediocre pump fuels and biodiesels into super diesel that will outperform the best premium pump fuels.

Archoil® achieved this with its new AR6900-D MAX. Rather than introduce another diluted cetane booster, they decided to release a concentrated chemistry product that contains 100% active ingredients. It provides optimum increases in cetane whilst being able to treat multiple tanks of fuel, rather than just one.

Archoil also added their patented fuel catalyst technology to improve combustion quality even further. It contains an optimum amount of 2-EHN with the remainder composed of the aforementioned catalyst, a synthetic lubricant that protects the entire fuel system against the harmful effects of low lubricity, low sulphur fuels, and carefully selected detergents that safely remove fuel system and carbon deposits. This results in an optimum combustion condition, comprehensive fuel system protection and cleaning, performance increase, and reduction in harmful exhaust emissions.

Archoil’s AR6900-D MAX offers the greatest value for the customer. At last, a complete and fully concentrated additive package that is a much better value than its competitors, but more importantly, much less expensive per tank than upgrading to premium diesel at the pump.

17 thoughts on “Cetane Booster – What is the Best?”

Patrick Queenan says:

February 6, 2020 at 11:32 pm

Hi
I have recently bought a new Jaguar XJ 3ltr, 2000 miles. I also have a Jaguar XF 3ltr. 50000 miles, which I have used AR6900-D MAX for quite some time now and I have been pleased with the results, better economy and cleaner running. I have just come across Oilsyn and have tried it in the XJ but it’s early days. My question is ,I have had the XF cleaned by a company using hydrogen for cleaning for carbon removal. Is Oilsyn a similar product if so what cleaner/ lubricant can I mix with it .
Thanks
Patrick

Reply
1. Andy says:
  
  February 10, 2020 at 3:27 pm
  
  That sounds like an intake based cleaner and if so it is not similar to Hybrogen. Hybrogen cannot be used with any other product except AR6850. However, AR6900-D would be a better all-round product.
  
  Reply
Frot says:

July 10, 2017 at 5:37 am

Good day
You refer to using an additive that is a proper match for the engine. The premium diesel fuel from a major brand in Australia has a ‘typical’ cetane rating of 51 and a minimum of 46.
How would I know whether 51 cetane is a good match for my turbo diesel engine?
Regards
Frot

Reply
1. Andy says:
  
  July 10, 2017 at 12:15 pm
  
  The only way to know for sure is to test. Start with the base fuel and then add 2-EHN (or 2-EHN based product) a little at a time. Continue to increase dosage (whilst not exceeding the recommended dosage set out on the product literature) until performance deteriorates or engine sounds worse. Then step back to previous dosage.
  
  Reply
Filip says:

May 22, 2017 at 2:34 pm

For rav 4 III D-Cat 2.2 177 should I use ar6200 or ar 6900 ? or mix it together ? 🙂

Reply
1. Andy says:
  
  May 23, 2017 at 9:43 am
  
  Not both. AR6200 can be mixed with AR6850 or pure 2-EHN though.
  
  Reply
Mike Palmer says:

November 16, 2016 at 8:31 pm

i have been using PowerService Diesel-Kleen with Cetane Boost fairly regulator since i got this truck. the truck had 100k miles when i purchased it. from my previous note, i am interested in the best cleaning, burning and mileage product available.

thanks again

Reply
1. Andy says:
  
  November 24, 2016 at 9:10 pm
  
  AR6900-D MAX.
  
  Reply
Gianluca Bottoni says:

October 19, 2016 at 2:34 am

Can i use ar6800 on my fiat 500 Multijet euro 6 with dpf or ar6900d is better? I use only premium diesel excelium total-erg

Reply
1. Andy says:
  
  October 20, 2016 at 9:26 am
  
  AR6900-D MAX is better.
  
  Reply
Andrew Williams says:

January 25, 2016 at 7:52 pm

We own Modern tractors with common rail & EGR. Have used Stanadyne performance formula in the past. Ordered some 6200 before I saw 6800, which I suspect is a closer match. Would you agree 6800 is a close match, or is there a better alternative

red diesel we use has a cetane of 45, if we add some pure 2-ehn (which I just spotted) with the 6200, is there enough lubricity?

Cheers

Reply
1. Andy says:
  
  January 25, 2016 at 8:29 pm
  
  AR6200 with pure 2-EHN is our most popular combination for low cetane fuels and is likely to be the best option for you due the to dispersal and catalyst technology. AR6200 improves lubricity by at least 10% so it should be fine. It can also be used at double dose (1:5,000) if required.
  
  Reply
David Bonham says:

November 21, 2014 at 12:43 pm

Hi

Indeed, is it better to use AR6800 rather than AR6200? Apart from the CN boost, are there additional benefits in AR6800?

Thanks

Reply
1. Andy Archer says:
  
  November 21, 2014 at 5:58 pm
  
  Hi, not really although the detergent is slightly stronger. The catalyst technology is also different and the performance difference compared to AR6200 will depend on engine design. Some of our customers prefer to use AR6200 combined with our pure 2-EHN rather than AR6800, simply because their engine responds better with the catalyst in AR6200.
  
  Reply
  1. Andrew Williams says:
    
    January 25, 2016 at 6:57 pm
    
    What is your pure 2-EHN called?
    
    Reply
    1. Andy says:
      
      January 25, 2016 at 7:39 pm
      
      It is called 2-EHN.
      
      Reply
Sarah Gerret says:

August 13, 2014 at 8:11 pm

Hi, i am currently using 6800 in my focus 2.0 and it runs much better but would 6200 be better?

Reply