Cold engine does not run smoothly

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Andy Beats
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Re: Cold engine does not run smoothly

Post by Andy Beats »

Interesting about the cetane booster in the diesel, I have a wee bottle of it at home to try in the wife's Evoque.
monkeyhanger
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Re: Cold engine does not run smoothly

Post by monkeyhanger »

Andy Beats wrote: Wed Oct 28, 2020 10:56 am Interesting about the cetane booster in the diesel, I have a wee bottle of it at home to try in the wife's Evoque.
The A4 is marginally more responsive with it and the mpg difference is very noticeable. I really noticed not putting it in prior to my 105 mile round trip on Monday.

Millers Ecomax is what I use. The can is about 4 years old and half used - we stopped using it when I chopped the wife's A1 1.6TDI in for my 2018 Polo GTI+ and we still had the Golf R. It stinks though!
Andy Beats
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Re: Cold engine does not run smoothly

Post by Andy Beats »

monkeyhanger wrote: Wed Oct 28, 2020 12:19 pm
Andy Beats wrote: Wed Oct 28, 2020 10:56 am Interesting about the cetane booster in the diesel, I have a wee bottle of it at home to try in the wife's Evoque.
The A4 is marginally more responsive with it and the mpg difference is very noticeable. I really noticed not putting it in prior to my 105 mile round trip on Monday.

Millers Ecomax is what I use. The can is about 4 years old and half used - we stopped using it when I chopped the wife's A1 1.6TDI in for my 2018 Polo GTI+ and we still had the Golf R. It stinks though!
It's more for keeping the DPF as clean as possible, TBH.
It's a Euro 6 car, so the DPF is really close to the engine (like, REALLY close..) and should run higher temps than older DPF cars
Still, I don't kind a few extra quid to chuck in some snake oil.
monkeyhanger
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Re: Cold engine does not run smoothly

Post by monkeyhanger »

Andy Beats wrote: Wed Oct 28, 2020 2:57 pm
monkeyhanger wrote: Wed Oct 28, 2020 12:19 pm
Andy Beats wrote: Wed Oct 28, 2020 10:56 am Interesting about the cetane booster in the diesel, I have a wee bottle of it at home to try in the wife's Evoque.
The A4 is marginally more responsive with it and the mpg difference is very noticeable. I really noticed not putting it in prior to my 105 mile round trip on Monday.

Millers Ecomax is what I use. The can is about 4 years old and half used - we stopped using it when I chopped the wife's A1 1.6TDI in for my 2018 Polo GTI+ and we still had the Golf R. It stinks though!
It's more for keeping the DPF as clean as possible, TBH.
It's a Euro 6 car, so the DPF is really close to the engine (like, REALLY close..) and should run higher temps than older DPF cars
Still, I don't kind a few extra quid to chuck in some snake oil.
I'm pretty sceptical about snakeoil products and wet panel filters etc., but Cetane boosting benefits are well established. Mine is Euro6 with Ad-blue, with the DPF pretty much stuck to the first bit of the exhaust manifold to heat up ASAP.

There's 2 factors to keeping a clean DPF -

1. Producing as little soot as you can in the first place (less soot to combust).

2. Have long enough journeys to combust whatever soot you produce (ideally passively).

The Cetane boosters help achieve a more complete burn - fewer and finer soot particles.

The Millers costs the equivalent of adding 2-3p a litre onto your fuelling costs if you're adding 1 to 2mL per litre of fuel in your tank. Or buy premium diesel at 8p+ per litre that comes with the same cetane boosting chemical 2-EHN.

When I bought my 5L tin, it was about £45, now it's about £80. I have seen 2-EHN being sold for about £38 per 5L, not sure what, if anything other than the 2-EHN is in Millers to claim detergents and lubricity agents (I call Bellshill on the lubricity claim - diesel is a lubricative fuel in itself).

I'd probably give a 500mL/1L bottle of 2-EHN from a reputable brand a go to try it.

People do use it in their domestic heating oil systems too and see less soot generation in the chimney/exhaust outlet.
Andy Beats
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Re: Cold engine does not run smoothly

Post by Andy Beats »

monkeyhanger wrote: Wed Oct 28, 2020 4:21 pm Mine is Euro6 with Ad-blue, with the DPF pretty much stuck to the first bit of the exhaust manifold to heat up ASAP.
Adblue is post DPF though, isn't it?
So how do Audi (and LR) raise temps for regens?
Renault inject more diesel, my Mini had EOLYS fluid that raised temps.
Maybe they figure the repositioned DPF raises temps enough, dunno. :?:
monkeyhanger
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Re: Cold engine does not run smoothly

Post by monkeyhanger »

Andy Beats wrote: Wed Oct 28, 2020 4:43 pm
monkeyhanger wrote: Wed Oct 28, 2020 4:21 pm Mine is Euro6 with Ad-blue, with the DPF pretty much stuck to the first bit of the exhaust manifold to heat up ASAP.
Adblue is post DPF though, isn't it?
So how do Audi (and LR) raise temps for regens?
Renault inject more diesel, my Mini had EOLYS fluid that raised temps.
Maybe they figure the repositioned DPF raises temps enough, dunno. :?:
Yep, Adblue is post DPF, as is all the active exhaust system. Just differentiating because early EU6 cars (like my 2013 Golf GTD) didn't have adblue and newer variants (from about 2017) do.

If there is a need to have active/forced regens because you never go far enough to get the DPF warm enough for passive regens (active is when your engine idles at 1000rpm instead of 800, the car seems surgey at low throttle inputs and the mpg drops a little), VAG inject fuel into the GPF to ignite whatever in there. If you interrupt an active/forced regen, the unburnt fuel gets dumped into the oil sump, thinning the oil.

When VAG moved the DPF from around the middle box of the exhaust to the back of the engine on the exhaust manifold, the warm up time of the DPF reduced a lot, so that 5 mile journeys were usually trouble-free, rather than 18 mile+ journeys.
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