XUD9 vs DW8 discussion

[moizeau]

Xud9 N/A, best engine I've ever had for reliability 450k, original injectors, recon pump at 200k, never looked at valve clearances or headgasket, never dropped oil on the drive (apart from a bit of green stuff) Got weighed in due to bodywork. Xud11 for low down grunt, drive in 5th all day long, uses less fuel due to the low revs, also running my bx17td (bag of spanners thread), now sorted, extremely quiet and I loving it again. Can't comment on HDIs as I've never had one, not sure with all the electronics it will still be running at 25 years old (economically viable ?).

ek how would you like an XUD!! auto in the Zant?

[ekjdm14]

Now that (assuming you meant XUD11) would be lovely, if only the gearbox could take it. From what I've been told, the HP14 won't even hold an XUD7TE so the torque of the 2.1 would eat it in short order. Strange you mention it but I was offered the engine out of the 406 we swapped for, but we decided for insurance reasons as much as anything to keep the car original.

If there was an autobox with the right ratios & the strength to not spit it's guts, a 2.1DT auto Xantia would be a magnificent thing. Then again, the last week has proven the NA engine is quite acceptable & able to hold respectable speed on a run anyway so no need for more power, it'd only possibly detract from the relaxed wafty ride.

As far as the HDi motors go, I'd say there's potential for them to be running/viable in 25 years. As long as the basic mechanical components are still hanging together I reckon the electronics side of them will be catered for by either specialist repair techniques (in much the same way they are now with companies like BBA) or potentially even enthusiast-built replacement systems (there's some precedent for that already with early failed ECUs being replaced with programmable units).

Don't forget that as the technology ages, so do the people who grew up with (and feel a connection with) said technology and learn how to keep it going for posterity.

[CitroJim]

the 2.1TD (XUD11) is a marvellous engine had one in a Xantia...

The original 8V HDi is a great engine and should be will good for 25 years... It's only a development of the XUD and retains all of its good points and a few improvements inherited from the 2.1TD... It's like a cross between the two...

[ekjdm14]

It's only a development of the XUD and retains all of its good points and a few improvements inherited from the 2.1TD... It's like a cross between the two...

That's a good way of looking at it, even the nominal capacity "splits the difference" between the XUD9 & 11 I see no reason why the electronics side of things wouldn't be just as viable as earlier systems, just as an example our Escort has a 27 year old ECU and ABS system which both still function fine, and some members are running/restoring/repairing computer systems of age too, so apart from the odd component failure and cases of water or impact damage I reckon the electronic controls will remain viable in the same way other complex yet obsolete tech has done. The repair techniques have changed over years but then so has the knowledge base of enthusiasts

Edit-: [/ramble]

[dnsey]

Theoretically, the ECU ROMs will lose their memory at some point, but I haven't heard of that happening yet.

[Pug_XUD_KeenAmateur]

Did I imagine it, or hasn't been reported that diesel emissions improve as well-maintained engines put on significant mileage?

interesting point: I swear my 249k XUD9na has got more poke and goes up hills better than ever the last few months (bought at 181k, 6yrs ago)

[ekjdm14]

Did I imagine it, or hasn't been reported that diesel emissions improve as well-maintained engines put on significant mileage?

interesting point: I swear my 249k XUD9na has got more poke and goes up hills better than ever the last few months (bought at 181k, 6yrs ago)

If it's improved the last few months, unless the bulk of your 68k has been in those few months I'd just attribute it more towards a potential fuelling or timing restriction having been fixed in that time... (although if the performance of any mechanical injected diesel engine changed noticeably over a short time, whether for the better or poorer, I'd have to pull a cover and check the timing belt tension. I've had lucky escapes before with failed tensioners on petrol engines that left the belt really loose & I can imagine if the pump timing was slightly out in the right direction on a diesel, a loose belt could allow it to improve).

[white exec]

Diesels do loosen up with age (best after 30-50k, so so much for the delights of a new car, traded in every couple of years!), but that shouldn't be showing up beyond 100k.

Diet has an effect. The best will never be had from cheap fuel, including all the supermarket stuff. Low-down torque will be what really suffers. Here, we know of sudden inclines that just cannot be done in 2nd on budget fuel, but need a drop into 1st. This just doesn't happen with good standard grade (Repsol here seems the same as the UK's legendary Esso), when the car powers up the same slopes with appropriate welly.

It's the same for both our 2.5 Citroen and 2.0 Toyota.

[ekjdm14]

Interesting point, and something I might have to "experiment" with when our local Esso 24hr station reopens after a refit. At the moment we've been using a mix of Morrisons & Jet brands but every little helps when you have 68 bhp and a slushbox

[white exec]

...and a good dose of Millers Diesel Power Plus, or Wynns Diesel Fuel Treatment - two similar products that really work to clean out injectors and pump, and improve the fuel's cetane value.
It's the lack of cleaning agents and cetane improvers that differentiates top-grade fuel from budget stuff. These additives are normally added at the distribution depot stage, apparently.
Give it a few tankfuls of decent fuel + cleaner to see the difference.

[van ordinaire]

Can't say I've noticed any difference relative to the source of the fuel, BUT, then again, it's not something I've carefully monitored or, in truth, paid any heed to at all. So I might do the same as ekjdm14 - if I remember.

As a side issue, how can that much maligned supermarket fuel really be any different? Anyone who's ever driven past a refinery will have seen the queue of tankers waiting to be filled, regardless of their livery! (interestingly, it's just the same at the Stella brewery).

As for additives, I did raise that issue in my blog but the responses were fairly non-committal. However, by a remarkable coincidence, I was trawling though my local factors' website this morning, & they carry a huge selection of diesel additives, including 3 by Wynnes (one of the biggest brand names in "snake oil") but, worringly, they provide no info. about (or claims for) their products. On balance, I think I might go for the Millers product, especially as I can probably get it at good price at the "Bristol" Classic Car, which is only a couple pf weeks off, now. However, I'd be interested in how/why that particular Wynnes product was chosen.

[Harlequin]

Whilst all tankers generally fill up from the same depots - its the additives added once hooked up that changes, an Esso card will give different percentages than say a Tesco filling card

[white exec]

Why the Wynn's brew? I agree that the shelves are full of snake oil when it comes to car additives, some pointless, some actually harmful.

I'm as sceptical as you are, but years ago was recommended to use some Millers 'Dieselclean' on our BX19RD, after it had suffered a bit of indifferent starting and lumpiness, despite checking everything electrical. Diesel Car magazine - required reading in the 90s - also carried articles on fuel quality and constituents, and recommended regular or periodic use of the stuff. I tried it - a 1:200 (remedial) mix for a couple of tankfuls, and then 1:1000 for normal filling - and was pleasantly surprised to see the end of the hesitation, and a noticeable improvement in torque, especially at low revs.

A few conversations with friends in vehicle workshops confirmed that Millers worked, and was something they often used first as an alternative to pump and injector stripping or replacement.

Concerned at the snake oil issue, and interested in what differentiated main brand diesel from Sainsbury's City Diesel* (one of the first ultra-low sulphur diesels, from Greenergy, iirc) I read up a bit on diesel fuel quality and contents, and discovered, amongst other things

- A sulphur content, although environmentally objectionable (hydrogen sulphide/bad eggs, smell; sulphur dioxide, acidic) provided pump and injector lubrication ('lubricity').
- The way and extent to which diesel fuel burned, and delivered useful power, could be modified by the addition of various substances, which acted as Cetane value improvers (roughly the diesel equivalent of octane value for petrol). One of these, commonly used in high-quality diesel fuels, was naphthalene.
- Such additives contribute a cost to the better fuels, and their use is limited in budget fuels.
- Diesel fuel production and its distribution system to tanker depots (in the UK at least) is frequently via the national fuel pipeline network, making 'base stock' common to many brands. It is the additives (including perfumes!) which differentiate the final pump product.

*Our BX19RD and 2.5 XM never ran well on City Diesel. Poor pulling power, and noticeably more gear changing. Fuel consumption actually worsened. A switch to Esso "2000" immediately restored performance.

Manufacturers' MSDS sheets can provide valuable insight into what is in chemical industry products, and the MSDS sheets for Millers Dieselclean (now Diesel Power Plus, iirc) listed naphthalene as a constituent, along with a couple of solvents and a petroleum base. The amber fluid has a very distinctive smell.

Looking for it here in Spain, I couldn't find Millers, but I did find Wynn's Diesel Fuel Treatment (1-litre can, Fleet Use), and opened one up - the same smell! Subsequently, I've also found another 1-litre product branded 3CV (I kid you not!) Tratamiento Diesel, virtually identical packaging and wording, so which appears the same, and is sold at Carrefour.

The MSDS sheets for all these read essentially the same, and I'm guessing they are the same, and likely from the same source. (Wynns is a major Belgian chemical company.)

Naphthalene? Cetane improvers? Plenty on the web about these, including experiments over decades to improve the power delivery (extent and type of burn) of diesel fuel. Some of these involved taking mothballs (naphtha) and grating them up and dissolving in the vehicle tank!

Not all cars, and not all drivers, seem to see a difference when using either Millers/Wynns/similar additive, but I always have: BX, ZX, XM and RAV4 D4D. The difference on the harsh-engined DI Toyota is really noticeable.

Benefits have been:
- more low-rev torque (less need to drop a gear for sudden inclines)
- better overtaking
- a quieter engine
- slightly better fuel consumption (1-2mpg)
- very low smoke readings
- consistently good starting

On the 'quieter engine' front ('smoother power delivery' is what the product says), my understanding is that the cetane improvers modify the way the fuel burns, to change what is effectively a 'sharp rap' of detonation with a budget fuel, into a 'steady push' of explosive power to the piston from an improved fuel. This both smooths out power delivery, and does it with less diesel clatter.

And right, some of the expensive bottles are snake oil. Some of the diesel improvers have been found to contain nothing more than . . . diesel.

[Harlequin]

I was allways recommended FORTE for oil / diesel additives over wynns

[white exec]

MSDS sheet should tell you what's in it.