Citroen XM Forum

Some interesting info, in the comments at the end too.
Does this affect our 2.0i and V6 ?
https://www.rac.co.uk/drive/advice/emis ... ffect-you/

As I understand it unless someone replaces the whole fuel system with E10 resistant stuff then no even current E9 fuel lines start degrading internally and should be replaced every 5 years

It’s also hydroscopic and corrosive
It also dosnt lubricate as well as normal petrol does do valves and piston rings will wear out faster
Our engines also arnt tuned for these fuels
It also has less energy so higher fuel consumption and lower power

I have used E10 in my XM in France (but not exclusively) for the past 5 years.

I think, but there seems to be no solid documentation, that Citroen upgraded the fuel system components a few years before the 2000 deadline in France.

Aside from the effects on fuel line components, E10 has lower calorific value than traditional petrol, so engines must be running in closed-loop mixture mode to operate correctly. I certainly can detect that when cold (and in open-loop) the ES9 engine hesitates a little on acceleration when running E10
This can be overcome by increasing the fuel rail pressure. For the ES9 engine, Bosch makes a 3.5 bar regulator which correctes the open loop mixture. The problem is that increasing the fuel pressure throws off the calibration of the fuel consumption in the trip computer, and it becomes about 5% optimistic.

Last year I swapped back to the original pressure regulator and (mostly) use 98 RON fuel now.

Petrol with Ethanol mixed in is more suceptible to containing water, which causes corrosion of aluminium and ferrous components.
Using a fuel additive that emulsifies the petrol/water mixture is a good idea. Isopropyl alchohol is a good water/fuel emulsifier.

The problem is the water is still present in the mix (ethanol, and IPA, are both hygroscopic).

The dangers of (standard DOT4) brake fluid absorbing water are well known - risk of fluid 'boiling' under extreme (caliper) heat, and rusting/corrosion of steel pipework and other metal parts. With hygroscopic fuel, the risk arises of corrosion of the fuel system. Adding IPA (itself water miscible) is not, surely, an answer. More to the point would be the addition of corrosion inhibitors to the fuel, in the same way that water-based coolant relies on these.

All, sadly, part of the dying swansong of internal combustion, and attempts to mitigate its environmental/climate impact. (You can bet the motor racing fraternity will secure an exemption.) A real shame that the most recent incarnations of both petrol and diesel power units - which, by all rights, should have been at their most powerful and efficient - have ended up hobbled by bolt-ons like DPF, EGR, etc., let alone DMF. Not exactly going out on a high, but maybe making all-electric look even more desirable.

Maybe we XM owners should count ourselves lucky that we were largely spared the frustrations of most of these compromising tweaks (with the exception of a certain amount of EGR), and that the primary focus of our engine design was smooth quiet power and efficiency, with an eye on emissions. XMs may be in parts complex, but this is relative, and nothing compared to the aggro that C5 (and especially C5-X7) owners continually report. We're a relatively lucky lot!

...time to turbo charge the V6 and make full use of all the benefits ethanol brings then

D

Dean wrote: ↑

Mon Mar 09, 2020 9:13 pm

...time to turbo charge the V6 and make full use of all the benefits ethanol brings then

D

I've been going blue holding my breath waiting for you on this one, Dean.
A twin turbo V6 should make the old girl move nicely...until the auto box explodes.

I doubt it would pop the box, they are a very strong unit but it would depend on how much turbo you used.
It will happen one day, as either Single turbo or supercharger setup, the later would probably be more auto-Xm compatible...

D

Dieselman wrote: ↑

Tue Mar 10, 2020 7:50 am

Dean wrote: ↑

Mon Mar 09, 2020 9:13 pm

...time to turbo charge the V6 and make full use of all the benefits ethanol brings then

D

I've been going blue holding my breath waiting for you on this one, Dean.
A twin turbo V6 should make the old girl move nicely...until the auto box explodes.

Dean wrote: ↑

Tue Mar 10, 2020 8:14 am

I doubt it would pop the box, they are a very strong unit but it would depend on how much turbo you used.
It will happen one day, as either Single turbo or supercharger setup, the later would probably be more auto-Xm compatible...

D

Didn't saab put 210bhp through them in the 9000s.. Which begs the question why the prv didn't go auto with 200bhp..

Yes i had one Paul, i think the Aero or Griffon that came as 225hp and the gearboxes were the same, it is not the driveline that is weak, it is just seal and valve failures that are the issue, ive never heard of nor seen a HP18 with worn out clutches or diff/driveline failure.

There must have been a reason they never used the auto in the 24v but most likely it was a space or heat issue, not a power issue.

D