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I'm undecided about engine oil additives. Are they cut out to be what their manufacturers claim or snake oil? Or are they even potentially damaging to the engine?
Back in the days when cars had carbs, the idling speed would noticeably increase as you poured in 'Slick 50'. The only logical reason for that is less friction?
 

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Discussion Starter #62
The regular XF mimics an LSD by applying the brake to the unloaded wheel. It works reasonably well but results in a voracious appetite for rear pads & discs.
That's interesting and would indeed explain better why rear pad wear is relatively high.
 

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Discussion Starter #63
I put the car in S mode just now coming home from work and what beautifully crisp and instantaneous shifting with paddles. Much better than before! :D
I then tried dynamic mode and was again impressed by the increased responsiveness.
I then combined S with dynamic mode and was borderline scared! 😳
The entire car seemed to change - revs went up significantly and the throttle responsiveness was incredible. In auto it would not change up gear until above 4000 rpm and felt like a racing car. It reminded me of the time I drove my brother-in-law's V8 Porsche Panamera 4S. I will not be using that combination too much I suspect.
 

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Try a remapped XFS 3.0D (275HP standard, approx 310HP now and bags more torque), or maybe I'll let you have a go in my XKR 5.0 V8, but maybe not in Dynamic + Sport mode on the first drive 😁

Best thing I did on the XFS was to add a tuning box. I'm scared to even think about tuning the XKR. But maybe......
 

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That's interesting and would indeed explain better why rear pad wear is relatively high.
Actually, I believe it is because the EBD system (electronic brakeforce distribution) uses the rear brakes a lot around town for "anti dive". And whilst the stability control system will indeed brake rear wheels individually as needed, the vast majority of drivers, the vast majority of time, are not "pressing on" enough to make that system trigger at all. Ditto traction control.

"Anti Dive" is what wears out rear pads faster than the fronts, especially on vehicles that live mainly urban lives.
 

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Discussion Starter #66
Try a remapped XFS 3.0D (275HP standard, approx 310HP now and bags more torque), or maybe I'll let you have a go in my XKR 5.0 V8, but maybe not in Dynamic + Sport mode on the first drive 😁

Best thing I did on the XFS was to add a tuning box. I'm scared to even think about tuning the XKR. But maybe......
perhaps if I was 20 years younger I would have taken you up on your offer... :)
 

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Discussion Starter #67
Actually, I believe it is because the EBD system (electronic brakeforce distribution) uses the rear brakes a lot around town for "anti dive". And whilst the stability control system will indeed brake rear wheels individually as needed, the vast majority of drivers, the vast majority of time, are not "pressing on" enough to make that system trigger at all. Ditto traction control.

"Anti Dive" is what wears out rear pads faster than the fronts, especially on vehicles that live mainly urban lives.
Thanks for that additional information on rear brakes.
Not sure if this could be one of the contributing factors to rear brake judder problems after a while. I have now twice had to change the rear brakes to get rid of judder when braking at speed.
First time I replaced everything (new calipers and disks) however only lasted just over a year before the speed judder started again and had to replace disks/pads again recently, which solved the problem.
Problem seems to be associated with pad transfer to disk, likely due to incomplete release of caliper after EPB hold. I am currently having problems getting hold of the new EPB return springs that have been upgraded according to technical bulletin #JTB00267NAS2 (parts C2P25746 and C2P25747), which will hopefully help.
 

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Interestingly.. (ish).. I had new pads and discs all round on my Sportbrake and the rear sensor wore through at approx 26K miles and the front about 500 miles later.. so pretty even wear, is it because of the self levelling suspension and/or the fair weight that's always in the rear of the car? or maybe as Wilf says that my car does relatively few urban miles is a factor as well... 🤷‍♀️ ...
 

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Discussion Starter #69
Back in the days when cars had carbs, the idling speed would noticeably increase as you poured in 'Slick 50'. The only logical reason for that is less friction?
I changed the engine oil yesterday, with the additive that I was given.

First warmed up engine before removing old oil from top using vacuum pump. Almost 7 liters in total came out! Not sure but this may have been due to the amount of cranking I had to do to eventually get car started a couple of weeks ago after changing the inlet manifolds. Perhaps some diesel was pumped into oil.

Next added 5 L fresh oil (5W30 SAPS C1).

I then carefully (slowly) poured in the 300 mL CERATEC additive into the elevated central hole of fuel filter housing, as shown below:

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Then added another 300 mL to empty bottle (to wash out all ceramic micro-particles) and again poured this into the filter area hole as well.

Then another 300 mL rinse of bottle and added as normal via engine oil filler.

So 5.9 L added in total.

Started up and let the concentrated additive initially work trough the main engine bearings (before its dilution with engine oil), as advised by Alexander from Speed-Profis. Let idle for a couple of minutes and then up to 2000 rpm on and off for a couple of minutes before turning off.

Checked the oil level (after again having to wait about 15 min before the reading came up!!) and it said to add 0.5 L and I decided not to. Says additive is for up to total of 5L engine oil...

Went for a run and read level again, which now said "OK".

Went for a longer drive today (had to take all my old engine oil, brake discs, pads etc from last year to waste disposal center) and I do indeed have the impression the engine is quieter than before.
 
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