LCI X5 3.0D Fuel Economy

[jdd]

Originally Posted by DanX5d

Late 04 X5D - stock engine, OEM 18" wheels

City trips of less than 15kms from cold start => 10.0 - 12.5L/100km
City trips with warm engine => 8.5 - 10.5L/100km
Melb Airport to Mornington, mostly freeways = 8.2L/100km

Driving to Sydney from Melbourne and back next week and plan to fill up at the end of each trip only. I will post the outcome when we return.
Cheers,
Daniel

Are those numbers from the trip computer or calculated?
Reason being is that the trip computer is very optimistic, in mine it reads about 15% lower than reality.

[DanX5d]

Yes I agree with the trip meter inaccuracy, although I have new tyres on the 18" 2004 mdl wheels and the inaccuracy is closer to 5%. Still not acceptable in my opinion. I will see what transpires next week. Cheers Dan.

[jdd]

I don’t believe wheel size plays any part in that if you have the correct size tyres fitted.

I have 19” wheels on mine and believe the rolling diameter of the wheel is the same as the 17 and 18” rims with the correct tyres fitted.

At 100kph on my GPS the speedo is showing about 103-104 so it’s pretty close.
The tacho shows dead on 2,000 RPM at this speed with the TC fully locked.

I’d be intrigued to know if the trip computer economy calculation can be calibrated.
I know it can on some other cars but not sure about the X5.

[DanX5d]

Hi JDD,
You are correct in that the wheel size is irrelevant, but I have a tyre spec fitted that is on the + side of the tyre standards sizing. Tyre makers are permitted +/- 4% for the OD of a tyre for a given size. It is the Rolling dia that you work the calculations from. That said, I have an electronic logbook fitted from my days in data logging devices and the speedo on my X5 over-reads by approx 5km/h everywhere including at 180. That is lazy work by BMW because they have offset the needle to read over everywhere to ensure they comply with design ADR's etc.
Recalibrating the computer calculation....I'm interested. I have other issues I need to sort with a custom re-cal like upshift points. Why the programmer felt the diesel engine needs to rev to 4500 for acceleration is beyond me. With a 6 speed box, 3800 would be tops with the current torque curve and the later X5’s with more gears are better programmed.
I just filled the tank up to the point where I can see the fuel and the calculation by odo and bowser and got 12.0L/100km. Trip computer said 11.3L/100km, so we are over-reading by 6%. Mind you I did not fill it up to the brim last time and I also was on level ground previously so the results are not exactly perfect.
Off to Sydney early tomorrow.
Cheers, Dan.

[DanX5d]

Back from Sydney and the BMW OBC over reads unnecessarily in my opinion just as JDD stated.
What was BMW trying to achieve by deluding its customers?


Economy data - Fully loaded.

OBC 7.4L/100km, Actual 8.2L/100km to Sydney.
On the way back I worked the engine hard up every hill on the highway and cleaned out the DPF to the stage where you could not see any smoke in the mirrors. It would have still been smoking but not as much. Several times we topped 180 before lifting off for the crest to resume our set speed of 115 (speedo) or 110 by the OBC.
Economy data OBC 7.6L/100km, Actual 8.4L/100km to Melbourne.
Range showed 130km remaining at Sydney end of the 940km trip

No Complaints apart from the NSW roadworks everytime I drive up the Hume.
Cheers, Dan

[jdd]

Those figures are not too bad considering the speeds you got up to and the fact it was fully loaded.
I’m not sure of the merit of pushing it as hard as you did to clean the DPF.
As far as I’m aware the DPF goes through a regen process when needed and I don’t think you can actually force this by your driving style.

Black smoke out the exhaust when pushed may indicate your EGR valve needs cleaning.
When I first got my X5 it would smoke quite badly on anything more then gentle acceleration. If you pushed it hard from a standstill you almost couldn’t see the cars behind it was that bad.
Since I cleaned the EGR valve and changed the extremely dirty air cleaner, the problem has all but disappeared.
It still puffs a small amount of smoke on hard acceleration which isn’t noticeable during the day, but at night you can see a very slight haze in the car headlights behind.

[JDM-20L]

Got a link to a "how to clean the EGR?" Mine suffers that smoke from time to time... but I swear using different diesel changes it? Better or Worse.

[DanX5d]

[QUOTE=jdd;851106]T
I’m not sure of the merit of pushing it as hard as you did to clean the DPF.
As far as I’m aware the DPF goes through a regen process when needed and I don’t think you can actually force this by your driving style.

I had the EGR valve update done early on as a blocked EGR valve can fool the unwary into replacing the turbo as they see oil in the intercooler and suspect the compressor seals. Mine has 195K on the original turbo and still going well.

I recall reading in the BMW tech literature that the DPF burn only occures after x time at operating temp, throttle position, load etc.

The DPF is known to block up on cars with repeated short trips on engines not getting up to operating temp for enough time to trigger the DPF burn off. It is not uncommon to hear of DPF fitted diesel cars being taken out on the motorways to give it a good clean out. My car has too many short trips so I thought a good run wouldn't hurt.
Cheers, Dan.

[x3oiler]

There is some detail here (nice site to bookmark btw) on how the Electronics decide to regenerate.

Regeneration, particulate filter - WDS

[jdd]

Very interesting article indeed, thanks for that.
What I also noticed while having a look on that site is the information about the trip computer fuel consumption calibration.
I suspected this was possible but hadn't found any evidence until now.. nice find !