: Tyre Pressures/ Improved fuel consumption



cadillac londoner
04-05-10, 12:44 PM
I inflated my tyres up to 35psi. On a trip to Suffolk this weekend from London the Trip com. said my 150ps Wagon manual averaged 50.4, up from the normal 48 as advised before.

Suggest everyone checks their tyres!

S70RMP
04-05-10, 01:47 PM
check the hand book and see if you can go upto 41psi like the saloons

thats suposed to give better mpg

Mazuk
04-05-10, 02:41 PM
The recommended pressure for 235-45- R17 is 35 psi.

S70RMP
04-05-10, 03:28 PM
I'm on 225/45/17 94w

ajp558
04-05-10, 04:30 PM
The recommended pressure for 235-45- R17 is 35 psi.

I checked my handbook at the end of last week following discussion on another thread. If I recall correctly, it actually says that the minimum pressure should be 35psi for 235 17" tyres (mine is also a TDi 150 Wagon). Later on in the same section it says that to maximise fuel efficiency 41psi is recommended.

I set mine to 40psi all round before family visits over the Easter weekend and I managed to get 55mpg on a 130 mile trip to the Midlands, and then got 50mpg on the way back with a more scenic route and more spirited driving. Getting 55mpg was a real struggle and using a lot of cruise control. My wife complained it was excruciatingly slow, mile after mile on the M4, A419, M5. I responded that that is how I feel when she is driving. :D

Mazuk
04-05-10, 05:19 PM
Thanks to all for this useful information.I had not noticed the "improved fuel economy" figure of 41 psi in the handbook.I`ll check the glove compartment figures tomorrow and increase my pressures.I guess the trade off may be a harsher ride .

cadillac londoner
04-06-10, 02:01 PM
OK all, I have inflated my tyres to 41ps. As I seem to be the highest mileage BLS driver I will report to you how fuel consumption/handling/ride goes over next couple of weeks.

Will let you all know!

S70RMP
04-06-10, 05:11 PM
I notived the ride went a bit firmer at 41 but nothing that I couldnt live with.

I have a run down to Cornwall in a few months for the Jack Johnson gig at the Eden Centre so I'm going to aim to get the best mpg I can on that trip

Lets just hope the price of diesel drops before then ! :eek:

S70RMP
05-03-10, 02:29 PM
OK all, I have inflated my tyres to 41ps. As I seem to be the highest mileage BLS driver I will report to you how fuel consumption/handling/ride goes over next couple of weeks.

Will let you all know!

Any news to report on MPG ?

I think i've done about 150 miles over the last 8 weeks

ExRPO1
05-05-10, 02:37 PM
I increased my tyre pressures to 41 psi following the first post on the subject.
I understand that the tank capacity is 58 litres. I recently did a trip of just over 600 miles on one tank (I didn't hang about either - some very spirited driving) and achieved just over 47 mpg. When I refilled, I calculated I had just over nine litres left in the tank (I think my sums are ok, but I'm sure I'll be corrected if not). Highest reading I've personally seen in the instrument panel, is 56 mpg, but that is doing about 56 mph on cruise control. All in all, getting a lot more mpg than my old 2.0L 150bhp petrol, so no complaints.

cadillac londoner
05-06-10, 08:34 AM
Any news to report on MPG ?

I think i've done about 150 miles over the last 8 weeks

Hi all. I have done about 2,000 miles on 41psi. It does not seem to have made much difference to fuel consumption.

O a run at 70mph with cruise still averages about 50.

The big difference I have noted is the performance at low speeds. There is a notable increase in acceleration with this pressure setting.

I am no car techno, but would one expect this? i.e. the higher your tyre inflation the quicker the aceleration? (something to do with grip?)

Car has now done 11,200 since 24/12/09, still no problems, no rattles etc.

I also found 2 more speakers the other day, if you include the sub, that now means 10 found. I know that on some posts people could only find 7, and the brochure says 11.

The 10 are, 3 on dashboard, 2 on front doors, 2 on rear doors and the 2 I have just found, 2 on rear hatch plus sub.

The other speaker may be somewhere at the front where the very pleasant lady tells you where to go etc. She seems to speak from the passenger side by the footwell.

Off to Belgium and Holland tonight, where the car is more common, so probably less stares of people wondering what that car is!

ajp558
05-06-10, 04:36 PM
Thanks for the update Cadillac Londoner.

With regard to increased acceleration with the proper trye pressure, I am surprised you notice a difference, but technically speaking the increased tyre pressure should reduce the rolling road resistance or frictional drag of the under-pressured tyre, and hence there is less friction for the car to overcome when accelerating, provided that the power doesn't exceed the limits of grip and hence cause wheel spin. I hope that makes some sense, but I would have thought any such change would not have been noticeable unless comparing almost flat tyres with properly inflated ones.

With regard to the mysterious 11th speaker, it is actually a second subwoofer. I have a pdf from Cadillac which illustrates all 11 speakers. The sub is as follows:

"Two 13-cm Nd Richbass woofers in a custom-engineered bass enclosure mounted in the spare tyre wheel well."

If I ever work out how to attach a pdf or jpeg I could upload the diagrams - one for the saloon and one for the wagon.

ajp558
05-06-10, 04:47 PM
Attached is the Bose speaker setup for the BLS Wagon, showing all 11 speakers. The brochure it is from doesn't show any copyright statements so I hope I am not breaking any forum rules. I love the touch-screen sound system and Sat Nav, and can't remember how I ever managed without the controls mounted on the steering wheel. :)

ExRPO1
05-10-10, 02:16 PM
I know we've kind of gone off topic with the speaker thing, but its interesting to see that the BLS Wagon has subwoofers in the spare wheel well as the saloon, certainly mine anyway, does not. In fact, I've now actually got a proper space saving spare wheel from a 2008 SAAB 9-3 in there. Who needs tyre foam!

S70RMP
05-11-10, 04:51 AM
i've been meaning to buy a full size replace for 2 years !