Shell Optimax

Aye, I've got that Evo mag Pdf'd somewhere.  They did use recent cars too, not lovely old shapes like mine <g>

And, their acceleration testing is probably far greater than normal road use, I don't want throwing back in my seat, on 95 or 98 R.o.n!!

As for fuel cleaning, I used to put a glug of injector cleaner in every 10 tank-fills or so.

I'm going back to 95, to keep my car alive, to keep my guides from crustin, and stop my wallet bustin, this old shape is gonna last, till the tax man he gone past, 10 long years to go, will it make it----I don't know.

Sorry, rap mode OFF.

OK.  Engine Adjustment.....I thought that my 1989 520i was "Set up" (At ECU level) to run on the higher octane stuff in the first place, so ordinary unleaded was too low R.o.n???

Also, if it was a mixture problem, all 6 bangers would be in same condition.  Only 3 were coked. Pots 2,4, and 6 if that is any help to anybody.

I do not know if my engine has a knock sensor.  Help please forum?

Coked up with crusty deposits, removable only by a small screwdriver, is a sign of Valve guide wear.  Even the pictures in the back of the <spit> Haynes manuals have that bit correct.  I put 6 newuns in, Champion brand this time. (NGK before)

Running.  Well, immediately, the warm tickover went up to 730 (Visual guess from dashboard dial) from about 690/700 when on ordinary unleaded.  690/700 is too low according to the books, 730 is within spec, so that made me think I was onto a winner.  Other than that, I cannot say that  I noticed any difference whatsoever, for my kind of fully legal driving. (OK, 80-85 on motorways when it's safe).  Track day attendees may say they notice a difference.  I say it has cost me £4.00 per tankful extra, for no apparent reason.  I'm knocking it on the head as from tonights fill-up unless this forum can pursuade me not to.

Right.

4 tankfulls of this have now been drunk by my old gal.

MPG?  Naff all difference whatsoever, on "To work and back" or long runs.

Also, after a 7 hour run from Torquay to Preston on Friday last, I left the car on Saturday,  Sunday, I had a "No start situation".  In my impatience I pressed the accelorator pedal, and the smell of fumes told me I'd wet my sparky world, so I took out the plugs to dry them.  These plugs are NGK, and are 2 months old.....Plugs 2,4, and 6 were coked up to hell!  This is an indication of Valve guides knacked, but the coincidence with my Optimax experiment...just coincidence?  In the end, I had to give the car an Oil Start, because I'd rinsed the cylinders with petrol.  The neighbourhood was pleased to have a cloud of burning oil at 10am Sunday morning!!!!

All spelling mistakes are Copywright protection!

When these men in White Coats turn up, don't worry, it's the BMW lab technicians, coming for your data.

"We have come for your data"  which is a b*st*rdisation of a musical cult film of the 1970's...oh, I'm wandering.

Now, if you swap back to ordinary punters unleaded, do you reckon your mpg would be significantly lower...that is the question.  6 months of each study please...publish results on here.

Peter - did the fuel economy you calculated tally with the OBC to the same extent on both runs? Surely the other possibility is that your local station either has some dodgy stuff in its tank which makes the economy worse, and/or isn't giving you pure Optimax even when it says it is.

Ian

I think I have found out why I was finding shell optimax less than impressive.

After a long drive to London over christmas I filled up the car to drive home and worked out my fuel consumpsion on the way down to be 32mpg. This was great considering the trip took 10 hours, because of big problems on the M1, and 4 of these which were actually stationary in a traffic jam. When I got home I filled up from my usual petrol station and calculated an MPG for the return trip of 30. Strange considering that this time there were no hold ups and the journey was pretty my a constant 70 - 80mph.

The next time I filled up I just happened to stop at a different shell station to the one I normally use. Fuel consumpsion was better by about 2mpg than it normally is. I have alternated a few times between my usual petrol station and a different one and it is the same every time. The only thing I can think is that the pump at my ex regular petrol station is saying you are putting in more petrol than you actually are, hence making you think that the car is getting worse MPG. It's bad enough that I have to pay 80p a litre for the stuff without being charged for extra petrol that I am not actually getting! 

Anyway, much happier with optimax now and I can indead confirm that my car gets better mpg than with Premium UL.

Its an average, as driving urbanly it shows mid 20s and on the motorway about  34mpg @about 70mph.

The OBC isn't most accurate best to do calculations when filling up as Peter says.

On a Motorway trip to Luton at a bit above the speed limit  it returned 32mpg.

Dave,

30mpg on a 2.8 mate? I'm currently getting about the same in an M3 Evo, and about 34mpg on a motorway. I suppose thats where you'll skin me in economical terms eh, on the motorway?