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Alan Skofic
New User
Username: 120l

Post Number: 6
Registered: 11-2018
Posted on Saturday, 05 January, 2019 - 21:20:   Edit PostDelete PostView Post/Check IP

What kind of fuel consumption should I expect from a Sliver Spirit?

Is there any difference to the Silver Shadow?

Regards

Alan
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Steve Emmott
Experienced User
Username: steve_e

Post Number: 39
Registered: 11-2018
Posted on Saturday, 05 January, 2019 - 21:57:   Edit PostDelete PostView Post/Check IP

Alan,

Technically the Silver Spirit should be better than the Shadow as it was improved with the fuel injection.

However there are so many variables in the way any car performs wrt fuel effeciency primarily the way it is driven and whether short or long journeys and the general state of engine.

Then you have to look at the general state of tuning of the car (correct timing etc)and whether everything is functioning correctly.

When I purchased my Shadow 30 years ago it returned around 10mpg on average.

Primarily this was caused by leaking choke stove pipes that were just rotten and fiddling fingers on mixture controls trying to accomodate from running rich.

Renewing the manifold tube and stove pipes with a full carb rebuild including correct adjustment on choke settings and retune brought my Shadow up to 18mpg average now on a long run.

My friends fuel injected Spirit returns an average of 20mpg and I would say we are both careful light footed drivers so Spirit should always come out better if general engine maintenance on both is good.
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Robert J. Sprauer
Prolific User
Username: wraithman

Post Number: 102
Registered: 11-2017
Posted on Sunday, 06 January, 2019 - 00:03:   Edit PostDelete PostView Post/Check IP

If you do the math and compare 10mpg vs 15mpg vs 20 mpg and approx annual miles driven the difference is a fraction of what you will pay for annual upkeep as a custodian for one of these cars. If you're concerned about fuel economy this would not be a motorcar for you.
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Roderick Waite
Prolific User
Username: rodwaite

Post Number: 196
Registered: 1-2012
Posted on Sunday, 06 January, 2019 - 00:03:   Edit PostDelete PostView Post/Check IP

Hello Alan - I have a 1984 Spirit with twin SUs and keep a careful check on fuel consumption. Echo (my car) is mostly used on short shopping type trips and the odd longer run (2 hours +) and returns 3.5 miles per litre (15.75 mpg in old money) on the shorter forays, rising to 4.0 miles per litre (18 mpg) on the longer runs. The SUs are regularly serviced and kept balanced every 6 months or so (her emissions readings on CTs are lower than many modern cars at 2.2 ppm - the max:
allowable for her is 5.5).
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Roderick Waite
Prolific User
Username: rodwaite

Post Number: 197
Registered: 1-2012
Posted on Sunday, 06 January, 2019 - 00:27:   Edit PostDelete PostView Post/Check IP

Not sure about that, Robert. I've had Echo for 9 years, and her maintenance bills so far is just over 9,000 or almost exactly 1,000 per year. Most of that (6,500) went in Year 3 on a major transmission , brakes and aircon overhaul. My next anticipated big bill will be for 4 new tyres (wince!). The difference between 10 mpg and 20 mpg would double the fuel bill, and assuming an average 4000 miles a year would add well over 1000 a year - way past my average maintenance cost. Of course my car is kept in good running order rather than showroom condition - she wouldn't win win any concours d'elegance ...
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Alan Skofic
New User
Username: 120l

Post Number: 9
Registered: 11-2018
Posted on Sunday, 06 January, 2019 - 01:25:   Edit PostDelete PostView Post/Check IP

Thanks

That's perfect.

I drive about 4000km a year with my classic and I'm a gentle driver.

It uses about 16mpg so I'll be no worse off. Much better because I love the Rolls Royce and I don't really like my current classic.

I also budgeted about $1500 per year for up keep so it's all shaping up.

Thanks again for your replies.

Regards

Alan
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Brian Crump
Prolific User
Username: brian_crump

Post Number: 174
Registered: 2-2007
Posted on Sunday, 06 January, 2019 - 06:21:   Edit PostDelete PostView Post/Check IP

Alan - I get about 22 mpg in freeway driving from my 1993 Spirit II. Around Sydney, about 18 mpg.
Regards,
Brian
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Larry Kavanagh
Grand Master
Username: shadow_11

Post Number: 312
Registered: 5-2016
Posted on Sunday, 06 January, 2019 - 09:53:   Edit PostDelete PostView Post/Check IP

At some stage during production (I think approx.1988) the Silver Spirit differential ratio was changed which allowed for cruising speed of 100 KPH at engine revs of approx. 2000 RPM and that delivered improved fuel economy compared to earlier models.
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Alan Skofic
New User
Username: 120l

Post Number: 10
Registered: 11-2018
Posted on Sunday, 06 January, 2019 - 17:09:   Edit PostDelete PostView Post/Check IP

Thanks again for the replies.

Larry, would you know what the earlier gearing was?

What year did the cars move from carburetors to fuel injection.
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Roderick Waite
Prolific User
Username: rodwaite

Post Number: 198
Registered: 1-2012
Posted on Sunday, 06 January, 2019 - 17:53:   Edit PostDelete PostView Post/Check IP

The change to fuel injection was spread over about 4 years, 1982 to 1986, when fuel injection was fitted to cars exported to the USA particularly, and then to all cars in 1986. I like SUs for reliability, simplicity, and ease of maintenance and adjustment, but they are a bit thirstier than injection.
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Alan Skofic
Experienced User
Username: 120l

Post Number: 12
Registered: 11-2018
Posted on Sunday, 06 January, 2019 - 20:18:   Edit PostDelete PostView Post/Check IP

I'm definitely thinking of getting a carburettored car because I think fuel injection will compromise the long term viability of a car because of failure of processors and availability of replacement processors / parts.

I may well be wrong?
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michael vass
Grand Master
Username: mikebentleyturbo2

Post Number: 520
Registered: 7-2015
Posted on Monday, 07 January, 2019 - 06:20:   Edit PostDelete PostView Post/Check IP

Go for injection, it's much more reliable and efficient ,the Bosch system has been used for years on mercs porche etc
I think the carbs are more complicated and need more maintenance.

Mike
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Patrick Ryan
Grand Master
Username: patrick_r

Post Number: 2060
Registered: 4-2016
Posted on Monday, 07 January, 2019 - 06:27:   Edit PostDelete PostView Post/Check IP

Alan,
The economy Brian mentions is fantastic, and this is what injection gives you.
My SS1 72 model would get around 12mpg around town, and 14-16mpg on the open road.

Id go for at least a Spirit II or later, and then the injection is reliable, and no parts issues.

If you really want a Shadow, well, I would definitely go for a series 1 with carbs and steel bars.
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Mark Aldridge
Grand Master
Username: mark_aldridge

Post Number: 594
Registered: 10-2008
Posted on Monday, 07 January, 2019 - 07:41:   Edit PostDelete PostView Post/Check IP

Alan I have a Shadow 1 (1975)and a 1988 Bentley8 Injected. I have had in the past a carburettor Spirit and a Carb Mulsanne. I would rather buy another injection car ( and probably will ), the carb ones are fussy to keep in perfect tune, slower and about 4mpg (UK) more thirsty. The Shadow1 has a different carb set up to the Spirit series and is in my experience a lot less fussy and more reliable , however 13 mpg is the norm !
Regardless of the above, if a Shadow or Carb Spirit comes up that I like, I would definitely buy, the carbs are not a deal breaker.
Mark
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Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 2039
Registered: 9-2004
Posted on Monday, 07 January, 2019 - 08:40:   Edit PostDelete PostView Post/Check IP

If the car is for high mileage I would go for injection.

As for the carb models they can do 24-28MPG this can easily work out with LPG cost wise being half the price of petrol.
The added benifits of running lpg are many.
Lpg cars have low carbon monoxide and carbon dioxide emissions with much less pollution.

No dirty carbon buildup in the engine oil or carbon build up in the combustion cylinders and valves.
With many other advantages.

Boot space is a little restricted though with a 90 litre tank.
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Larry Kavanagh
Grand Master
Username: shadow_11

Post Number: 313
Registered: 5-2016
Posted on Monday, 07 January, 2019 - 11:12:   Edit PostDelete PostView Post/Check IP

Alan, Fuel injection wasn't introduced in the UK until late 86/early 87 but was standard from 1980 in the USA. I don't know the date of introduction in Oz. I'm not sure when the final drive ratios were altered to 16/43 (2.69:1) but I think that it coincided with the introduction of fuel injection and 4 speed gearbox but I'm guessing. Later Mulsanne models had a 2.28:1 final drive ratio which allowed for 70 MPH cruising @ 2000 engine RPM and this improved fuel economy further allowing mid 20s MPG with a light right foot. Sorry I can't be more specific with dates when the final drive ratios changed but no doubt some other more genuine geek will know and advise.
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Robert J. Sprauer
Prolific User
Username: wraithman

Post Number: 104
Registered: 11-2017
Posted on Monday, 07 January, 2019 - 23:08:   Edit PostDelete PostView Post/Check IP

Fuel injection was standard on US delivery cars starting for the 1981 model year. Cars delivered to California used FI to meet the pollution demands in 1980.
The FI system is Bosch and extremely reliable having been used in MB, Ferrari, Porsche and more.
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Alan Skofic
Experienced User
Username: 120l

Post Number: 13
Registered: 11-2018
Posted on Tuesday, 08 January, 2019 - 15:37:   Edit PostDelete PostView Post/Check IP

Thanks for the information.

So, living in Australia, if I want a fuel injected three speed auto I'm looking for a 1988-1991 car?

Regsrds

Alan
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Roderick Waite
Prolific User
Username: rodwaite

Post Number: 199
Registered: 1-2012
Posted on Tuesday, 08 January, 2019 - 17:10:   Edit PostDelete PostView Post/Check IP

Hi Alan - fuel injection came into general use in late 1986, and I think 4 speed transmission came in in 1988 - so a 3 speed FI car would be 1987/8. What would you use the car for? Distances between urban centres in Australia are vast, so for inter-city runs the 4 speed FI is right ... or another car altogether! My concern would be that, although FI is reliable, it is already at least 32 years old and way out of date ... what decided me in the end - was the colour! Willow Gold has to be the most appropriate colour ever for a Spirit ...
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Alan Skofic
Experienced User
Username: 120l

Post Number: 14
Registered: 11-2018
Posted on Tuesday, 08 January, 2019 - 19:46:   Edit PostDelete PostView Post/Check IP

Roderick

Your comment on Fuel injected systems being already old is what was driving me towards carburrettored cars.

Yes I intend on doing long distance runs at speeds up to 120.

I also really want to keep the car long term, very long term.

That's why I was trying to avoid micro processors
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 2135
Registered: 6-2006
Posted on Tuesday, 08 January, 2019 - 20:06:   Edit PostDelete PostView Post/Check IP

Good call. Carbs are slightly less trouble. Completely bomb proof but not idiot proof ;)

But not much. Early injection is very simple and also bomb proof. Yes a bit more to go wrong but used parts available.

If you're mainly driving on non mountainous roads go for a later diff.
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Steve Emmott
Experienced User
Username: steve_e

Post Number: 41
Registered: 11-2018
Posted on Tuesday, 08 January, 2019 - 21:23:   Edit PostDelete PostView Post/Check IP

''I intend on doing long distance runs at speeds up to 120.''

Alan is that 120MPH or 120KPH
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Roderick Waite
Prolific User
Username: rodwaite

Post Number: 200
Registered: 1-2012
Posted on Tuesday, 08 January, 2019 - 22:53:   Edit PostDelete PostView Post/Check IP

Another thing that puzzles me rather, is the claim that FI increases the bhp by 50% - from the nominal 200 to 300 - yet uses less fuel to do so. That smacks of the black arts to me - a 25% increase is attributable to the precision of the amount of fuel being delivered at the exact time required, but 50% seems a bit much - is this a measured figure?

For 120mph, the engine would have to be doing 4000rpm (pre 1988), but I think it peaks at 3500 so couldn't do it. So kph ...
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Mark Aldridge
Grand Master
Username: mark_aldridge

Post Number: 595
Registered: 10-2008
Posted on Tuesday, 08 January, 2019 - 23:09:   Edit PostDelete PostView Post/Check IP

Paul do you know chassis no.s when diffs changed.
Mark
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Steve Emmott
Experienced User
Username: steve_e

Post Number: 42
Registered: 11-2018
Posted on Wednesday, 09 January, 2019 - 00:56:   Edit PostDelete PostView Post/Check IP

Roderick I did ask 'tongue in cheek' as I suspected Alan was quoting 120KPH converting it for the French area you are from.

I have had mine showing 3 figures on the speedo but only just to see how the car did perform at higher speed.

If I recall the top speed put out at launch on the Shadow 1 was 115MPH so your figures would appear quite correct.

Not sure if fuel injection or any later upgrades made any improvement to the top speed figures but Silver Spirit shows top speed at approx 125MPH.
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Vladimir Ivanovich Kirillov
Grand Master
Username: soviet

Post Number: 1302
Registered: 2-2013
Posted on Wednesday, 09 January, 2019 - 02:10:   Edit PostDelete PostView Post/Check IP

I have a sure fire way of calculating precisely fuel economy.

Firstly, never look at the price on the bowser. Secondly, never fail to violently depress the accelerator pedal to the floor. Thirdly, never look at posted speed limits but at the road itself.

Ever since the motor car was invented parasitic governments have sucked severely on the purse of the motorist.

When you drive a Rolls Royce (or even a Bentley) it is essential to realise you are totally beyond nonsensical contemplation of hideous notions of fuel economy or other riff raff thoughts.

This is simply because the quality of the drive is far superior than common class transport provided by oriental basket weavers.

By all means increase the power by say nitros oxide but never give a bugger about toady concepts of fuel economy because you are far beyond all that toss when you drive a Rolls Royce (or even a Bentley).
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Roderick Waite
Prolific User
Username: rodwaite

Post Number: 201
Registered: 1-2012
Posted on Wednesday, 09 January, 2019 - 19:23:   Edit PostDelete PostView Post/Check IP

Oh Vladi! You are a card ... ! I don't think I've ever filled the tank on Echo. In fact I have a feeling that French petrol pumps stop at 99.99 (a safeguard for RR owners who fall asleep while filling up).

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