Mk1 Fuel Consumption

[maneesh]

A note to all those considering buying a Mark 1 LS400 but put off by potential cost of petrol. I got 26mpg this weekend when driving at a constant 65mph on the motorway (set on cruise control). I'm pleasantly surprised! Not bad for a 12 year old car IMHO!

Incidentally, how do LS400s do on economy compared to S-classes and 7-series of a similar age? Anyone got experience of these different cars? The LS400 has got better aerodynamics than the equivalent German offerings, as far as I heard.

[btorz]

Not sure about mercs etc. but on my Mk IV (112000 miles) doing the same exercise, I get over 30 to gallon. Pretty good for a 4 litre V8.

[maneesh]

That's not good, it's brilliant!

I went and saw a Bentley 1994 model, and it was 12mpg in town, and 20mpg on a run. Strangest was a friend's Jaguar XJR who floored most of the day and the computer reported 9mpg average!

[Jason 92 Mk1 LS400]

I always get over 40MPG in my LS400 :P

(yep, it's got a LPG conversion - well worth the investment considering the number of miles I do)

On a run (motorway) 50MPG

:winky:

[2ard]

Jason,

Have you found that there is a significant drop in performance using LPG ? Does the car pull as much as before? Can you simply switch between fuel and gas, or do you get issues with it?

How much did the full install cost for your one?

@ 40MPG that's well worth thinking about !

[andyman1966]

I always get over 40MPG in my LS400 :P

(yep, it's got a LPG conversion - well worth the investment considering the number of miles I do)

On a run (motorway) 50MPG

:winky:

hi jason,i had my 93 ls converted when i 1st got it i get 15 mpg round town and 22 on a run have u had any problem with the conversion,as in back fires or bad idling

[ColinBarber]

The MPG figures are based on petrol/lpg cost differences and not the actual mpg figures.

[maneesh]

Yes, that's what I thought too. LPG doesn't give you better fuel economy over unleaded. It's just half the price of unleaded. Once they raise the tax on LPG (only a matter of time!), the difference in costs will narrow.

[ColinBarber]

LPG gives a slightly worse mpg over normal unleaded.

[Jason 92 Mk1 LS400]

To answer some of the above -

Jason,

Have you found that there is a significant drop in performance using LPG ? Does the car pull as much as before? Can you simply switch between fuel and gas, or do you get issues with it?

How much did the full install cost for your one?

@ 40MPG that's well worth thinking about !

(Sorry dont know how to do a nice box !)

Yes there is definatley a drop in performance, 0-60 times suffer, but on motorway driving you would never know - the saving outwieghs this anyway

"Normal" driving you would never know

Flick between gas/petrol with flick of switch

Never (touch wood) had any problems with the conversion (it was a proper LPGA approved one)

Installation - the car was converted when I bought it. I was looking for a LS for quite a while (looked at loads that were all dogs) - this was a "well priced" dog with fleas, but I saw the potential (and saving from LPG) - I was told the installation would have been about 2K.

I did fill the petrol tank once (£53.00) and run without LPG - what a shock that was

I am now a LPG convert - Looking for a Mk4 with or without LPG - if without I would definatly convert it.

Did sombody mention raising tax on LPG - NOOOOOOOOOOOOOOO

Oh yes, my MPG figure are not actuals (as you point out) it is based on Petrol price to LPG price ie £15.00 of LPG gets between 175 and 200 miles

Thank *** for Morrison's 29pence per litre.

cheers !

Ps - Only 1 bad point - lost my boot thanks to LPG tank (it's a big-un!)

[Steve]

interesting thread

if you switched to unleaded des the performance remain normal?