LPG vs Diesel MPG

LPG, Bio Diesel, Hydrogen, Fuel Cell Questions and Answers last answered over 2 years ago.
You may also want to visit the 80-90 Wiki(pedia) for a more structured index of T25 repair, maintenance, technical and ownership topics.

Moderators: User administrators, Moderators

User avatar
Trundler
Registered user
Posts: 171
Joined: 08 Aug 2006, 12:08
80-90 Mem No: 2998
Location: Nateby, Lancs

Post by Trundler »

WEAZLECHIN wrote: i now own a haulage business and i can say from vast experience that a non turbo driven well, will give better mpg than turbo of the same year(driven well).

Anyone who has ever taken the trouble to learn about engine tuning and efficiency knows that the big problem with ANY piston engine is getting it to consume air (putting fuel with the air is a trivial matter by comparison). High percentage cylinder filling is the holy grail of engine efficiency, whether you are doing it for power or economy.

If all other things are equal (and they rarely are - the driver's right foot being a major culprit) then a turbo is ALWAYS more efficient than a non-turbo, simply due to improved cylinder filling. That's why VWs "Umwelt" (environment) engine was a turbo-diesel, tuned for economy rather than power. Think you know better than VW?

User avatar
Trundler
Registered user
Posts: 171
Joined: 08 Aug 2006, 12:08
80-90 Mem No: 2998
Location: Nateby, Lancs

Post by Trundler »

Oh, by the way, I was involved with Stuart Bladon's record economy drives in the early nineties (including over 1000miles on a tankful in a normal road car). These were always done in turbo-diesels. The records for distance on a tankful back then were all held by the Audi 100 2.5TDI (5cyl) :wink:

User avatar
HarryMann
Admin/Mod
Posts: 9609
Joined: 30 Sep 2005, 11:40
80-90 Mem No: 379
Location: Herts, UK

Post by HarryMann »

If all other things are equal (and they rarely are - the driver's right foot being a major culprit) then a turbo is ALWAYS more efficient than a non-turbo,

True!
The inverse of BMEP is SFC (specific fuel consmption);
BMEP is obviously improved with a turbo, thus sfc goes down

Edited to make more sense :) [HM]
Last edited by HarryMann on 19 Sep 2006, 17:03, edited 2 times in total.

The 80-90 Tech Wikipedia Your 1st port of call :idea

1.9TD Syncro Doka / Syncro Kastenwagen / 16" Kombi Camper
Syncronaut No. 1

User avatar
toomanytoys
Trader
Posts: 2870
Joined: 11 Oct 2005, 18:37
80-90 Mem No: 41
Location: Boston area, South Lincolnshire

Post by toomanytoys »

Hi Dave, hope to catch up with you in the next weeks, will be in the UK...

Just as a side note to this, I have done a silly amount of KM in my syncro doka in the past 7 weeks.. like 7000+km....
Its been doing 24-26mpg.... on petrol.... sitting at about 3800rpm on the autoroutes...
Wish it was on LPG....

The velle was doing the same trips, on LPG and that thing has paid for itself in the 6 years since I converted it... ;pg used to be 17-24 on either fuel, but nor;ally about 20 -22 on LPG...

The umwelt was designed primarily as a "clean" engine, they even did a version for Switzerland that turned itself off and on at traffic lights etc, when stopped for more than 5 seconds or summat...

Simon Baxter
Trader
Posts: 3117
Joined: 08 Oct 2005, 19:36
80-90 Mem No: 1
Location: Huddersfield, WeYo.
Contact:

Post by Simon Baxter »

Golf Ecomatic, 1994 and 1995.
'86 VW T3 syncro panel
'89 VW T3 Westy Atlantic
'81 Porsche 924
SJ Baxter LTD/Brickwerks

User avatar
Ian_Fearn
Registered user
Posts: 44
Joined: 09 Aug 2006, 16:06
80-90 Mem No: 0
Location: Derbyshire

Post by Ian_Fearn »

So why is the TDi Golf more economical than the Umwelt Golf?

I had an Umwelt golf which was way slower and less economical than my mates Vento TDi that had done twice the mileage.
1985 Syncro Westfalia LPG

User avatar
HarryMann
Admin/Mod
Posts: 9609
Joined: 30 Sep 2005, 11:40
80-90 Mem No: 379
Location: Herts, UK

Post by HarryMann »

Are Tdi Golfs not turbocharged?

The 80-90 Tech Wikipedia Your 1st port of call :idea

1.9TD Syncro Doka / Syncro Kastenwagen / 16" Kombi Camper
Syncronaut No. 1

User avatar
Ian_Fearn
Registered user
Posts: 44
Joined: 09 Aug 2006, 16:06
80-90 Mem No: 0
Location: Derbyshire

Post by Ian_Fearn »

Yes, they are but they're also intercooled, the umwelt isnt.
1985 Syncro Westfalia LPG

User avatar
Trundler
Registered user
Posts: 171
Joined: 08 Aug 2006, 12:08
80-90 Mem No: 2998
Location: Nateby, Lancs

Post by Trundler »

As tmt says, the Umwelt was designed to be a clean engine but it was based on a much earlier engine than the TDI, which is a more modern direct injection design. Direct injection turbo diesels are THE most economical - witness the "3 Litre" Lupo; 1.4 litre TDI and uses under 3 litres of Diesel per 100km. :shock:

Mind you, I had an old technology Audi 80 1.6 TD (non-intercooled version) and that could be persuaded to do 65mpg on a long run without using any special economy techniques.

User avatar
monkeynut
Registered user
Posts: 105
Joined: 18 Jan 2006, 21:45
80-90 Mem No: 4715
Location: Forest of Bowland, thats oooop north
Contact:

Post by monkeynut »

HarryMann wrote:Are Tdi Golfs not turbocharged?
yup n intercooled
And its the engine im running at the moment (AHU) I cant fault it for Torque n Horses and most of all fuel
could do with fitting a water to air intercooler though
My van is rusty and smells like a chippy

User avatar
HarryMann
Admin/Mod
Posts: 9609
Joined: 30 Sep 2005, 11:40
80-90 Mem No: 379
Location: Herts, UK

Post by HarryMann »

Monkeynut, have you got a Doka or a Bus T25?

The 80-90 Tech Wikipedia Your 1st port of call :idea

1.9TD Syncro Doka / Syncro Kastenwagen / 16" Kombi Camper
Syncronaut No. 1

User avatar
Trundler
Registered user
Posts: 171
Joined: 08 Aug 2006, 12:08
80-90 Mem No: 2998
Location: Nateby, Lancs

Post by Trundler »

Just in case Monkeynut is not back for a while I'll answer for him...

It's an F-reg Transporter panel van with the TDI engine and a very stealthy camper conversion (no side windows, no pop top) :wink:

ROBS T25
Registered user
Posts: 1335
Joined: 17 Nov 2005, 20:35
80-90 Mem No: 2292
Location: NORTH WALES MEMBER 2292

Post by ROBS T25 »

cracking thread loadsa info there guys really interesting
i have a 2ltr td rover 200 (bubble shape) which i occasionally run on SVO i mix 50/50 and seems fine although does get a little noisier and mpg is worse better on diesel but cost to mpg is better so winning all round
my camper is LPG and is fantastic mpg 20-24 average i do around 130-150 mls a week short trips i dont screw it drive normal much better and if i had the choice LPG wins hands down
There are 3 kinds of people in this world.......
those who can count and those who cant!!!!!!!

philippacman
Registered user
Posts: 1149
Joined: 30 Jan 2006, 19:43
80-90 Mem No: 2371
Location: NORTH WALES,

Post by philippacman »

sorry ROB as you know i cant drive like me nan at 55mph got to get a move on matey so TDI gotta win over gass for me, each to his own though a mate 8)
if its not broke dont fix it, or i will ;-)

BE NICE LIFE IS TOO SHORT,drink more beer

ROBS T25
Registered user
Posts: 1335
Joined: 17 Nov 2005, 20:35
80-90 Mem No: 2292
Location: NORTH WALES MEMBER 2292

Post by ROBS T25 »

yeah yeah phil whats the bloody rush we get there when we get there no need to rush mate you got 3 kids in the van it omly takes 1 kn@bhead to ruin your day and life i love tootling along at 55/60mph safe economical and lou dont bend my earhole so im happy at that
There are 3 kinds of people in this world.......
those who can count and those who cant!!!!!!!

Locked