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Diesel or TurboDiesel ?



 
 
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  #1 (permalink)  
Old January 11th 04, 07:32 PM posted to uk.rec.motorcaravans
SandS
external usenet poster
 
Posts: 97
Default Diesel or TurboDiesel ?

I'm looking for my first Diesel Van having used trusty Bedford
1.8 and 2.3 Petrol units in the past. My only experience of a
Diesel has been a 1.8TD Mondeo which (performance-wise) was very
disappointing.

1) I've read some recent posters praising the advantages of the
TD over the normally aspirated Diesel but can anyone provide some
genuine output/performance stats (particularly on the 2.5
Peugeot) to demonstrate this. Whilst the Turbo will undoubtedly
give more power through "packing" the chamber is it really
significant considering the engine must run a lower compression
ratio to compensate for the boost pressure?

2) The turbo lag on the 1995 Ford 1.8TD was terrible with the
turbo not coming in until 2200-2500RPM. As most of my driving is
in towns / country roads this was a major problem, particularly
at the numerous busy Roundabouts I have to traverse each day.

3) The likelihood of Turbo failure is worth considering on the
older motors I'll be looking at and the comparative simplicity of
the non-turbo version. I know turbos are expensive and
disintegration of the compressor turbine will probably destroy
the engine but in reality how long could one sensibly expect a
Turbo to last before replacement is advised (assuming correct
servicing and good oil).

I'm undecided but on balance (as costs are tight and I need to do
all my own maintenance) I'm leaning towards a non-Turbo Diesel
(or a petrol of course, but I've no idea of how less frugal this
would be in a medium sized coachbuilt).
Constructive comments most welcome.
Thank you,
Sandy


Ads
  #2 (permalink)  
Old January 11th 04, 09:33 PM posted to uk.rec.motorcaravans
QrizB
external usenet poster
 
Posts: 95
Default Diesel or TurboDiesel ?

On Sun, 11 Jan 2004 20:32:13 -0000, "SandS"
wrote:

I'm looking for my first Diesel Van having used trusty Bedford
1.8 and 2.3 Petrol units in the past. My only experience of a
Diesel has been a 1.8TD Mondeo which (performance-wise) was very
disappointing.


The (old) Ford 1.8TD was a bit of a dog, all things considered. The
current one is considerably better.

1) I've read some recent posters praising the advantages of the
TD over the normally aspirated Diesel but can anyone provide some
genuine output/performance stats (particularly on the 2.5
Peugeot) to demonstrate this. Whilst the Turbo will undoubtedly
give more power through "packing" the chamber is it really
significant considering the engine must run a lower compression
ratio to compensate for the boost pressure?


I'm amazed you're asking this question. Unfortunately I' don't have
any specific figures for you, but IME a 2.5 n/a diesel will come in at
80 hp or so, and a turbo at 100 to 130 hp.

3) The likelihood of Turbo failure is worth considering on the
older motors I'll be looking at and the comparative simplicity of
the non-turbo version. I know turbos are expensive and
disintegration of the compressor turbine will probably destroy
the engine but in reality how long could one sensibly expect a
Turbo to last before replacement is advised (assuming correct
servicing and good oil).


I'd expect it to last for a quarter of a million miles at least.

I'm undecided but on balance (as costs are tight and I need to do
all my own maintenance) I'm leaning towards a non-Turbo Diesel
(or a petrol of course, but I've no idea of how less frugal this
would be in a medium sized coachbuilt).


Gazz has a table of fuel consumption data:
http://www.kampenwagen.co.uk/fuel%20...on%20table.htm

TDs appear to get better fuel copnsumption that n/a diesels. The
petrol engines listed generally manage 20 mpg or less in a full-sized
'van.


--
QrizB

I sound like I know what I'm talking about, but don't
be fooled.
  #3 (permalink)  
Old January 12th 04, 01:12 AM posted to uk.rec.motorcaravans
CampinGazz
external usenet poster
 
Posts: 339
Default Diesel or TurboDiesel ?


"SandS" wrote in message
...
I'm looking for my first Diesel Van having used trusty Bedford
1.8 and 2.3 Petrol units in the past. My only experience of a
Diesel has been a 1.8TD Mondeo which (performance-wise) was very
disappointing.

snipped all the good stuff

think the best thing to do is go and test drive a van with a N/A diesel
engine, and hten one with a TD engine,

i ues to have a VW LT 35, with the 2.4 litre non turbo, diesel engine, i
converted it into a camper van, and it weighed just under 3 tons (2.9 tons
exactly when i last weighed her before i took her appart)
with the normaly aspirated engine, she was dead, 70 mph was reachable.. but
only after a long wind up, around town she was ok, but then a push bike is
ok around town,
the common thing that would anny me was i'd be doing 45 to 50 in top gear,
changing down made the engine scream like hell, and pushing the pedal to the
metal in top at 50 mph.. and 2 minutes later i'm doing 51 mph.. if the wind
was behind me,

after a year of that, i sourced a second hand turbo diesel engine for my
van, got it re-conditioned, fitted it, and it transformed the van, she'd do
90 mph with ease, (the weight was still the same, just under 3 tons) around
town she was much quicker, on the open road, doing 50mph in top, push the
pedal to the metal, and 20 seconds later you were pusing 80 mph,

and the best bit.. with the N/A diesel engine.. i got around 18 to 21 mpg,
prolly because you have to drive everywhere with the pedal to the metal,
with the turbo diesel, (exact same engine size and configuration as the N/A
diesel, jsut a turbo bolted on the side, and a set of oil spray jets under
the pistons to stop them burning through when running high boost for a long
time.. compression ratio was the same between the engines) i'd get from 22
to 25 mpg,

i towed a car on an A-frame for 4 years, something i would never have
considered without the turbo diesel engine in the van, the car weighed 680
kilos, and i never knew it was on tow unless i looked in the mirrors,

the high and low compression engines.. not sure that's still applicable
nowadays, i've always had the genuine workshop manuals for all the van's
i've owned, got an iveco turbo daily now.. have the manual for it, and the
turbo diesel and non turbo diesel engines run the same compression ratios,

Where compression ratios are different are between indirect injection
engines, and direct injection engines, indirect injection engines run a
lower compression ratio,
(indirect injection engines have the injectors squirt the diesel into a
pre-combustion chamber in the head, which is ignited and expands through the
hole in the head to push the piston down, they also almost always have glow
plugs , a direct injection engine squirts the diesel directly into the
compression chamber.. which is a well in the piston, and direct injection
engines dont usually have glow plugs.. no where to put em, (they do have a
glow plug light on the dash, but that's for a thermostarter, a devise that
heats diesel up and injects it into the inlet manifold a bit like a 5th
injector on a petrol engine.. just with the added heat, direct injection
engines dont have a glow plug in each cylinder like indirect injectione
engines have)

expensive turbos to go wrong... i suppose if you get a new turbo from
the factory then yes,, but last time i had a turbo re-conditioned it cost me
250,
the compressor wheel is not something that has a habit of breaking up,
unless something hits the spinning wheel, i.e a bolt left in the air filter
pipes.. but it would have gone into the engine if there was no turbo there
anyway,
the only time the compressor wheel breaks up is if it's over revved, they
run at about 100,000 RPM anyway, so are easily rated to handle more than
that safely, and it's very hard to get a situation where the turbo would
over rev with out you knowing about it, that's what the waste gate is for in
the turbine housing, and why you usually have a light on the dash to warn if
it's stuck.. moden diesel engines shut the fueling down if the waste gate
ever sticks open.

Turbo lag.. that's a hard one, i have it on my iveco, but i'm running her
empty at the moment, (not started the conversion into a motorhome yet) but i
only get turbo lag when first pulling off, once the revs hit 1900 rpm, she
takes off like a rocket, and as you change up at about 3200 rpm, the next
gear drops your engines revs down to about 2400 rpm, so the turbo is back on
full boost in a few milliseconds,
changing up too soon will drop the rpm's out of the turbo boost range, then
you'll have a bit of lag, but you soon learn to drive in the boost ranges of
the engine..especialy when you've got a heavy motorhome and a big engine.

remember that a coachbuilt motorhome will most likely be very near the max
weight of the vehicle, so you want all the power you can get,
and i've always found that turbo lag diminishes the heavier the van weighes,
the engines working harder so your on boost a lot more.

9 out of 10 drivers get better fuel economy with a turbo diesel compared to
the equivelent N/A diesel engined van, of course that depends on how you
drive it, drive at 90mph everywhere, and you will use more fuel, but do 70,
and you'll usually be on half throttle on motorways, and thus saving fuel,
with a N/A engine you'll be struggeling to do 70 most likely, and have your
foot on the floor, so use more fuel.. to go slower

i'll never ever buy a van or car without a turbo diesel engine ever again,
sure there's a couple more parts that could go wrong, but that's true of any
modern engine,

You could buy a N/A engine just to make sure the turbo never needs
re-building, and the day after you buy it something could give way inside
the injection pump (most people will tell you they cost ove a grand to
replace, you can get them repaired, i had the throttle assembly totaly
replaced on my vans pump, and all seals and any worn components replaced,
with a full re-calibration done, cost me 150)
or you could own the van with a non turbo engine a year, then the cam belt
snaps, sure it could happen to a turbo engine too, but it just shows there's
a lot more to worry about than a bolt on item like the turbo.


  #4 (permalink)  
Old January 12th 04, 07:16 PM posted to uk.rec.motorcaravans
SH[_2_]
external usenet poster
 
Posts: 25
Default Diesel or TurboDiesel ?

Ignorance is bliss.

"Tone" wrote in message
s.com...
On Sun, 11 Jan 2004 20:32:13 -0000, "SandS"
wrote:

I'm looking for my first Diesel Van having used trusty Bedford
1.8 and 2.3 Petrol units in the past. My only experience of a
Diesel has been a 1.8TD Mondeo which (performance-wise) was very
disappointing.


My reason for buying an NonTD of a TD was that the less things and
engine has on it the less chance there is of things going wrong.

I have NEVR experienced a problem with a bog standard Diesel engine
other than probably a leaking Injector pump.

One is constantly hearing and reading of problems with waste gates etc
on TD's.

I just dont see the need for a Turbo on a motorcaravan..
Sports car yes, Motorcaravan no.




  #5 (permalink)  
Old January 12th 04, 08:31 PM posted to uk.rec.motorcaravans
CampinGazz
external usenet poster
 
Posts: 339
Default Diesel or TurboDiesel ?


"Tone" wrote in message
s.com...
On Sun, 11 Jan 2004 20:32:13 -0000, "SandS"
wrote:

I'm looking for my first Diesel Van having used trusty Bedford
1.8 and 2.3 Petrol units in the past. My only experience of a
Diesel has been a 1.8TD Mondeo which (performance-wise) was very
disappointing.


My reason for buying an NonTD of a TD was that the less things and
engine has on it the less chance there is of things going wrong.

I have NEVR experienced a problem with a bog standard Diesel engine
other than probably a leaking Injector pump.

One is constantly hearing and reading of problems with waste gates etc
on TD's.

I just dont see the need for a Turbo on a motorcaravan..
Sports car yes, Motorcaravan no.


OK lets put it antoehr way.. you have a van, it weighs 3.5 tons, (if its a
coachbuilt, then yes, it most likely does weigh close to it's maxumin
authorised weight) you have a N/A engine in it, to get going anywhere you
have to have th throttle on the floor all the time, to keep up with traffic,
throttle on the floor, to get up hills, throttle on the floor and drop down
2 or 3 gears and so on.

Same motorhome, same weight, TD engine this time,
to get going, you use 1/2 to 3/4 throttle, to keep up in traffic you use 1/4
to 1/2 throttle, to climb a hill you use 3/4 to full throttel depending on
the severity of the hill, maybe dropping down one gear if it's a steep hill
like that one on the M62.

Which engine is going to last longer, and which one will return better fuel
mileage, and which one will generaly be less stressfull to drive all day
long.

Yes certian old models of vans had problems with sticking wastegates, namely
the predicessors to the pug boxers, this was caused by lack of use, and the
fix was simple and cheap.. you make a tool up out of a coathanger, and hook
it over the waste gate lever and pull it back manualy a few times, this
free's it off, and your set for antoehr year or 2 of letting the van sit on
your driveway.. or you could just use the van properly.. get away at
weekends, go for a little run on an evening and so on and you'll be
excersicing all the mechanical parts and keeping them working.

But even those vans that were notoriouse for having a sticky wastegate when
left unused for too long had a warning light on the dash, if it ever
illuminates you back off the throttle, and nothing bad will happen,
even better, fit a turbo boost guage, that can be one of the most handy
gauges you can fit appart from an EGT gauge, then you'll see instaintly if
the boost goes higher than it should, it'll even tell you when your lugging
the engine, and you'll very soon see why you have no go when you have the
revs too low.. as there's no boost being produced before a certian rev
setting.

I HAVE suffered a serious problem with a N/A diesel engine, a con rod cap
let go after driving for 2 hours with the foot on the floor.. the only way
to get the truck to get anywhere (was an old dodge 50, with i think an old
perkins engine in her)

Also had a catastophic faliur in the turbo diesel engine in my iveco i have
now... number 4 exhaust valve snapped in half at 70 mph, totaly wrecked the
head, piston, liner, took out the turbo but only as a result of the debris
from the valve going the only logical way out of the engine it could take,
the exhaust manifold.. and hence through the turbine wheel,
but if that had happened on a non turbo engine, the only difference in the
final bill for the repair work would have been minus 140 for the
re-building of the turbo,

Dad's mondeo..1.8 TD, had it's cam belt replaced by ford at 60k miles, had
the tensioner replaced at the same time, 4 months later the cam belt
snapped, cause the plastic tensioner wheel breaking up, ford had replaced
the metal wheels and not the plastic ones,
but again, a wrecked engine, and absolutely nothing to do with the turbo in
any way.

i really don't understand why people are so frightened of turbo's, they are
damn simple things.. you have the bearing housing with a couple of bearings
and a few millings for the oil feed and return, the spindle, a compressor
wheel, a turbine wheel, compressor housing and turbine housing, and a
wastegate and it's actuator,

2 moving parts, (the turbine and compressor wheels on the spindle is the 1
rotating item when it's assembled)
as you accelerate you burn the fuel, producing exhaust gasses, they are
passed over the turbine wheel, which causes the wheel to spin, the
compressor wheel on the other end of the spindle rotates with the turbine
wheel, and so produces a boost to the air level entering the engine,
as more air enters the engine, more fuel is injected, causing more exhaust
gasses, which drives the turbine wheel faster, producing more boost and so
on,

When the compressor side of the turbo creates a set pressure.. usually about
1 bar, that pressure operates an actuator which pushes or pulls the waste
gate open.. this is just a valve in the turbine housing that when opened
lets the exhaust gasses bypass the turbine wheel, thus preventing it from
spinning any faster, it opens the valve enough to controll the speed of the
turbo this way.

On most TD engines you'll have a second safety valve.. called a dump valvem
this is in the inlet manifold and is set to a slightly higher pressure than
the wastegate's fully open stroke, (it's a simple spring loaded plunger, a
certian air pressure overcomes the spring pressure keeping it shut) it's
there so that in the event of the wastegate sticking closed, the dump valve
opens up and lets the compressed air exit the inlet manifold (and on most
cars it's sends it to the air filter pipework.. it's the boy racers that fit
atmospheric dump valves to give them the Pssshhhhttt sound when they shut
the throttle.. which a diesel cant do as it dosent have a throttle like a
petrol engine does, diesels regulate the amount of fuel going into the
engine controll it's speed) anyway, when the dump valve opens, the
compressed air dosent get into the engine, so you loose power, thus spooling
the turbo down that way.

On the older TD engines you'll ahve a pressure sensor in the inlet manifold,
this will bring on a warning light if it ever detects a pressure over that
which the waste gate should have opened at, this light comes on before the
dump valve opens, so you effectivly have 3 methods of stopping the engine
from being dammaged.. which to do so you'd have to keep the pedal to the
metal while the wastegate failed to open, and have a very light load on the
engine.

More modern TD engines have the engine managment systems shut off the diesel
supply if it ever detects an over boost situation, and the engine dosent
have to be a common rail diesel either, you can still ahve mechanical
injection and have parts of the pump controlled electronicaly, at the very
least the shut off solenoid.

But at the end of the day, the best thing to do is drive a motorhome with a
N/A diesel engine, then drive the same type of van with the TD engine, and
then make up your mind to whether a turbo is for you or not,
if your worried about mechanical faliure, then believe me, cam belt faliure
out numbers turbo faliure by about 1000 to 1,
so i'd be more interested in buying a van with an engine that has a chain
driven cam shaft rather than an elastic band if the remote possibility of
catastrophic engine faliure was one of the deciding factors in buying the
van.

One little tip to any TD engined van drivers out there tho.. the worst thing
you can do to your engine is pull off of a motorway or any road where you've
been driving fast, and shut the engine off the second the van comes to a
stop,
the turbo will still be spinning (takes a while to spool down from around
80,000 rpm which is common at 70 mph), and all of a sudden you remove the
oil supply to the turbo's bearings when you stop the engine (oil pump stops
with the engine)

The turbo's shaft floats on a film of oil, so when the oil supply is
removed, the shaft drops onto the bearings.. it's only a fraction of a mm,
but its enough to cause a slight flat spot over time,
but more of a problem is heat soak, a turbo runs very hot.. it's designed to
so don't worry (a diesels exhaust at the manifold (turbo or not) runs at
around 6 to 700 degrees C, a petrol engines exhaust in the exact same
space.. again turbo or not runs at around 1000 degrees)
and when you shut an engine off, the heat will build up as the cooling
system is shut down, air flow over the parts stops, and in the turbo, the
exhaust gasses traveling down the pipe were taking heat away,

if you dont let the turbo cool down a little bit (just leave the engine
ideling for a few seconds before shutting it off after a fast run, that's
all you need to do) the oil in the bearings of the turbo can get so hot it
turns to carbon.

That's one thing that can land you with a 250 repair bill at a later stage
in the engines life, and it takes a few seconds to prevent,
but in all reality you should let any engine idle for a few seconds after
it's been running fast,
you as a human wouldnet like it much if you ran 20 miles at 15 miles per
hour, then at the end of the 20 miles just stoped dead, didnt drink
anything, didnt cool down or owt,
why treat your engine differently


  #6 (permalink)  
Old January 13th 04, 08:01 AM posted to uk.rec.motorcaravans
Andy R
external usenet poster
 
Posts: 821
Default Diesel or TurboDiesel ?


"SH" wrote in message
...
Ignorance is bliss.

"Tone" wrote in message
s.com...
On Sun, 11 Jan 2004 20:32:13 -0000, "SandS"
wrote:

I'm looking for my first Diesel Van having used trusty Bedford
1.8 and 2.3 Petrol units in the past. My only experience of a
Diesel has been a 1.8TD Mondeo which (performance-wise) was very
disappointing.


My reason for buying an NonTD of a TD was that the less things and
engine has on it the less chance there is of things going wrong.

I have NEVR experienced a problem with a bog standard Diesel engine
other than probably a leaking Injector pump.

One is constantly hearing and reading of problems with waste gates etc
on TD's.

I just dont see the need for a Turbo on a motorcaravan..
Sports car yes, Motorcaravan no.


A motorcaravan needs sufficient power to perform adequately. Whether that's
achieved by a big, naturally aspirated diesel, a smaller turbo diesel, a
petrol, steam or gas turbine engine is largely irrelevent provided it does
what the driver wants.

A naturally aspirated diesel has a lousy power to weight ratio, if you put a
turbo on it it gets near to what you get from a naturally aspirated petrol
engine. The increased power to weight ratio is the main reason turbos are
used extensively on trucks.

Finally, because of their characteristics, you don't get a lot of diesel
engined sports cars.

Rgds

Andy R


  #7 (permalink)  
Old January 13th 04, 05:57 PM posted to uk.rec.motorcaravans
SandS
external usenet poster
 
Posts: 97
Default Diesel or TurboDiesel ?


"CampinGazz" wrote in message
...

"SandS" wrote in message
...
I'm looking for my first Diesel Van having used trusty

Bedford
1.8 and 2.3 Petrol units in the past. My only experience of a
Diesel has been a 1.8TD Mondeo which (performance-wise) was

very
disappointing.

snipped all the good stuff

think the best thing to do is go and test drive a van with a

N/A diesel
engine, and hten one with a TD engine,

i ues to have a VW LT 35, with the 2.4 litre non turbo, diesel

engine, i
converted it into a camper van, and it weighed just under 3

tons (2.9 tons
exactly when i last weighed her before i took her appart)
with the normaly aspirated engine, she was dead, 70 mph was

reachable.. but
only after a long wind up, around town she was ok, but then a

push bike is
ok around town,
the common thing that would anny me was i'd be doing 45 to 50

in top gear,
changing down made the engine scream like hell, and pushing the

pedal to the
metal in top at 50 mph.. and 2 minutes later i'm doing 51 mph..

if the wind
was behind me,

after a year of that, i sourced a second hand turbo diesel

engine for my
van, got it re-conditioned, fitted it, and it transformed the

van, she'd do
90 mph with ease, (the weight was still the same, just under 3

tons) around
town she was much quicker, on the open road, doing 50mph in

top, push the
pedal to the metal, and 20 seconds later you were pusing 80

mph,

and the best bit.. with the N/A diesel engine.. i got around 18

to 21 mpg,
prolly because you have to drive everywhere with the pedal to

the metal,
with the turbo diesel, (exact same engine size and

configuration as the N/A
diesel, jsut a turbo bolted on the side, and a set of oil spray

jets under
the pistons to stop them burning through when running high

boost for a long
time.. compression ratio was the same between the engines) i'd

get from 22
to 25 mpg,

i towed a car on an A-frame for 4 years, something i would

never have
considered without the turbo diesel engine in the van, the car

weighed 680
kilos, and i never knew it was on tow unless i looked in the

mirrors,

the high and low compression engines.. not sure that's

still applicable
nowadays, i've always had the genuine workshop manuals for all

the van's
i've owned, got an iveco turbo daily now.. have the manual for

it, and the
turbo diesel and non turbo diesel engines run the same

compression ratios,

Where compression ratios are different are between indirect

injection
engines, and direct injection engines, indirect injection

engines run a
lower compression ratio,
(indirect injection engines have the injectors squirt the

diesel into a
pre-combustion chamber in the head, which is ignited and

expands through the
hole in the head to push the piston down, they also almost

always have glow
plugs , a direct injection engine squirts the diesel directly

into the
compression chamber.. which is a well in the piston, and direct

injection
engines dont usually have glow plugs.. no where to put em,

(they do have a
glow plug light on the dash, but that's for a thermostarter, a

devise that
heats diesel up and injects it into the inlet manifold a bit

like a 5th
injector on a petrol engine.. just with the added heat, direct

injection
engines dont have a glow plug in each cylinder like indirect

injectione
engines have)

expensive turbos to go wrong... i suppose if you get a new

turbo from
the factory then yes,, but last time i had a turbo

re-conditioned it cost me
250,
the compressor wheel is not something that has a habit of

breaking up,
unless something hits the spinning wheel, i.e a bolt left in

the air filter
pipes.. but it would have gone into the engine if there was no

turbo there
anyway,
the only time the compressor wheel breaks up is if it's over

revved, they
run at about 100,000 RPM anyway, so are easily rated to handle

more than
that safely, and it's very hard to get a situation where the

turbo would
over rev with out you knowing about it, that's what the waste

gate is for in
the turbine housing, and why you usually have a light on the

dash to warn if
it's stuck.. moden diesel engines shut the fueling down if the

waste gate
ever sticks open.

Turbo lag.. that's a hard one, i have it on my iveco, but i'm

running her
empty at the moment, (not started the conversion into a

motorhome yet) but i
only get turbo lag when first pulling off, once the revs hit

1900 rpm, she
takes off like a rocket, and as you change up at about 3200

rpm, the next
gear drops your engines revs down to about 2400 rpm, so the

turbo is back on
full boost in a few milliseconds,
changing up too soon will drop the rpm's out of the turbo boost

range, then
you'll have a bit of lag, but you soon learn to drive in the

boost ranges of
the engine..especialy when you've got a heavy motorhome and a

big engine.

remember that a coachbuilt motorhome will most likely be very

near the max
weight of the vehicle, so you want all the power you can get,
and i've always found that turbo lag diminishes the heavier the

van weighes,
the engines working harder so your on boost a lot more.

9 out of 10 drivers get better fuel economy with a turbo diesel

compared to
the equivelent N/A diesel engined van, of course that depends

on how you
drive it, drive at 90mph everywhere, and you will use more

fuel, but do 70,
and you'll usually be on half throttle on motorways, and thus

saving fuel,
with a N/A engine you'll be struggeling to do 70 most likely,

and have your
foot on the floor, so use more fuel.. to go slower

i'll never ever buy a van or car without a turbo diesel engine

ever again,
sure there's a couple more parts that could go wrong, but

that's true of any
modern engine,

You could buy a N/A engine just to make sure the turbo never

needs
re-building, and the day after you buy it something could give

way inside
the injection pump (most people will tell you they cost ove a

grand to
replace, you can get them repaired, i had the throttle assembly

totaly
replaced on my vans pump, and all seals and any worn components

replaced,
with a full re-calibration done, cost me 150)
or you could own the van with a non turbo engine a year, then

the cam belt
snaps, sure it could happen to a turbo engine too, but it just

shows there's
a lot more to worry about than a bolt on item like the turbo.


Thank you for this very thorough and informative reply. Thank you
also to ALL the others who have posted constructive
comments/views on this issue. I'm sure there isn't a "Right"
choice as such but its given me a lot to consider and I will
probably rethink my priorities as a result.

I'm was surprised the TD compression ratio is the same but
looking at it now I was thinking of a petrol engine where the
fuel/air mixture would prematurely detonate where as the Diesel
can get away with it due to different fuelling characteristics
(i.e. almost simultaneous injection and ignition?).

I'm still not sure about the longevity of Turbos. I was looking
for a Volvo 850 T5 recently and there were a lot at the 100k-120k
mark with "recent turbo replacement". The comment regarding
impeller disintegration was related to an article I read
somewhere that when the central bearings wear on a turbo it
allows the turbines to move closer to the casing and eventually
strike it. Given the staggering speed of the turbines this would
be serious. Addressing these 2 points perhaps a Diesel Turbo is
likely to be less stressed than the T5, and that one gets some
audible warning of impending bearing failure.

Thank you again for the helpful comments.
Best wishes,
Sandy


  #8 (permalink)  
Old January 14th 04, 10:02 AM posted to uk.rec.motorcaravans
Les Rose
external usenet poster
 
Posts: 45
Default Diesel or TurboDiesel ?


"Tone" wrote in message
...
On Tue, 13 Jan 2004 09:01:02 -0000, "Andy R"
wrote:

snip

And a tiny T4 VW needs a 2.5litre TD ??? Rubbish. I can cruise
happily and with reasonable economy at 70MPH in my normally aspirated
2.4 Diesel T4


A naturally aspirated diesel has a lousy power to weight ratio, if you

put a
turbo on it it gets near to what you get from a naturally aspirated

petrol
engine. The increased power to weight ratio is the main reason turbos

are
used extensively on trucks.

Finally, because of their characteristics, you don't get a lot of diesel
engined sports cars.


I know
I build them


Though Renault have built a Diesel sports car that takes the arse off
a lot of sportscars

This thread has gone on for quite long enough. For goodness sake go and
drive a few and see what you think. I did, and all the non-turbos were
absolutely dire. Yes, you can get away with a big non-turbo in a small
motorhome but I'm talking about 5-berth. The reliability issue was nailed
years ago. Turbochargers are not new - first used in the 1920s IIRC. I have
been running a Citroen ZX TD for 10 years. It's an absolute stormer and has
thus been hammered all its life - on 140k now, and no engine problems
whatever. OK you need 2000 rpm for fireworks but once there the throttle
response is excellent. Does 53 mpg at 80 mph. The main economy advantage of
a diesel is at part 'throttle', because compression pressure is always the
same whatever the power setting, and high compression pressure gives good
efficiency. If you have to drive flat out all the time you lose the
advantage. IMHO there is no contest. If there were reliability problems HGVs
would not use them, with the mileages they do.


  #9 (permalink)  
Old January 14th 04, 03:33 PM posted to uk.rec.motorcaravans
Les Rose
external usenet poster
 
Posts: 45
Default Diesel or TurboDiesel ?


"Tone" wrote in message
s.com...
On Wed, 14 Jan 2004 11:02:42 -0000, "Les Rose"
wrote:

snip
Apart from which I might agree with you if Motorhomes were driven at
respectable speeds but not most of the muppets who drive TD's
Most of them sit on 30 MPH in 70 areas.
I suppose its a leftover from their caravanning days.


I give up. I am not into flame wars or controlling this NG for that matter.
Once people start to get abusive it stops being fun. Anybody is quite at
liberty to post whatever drivel they like but I am not going to exchange
insults.


  #10 (permalink)  
Old January 14th 04, 09:44 PM posted to uk.rec.motorcaravans
SH[_2_]
external usenet poster
 
Posts: 25
Default Diesel or TurboDiesel ?

Tone
You seem to have very solid opinions based upon little or no fact /
experience. Maybe you should become a politician at least you won't be alone
there..

"Tone" wrote in message
s.com...
On Wed, 14 Jan 2004 16:33:30 -0000, "Les Rose"
wrote:


"Tone" wrote in message
ws.com...
On Wed, 14 Jan 2004 11:02:42 -0000, "Les Rose"
wrote:

snip
Apart from which I might agree with you if Motorhomes were driven at
respectable speeds but not most of the muppets who drive TD's
Most of them sit on 30 MPH in 70 areas.
I suppose its a leftover from their caravanning days.


I give up. I am not into flame wars or controlling this NG for that

matter.
Once people start to get abusive it stops being fun. Anybody is quite at
liberty to post whatever drivel they like but I am not going to exchange
insults.



Then refrain from posting pompous stuffy drivel like this

"This thread has gone on for quite long enough."

What bloody arrogance !




 



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