Renault truck diesel engines amazing why poor car diesels?
Discussion
So Renault make truely amazing truck engines their eurotrotter 16ltr is a work of art and at the racing trucks they are very good too.
So why when it comes to cars do they offer only a 2ltr diesel with run of the mill spec and performance?? Surely they have truck working knowledge to use on cara
So why when it comes to cars do they offer only a 2ltr diesel with run of the mill spec and performance?? Surely they have truck working knowledge to use on cara
Their 1.5 dci is one of the most economical engines on sale. It's also one of the lowest co2 output without a dpf.
The 2.0 dci is available with 180 bhp. About as powerful as a single turbo diesel is at tho moment I thought?
Diesels aren't my cup of tea but it seems Renault are definately up there at the top and matching BMW and Audi.
The 2.0 dci is available with 180 bhp. About as powerful as a single turbo diesel is at tho moment I thought?
Diesels aren't my cup of tea but it seems Renault are definately up there at the top and matching BMW and Audi.
tvradict said:
Probably has something to do with the renault truck engines being rebadged Volvo truck engines for the last ~5 years.
The 16ltr engine you talk about is the Volvo D16, and is probably the best engine Volvo have ever made.
Well that explains it fully. The 16ltr engine you talk about is the Volvo D16, and is probably the best engine Volvo have ever made.
Are truck engines now downsizing or going for sequential turbos with the objective of same power and torque as existing or higher porkies with higher MPG?
I believe a truck pulling a fully laiden wagon does 5mpg - if they could increase those trucks economy every person in the country could benefit from cheaper goods.
Welshbeef said:
Well that explains it fully.
Are truck engines now downsizing or going for sequential turbos with the objective of same power and torque as existing or higher porkies with higher MPG?
I believe a truck pulling a fully laiden wagon does 5mpg - if they could increase those trucks economy every person in the country could benefit from cheaper goods.
Sorry, I've had a few sherberts this evening and forgot to add a vital part. Renault (the car maker) wont be able to use technology from Renault Trucks, because Volvo Group bought renault trucks a few years ago, which is one reason why the truck engines are so good.Are truck engines now downsizing or going for sequential turbos with the objective of same power and torque as existing or higher porkies with higher MPG?
I believe a truck pulling a fully laiden wagon does 5mpg - if they could increase those trucks economy every person in the country could benefit from cheaper goods.
I havent noticed any downsizing, the big push for the last few years has seen an increase in engine size, Volvo took the D10 engine and bored it out first to 12 litres for Euro 3, and now to 13liters and added EGR technology to meet Euro 5 regs. Every major truck manufacturer seems to have a large engine pushing out ~700hp/3000lb,ft, and they are uing Auto boxes to try and get the MPG up.
10mpg seems to be about average for trucks on long runs AFAIK, reduce that to 7-8mpg for local work.
Welshbeef said:
So Renault make truely amazing truck engines their eurotrotter 16ltr is a work of art and at the racing trucks they are very good too.
So why when it comes to cars do they offer only a 2ltr diesel with run of the mill spec and performance?? Surely they have truck working knowledge to use on cara
Wrong, have you driven the DCi 175 RSport Megane? It's one of the torquiest and smoothest Diesel engines you can buy and thanks to balancer shafts it's extremely free-revving right to the 5200rpm redline.So why when it comes to cars do they offer only a 2ltr diesel with run of the mill spec and performance?? Surely they have truck working knowledge to use on cara
It's No more laggy than the Petrol Rsport Megane too.
I guess to say that is missing the point of it 
Pentoman said:
"Paging OP..."
I've heard the 1.5 is good. Wonder what those 2.0 megane renaultsports are like? Obviously the petrol has a good record. Wonder if the diesel is a down step too far.
The 175 is a lovely engine. Obviously it sounds like a diesel, but the chassis works well with the torquey diesel. Iyt hammers nicely around the twisty stuff.I've heard the 1.5 is good. Wonder what those 2.0 megane renaultsports are like? Obviously the petrol has a good record. Wonder if the diesel is a down step too far.
Pentoman said:
"Paging OP..."
I've heard the 1.5 is good. Wonder what those 2.0 megane renaultsports are like? Obviously the petrol has a good record. Wonder if the diesel is a down step too far.
The 175 is a lovely engine. Obviously it sounds like a diesel, but the chassis works well with the torquey diesel. Iyt hammers nicely around the twisty stuff.I've heard the 1.5 is good. Wonder what those 2.0 megane renaultsports are like? Obviously the petrol has a good record. Wonder if the diesel is a down step too far.
Welshbeef said:
Are truck engines now downsizing or going for sequential turbos with the objective of same power and torque as existing or higher porkies with higher MPG?
I believe a truck pulling a fully laiden wagon does 5mpg - if they could increase those trucks economy every person in the country could benefit from cheaper goods.
Taking a fag packet average family car as weighing 1.5 tonnes, that 44 tonne truck at 5mpg is, in equivalent terms, 145 plus mpg. I believe a truck pulling a fully laiden wagon does 5mpg - if they could increase those trucks economy every person in the country could benefit from cheaper goods.
In terms of weight pulled per unit of fuel used, you might find it's the cars that are rubbish on fuel compared to the trucks.
Although I must say that it is just my 'off the top of my head' maths, which may be way off.
Super Slo Mo said:
Taking a fag packet average family car as weighing 1.5 tonnes, that 44 tonne truck at 5mpg is, in equivalent terms, 145 plus mpg.
In terms of weight pulled per unit of fuel used, you might find it's the cars that are rubbish on fuel compared to the trucks.
Although I must say that it is just my 'off the top of my head' maths, which may be way off.
I see your point. In terms of weight pulled per unit of fuel used, you might find it's the cars that are rubbish on fuel compared to the trucks.
Although I must say that it is just my 'off the top of my head' maths, which may be way off.
So in which case turning that on it's head why are diesel cars are relatively poor.
Renault get a fair bit of undeserved stick - especially when it comes to their diesel engines. Yes, they made a monumental cock up with the 2.2dci - it was a horrid engine which would randomly consume itself. It was bad from the beginning and was bad till the end. The other dci engines are great however! The very earliest dci engines (pre-2004) suffered with premature turbo failure due to a s
t turbo and oil feeds and excessive service periods. Once this was sorted all was well!
The 1.5, 1.9, 2.0 and 3.0 dci engines are fantastic and pull extremely well and smoothly (much smoother than the 'jag' unit in the X-type which delivers its power using and on/off switch).
Three rules though (common to ALL diesels!):
1 - Change the oil regularly (every 12k, preferably less) and use fully synthetic oil. Oil is your engines blood. It not only lubricates but it cools too - especially important with the turbocharger! If the oil is allowed to become lumpy it can clog causing oil starvation to the turbo (and other parts) meaning it will self-destruct. A self destructing turbo can be ingested by the engine, destroying it, or it can allow engine oil into the intake system meaning the engine will rev up until it blows, or will drink itself dry of oil and seize permanently.
2 - Take it easy until the car warms up! Without the oil being up to temperature and pressure it cannot do its job preperly so the turbo will suffer premature wear. Also, let the engine run for a few seconds before turning off. This allows the oil to cool the turbocharger and ensures that the turbo blades are not still spinning when the oil pressure drops due to the engine being turned off.
3 - Don't drive too gently once warmed up! Clogged EGR valves and injectors due to soot build up are costly to fix and in some cases can lead to turbo failure if the EGR valve sticks.
I've got the 120bhp 1.9dci in my Scenic and after 1 year of owenership am very happy! Although the electric window regulator brackets are st!!! But that's another matter!
t turbo and oil feeds and excessive service periods. Once this was sorted all was well!The 1.5, 1.9, 2.0 and 3.0 dci engines are fantastic and pull extremely well and smoothly (much smoother than the 'jag' unit in the X-type which delivers its power using and on/off switch).
Three rules though (common to ALL diesels!):
1 - Change the oil regularly (every 12k, preferably less) and use fully synthetic oil. Oil is your engines blood. It not only lubricates but it cools too - especially important with the turbocharger! If the oil is allowed to become lumpy it can clog causing oil starvation to the turbo (and other parts) meaning it will self-destruct. A self destructing turbo can be ingested by the engine, destroying it, or it can allow engine oil into the intake system meaning the engine will rev up until it blows, or will drink itself dry of oil and seize permanently.
2 - Take it easy until the car warms up! Without the oil being up to temperature and pressure it cannot do its job preperly so the turbo will suffer premature wear. Also, let the engine run for a few seconds before turning off. This allows the oil to cool the turbocharger and ensures that the turbo blades are not still spinning when the oil pressure drops due to the engine being turned off.
3 - Don't drive too gently once warmed up! Clogged EGR valves and injectors due to soot build up are costly to fix and in some cases can lead to turbo failure if the EGR valve sticks.
I've got the 120bhp 1.9dci in my Scenic and after 1 year of owenership am very happy! Although the electric window regulator brackets are s
t!!! But that's another matter!Edited by flakeypaul on Saturday 25th June 10:58
Welshbeef said:
I see your point.
So in which case turning that on it's head why are diesel cars are relatively poor.
Much higher power to weight ratio? So in which case turning that on it's head why are diesel cars are relatively poor.
Lot more stop start?
Able to accelerate significantly faster (acceleration kills fuel economy)?
Higher top and/or cruising speed?
Smaller engines are much less efficient? (or more difficult to make efficient, trucks were running direct injection/common rail/euro 3-4-5 emissions long before cars were).
Although they're not very aerodynamic, their frontal area's not that bit for their weight.
Truck engines have relatively how power outputs for their capacity (say 220hp from 6 litres), have a small rev range (1500 rpm at most), and don't rev particularly highly. It's probably not difficult to make an engine more efficient over a short rev range, than it is a large one, although I'm now in the reams of guesswork.
I'm not entirely sure, but all the above are reasonable reasons (or educated guesses
) that I can think of.A laiden truck is 40,000kg and top end power is 700bhp so 17.5bhp/tonne
And it has 2000lbft so 50lfbt/tonne
Long range mpg 10mpg
Bhp/ltr 44
Take my 330d 231bhp 369lbft weight c1500kg
Bhp/tonne is 154
Torque/tonne is 246
Long range mpg c53mpg.
Bhp/ltr 77
Basically to me that says that truck engines are very unstressed they could easily downsize and gain notable mpg but run higher specific output
And it has 2000lbft so 50lfbt/tonne
Long range mpg 10mpg
Bhp/ltr 44
Take my 330d 231bhp 369lbft weight c1500kg
Bhp/tonne is 154
Torque/tonne is 246
Long range mpg c53mpg.
Bhp/ltr 77
Basically to me that says that truck engines are very unstressed they could easily downsize and gain notable mpg but run higher specific output
Welshbeef said:
Basically to me that says that truck engines are very unstressed they could easily downsize and gain notable mpg but run higher specific output
The lower specific output and having an unstressed engine helps the long term ability of the engine though, you don't see too many cars with 7 figure mileage.700bhp isn't too common either, maybe only on the long distance fleets. Most of the fleet in our place is between 420/480bhp for the artics, around 250/300bhp on the rigids. Big emphasis on economy now, all ours are limited to 90kph and fitted with a system to flag up harsh acceleration/braking, high revs, long idle time etc. It has made a big difference too, fleet average is 11mpg now and thats all quite local work (within NI anyway).
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