[SmartCat]

Let's take a look at the curious case of 2.0 TDI engine which is shared between Volkswagen, Skoda and Audi. This engine is available in four states of tune - from 110 BHP/250 Nm to 190 BHP/400 Nm. The advantages of having a single engine with different power/torque outputs are obvious - you don't need to have 3 separate engines for 5 or 6 models.



Questions :

1) How different are the engine internals in its different iterations? Is it the same exact engine, but with different ECU or fuel/air mixture settings? Or is it possible that the engine in Rs. 70 Lakhs Audi A6 is packed with (invisible) technology when compared to its twin in Rs. 25 Lakh VW Jetta?

2) Audi A6 (191 BHP/400 Nm) has an ARAI FE of 15.2 kmpl. But the same engine in a Skoda Octavia (143 BHP/320 Nm) offers a FE of 19.3 kmpl. Now this makes sense, because one would assume - higher the power, lower the fuel economy

However, look at the weight columns - Octavia weighs 1.4 Tonnes and A6 weights 1.8 Tonnes. So the difference in the fuel economy is probably due to weight difference, rather than power/torque output difference. If we look at the "Fuel Economy Per Tonne" (I know ), the same engine in different states of tune offers roughly the same Fuel Economy (in a theoretical 1 tonne car) -> 25 to 27 kmpl.

Basically, VW guys are increasing power/torque by 50% plus but with no change in fuel economy. Another way to look at this - detuning this VW 2.0 TDI engine doesn't seem to offer any fuel economy benefits. How on earth is this possible (or what exactly is happening here)?

3) Why reduce the power output in a Jetta/Octavia? Why not offer it in 190 BHP guise, especially since there doesn't seem to be power vs fuel economy issue?

[Jeroen]

It would be interesting to understand what the differences are between these “same” engines. I would think that the electronics have a large role to play. But the difference between the lowest and highest output is remarkable, so I suspect they might have added/changed a few bits.

I don’t have the exact numbers to mind, but it’s not unusual to see upwards of 30-40% additional power being offered by manufactures for just a different ECU or probably not even that. Just a different mapping, that’s all.

I’m not sure you can come to any conclusions when it comes to fuel efficiency by looking at power output, weight and kmpl only. Cd- values and other factors (tires) could play a major role as well.

I thought I would google a bit see what comes up. But these days when you enter any string that contains VW and diesel you end up with a billion trillion hits about their problems with their scandalous diesel-gate.

Jeroen

[d3mon]

Originally Posted by smartcat

Questions :

1) How different are the engine internals in its different iterations? Is it the same exact engine, but with different ECU or fuel/air mixture settings? Or is it possible that the engine in Rs. 70 Lakhs Audi A6 is packed with (invisible) technology when compared to its twin in Rs. 25 Lakh VW Jetta?

2) Audi A6 (191 BHP/400 Nm) has an ARAI FE of 15.2 kmpl. But the same engine in a Skoda Octavia (143 BHP/320 Nm) offers a FE of 19.3 kmpl. Now this makes sense, because one would assume - higher the power, lower the fuel economy

However, look at the weight columns - Octavia weighs 1.4 Tonnes and A6 weights 1.8 Tonnes. So the difference in the fuel economy is probably due to weight difference, rather than power/torque output difference. If we look at the "Fuel Economy Per Tonne" (I know ), the same engine in different states of tune offers roughly the same Fuel Economy (in a theoretical 1 tonne car) -> 25 to 27 kmpl.

Basically, VW guys are increasing power/torque by 50% plus but with no change in fuel economy. Another way to look at this - detuning this VW 2.0 TDI engine doesn't seem to offer any fuel economy benefits. How on earth is this possible (or what exactly is happening here)?

3) Why reduce the power output in a Jetta/Octavia? Why not offer it in 190 BHP guise, especially since there doesn't seem to be power vs fuel economy issue?

1) Injectors, turbo, tuning, strengthened internals. Plenty of things are different between these engines.

2) Weight doesn't always dictate fuel economy. It dictates that while you're accelerating. But for cruising, aerodynamics play a larger role. You're only fighting against the wind to maintain a steady pace - and hence, the overall fuel economy (especially the 'rated' FE) doesn't really scale perfectly with weight. Also, in some cases, a more powerful engine can be more efficient as well, but only when it's operating in its peak efficiency zone, as compared to the less powerful engine, which is being forced to work harder. For instance, if you slap a bigger turbo on to the same engine, like they've done for the 170/190PS models, once the turbo is on boost, it's providing more air, and hence more efficient combustion to produce 100 PS than the 140PS engine. Makes sense?

BTW there's also a 2.0 BiTurbo that VW have, which has two turbochargers and produces a mind blowing 240 BHP from a 2.0 Diesel!

https://www.youtube.com/watch?v=RnMlIiCWQcg

Also reminds me of that top gear episode where they compared the FE for an M3 vs a Toyota Prius on a race track. The Prius went flat out, while all the M3 had to do was to keep up. And guess what, the M3 was actually more fuel efficient than the Prius under those conditions!

https://www.youtube.com/watch?v=F04MXepYiBs

3) Costs and Market differentiation.

[SmartCat]

Originally Posted by Jeroen

I’m not sure you can come to any conclusions when it comes to fuel efficiency by looking at power output, weight and kmpl only. Cd- values and other factors (tires) could play a major role as well.

Coefficient of drag, rolling efficiency of tyres and gearbox setup matters, I agree. But isn't their effect on fuel economy negligible when compared to weight of the vehicle?

Since all are premium vehicles with roughly the same top speed, I'd be surprised if there is a significant difference in tyre quality (and hence rolling resistance). SUV's like Q5 are likely to have higher Cd than something like A3 though



But according to this blog, when Cd is reduced from 0.32 to 0.29, the savings in fuel economy is just about 6%.
http://hamiltonianfunction.blogspot....s-of-fuel.html

I thought I would google a bit see what comes up. But these days when you enter any string that contains VW and diesel you end up with a billion trillion hits about their problems with their scandalous diesel-gate.

Yeah .

I thought of Googling the engine weight of 2.0 TDI in different VW group cars to see if there was any significant difference. But all I got was links to their emission issues.

Originally Posted by d3mon

1) Injectors, turbo, tuning, strengthened internals. Plenty of things are different between these engines.

If this is the case, then yes, there is no mystery. Everything falls into place.

[Dr.Naren]

Turbo charger and ECU tuning are different for sure across the different versions of the same engine. Injectors, High pressure CRDI pump would be the other components.

Both VAG and after market tuners are enjoying it. Win win situation.

[reignofchaos]

Modular engines are the name of the game these days. As someone mentioned, the same engine has the capability to be tuned between from 110 PS to 240 PS. Using the same basic block for various different engine configurations and limiting the power outputs in some other way such as turbocharger size/number or fueling/ECU limits allows the manufacturer economies of scale especially for 2 liter configurations that are used these days right from hatchbacks to large SUVs/Luxury sedans.

What this allows manufacturers is to let the engine be targeted to very specific emission (CO2) norms based on government/environmental law defined classes. Along with VW there are a few other makes that do it - Nissan with the 1.5 K9K, BMW with the B47 and Mercedes with the 2.2 liter diesel.

However the king of modular engines is Volvo with the VEA engine that uses the same 2 liter block for both petrol and diesel engines. The petrols are designated T2, T3, ... T8 and have varying outputs ranging between 120 HP to 367 HP and also a 408 HP hybrid. The diesels are D2, D3... D5 and have power outputs between 120 HP to 235HP and a 302HP hybrid. The emissions vary between 90g/km to 179g/km. Many of the lower variants are based on software ECU locks, the hardware being exactly same as a higher variant which is super nice if someone wants to tune the lower variants.

[Jeroen]

Originally Posted by d3mon

1) Injectors, turbo, tuning, strengthened internals. Plenty of things are different between these engines.

Thanks, this is very generic. You can add adjust valve timing, polish air channels, adjust gear ratio’s and some more. I would like to understand the real difference between those different variant. Would be interesting to see how far they use ECU adaption, at which point do they start altering the turbo etc.

Originally Posted by d3mon

2) Weight doesn't always dictate fuel economy. It dictates that while you're accelerating.

To an extend, how you accelerate, how fast for how long is even more relevant. Although those tend to be standardised in tests.

Originally Posted by d3mon

But for cruising, aerodynamics play a larger role. You're only fighting against the wind to maintain a steady pace - and hence, the overall fuel economy (especially the 'rated' FE) doesn't really scale perfectly with weight. Also, in some cases, a more powerful engine can be more efficient as well, but only when it's operating in its peak efficiency zone, as compared to the less powerful engine, which is being forced to work harder. For instance, if you slap a bigger turbo on to the same engine, like they've done for the 170/190PS models, once the turbo is on boost, it's providing more air, and hence more efficient combustion to produce 100 PS than the 140PS engine. Makes sense?

I would think for cruising weight is actually pretty much a constant. The variables come from aerodynamics, resistance and such. which are also speed dependant.

Providing only more air doesn’t make the combustion more efficient. It allows more fuel to be injected per cycle, therefor raising, potentially, the power output.

Originally Posted by smartcat

Coefficient of drag, rolling efficiency of tyres and gearbox setup matters, I agree. But isn't their effect on fuel economy negligible when compared to weight of the vehicle?

Since all are premium vehicles with roughly the same top speed, I'd be surprised if there is a significant difference in tyre quality (and hence rolling resistance). SUV's like Q5 are likely to have higher Cd than something like A3 though

Attachment 1623057

But according to this blog, when Cd is reduced from 0.32 to 0.29, the savings in fuel economy is just about 6%.
http://hamiltonianfunction.blogspot....s-of-fuel.html

Probably, but it’s still a factor. Of course already factored into these fuel efficiency factors. The faster you drive the more relevant these factors become. In busy stop and go city traffic they are probably negligible.

Remarkably, the tires also add to the Cd value. Their width is a factor in the calculation.

Originally Posted by Dr.Naren

However the king of modular engines is Volvo with the VEA engine that uses the same 2 liter block for both petrol and diesel engines. The petrols are designated T2, T3, ... T8 and have varying outputs ranging between 120 HP to 367 HP and also a 408 HP hybrid. The diesels are D2, D3... D5 and have power outputs between 120 HP to 235HP and a 302HP hybrid. The emissions vary between 90g/km to 179g/km. Many of the lower variants are based on software ECU locks, the hardware being exactly same as a higher variant which is super nice if someone wants to tune the lower variants.

Correct, this was the exact example I was thinking off. I have had a Volve S60 D5 and the only difference between the D5 and the model below it was the ECU mapping. No other modifications whatsoever!

Jeroen

[abhishek46]

Originally Posted by smartcat

Let's take a look at the curious case of 2.0 TDI engine which is shared between Volkswagen, Skoda and Audi. This engine is available in four states of tune - from 110 BHP/250 Nm to 190 BHP/400 Nm. The advantages of having a single engine with different power/torque outputs are obvious - you don't need to have 3 separate engines for 5 or 6 models.

Excellent thread and presentation.

Can you include the 'bi turbo' version of the 2.0TDI used in passat as well in the table.
240PS with 500NM torque.

VW/any other manufacturer wont give us extra power for nothing.
If you need more power, they will eek more cash out of your purse and push you higher up their product chain, where margins are more for not just the sales, but for services/parts as well.

[devarshi84]

http://www.team-bhp.com/forum/techni...-variants.html

Thread with a similar question for a different engine. The same applies here. Check post no 13 in the link.

[venkyhere]

This is what I "conjecture" :

There must be a basic mode for this engine to work (standard injectors, standard rail pressure, standard turbo size), with just minimal technology. It must have a torque vs rpm and BHP vs rpm curve. In the case of high end audi's, all the "technology" must be in delivering more air and more fuel proportionately, which must use costlier components (ECU firmware "quality" can't be very different - it is likely the same piece of code working with different parameters). But my gut feel says they can only squeeze the juice out of the engine at certain rpm "zones". In other words, 110 BHP tune would have a much flatter torque vs rpm curve than the 240 BHP tune (does it, actually ? )

In other words, of course better components are involved, but the richness of the explosion roughly remains same (nobody would design an engine that burns too lean or too rich anyway) - could be why the FE remains roughly the same (at cruising speeds, I am assuming all these cars are similarly aerodynamic and have roughly the same rolling resistance - weight plays lesser role while maintaining a steady speed). It's only how much extra air/fuel can be "pumped in" before the explosion, that sets one tune apart from the other.

Another way of validating above theory is to compare their FE in traffic jams - Im sure the heavier cars and the ones with humongous turbos will fare badly than the smaller cars with smaller turbos

[Numb_Locked]

Another reason could be the Gearbox limitations, in observation of the ongoing trend, it appears that the lower cost transmission used in less expensive models with the same engine have the Power & Torque limited (e.g. DQ200 / DQ250). This has also been noted with other manufacturers with their products at the other end of the spectrum, case in point TATA 1.4L Dicor capable of 110hp/170Nm normally, is limited to put out just 70hp/140Nm due to the limitations of the TA65* it is paired with.

[Jeroen]

Originally Posted by devarshi84

http://www.team-bhp.com/forum/techni...-variants.html

Thread with a similar question for a different engine. The same applies here. Check post no 13 in the link.

That’s a very good summary of the real difference per engine type. Would be nice to see it for this range of engines and the same engines covers such a broad range of output!

Jeroen

[Dr.Naren]

I found a good PDF document which explains the EA288 VAG engine in detail.

Also, one could find out the differences between various versions by doing a detailed study on parts catalogue. This is what most of the tuners do and no wonder why VAG cars are modded the most.

[sawnilrules]

There are two configurations available in 2.0 ltr TDI within VW Group.

There’s the 2.0 R4 16v TDI PD 103-125 kW & the 2.0 R4 16v TDI CR 81-176kW. Externally on cars, the batching still stands as 2.0 TDi, but the internals vary.

While the 2.0 R4 16v TDI PD 103-125 kW belongs to Motor type: EA 188 / parts code prefix: 038

The 2.0 R4 16v TDI CR 81-176kW belongs to Motor type: EA189 / parts code prefix: 03L, ID codes: CAGA, CAGC, CAHA, CBEA, CBAB, CFFB, CBBB, CBDB, CBDC, CEGA, CFGB, CFCA, CFJB, CJAA, CLJA & Motor type: EA288 also shares the same internals.

The former engine is used in Audi 8P A3, Audi B7 A4, Audi B8 A4, Audi C6 A6, Jeep Patriot 2.0CRD (BKD: 09/07) SEAT León Mk2, Škoda Octavia (BKD: 11/08->), Škoda Superb (BKD: 01/09->), Volkswagen Golf Mk5, VW Jetta Mk5, Volkswagen Touran, VW Passat B6

While the latter one has higher application range Audi TT Mk2 2.0 TDI quattro (CBBB: 06/08-05/10), Audi 8P A3 (CBBB: 07/08->), Audi B8 A4, Audi Q5, SEAT Leon Mk2 (1P), SEAT Altea, SEAT Toledo Mk3 (5P), SEAT Exeo, Škoda Octavia Mk2 (1Z) (125 kW), Škoda Superb Mk2 (3T) (103/125 kW), Škoda Yeti (81/103/125 kW), Volkswagen Golf Mk6, VW Jetta Mk5 TDI CleanDiesel (103 kW), Volkswagen Tiguan, Volkswagen Passat CC, Volkswagen Passat, Volkswagen Transporter (T5)

This probably to a point explains why the range is so strong. These are two different applications named as one externally.

PS The EA189 was the series which was under the emission scandal.

[racer_ash]

In addition to the above, the EA188 is a Pumpe Duse system incorporating unit injectors whereas the EA189 is a Common Rail unit and is a derivative of the EA188 though I presume both are in active service. There is a reduction in the compression ratio from 18 to 16.5 from EA188 to EA189 due to a bigger combustion chamber.

More details here:

http://www.motorreviewer.com/engine.php?engine_id=43
http://www.motorreviewer.com/engine.php?engine_id=42

I must say I am impressed by the power/torque range this engine is capable of. Truly a jack of all.