Hi,

There seems to be a move from the vag group to move away from electronic unit injection (PD) to 2nd or 3rd generation common rail.

I thought that PD/ EUI technology was more efficient than common rail because of the high injector pressures delivered by individual pumps supplying each cylinder, as opposed to common rail which has one pump.

Does anyone know if the performance of 3rd generation common rail has outperformed PD/EUi?

Best wishes

john

[email protected]

It may be something to do with the cost of having 1 injection pump rather than 4 expensive injection pumps.

Jon, I agree. However, this has been the case for a long time and it hasn't stopped them till recently !

John

It may be something to do with the cost of having 1 injection pump rather than 4 expensive injection pumps.

..............and getting it thro' the Euro emissions law!

................and quietening things down to competitors' noise levels

Hi' date='

There seems to be a move from the vag group to move away from electronic unit injection (PD) to 2nd or 3rd generation common rail.

I thought that PD/ EUI technology was more efficient than common rail because of the high injector pressures delivered by individual pumps supplying each cylinder, as opposed to common rail which has one pump.

Does anyone know if the performance of 3rd generation common rail has outperformed PD/EUi?

Best wishes

john

[email protected]

John,

what makes yo think there's a move towards common rail?

VW uses the PD and Audi common rail....the new 168bhp diesel, apparently, is still a PD but uses Piezo injectors....according to Autocar.

PDs are noisier due to the pumps being shut down and much more suited, again apparently, to the type of customer of VW, Skoda, Seats. Audis, being higher in standing, require the quieter more refined common rails.

John' date='

what makes yo think there's a move towards common rail?

VW uses the PD and Audi common rail....the new 168bhp diesel, apparently, is still a PD but uses Piezo injectors....according to Autocar.

PDs are noisier due to the pumps being shut down and much more suited, again apparently, to the type of customer of VW, Skoda, Seats. Audis, being higher in standing, require the quieter more refined common rails.[/quote']

So Audi is positioned to compete with Ford/Peugeot/Citroen/Toyota/etc.??

I've seen nothing that confirms the new 168bhp piezo injector diesel is or is not PD; thats unclear at the moment.

So Audi is positioned to compete with Ford/Peugeot/Citroen/Toyota/etc.??

Can than not be said of the same for BMW and Merc? Forgot to say A3/A4 also use the PD engines but the A6 and A8 use common rail.

The whole PD/common rail philosophy of VW PD and Audi common rail I read in an interview by Autocar with the chairman of VAG' date=' Pischstrader (sp.).

I've seen nothing that confirms the new 168bhp piezo injector diesel is or is not PD; thats unclear at the moment.

Only quoting what was said in Autocar.....VAG have invested a lot of money in the PD technology...does't seem to make sense in suddenly changing to common rail although they already have common rail tech.

My Fabia vRS anyway, is much quieter than my previous Mondeo TDCi. I read lots of reviews throughout the t'internet that said the Common-Rail system used in the TDCi wasn't as quiet as the PD system used by VW and I can testify to this. The 130 engine now has beenn out for a few years but even the more refined one in the new Focus / C-Max is still noiser than the VAG-PD 130 engine in my vRS. I also believe (unbaised) that the VAG-PD engine certainly in my vRS anyway is the most sporty sounding diesel I have ever heard, it actually sounds nice under hard acceleration (friends/family have commented on this also).

My Fabia vRS anyway, is much quieter than my previous Mondeo TDCi. I read lots of reviews throughout the t'internet that said the Common-Rail system used in the TDCi wasn't as quiet as the PD system used by VW and I can testify to this. The 130 engine now has beenn out for a few years but even the more refined one in the new Focus / C-Max is still noiser than the VAG-PD 130 engine in my vRS. I also believe (unbaised) that the VAG-PD engine certainly in my vRS anyway is the most sporty sounding diesel I have ever heard, it actually sounds nice under hard acceleration (friends/family have commented on this also).

I too like the sound of the traditional VAG TDi both PD and its predecessors with high pressure distributor pumps. However we only represent a small part of the marketplace. Joe Public is over influenced by the magazines and his petrol engine experience. See recent What Car group test OctyII 1.9 TDi PD/Focus TDCI/Citroen C4 HDi/Golf 1.9 TDi PD where much is made of the claimed quieter (near identical) CR engines in the Ford and Citroen and the Octy engine is descibed as raucous.

I would expect the optimisation of your motor through re-mapping to lead to it sounding subtly different to standard. Does it?

Can than not be said of the same for BMW and Merc? Forgot to say A3/A4 also use the PD engines but the A6 and A8 use common rail.

Yes, but the point is Audi is positioned to compete with BMW and to a lesser extent with Merc. and could not care too much about what non-premium brands are doing. There is a mix of CR and PD engines in the A6 and facelifted A4 ranges. The A6 uses the TDi 140 PD and the A4 the 2.7 TDi V6 CR.

The official VAG Group market targets are Audi/BMW, VW/Merc., Skoda/Volvo and Seat/Alfa. All of those competitors use CR so if VAG see this as a significant commercial disadvantage they will change.

Agreed VAG have invested heavily in PD but this may be near to amortisation considering the number of PD motors they have sold/shared costs with Bosch/shared costs with the truck industry which is a heavy EUI/PD user.

VAG aint gonna go PD for their big-ass engines.... i wouldnt like to imagine having to buy 10 PD injectors for the toerag... lol

PD technology is beginning to lag behind 3rdgen common rail.. PD is theoretically more economical and effective in producing big power figures... BUT its very expensive and needs special maintinence (eg high quality PD oils)

with each generation of Common rail, the engines get quieter, more refined, and the fuel rail pressure rises.. hence how the latest BMW diesel engines are so damn good... and how the 3l D has had almost a 50bhp hike since it was first released.

PD was great when it was first released... but its beginning to show its age. altho ive yet to drive another diesel engined car that comes close to the driveability and revvyness of the PD unit

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I don't really mind what engine technology a car uses in all honesty - common rail, PD, whatever. At the end of the day what will matter is what the law requires, how much noise it makes, cost and performance. It's all a balancing act and no doubt Skoda will do whatever they feel is best.

Was happy with the way the vRS did it's test drive, so it can't be that bad