The FQ400 example is not turbo lag either, it's due to the engine being below the boost threshold and being unable to spool the turbo.
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Worth paying a premium for a diesel engine?
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Posted 1 year ago #
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The FQ400 example is not turbo lag either, it's due to the engine being below the boost threshold and being unable to spool the turbo.
Very good point.Posted 1 year ago # -
When did I say that? Please read my post properly before you accuse me.
You said diesel fuel economy was a myth. What I took that to mean was that we are all somehow deluded in thinking diesels are more economical - ie we think they are and they are not, which in turn is like saying we are wrong.
Its actually 11 different cars, over about 20,000 miles in total. 3 petrol, 8 diesel.
And how many cars are on the market?
So you don't actually know at all then? You're just guessing based on no experience, and you argue that I'm wrong? Strange logic...
Well I have owned and driven petrol cars, and so have my mates. I've just never driven a new model petrol Passat which is why I said 'imagine'. I used to own an old one which got 38mpg on only gentle long country drives, no town driving. Published figures for Passats are either 42mpg or 38mpg depending on which power option you go for, and that's the very impressive TSI engine which as I've said before is very possibly a rival to the diesels in the Passat, particularly in terms of emissions. However I don't think this level of technology is widespread yet.
As for a 3.0L petrol being a like for like comparison with a 2.0 TDI, again I don't agree. Fuel costs, insurance and tax must mean it's a more expenisve premium option, surely? What fuel economy do you get in real life?
i can say that as mine wasn't a VW engine, they are know for the lumpy way the deliver power
Not any more mate. That was the old VW diesels, new ones are much better.
I just checked the VW price list - a 1.4 TSi 122hp Passat is £1,100 cheaper than the 110hp TDi, and does 9mpg fewer - 42 vs 51. So about 4 years payback ish based on 12k miles a year. VED savings are £25/year. On the other hand, the Bluemotion version is available at 63mpg and £1700 premium over the 1.4 TSi, which would pay back in 3.5 years ish for fuel - but the VED is £120 per year LESS than the petrol.
Bear in mind this is the one of the most efficient petrol engines out there.. I must say I am actually quite interested in it as an alternative to diesel because of its lower emissions and even power delivery. But as for standard NA petrols - no chance.
And let's not forget, cost is not the only factor here.
Posted 1 year ago # -
regarding the VAG TSI petrol engines, on paper they have good eonomy, but the one i drove for a few hours i found i had to drive it very 'careully' to get the published figures, unlike diesels where i just tend to drive relative to the conditions and trafic and it gives very good mpg.
I've also had a few VAG car dealers telling me that the economy on the TSI isn't as good in real life. Now this could be because they are new engines and a lot of them havent 'run in' so ecomony will improve, or could need some tweaks to the ECU on them as they are new technology.
Posted 1 year ago # -
i can say that as mine wasn't a VW engine, they are know for the lumpy way the deliver power
It was the older 1.9 i ment.Not any more mate. That was the old VW diesels, new ones are much better.
The whole point of hte FQ item was to show how poor the car was off boost as it had been total desgined around the turbo.
Harmitans - Member
Isn't that what turbo lag is? ie waiting for the turbo which is laging behind the engine. It can happen when you change gear and drop out of the turbo range or if you are off boost.
The FQ400 example is not turbo lag either, it's due to the engine being below the boost threshold and being unable to spool the turbo.
Posted 1 year ago # -
There is a difference. Below the boost threshold the turbo will not spool however long you wait. Above the threshold the time between opening the throttle and the turbo generating boost pressue is the lag time.
If the engine produces enough torque below the boost threshold then the car will accelerate slowly until it reaches the boost threshold, the turbo will then spool and the car will accelerate faster. All the FQ400 example shows is an engine that doesn't have much torque below the boost threshold and a reasonably high boost threshold.
Posted 1 year ago # -
"And how many cars are on the market?"
So do I have to drive every single car on the market to make my argument valid. It's at least better then your comment:
"I've just never driven a new model petrol Passat which is why I said 'imagine'. I used to own an old one "
Ahhh, a direct comparison like I've been able to do?
No."And let's not forget, cost is not the only factor here."
Yes I know, diesels drive like crap. If I could choose the car I have I'd go for petrol because:
a) I have learnt how to change gear at an appropriate time (do the diesel advocates really think having to move your hand and press your foot down really stressful?). If you really can't be bothered to change down a gear then I hope you can be bothered to brake!!
b) I like to drive - I don't just have it as a "tool" - Q. - are the bikes you choose the most efficient for how you ride? Don't get me started about singlespeeds!
c) I can tell the difference between different handling cars.
d) I can do maths.Posted 1 year ago # -
Who cares. If you want a diesel buy a diesel. If you want a petrol buy a petrol.
I run a diesel for work and look forward to driving my wifes petrol polo at the weekends. I have driven more miles in diesel VW's than i car to remember. The end result, its a diesel, end of.
I sell commercial vehicles for a living and diesel rules, but really, for joe bloggs who drives 15k per annum there isnt really a defining argument for or against either engine.
Lets discuss the merits of bigger brakes on your bikes, its a similar ever decreasing circles type argument which gets tedious
Posted 1 year ago # -
Robdob, am I wrong about the Passats? Are the diesels more efficient than the petrols? Yes. No-one apart from you argues this. I showed you some figures which showed that the payback time in terms of money is 40-50 thousand miles, which is what everyone else has been saying all along. So what's your point?
You seem to be making up loads of strange arguments and I am not quite sure why. You are allowed to prefer petrol, that's ok - just don't say wrong things about them not being efficient. That's what I was trying to call you on, really. How else do you explain the 57mpg Seat Ibiza or the 65mpg Bluemotion Passat?
About changing gear - it's effort. Small, but it's there. Otherwise why did people invent automatic gearboxes? Again, you are allowed to enjoy changing gear, as I would if I were faced with a windy mountain road, but again on a motorway it's a different game. I know how to do it, and I am a fine driver from a technical point of view.
Out of interest, why did you bother typing that stupid stuff about me not bothering to brake? Was it really worth it?
Posted 1 year ago #
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