Mash
|
| posted on 26/11/17 at 08:53 PM |
|
|
TFSI or TDI
No 1 Son is looking to change his car for something a little more family friendly. Currently he has an Audi A5 S-line 2.0 TDI.
He is looking at an A3, and going newish used, so given the choice between another diesel or one of the newer economical petrols, what do you guys
think ?
The TFSI motors seem to give almost as good mileage as the TDIs, and similar performance, but he's wondering what might be in store for diesels
in the future, although this budget wasn't too bad.
|
|
|
|
|
SJ
|
| posted on 26/11/17 at 09:06 PM |
|
|
Can't comment on Audi but I've just swapped my 2.0 tdci Mondeo for a Mazda 6 2.0 petrol. Real world mpg is about 5 less than the Mondy
[but unleaded is slightly cheaper] and the engine is so much nicer, though obviously has a lot less torque as it is normally aspirated.
I would definitely go for a petrol if making the same choice again.
Stu
|
|
|
mark chandler
|
| posted on 26/11/17 at 10:22 PM |
|
|
Went through this with my father, he has run perfomance diesels for a few years he is now going turbo petrol to safeguard for the future.
|
|
|
bi22le
|
| posted on 26/11/17 at 10:44 PM |
|
|
I currently have an A4 2.0 TRI s-line, so the same as your son.
I'm not staying with diesel, I'll be going for a petrol. Stick with TFSI Audi and maybe an S4 or S5.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
|
|
|
Pete Jordan
|
| posted on 26/11/17 at 11:34 PM |
|
|
I've had various Audi A3 2.0 TDis for the last 12 years but when I heard that the recommendations we've been given for years by successive
governments that diesels were better for the environment was all wrong I decided to get rid of the diesel and go petrol.
I really like the A3, so am now driving a 2015 A3 S-Line 1.4 TFSI (150bhp). Not so much torque low down but plenty of power and pretty good fuel
consumption. Oh and my road tax has gone from £110 per year to £20 per year!
Just my opinion but my advice would be to go petrol because I think diesel values are going to fall significantly over the next few year.
Pete
|
|
|
roadrunner
|
| posted on 26/11/17 at 11:38 PM |
|
|
I have an A6 tfsi.
Not going back to diesel.
Mines the 3.0 litre supercharged version . It's not great on fuel. But the 3.0 TDI isn't much better.
If he goes for an Audi , get a Quattro. Another thing I won't Go back to, two wheel drive tin tops.;-)
|
|
|
obfripper
|
| posted on 27/11/17 at 12:17 AM |
|
|
At some point there will be some type of backlash against direct injection petrols, these have particulate emissions are 10x higher than any dpf
equipped diesel and they are pm2.5 to pm0.1 types that can be absorbed directly through the skin.
These type of particulates are produced slightly with a port injection engine, but are 1000x higher with direct injection.
The nox emissions are also high when running in stratified mode in comparision with port injection and most diesel engines.
Some euro 6 petrol engines will have particulate filters and nox traps to combat this, but there is a good chance they will suffer the same problems
that the early dpf diesels suffered.
It's not a problem while covered under warranty, but when 5-10 years old they may be costly to own.
The mpg is a bit of a variable thing as it is driving style dependant, given light loads there is not much between diesel and di petrol, however
increase the load (or speed) and the petrol fuel consumption increases at a higher rate than the diesel does. This is due to diesel combustion being
more thermally efficient, and diesel having a higher energy density per litre.
There are also a lot of coking problems with di petrols, again not a problem while under waranty, but when that's expired the cost of decoking
and in more extreme cases valve/seat replacement is going to sting. I have seen these problems with vag tsi/tfsi engines and bmw n54 engines and the
repairs don't come cheap.
Some toyota di engines have port injection combined with direct injection, this cleans the insides of the intake system and help to stop valve coking
and wear.
Going back to the a3, the diesel is fairly much the same as the a5 apart from a different egr valve setup that generally fails between 50 and 100k
miles. This will cost 6-800 quid to replace if not covered under a warranty.
The tsi/fsi/tfsi need regular oil changes to prevent high pressure fuel pump cam follower wear and to reduce the carbon depositing in the inlet
system, a car with irregular service history is to be avoided.
Dave
|
|
|
mcerd1
|
| posted on 27/11/17 at 08:26 AM |
|
|
the big question is what kind of driving does he do ?
diesel is still going to be a good choice if he spends all day on the motorways, but not so much for stop start trips across the town....
(without long enough runs to get everything up to temp the DPF will cause problems on any diesel)
[Edited on 27/11/2017 by mcerd1]
-
|
|
|
nick205
|
| posted on 27/11/17 at 09:44 AM |
|
|
I've driven and been a fan of VAG TDIs for many years now, but was doing anything up to 30k miles per year. For me TDIs drive very well and I
like the more relaxed rev nature. That said I currently can't drive on the roads due to epilepsy, but times and opinions seem to be changing.
Petrol engines seem to be improving on MPG and diesel falling out of favour. It may lead to a drop in diesel car values and mean pertol is a safer
bet financially.
As above, it has to be asked what sort of driving he does - big motorway miles - urban etc?
What are his views on road tax - it seems the government are likely to try and "de-favour" diesels with road taxes!
|
|
|
Mash
|
| posted on 27/11/17 at 02:00 PM |
|
|
Thanks for all the advice folks.
He's driving mainly short distances to work, Edinburgh to out of town, so lots of stop start and speed bumps. So you've pretty much
convinced me that petrol is the way to go. He'll probably look to change in about 4 years so could re-evaluate then.
I passed on your comments to him, so we'll see what he decides 
|
|
|
mcerd1
|
| posted on 27/11/17 at 02:59 PM |
|
|
quote:
Originally posted by Mash
He's driving mainly short distances to work, Edinburgh to out of town, so lots of stop start and speed bumps. So you've pretty much
convinced me that petrol is the way to go. He'll probably look to change in about 4 years so could re-evaluate then.
poor man - I'm just glad I don't need to suffer those roads every day anymore 
mind you in 4 years time those idiots in Edinburgh council might have banned all cars from the town anyway.....
[Edited on 27/11/2017 by mcerd1]
-
|
|
|
