V6 2.5 auto - acceleration

[Parapadakis]

Hello all, I am a new owner of 06 Superb V6 2.5 TDI Auto.

Thank you to this forum, it has been an excellent source of info so far, I have discovered all sorts of interesting things about my new toy :-)

I'm looking for some advice, before I start touring the garages. After driving a Passat V5 (2.3) petrol manual for 14 years, it's the first time I have an Auto Diesel and I would like to know if what I am experiencing is normal...

Starting from standing, the car just does not accelerate! It runs very smoothly, but if I don't push it above 2000 rev, it's just embarrassingly (not to mention dangerously!) slow to pick up speed. After the turbo kicks in, it then accelerates too hard! I can't find a happy medium that accelerates smoothly.

The other thing that bugs me, is the economy. I get about 25-28 driving around town, and about 35-39mpg driving long distances. Is that normal for the 2.5 V6? That's roughly the same I got with my Passat petrol.

I wonder if this is just me having to learn to live with diesel, or do you thing I need to have the car checked?

Thanks,

George

[grr666]

I think part of the problem is you are coming from a naturally aspirated petrol car

and are now in a charged induction diesel car. They are a completely different

animal. You'll probably not get the best mpg until you've adopted your driving

style to suit. As odd as it may sound, a remap may be the answer which will make the

power delivery smoother and run across a (slightly) longer rev range.

(ie, more like a petrol engined car)

The VAG tdis are a bit feast or famine they way they come set up from the

factory, sod all go up to a point and then ALL THE POWER over a very narrow

rev range then gasp as they suddenly run out of puff again.

I'd also make sure the MAF is working correctly (Vagcom checks) and ensure

there is a clean air filter in there. As both of these could also effect MPG and

performance. Good places for remapping are Shark performance and Unit 18.

Both of the above are site sponsors and have their own forums where you can ask

any questions directly. Don't forget, a remap is just that and it doesn't necessarily

mean getting all the performance you can out of an engine, it can also improve

drivability and economy. It really depends how you have it done.

Shark performance forum

Unit 18 forum

Oh, and welcome to Briskoda by the way.

[Parapadakis]

Thank you! That was fast! Advice on remapping was going to be my next question... It was one of the reasons I decided to switch to TDI in the first place (although I was originally looking for a 1.9).

Has anyone here remapped the 2.5? What was your experience?

Thanks

[Parapadakis]

PS. I'll check the other forums in your post too... Thanks!

[Cown]

The 2.5 TDI could easily do 200bhp. The best thing though is the economy boost and much smoother running engine.

[grr666]

And you're local to Unit 18.

Seems rude not to

[Parapadakis]

Very local indeed! :-) I'll drop them a note and see if I can swing by during the week for a chat. Thanks.

[Parapadakis]

Very local indeed! :-) I'll drop them a note and see if I can swing by during the week for a chat. Thanks.

[vk10]

Welcome to the forum and congratulations on your new toy.

Mpg is about right, mine does the same, maybe worse in town. Turbo,on these kicks in at about 1800rpm

I haven't had a remap yet, bur going to consider the same option. But with the massive experience ive had with this engine, if i were you i would first check the injection pump timing on vagcom. It needs to be within spec and very often when its retarded there is a sudden boost of power and sluggish,start.

[Parapadakis]

Thanks VK10, yes I read your tail of woes in your other thread...

I am hoping that I can get away without starting to fiddle too much with the tuning. I have ordered a VAGCOM though, and I will check the readings when I get it (and figured out how to use it!).

What would be ideal, is to find a garage that has actually got experience with the 2.5 and is familiar with its quirks.

Any more 2.5 owners in this forum??

George

[oh_superb]

I filled up today - 549 miles to the tank - on a 2.5 tdi tiptronic. Last fill-up was in France. SInce then I have come up to Northampton, commuted to work for a week, down to london, through london, to south coast, back up to Northampton, average 43mpg.

Around town these cars will do mid 20's at best. The torque converter is slippery, no lock until about 2000 rpm, which just does not suit the nature of the engine.

On a run, I have had it up to 54 mpg over 50 mile distances, but that was very slow traffic, but fast enough to enable 5th gear, but tend to get around 42-44 mpg at legal speed limits. Interestingly, caning it in Germany does not make it much worse, I mean I get around 37-38 mpg cruising mostly 90-100 mph. This is where it beats a 1.9 in the economy department.

The remap helps in livening up the V6 lump, and reducing the turbo kick which by default is too late and too violent out of the factory. You can make the turbo come in sooner making it more drivable and pleasure to own.

Edited 11 June, 2013 by oh_superb

[ericsuperbee]

I reckon on around 44mpg on a run. Anything will beat a 2.5 away from the lights - get used to it! In reality the gearbox is not well matched to the torque on the engine. I allow 1st > 2nd in auto, wait for it to stop diddling between 2 & 3, then tip 3>4>5 so that I am in 5th by around 40mph - then you can get going. In full auto it won't change into 5th until 50mph plus so economy goes out of the window.

[jimbof]

Does anyone know if there is any way to tweak the auto box to get into 5th earlier?

I'm driving for max economy on my 1.9 auto at the mo and am currently running at 50MPG for the last 400 miles - but it depends on flipping over to manual as you say as I can get it into 5th at around 43mph manually versus usually 50 under minimal acceleration.

[Parapadakis]

Anything will beat a 2.5 away from the lights - get used to it!

Yes, I'm starting to learn that ;-)

Does anyone know if there is any way to tweak the auto box to get into 5th earlier?

Now, that's very interesting! I find that my box shifts up too early! I couldn't get it higher than 3K on auto, before it shifted up the gears. Yesterday though, I went to visit Alistair at Unit 13 (many thanks for your time Alistair!), who took me for a drive and suddenly my lazy car was revving between 4.5 and 5K quite happily! Apparently it all has to do with how fast you put your foot down, as it shifts the auto into a sportier mode, which changes up much later. It still does not cure the flat spot on starting from idle, but at least it accelerates much faster once it gets going... Looks like I've been too gentle with it :-)

I don't think this will do much to improve my economy of course, but at least I'm less scared lunging forward onto roundabouts, or turning into T junctions.

Who'd think that after 30+ years of driving, I'd have to learn how to drive all over again?... ;-)

[grr666]

Alistair is a good chap.

Are you decided on whether or not to map it?

[Parapadakis]

Update!

Took the car to Indie-Tech today for service and asked them to drive it around and give me their views on the acceleration issue. They had some interesting feedback: apparently, it looks like "the gearbox is holding on to the gears a bit too long". Normally they would suggest a change of auto oil, but as mine was done recently (I was told when I bought it, but have no evidence either way), they also suggested that it may be a MAF issue, as it is involved in the gear-s gifting logic, and they are known to give wrong readings without generating an error code.

Now, I am reluctant to fork out £100+ for a new MAF, on the off-chance that it may improve something.

What do you guys think? could it be the MAF? Also, Is there a way of checking if the auto oil was indeed changed and if the oil was right?

Thanks!

[MilanM]

I hope so, that no one are going to be mad at me and my point of view. This forum allowes diferent thoughts about some things and I would use that adventage to say what I mean.

Superb like Superb, some hates her, some loves her...but all them respect her.

I think that, there is realy no point to chip 2.5 TDI, as I have for long period, and I know what she can and how she likes to be driven.

Sorry for my English I dont use Gt.

Back to subject...I know many people will say more is good, but hey, more isnt always better...well thats my opinion.

If I wanted to buy quicker car, I would buy some sporty, exotic or similar car...I exactly knew what I want, when I was buying.

Luxury, big crouzer with decent motor(for me best in world), with that diesel sound, and who can give me speed when I wanted.

@ Parapadakis, sorry for off....

 

[Parapadakis]

No worries Milan, sometimes you just have to share the love of your motor... ;-)

[oh_superb]

The best thing to do is to compare to a known good one and see if the claim is indeed true.  Sounds like an iffy statement to me.  The tiptronic is a "learning box" so it will adjust to your driving style.  If you keep booting it, it will start holding onto gears for longer.  If you are running a grandad cycle, it will adjust and upshift early.

[Raptor]

2.5 Tiptonic 2007. The mpg seems about right to me. Had mine now for 6 years. Being too gentle is not helpful but mpg does suffer around town ( in grandad mode ! well I am one it fits :0),  so I use the manual shift where possible to get into the higher gears, averaging about 28 - 34 depending how many youngsters are in front trying to find fourth.

Foot down in auto on the motorway and it will return about 48 mpg. 

Seems to me you are there about with mpg, try being a bit fore forceful on motorway acceleration and see this helps.

[Parapadakis]

Thanks @Raptor. Acceleration on the motorway is not a problem, just accelerating from standing start.

[Whito!]

I noticed same problem took back to dealer to check no fault,sugested i drive another one to compare.I had to wait months for simular 2.5v6 to come in to the dealer so had to keep checking web site.they did let me drive one when it came in guess what bloody same,learnt to live with it after 3years.