Turbo Speed....?

[ScottyP45]

I notice, now that my ears have tuned into the (much quieter my Alfa TDi) turbo whine from the 1.8T, that it seems to slow down at a certain revs!

When it hits 2k rpm, it spools up quick and the car pulls like a rocket, then as it passes thru 2800 rpm, the turbine slows down considerably,and after 3k its a much lower pitch and the car seems to stop pulling so hard.

Is this normal, or a fault? Or an EGR behaviour?

(My previous car, an Alfa 156 TDi has a much louder turbo obviously but it never leaves full whine once it gets there, i.e. after spool up it holds its tone at max until you let off the throttle.)

Any ideas guys?

 

[TFSI]

Its EGR or wastegate (if fitted) activity probably but might be worth further investigation.

 

[ScottyP45]

yeah, I think so too. Only had the car a week so hopefully nothing drastic is wrong. If its a leaky EGR or wastegate it should be fixable i suppose without too much cash or effort.

Anyone else had this?

 

[Nickynibbles]

Your car is fitted with a variable vane turbo so the pitch angle of the turbo blades will actually vary depending on what the ecu tells it to do, this is most likely what your experiencing happening. The 1.8T wasnt designed to shred the tyres but be as smooth as possible so it'll give you a kick to start but then a progressive but constant pull all the way up to peak power. Most people just dont notice the change though!

 

[ScottyP45]

cheers for the reply mate.

It does seem that the power comes in viciously at 2k, then from 3k to 4k i find myself pushing the throttle to the stop without meaning to as the power seems to stop building after 3k, and say in 3rd or 4th gear overtaking on m-way its not startling, however in any gear from 2k to 3k its neck-snapping.

Surely thats not normal?

BTW its a 52 plate 163 Sport model, forgot to say earlier...

 

[Nickynibbles]

I had a 3.0 v6 so cant comment on the day to day life of a 1.8T, just remember what it was like when I test drove one a few years ago and decided it was too slow! Your alfa oil burner would of been producing a lot more torque than the petrol 1.8T which your obviously noticing with your motorway overtaking! Simple things can be done to tidy up the car like a spark plug & air filter change, reset the ECU by disconnecting the battery for 15 mins which should ensure your achieving at least the expected 163bhp. If she's still just too slow for you then remap is your simplest way forward which should net you 20% increase in bhp & torque without detriment to reliability and actually improving mpg return!

 

[bubstar]

Your car is fitted with a variable vane turbo so the pitch angle of the turbo blades will actually vary depending on what the ecu tells it to do, this is most likely what your experiencing happening.

Are you sure the K03 is a variable vane? I was under the impression variable vane was diesel only until the 997 (911) turbo.

OP - get yourself down to Jim at Star Performance , he'll see you right :thumbsup:

BUB

 

[ScottyP45]

Are you sure the K03 is a variable vane? I was under the impression variable vane was diesel only until the 997 (911) turbo.

OP - get yourself down to Jim at Star Performance , he'll see you right :thumbsup:

BUB

Aye, good call mate, I met Jim a few years ago and repaired his rolling road 'puter for him when he was outside thornton, as my work wanted too much money to send me to it, so i went in my own time and fixed it free (after all he's a VAG tuner so I was honoured to do it lol)

Now.....to call in that favour.....

Now dont get me wrong, the Audi is MUCH faster than the Alfa from a standstill, but yeah im probably missing that huge chunk of TDi torque that made gears redundant and you could just put the foot down in 5th and whoosh past stuff, gotta get back into petrol mode and use the gears more