Hi all

When do you find the turbo actually starts boosting in real-life situations on a stock A4 1.8T motor? According to the manual, I should be feeling it from 1950 rpm, but in practice it only seems to come on line from about 2800 rpm. It's the 120kw motor with the K03-S turbo (I think?). It's particularly noticeable if you're in second "gear" (multitronic) at 2000 rpm and apply full throttle (I know it's not great to do that, but I've been experimenting a bit). Thoughts?

Cheers

If you are up here in Gauteng you generally "loose" 800 rpm relative to the coast. It sounds like that is exactly the difference you are seeing. Unfortunately nothing in life is free A turbo car gains about 12% on a normally aspirated car up here, but the price is more lag!

Hi

It doesn't sound like a K03, but the later (2000 on, if that's the way I understand things) K04. The pre 2000 models used to boost at 1750 and later models at 2000.

-Thomas

Boost kicks in at about 1800rpm, perhaps less noticeable with the Tip 'box, 2800 sounds awfully late, even so.
Best thing is to hook up a boost gauge. At GP altitudes you will be boosting about 0.1 bar plus more due to atmospheric compensation.
The above is subject to variation depending on your car, but is consistent with my findings on the K03S turbo variant.

It starts boosting early but I think it only reaches peak boost at around 2500rpm - 2800rpm....this should be where you feel the push

Audi A3 1.8T
ex "BroSpeed" RXi