Post
by Dippy » Fri Jan 02, 2004 3:11 pm
It is certainly true that you should NOT warm the car up in idle. You should always drive the car very soon after start-up.
However it is also important to warm the oil before stressing the turbos because they have an oil bearing. When the oil is cold it is quite viscous and so the turbines will not spin smoothly. So use of boost, particularly at high revs, risks wear.
I drive quite carefully until my oil gauge lifts off the 60 mark. Then until it reaches 80 I use boost only gently and try to still keep revs low. I think it's fine from 80 and will reach a typical of 90 very quickly. After lively driving it will easily get to 100, and 110-120 is not unknown, especially in Summer. Considering the gauge goes up to 180 I don't think 120 is anything to be worried about as long as you give it a chance to cool back to 90 afterwards.
As for the original question, there's no doubt that less than 20mpg for average driving is poor and indicates a problem. When my S4 was stock I averaged 21-24mpg. Now it averages 22-25mpg. This indicates that possibly the OEM ECU map is not what it should be!
2001 Silver S4 Avant
AmD remap, APR R1 DVs, APR bipipe, Full Miltek exhaust
H&R coilovers, AWE DTS, Porsche front brakes, Short-shifter, 18" RS4 replicas
Defi-HUD boost gauge / turbo-timer (with afterrun pump modification), Phatbox
