VAP

As I mentioned in an earlier post I've been running with no fans or shroud for well over a week now. I figured I could do this as I did it once before when I was doing EFK prototypes for 1.8T A4's with viscous clutch/electrical fans and shorter serp belts. That car never over-heated in spite of running AC and idling at redlights during rush hour with no fans installed during the hottest months of the year, July/August.

However I have found that the 2.8 not only runs fine with no fan/shroud assembly, it in fact runs cooler. Now before you accuse me off hanging off the crack pipe let me tell you what I "think" the reasons are.

Our stock fans are so "blade dense" that I think the air entering the radiator gets trapped between the radiator and fans. I dont think there's enough space between blades to allow as much air that gets in the radiator out of the fan shroud. That it becomes a positive pressure area which then compounds the problem. Once a positive pressure is built up in there less air can now enter the radiator cooling fins due to the slower release of air into the engine compartment probably caused by fan blade restriction.

My car even with new radiator, thermostat, G12 coolant, hoses, water pump et al always runs maybe 1/8" higher than the "normal" hash mark index on the coolant gauge. With no fans or shroud installed it only gets to the normal mark when idling at a redlight or in my drive or garage for an extended period. When driven even at low city street speeds it's 1/16" back (low side) of "normal" and when on the highway its 1/8" back of the normal mark.

I'll be interested to see if I can keep those gauge settings with the Spal fans due to them having so much more space for air to flow between fan blades.

TurboEnvy52

Is this on your S4 and is your S4 the I5 turbo?

Curious if this is something i should look into for the CQ. I know my car runs really warm when idling, yet pretty cool on the highway or cool days (60's). I know in the winter the car never even gets to the normal line, which i think means the fans never even come on in the winter.

-JIMMY

Hokie - STI avant

So there is no shroud. Have you thought about going that route?

Mike

VAP

and caused the radiator to leak. Also when you mount that way you only pull air from the radiator directly under the fan. Shrouds allow you to pull air in from 100% of the radiator cooling surface area.

VAP

this is on a 95 90 sport Quattro

Hokie - STI avant

ah, ok that makes sense.