TTop Gun

...between runs on Saturday, and it didn't do a hill of beans towards cooling it. If you're putting a water tank under the hood, it's going to be spraying water much hotter than 90F when you're stopped in traffic.

I've been meaning to take an infrared pyrometer (the thing that G.H was using to measure the tire temps on Friday, Julie) to the intercooler, and make graphs of cooling it with water, a 375 CFM leaf blower, and just parked with the hood open. Heat soak between runs is killing the submarine's performance on hot days.....

juliem

donp did this with his S4 and posted lots of data but I don't know what to do with it in regards to the TT

One other question - is there a fan that will draw enough to keep the heak soak down and not block flow at highway speeds? Hmmm

TTop Gun

...under $20 in the boating aisle of the local Wal-Mart the last time that I looked. It fits inline to a 3" or 4" piece of round duct hose, and the one that I have looks like it will pass air just fine with the fan off. If you wire it up to some sort of thermostat, you can even make it turn on/off automatically and still be under $30 total. The only question is whether there's room between the bumper inlet and the IC to fit this fan in.

Oh, it does bear mentioning that these types of fans are good for moving lots of air, but absolutely will not pressurize anything. In other words, don't restrict the outlet too much or it won't move *any* air.....

juliem

But if it is in front of the IC, isn't the IC providing resistance to the air flow?

TTop Gun

...front side of the IC??? If not, then it's just a fan blowing on it with zero restriction.

I was just thinking of just slapping together a cardboard duct that would hold the blower over the bumper air inlet and seeing if it made a difference before investing in ductwork and stuff. For my problem, I'm just going to carry a gas-powered leaf blower to grid and point it at the IC between runs. This is assuming that my pyrometer experiments show that it makes a difference.....

juliem

I'd be interested in your results

TTop Gun

I'll e-mail them to you as soon as I do the experiments.

WClark

I have an A4 1.8T. When I first got my VAG-COM I was stepping thru all the stuff I could see with the engine idling in my garage on a moderate summer evening. I happened by the charge air temp fairly soon after starting thecar up and noticed the temp was pretty close to ambient. A few minutes later I happend back to that block and the temp was some 30F above ambient. I wasnt sure what was happening but I decise to put a floor fan in front of the IC inlet. Even without very precise control of the air source - just blosing in the general direction of the front of the car with a 24" fan, the charge air temp dropped back to near ambient very quickly.

My guess is that a non-ducted fan - slightly smaller than the IC - that is located a short distance in front or behind the IC to allow natural air to flow thru and around it when the vehicle is moving will provide the needed air movement. I dont think this has to be well sealed or a real big fan since it doesnt take much to cool the charge air when there is no boost heating going on.