Hot weather driving

In southern Arizona, we typically will have days where the temperature is in the 102-106F range (sometimes hotter). In looking at the engine arrangement in my car, it sems to me that with the car idiling in traffic or moving slowly, there will be a significant amount of hot rejected air being recirculated into the engine again. So far, the oil temperature indication has not gone more than a couple of degrees past vertical on the temp gauge.
Anyway, I try to avoid driving my car in slow traffic and not driving during the hotter part of the day (10:00-18:00).
Am I being too paraniod? Has anyone in the club done any temperature profiles/analysis of their engines in a hot environment?
Any insight will be greatly appreciated. Thanks.
Cheers!

You should talk to PhotoAaron at SpyderClub.com. He's in Phoenix and is a real VW guru.

Tom,
I live in Las Vegas and have driven mine over the past 3 summers and have experienced temps of 105-112 or so. So far I have seen the gauge slip past the vertical only by a couple of degrees. I do have the rear bonnet scoops and perhaps they help in venting the hot air out of the engine bay at slow speeds. At high speed they seem to take air in.
I find the biggest problem to be that it feels like you are sitting in a microwave oven at slow speeds and being slowly roasted.
Hans

New menu selections::

1. Hansbeef dip sandwich 2 minutes on timer: Heat range High
2. Hans pot pie 14 minutes on timer: Heat range High
3. Macaroni and Hans 5 minutes on timer: Heat range High
4. Scrambled Hans 5 minutes on timer: Heat range Medium

Larry,
You got it all wrong again.
1. SAUER-KRAUT (get it?) 5min medium heat
2. Bratwurst
3. Wiener Schnitzel
4. Spaetzle
6. Kartoffel Knoedel
5. Pilsener Urquell (for the thirst)
Leave the pot pie and all that other wimpy stuff for our wimpy eaters.
Hans

And BTW for us Americans, the original Wiener Schnitzel has nothing to do with hot dogs.

Joe,

Guru? Nope, just a guy with no social life and too many metric tools at my disposal. :)

I IM'ed Tom about my experiences. I think my fender vents really help some cool air in, or hot air escape. I do get hot oil temps in stop and go traffic, especially when the ambient temps are over 100. However when I get an open road and get the rpms up, the oil temps drop FAST. I have also employed all the hot weather tricks I have learned through the years. Doghouse shroud and fan, NO thermostat flaps, oil sump, rich jetted carbs, retarded timing, ect... I do think you could rig up some diverter flaps that would pull air from under the belly pan and up into the engine compartment. Anyone try that?

BTW: My biggest pet peeve with most of the 550's out there. If your running a doghouse shroud, please use the deflector tin so that the hot air that is flowing over your oil cooler isn't blown right at the # 3 and 4 carb. Ok, off my soapbox and on with my day.

Aaron

Gents: Thanks for the help. I'll definetly add the deflector tin to my cooler.

Bear in mind our car is a 6 not a 4, but hot weather problems seem to be a shared issue. Our car has the van shroud extremely close to the firewall, in fact we actually cut a portion of the fire wall out to accomodate the fan (then made a cover for it).

We were having heating issues in the hot weather. Contrary to popular belief, all of Oregon is NOT cool... We've been over 100 degrees almost every day the last couple of weeks. The car seemed to maintain acceptable temperatures 180-200 around town unless you really start pounding on it. Then it would climb to about 220 and we'd find a place to shut her down. Oddly enough, once you held the speed up above about 50mph, it would get hot REALLY FAST. We decided the problem was air flow to the fan.

I think Steve fixed this. He bent a piece of sheet metal to form a diverter under the belly pan up to the front of our engine. It only extends down about 1 inch, but it is very wide. This pulls air up to the front of our engine where the fan can get to it. I believe it solved the problem. I drove the panties off it yesterday and couldn't get it over 200 (and the air temp was 100).
angela

Angela, did the bottom scoop help hold the car down at high speed as well as help the cooling?

In all honesty, I have not investigated the top speed yet. The alignment is done with the front wheels pointing exactly straight ahead and I don't like it (toe in/out). Now that we have about 500 miles on it, I'm going to take it back in and have it adjusted. I want it more dead on center. Right now it's got the reflexes of a crack addict on ice skates.

The deflector makes the air flow thru the engine bay. It flows thru the fan to cool and now evacuates out of the grills. Before, there was a big pressure area with zero flow. Hey, you know what we could do? Remember the old Chapparal "sucker" cars with the big fan that pulled the body down to the track? Worked so well that they were outlawed immediately...

I doubt the deflector will hurt the handling on my car, but remember that mine (oops, ours) is heavier than most. Will let you know if it proves to be a problem.
angela

Angela; I was thinking it would tend to suck the car down a little since the intake is in front of the rear wheels. Be careful driving through water puddles so you don't make the 911 water cooled. Too bad someone dosn't make a fan shroud for the 911 that is backwards to pick up air from the grills in the engine cover.

The Chaparral 2J's competed for a while with the 2 Onan engines driving the exhaust fans out the back. They generated more downforce than the weight of the car which theoretically would have stuck upside down to the ceiling.

There's someone in Australia making a fan shroud for the 911 that looks like the one on the Porsche race cars. It is mounted flat on top like a corvair. That would really be the bomb on this car but it is quite expensive. Maybe on the next one we build...

The chapparal cars were a good example of thinking outside of the box. Innovation is a wonderful creative force!

I'll watch out for the puddles. But for the record, this is really NOT the best car on wet pavement. I drove it in the rain once. Once. Had serious 3rd gear traction problems. 1st and 2nd I just feathered it off the idle. I romped on it in 3rd thinking I was "home-free". WRONG. Absolutely slide-ways. Numerous corrections before we could agree on direction of travel. Believe I threw that pair of britches away.

angela