Driving in the heat (89 Turbo model)

[89TRBO]

As we seem to be getting some hot days out there, any tips for driving in the heat? I'm anticipating approximately 95 degree heat on a road trip I'm taking soon, just wondering if anyone had any tips. I drive an '89 turbo, now a 3.4 L.

Thanks!

[GaryR]

Electric AC conversion? You 89 is worth a kazillion dollars and you have no AC or added oil cooling?

[Schulisco]

First and foremost: Check the mixture. 930's have to run significantly richer than Carreras and SCs. The richer mixture has several reasons:
- internal cooling of the cylinder (richer mixture burns at lower temperatures)
- richer mixture prevents pre-ignition/detonation, especially at boost pressure and high temperatures

Also very important:
- Check the distributor and it's correct ignition timing throughout the RPM range
- use fresh motor oil for these high temperatures (20W50 or 10W60)
- check the spark plugs and ignition harness
- check if - if present - the cooling fan on the oil cooler in the right fender switches on and works at 118°C / 244°F and make sure that the thermostat opens correctly and switches on the oil cooler
- Pack a spare V-belt and hook wrench
- check the fuel system for leaks to prevent fuel leaks and catastrophic failures (burning engine), replace old worn fuel hoses!
- check for vacuum leaks
- pack a fire extinguisher!

More threads here in the forum talking about heat and 911's (mostly naturally aspirated cars, but they have the same problems when running in the heat)
https://forums.pelicanparts.com/porsche-911-technical-forum/213513-heat-soak-911-engines-info-needed-what-function.html
https://forums.pelicanparts.com/porsche-911-technical-forum/609357-early-911s-extremely-hot-weather-foolish-notion.html
https://forums.pelicanparts.com/porsche-911-technical-forum/153712-driving-911-hot-ca-summer-day.html
https://forums.pelicanparts.com/porsche-911-technical-forum/621277-1984-carrera-3-2-running-hot.html

Thomas

[89TRBO]

I'm more concerned for the engine than for myself, and yes I do have AC

Originally Posted by GaryR

Electric AC conversion? You 89 is worth a kazillion dollars and you have no AC or added oil cooling?

[89TRBO]

Any tips for how to drive/run it, things to avoid running-wise?

[OldSpool87]

Moving is better than sitting. I’ve been driving my ‘87 930 in 90 degree weather. Stop n go Long Island traffic. Run Mobil 1 15w50 synthetic. I run oil level about mid way on the gauge and verify with dip stick. Temp gauge might get to 9 o’clock while sitting in traffic. My AC is like warm dog breath.

[David Inc.]

Don't overthink it. If your oil circulation and fans are operable you'll be find. Stuck in traffic for an hour in the heat? Just keep an eye on your gauges.

Moving you have no problem.

[Schulisco]

Originally Posted by 89TRBO

Any tips for how to drive/run it, things to avoid running-wise?

If the car is technically in good condition it should perform also in the heat, but of course it will feel better when running on lower temperatures, no question. That's what I wanted to say - keep the car well maintained so that everything works as designed and in specification, then if will do the job as well in the heat.

Concerning your question how to run it - not too low and not too high revs, this keeps the fan running fast enough to produce a good compromising amount of cooling air, use high octane fuel (ignition!), do not run it with high load, if you do, don't do that long.
Before your next stop, reduce your speed a few minutes beforehand to cool the oil and engine and avoid overheating the engine when you stop. A sudden stop will cause a heat build-up.
I guess at modelyear 1987 Porsche started to add a heat operated switch in the shroud to run the heater blower additionaly, even when heating was not used. The hot air vents through the heat flap boxes. It helped to cool the engine when being in a traffic jam or so. Probably you can add a switch to operate the blower manually without heating up the cabin.
The engine oil will be much more stressed when running hot over a period of time. So an earlier oil change is also recommended before interval.

[JacobS911]

I say enjoy the trip!! How many miles you planning on putting in?
I run mine on big 1000 mile weekend trips.. 8-12hrs a day nonstop through the mountains out here with no issues and hitting triple digits in the summer in places. Have a front mount oil cooler but with no fans. Runs great..and its run hard! temps do creep at idle in traffic so just keep an eye on those but if you have fans to aid you in those situations you should be solid. I always check oil level on the dip stick at gas fill ups just to make sure the oil gauge isn't lying to me.
Reiterate the supplies..fan belt/random tools/fuel relays/fuses/tire plugs.. anything else you think you may need.

[bkreigsr]

On my trip to Amelia Island in 2021 (77 930), I was stuck in a traffic jam on I-95 for about 50 minutes in 95 degree sun outside Santee, SC.
FWIW, I do have a 10.5" Spal fan with a manual switch on the cooler.

I sat watching the oil temp go from 170 to 340 (pegged) debating if I should shut it off for an hour or so, but my concern was that it would not restart fearing vapor lock. If you raise the engine lid, the fan will be pulling ambient hot air from the atmosphere vs pulling it down from the roof line.

So I sat in the car trying to leave enough room to do a second gear-crawl up two of three spaces every time we started to move.
When the jamb cleared, I pedaled it in the right lane until the temp returned to 210 for about another 20 miles doing 65-75.

After that, and on the return trip to NJ I drove it as l usually do.

After I got home the next day, I dropped the oil and sent it out to Blackstone. The only thing that was out-of-wack was viscocity at 100 and 210 degrees. (A lot thinner than prior tests and below recommended values) [PM me if you want to see the oil report.]

Bottom line - these cars/engines are as tough as nails. Don't sweat an occasional spike in traffic past 210 degrees.

Have fun - Bill K

[GH85Carrera]

I drove my non turbo 85 to southern New Mexico recently. Going into Alamogordo, and on to Roswell it was 105. That was not an issue, but some of the LONG long mountain up hill roads to the pass were. My oil temp was the hottest I ever have seen at 230, but as soon as I crest the pass, and started down the hill, the temp dropped back to 210.

My 85 dis come with the front cooler, but no fan. I added a fan, and it is on a toggle switch, and I turn it on when the temp is approaching 210. And contrary to common comments on this board, the fan does indeed help on the highway at 75 MPH, so I just leave it on once it gets to those temps.

I would suggest you find at what temp your fans turn on, and if they are the factory 250 switches change them to 210 degree switches. 250 is too dang hot.

I was not happy about the 230 I saw for 20 minutes, but the downhill parts saw the temps drop. And my AC was blowing 37 degree air all over me and keeping me cool.



I had no issues just driving around town in traffic at 105. Just going up the mountains requiring a lot more throttle.

[911obgyn]

I found driving at 65 mph traffic in AZ i had to shift to 4th gear to keep oil temps cooler. Keep revs above 2.5 k for fan to move air.