Kevinmacd

Water temp is not indicitive of a warmed up engine, oil temp is. The engine is not fully warmed to get on it hard until you can get an oil level reading!

drcheap

I asked Matt from Motor Werks Racing about adding an oil temp gauge and he noted that water temp was correlated with oil temp in the 996 TTs. My asking was based on my experience with several of my cars past and present where water temp came up way before the oil temp came up. I have always been told to not work an engine hard until oil tem was up and stable...

Good points about air cooled rpm minimums and the need for higher rpms on 996 et al NA engines to keep the oil flowing to the intermediate shaft bearing..

..interesting comments about minimum rpms ranges on a TT...thanks..

mffarrell

Oil temperature is probably the most important thing to know, specifically for those of us who are pushing our cars hard. Free reving (or worse - racing) on an engine that has not fully reached it's oil operating temperature is extremely dangerous. But don't think that the coolant gauge will tell you this information - it won't.

As a general rule of thumb, after the car is warmed up, oil tends to be a few degrees warmer than the coolant (usually 10-15 degrees Fahrenheit).

However, it takes much longer for oil to come up to temperature than coolant. When you start your car in the morning, most of us are wise enough to not romp on the car until the coolant gauge is up to operating temperature. This is certainly better than romping on it cold, but it's still not quite ideal.

You see, the oil, especially in colder ambient temperatures, takes several times longer to come up to temperature.

Oil will not get to complete operating temperature easily by simply idling, it requires driving around and putting SOME load on the engine. I see people in the pits at races all the time reving their motors to 'warm the engine up'. It won't do any good and is only putting premature wear on the car.

The best way to get a car's oil temperature up is to simply drive it around for a few minutes. Ideally you'd have an oil temperature gauge to tell you when it's at operating temperature - and oil pressure gauge (lower pressure) would also tell you this information.

993GT

I've reported on oil temps vs water temps for warm-up here before...
Oil temp very closely follows the water temps on GT1 engines...

jhbrennan

"been told to..." - consider the source too - who's doing the telling and why is it a credible statement?

Mike Murphy

Yes, this is true because the oil cooler can act as an oil heater in order to bring temps up quickly for emissions reasons.

The most important part of oil temperature is actually oil flow.

Berra

I have a simple rule. I drive a good 15-20 min before putting load on the car, it's not only the engine that needs temp but also transmission and diff fluids.

autobonrun

Ever notice that when you're in your warm up period, without fail the mustangs and corvettes pull up next to you and rev their engines. I think there is a "must drive slow, warmup period" sign that pops up on the outside of our cars that we don't know about. Not that anyone races, just saying.

As far as rpms, I can't even get out of my subdivision at 2k rpm or below with hills in every direction. I've always started out around 3k or less.

In my M5, the "safe rpm" indicator lights give you some idea about when it's safe to increase engine revs. I use them in conjunction with the oil temperature. This time of the year, they start out at 4500 then go out one at a time as the engine temperature rises until it indicates its safe to run full rpm. During the winter, they start out around 3500 rpm.

The bottom line is do a reasonable warm-up and don't lug the engine regardless of engine temperature. Reasonable is matter of common sense. I really wouldn't worry about whether it's kept under 2k or 3k rpm; either will provide a gentle warm up period. IMO.

drcheap

Excellent info-and I agree not lugging the engine is important..c

dprantl

IMO "lugging" is a thing of the past and doesn't really apply to modern engines with EFI and a sound internal design. The only thing lugging can do these days is to put stress on connecting rods and cranks, but not as much as when you are at full throttle approaching redline anyway. I would have blown up many engines by now if lugging really was a problem. My old supercharged 928 made an instant 320lb.ft torque to the wheels at 1,500 RPM and I exercised that almost every day for over 50k miles with the car already having over 200k miles on it. Same with all the other turbo/supercharged cars I have owned in the past and never had any issues (4, 6 and 8 cylinder engines). In normal mode, my wife's stock C32 AMG tries really hard to not downshift and can build over 10 psi of boost at 2,000 RPM.

Dan

Mike Murphy

Sorry, typo. I meant 1,500 and changed it to that.

The torque curve on these engines shows that peak torque is well above 90% at 3,000, so there's plenty of reason to make use of all that torque.

Again, my advice for all is to check the owners manual.

Macster

The problem is at low RPMs the oil pressure is also low. My Turbo's (hot) oil pressure doesn't climb to "4 bar" until a bit over 2K. Thus in higher gears I tend to avoid driving the car in such a way that engine RPMs (and oil pressure) get too low.

s65e90

This, exactly. They almost mirror each other until water temp peaks then oil will rise to @ 200 depending on temp/moving or not, etc.

Lugging an engine has always been worse than revving it out. It's common mechanics. An engine wants to turn once running. Imagine being in a low gear on a 10-speed bike, going slow and then trying to pedal. The strain on your legs and knees would be immense. It's the stress on the crank/rods that is the issue. And IMO I don't see how it's only related to a Porsche. It's relatable to most engines.

Mike Murphy

Some engines - not sure if this is one of them - use oil jets to cool the bottoms of pistons. Yet another reason why we would want to get those RPMs and temperatures up a bit.

jungt

Does anyone have any experience with the PDK transmissions to see what RPM's they shift and stay at? That would indicate what Porsche feels is appropriate?

John