lug lug lug

[flipper]

Ok, at what rpm's do people feel the lugging line is?
I drive casual until the spirited driving bug grabs me.
By casual I mean shift about 3-3500 and cruise at 3. Highway is 5th gear 70ish @ 3
Is that lugging?

[Tierce]

3k on the highway is about right.

[insite]

i think cruising (no acceleration) at 2500 or higher is fine. to accelerate, i like to be above about 3200 RPMs.

[Ray S]

Really depends on the motor doesn't it?

After all 2,000 RPM's on a Honda S2000 is a lot different than 2,000 revs on an C5 with an LS1.

For Boxsters, I'd say anything north of 3,000 RPM is fine.

[Turboflyer]

This is why all the really cool people have the tiptronic trans. Never a lugging problem.

[Macster]

Originally Posted by flipper

Ok, at what rpm's do people feel the lugging line is?
I drive casual until the spirited driving bug grabs me.
By casual I mean shift about 3-3500 and cruise at 3. Highway is 5th gear 70ish @ 3
Is that lugging?

if you allow engine RPMs to drop down under 1200 or so while that's not necessarily lugging oil supply/pressure is RPM dependent.

Thus the higher the gear selected the higher the minimum operating rpm.

Say 1200 is the max, err min in 1st, maybe 2500 would be the min. in 5th.

Also, even though the engine isn't being lugged you have to be aware that acceleration isn't going to be brisk. One can accelerate the car from say 2000 rpms in 5th gear to anything up to top or max speed but I would advise avoiding nailing the throttle until the engine has had some time to gain RPMs and is higher up in its HP and torque output.

This is all with engine/oil up ot operating temperature and at sea level or at least not high enough engine suffers from altitude "sickness" or you're not driving up a fairly steep grade.

A cold engine would prefer a bit higher min rpm for each gear and even gentler action with the throttle and I've climbed some pretty good grades in 5th at 75mph or higher, if the speed limit drops to say 65mph or lower I usually drop down to 4th just to keep the engine in a bit of its fatter hp/torque band.

These grades obviously involve some increase in altitude like around 7700 feet (or so at least around the Flagstaff area which in my trips east is generally the highest altitude I drove cause I seldom jump up and continue east on I-70) so the engine is not making full hp due to the effects of altitude.

Then there is heat. Even if altitude lower, in some areas of southwest temps. can be quite high and high engine loads at low rpm in times of high ambient temperature should be avoided if possible.

In your case 70mph in 5th at 3000 rpm sounds reasonable and is not lugging unless your going over a 10,000ft+ mountain pass with a dead cold engine...

Sincerely,

Macster.

[First986NJ]

Never below 2800 RPM !!

...... it has been hinted at, by some very credible people, that lugging these motors below 2800 RPM contributes to IMS failures. I'm not saying that there is necessarily published data to back this up yet, but there are some prominant Porsche performance engine people who strongly advise against lugging these motors below 2800 RPM - ever.

They also say that the oil should be changed 2x as often as Porsche recommends as well, and that a move away from Mobil 1 oil should be made. However, I have not been able to discern what oil(s) and viscosities should take the place of the recommended Mobil 1, or if it should still be synthetic oil or not.

[smlporsche]

I would never drive a Porsche below 3K.
Personally I shift at 4K at a minimum and usually never use sixth gear unless I'm driving above 80 MPH on the highway.
On track I never use sixth...
These cars sound so much bettter above 4500 RPM's

[Macster]

Originally Posted by First986NJ

Never below 2800 RPM !!

...... it has been hinted at, by some very credible people, that lugging these motors below 2800 RPM contributes to IMS failures. I'm not saying that there is necessarily published data to back this up yet, but there are some prominant Porsche performance engine people who strongly advise against lugging these motors below 2800 RPM - ever.

They also say that the oil should be changed 2x as often as Porsche recommends as well, and that a move away from Mobil 1 oil should be made. However, I have not been able to discern what oil(s) and viscosities should take the place of the recommended Mobil 1, or if it should still be synthetic oil or not.

2800 rpms in the lower gears is quite acceptable and cruising in all but the mountainous terrain at 2800 rpms is acceptable to.

My Boxster's spent a lot of time with engine running at less than 2800 rpms even in 5th gear and has not suffered because of it.

As I touched upon above, lugging is not a fixed rpm/gear relationship but load and expected acceleration response and deliverable torque expectations as well.

Cruising even at 2500 rpms in 5th is ok, but I think it border line lugging to flooring the throttle and demanding/expecting the engine to torque its way up to passing speed. This subjects the engine to extremely high loads and that ain't good for it. Will engine go boom? No. But it can cause accelerated wear in certain areas.

I agree with the 2x (at least) oil change interval. Even when I bought my car in '02 and the recommended oil change mileage interval was 15,000 miles I thought that excessive and settled on 5000 miles. 7500 could be acceptable if one's use of the vehicle didn't fall into severe, which includes low speed/stop go driving, lots of idling, in high ambient temperatures, dusty conditions, or short trips.

Getting into car and driving 7500 highway miles -- even in a week or so (as I have nearly done more than once) after an oil/filter service vs. driving 7500 miles in short trips over a year's time are two very different kinds of usage.

There is some uprising/ground swell against Mobil 1 oil. Whether it is justified or not I can't say. If one has in mind using a "better" oil that at least conforms to the oil requirements Porsche specifies and in using this oil doesn't void the factory (or aftermarket) warranty I see no harm in switching away from Mobil 1 oil to this other oil.

Sincerely,

Macster.

[curt_928]

This is getting rediculous. "Sorry officer.. I can't do the speed limit in 5th gear. I'm lugging the engine."
I admit my Boxster is my commuter and I take it mellow.. I guess I always "lug" it. No engine problems yet on the original engine.. 7500 mile oil changes though..

[blue2000s]

Folks, lugging an engine is not just driving it around at low rpm. You can drive this car on a flat road at 1000 RPM all day, every day and never have a problem. Lugging is when you introduce a load to the engine at a low RPM. This forces the engine to try to overcome significant motive forces without much momentum or leverage. If you are driving around at 1000 RPM and floor it, that's lugging. This phenomena depends on conditions. You can theoretically lug an engine at redline if the road load is too great.

Think of it as trying to remove a lug nut with your fingers on the socket heat instead of at the end of the wrench.

Porsche recommends not trying to accelerate the car from below 2000RPM. This is a good rule to go by.