driving below 2800 RPM = trouble?
 

Snipped from the internets...
Ever since the last year's oil hijacking by the NYMEX speculators I picked up the habit of driving AT the speed limit. When gas crashed back to below $2 I continued my frugal driving, keeping the car in th 6th gear on highway and rarely keeping the RPM's above 3,500K. Not just to save gas but I figured I'd do the real driving at the autocross and cut down on engine wear. My car by the way, is only driven weekends and 90% of it on the highway the other 10% usually darting around lower Manhattan. Guess I'll have to keep it in 3rd gear more often.

I'm skipping Mobil 1 for the first time ever. I'm thinking of going with Castrol Syntec 5W40. I hear there are issues with Royal Purple "shearing".
Flamesuit on...

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"What do you all think, lower RPM's = less probability of IMS failure?"
__________________________________________________ ____

"Absolutely not.

The exact opposite has been true.

We have yet to see a single IMS failure from an engine that has been driven hard and thus far we have the biggest library of documented failures on this Continent.

Most IMS failures come in stop and go street driving, or in cars driven by Women.

The statistics prove that these engines like to be driven more aggressively, this information is included in the December 08 Excellence article on the M96 engine that features our development program.

The key to reducing IMS issues is to reduce the oil change intervals provided by Porsche by 1/2 and use an oil other than Mobil 1. If you coupkle this with a driving style that a Porsche is designed for your chances of having a failure are greatly reduced.

Do NOT drive at less than 2800 RPM and do not lug the engine!!!!!!!!! Nothing is worse and nothing has proven to kill the oil faster!

I have been TRYING to make the IMS fail in one of our test cars for the past 8 months or so. I hold the car WAO against the rev limiter for 2-3 minutes at a time, flog it in second gear against the limiter for as much as 5 solid miles at a time. When the car fires up, stone cold I hold it WAO for at least 45 seconds. There IS NOTHING that can be worse on an engine than this kind of abuse since the engine sees a huge temperature differential and it's not even well lubricated when it fires up and revs immediately to oblivion.

I have been doing this for almost 20K miles and have not changed the oil since I began the process of "flogging". The engine is equipped with full data acqusition as well as oil condition monitoring systems and the data has remained consistent since I began the torture. The engine has 75K miles on it now.

I'll post a durametrics data log over the weekend showing the RPM and abuse this baby has seen and you won't believe it.

It appears that Boost may be required to kill this engine before January when I'll be pulling it to swap one of my 2.9s into it. "


--------------------

Jake Raby
Raby Enterprises Inc
www.flat6innovations.com

You may have a point here. I blew my 3.2 last November driving it very nicely. But now I have a 3.6 :D And im broke lol.

Good news? I thought (obviously incorrectly) that since it was water cooled, then it wasn't necessary to keep the rpm's high. I usually try to keep it between 2500-3000.

I agree that driving properly will not only give the owner more fun while he or she owns the car, but seams to be proper for these engines.

However, I beat the bush pretty hard trying to find the right oil, and haven't heard of Royal Purple shearing. I'm not saying I didn't miss it, just haven't seen anything as of yet. BTW I'm using RP 5w-40 at this time.

What does "lug the engine" mean?

I've heard of this lower RPM's = IMS failure as well.

Thankfully I’m always driving between 4-7K RPM..I like using lower gears while cruising...3rd usually up to 65-75 MPH.

how much of this applies to Tiptronic transmission boxsters? (probably a dumb question)

also on my Tip, how long is it "safe" to stay in first when first starting the car?

i'm always in a rush to get it to 2nd (as it stays above first until you turn the car off)

I have no intent of flaming anyone, just increasing all of our collective knowledge. Just did a quick search concerning HTHS ratings, if your oil has an ACEA rating of A3, it should have a HTHS rating of 3.5 or greater. This is, I believe Porsche's requirement. :cheers:

I would also like to hear something on this as I have a tip. I thought I read somewhere that tips are not as prone to IMS failures as manuals are, but is that because there are more manual cars out there? I try to wind mine up as much as possible once she's warm, but I am in a lot of stop and go traffic.

That's like when you slow down to pay a highway toll and then you try to take off with the car still in 5 or 6th gear because you're too lazy to downshift.


My lazy move is skipping 5th gear. I go from 4th to 6th. So I think that's kinda like lugging..

p.s.
There's a case of RP 5W40 sitting at a local NAPA dealer. They're wanting like $12 a quart. I don't mind the price but Castrol Syntec is like half the price. Is it really twice as good? I've seen the load machine tests but I'm not sure how real world they are. And of the dozens of oils that Porsche has tested and recommeded why isn't RP in there? Is it purely business?

The Tiptronic cars are less prone to RMS failure... NOT IMS failure.

This is most likely because there is no direct mechanical link to the crankshaft. With a torque convertor, the link is fluid, with a clutch, it's mechanical.

:cheers:

Ahhh, thanks for the clarification. Wishful thinking on my part:rolleyes: But, I guess if you are running a tip car in the Drive mode the transmission will keep the engine from "lugging" with the downshifts. Which from the sound of it is a good thing.

Good point. In fact, I'm in Drive about 99% of the time unless I get in slow traffic, or on a 25MPH Pkwy. Then I go manual and usually stay a gear below what the dme would otherwise do in order to keep the revs up.

Don't forget, both your oil pump and your waterpump are rpm dependent!

:cheers:

Here I am checking the forum on Saturday morning at 5:45 am waiting for the wife to order me around to set up tables for her garage sale and I read this thread.

It warms my heart to no end that my gut feeling is right when I'm behind the wheel of my Boxster:

DRIVE IT LIKE YOU STOLE IT ... it's good for the motor.

I'd rather wear out the motor from increased friction than have an IMS failure because I babied the thing. When my motor blows, it had better be due to being thrashed for many many miles, not babied too much.

Now I must go out and set up tables in the dark and take orders from "the Boss."

"Whipping Boy reporting for duty, Ma'am!"

How much for this coffee pot? And for these garden tools? And what about the plastic pig holding flowers? I don't see a price on the Boxster?

6:47 am

Tables set up, many many loads of crap taken to front yard.

burned out boxster is only $500. Price is negotiable

I have done my morning duty and will now wash dog, bmw, porsche, and do a 15 gallon water change on the marine aquarium at my office.

Then I'm off to a funeral of a distant friend (very close to my older brother, but not me) who was murdered on Monday morning and his body was set ablaze like the Boxster in this thread to cover up the beating he received. (No need to post "I'm sorry for your loss" comments. I just thought it was odd that I'd be commenting on a thread for a burned out Porsche and the same thing happened to this guy!)

Heck of a day, this!

Wow. Interesting story. I guess I should change my driving style. I was shifting pretty early and also skipping gears like going 1-3-5. That was to save my clutch mostly. Or can I still do this just rev higher?

Unless you are lugging the engine, I would like someone to explain to me how the RPMs contribute to IMS failure? Are you suggesting that a flawed engine design responds BETTER to more internal stress and friction?

How can that be, please enlighten me.

Again, I am not talking about lugging the motor, although I am not sure how the Tip will allow you to lug it if you are in auto mode.

I am open but skeptical!

:rolleyes:

Hey Brucelee, I just watched Enter the Dragon a few days ago on TV, it never gets old. You really can't lug the engine if it is in auto mode, but if you are in manual mode and you are in 4th gear and have to slow down due to traffic, etc. and don't downshift manually, you can definitely lug the engine in that scenario.

If I've understood Jake Raby and Charles Navarro's comments correctly, the higher rpm translates to higher oil pressure which feeds the IMS bearings at a greater volume, reducing friction (I know, the bearing is supposed to be sealed, but likely leaks).

This is also why they recommend removing the outer seal to allow greater oil flow.

And for what it's worth, I only use Royal Purple in my Box S. Tried it in my '73 911, but leaked too much; so back to good 'ol 20W50 Castrol GTX Dino juice (though it's looks like Brad Penn going forward).

From everything that I have gathered from the information presented on several other Boxster forums, here's what I understand as being the issue:

At lower RPMs, the Vario-Cam system is actuating the valves at certain rpm ranges.
During the period that the VC system is being actuated, this places an additional load on the IMS, as the IMS is what connects the Camshafts to the Crankshaft.

During high rpms, the cams are already in their maximum position, so they don't place any greater load on the IMS and its bearing. At lower rpms, there is a much greater strain.

Lugging the engine, which technically qualifies as any event that start out at a low rpm in a high transmission gear, with large throttle opening, places a large strain on any engine, but on this engine, because of the design using an IMS, and the weak bearing, this wind up becoming a weak link in the engine.

If you think about most other engine designs, the camshafts are directly actuated by the crankshaft either by a timing chain, a timing belt, or by timing gears. This engine is different, and presents a weak link between the two.

So, here is the most simple way to explain the current thinking on why Boxster engines are having a high rate of IMS bearing failures:

Basically, lugging the engine places a greater load on the IMS and its bearing than is healthy. Excess load on the bearing leads to seal failure. Seal failure leads to oil intrusion, which washes away the lubricating grease in the bearing. Long oil change intervals combined with lugging and cold running lead to fuel contamination of the oil, which leads to fuel contamination of the IMS bearing, which then leads to its failure.

So several things can help lessen the chances of IMS failure:

More frequent oil changes with top quality oils. Somewhere in the 5k to 7500 range is being claimed as the best.

Run the engine up through the rpm range in every gear, and stay away from the 2300 to 3000 rpm range for long periods of time (don't drive cross country at exactly 55 mph).

Have the IMS bearing seals removed to allow constant oil access to lubricate it.

Buy a 2009 Boxster instead. :)

BC.