driving below 2800 RPM = trouble?

[Paul]

I like your 18" 5 spoke wheels, tell me more and where to find a set.....

[Paul]

Ruf is not needed to do these conversions, there are much less expensive options out there:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=120386821494&sspagename=STRK%3AMEWAX%3AIT&viewitem=

[Perfectlap]

Originally Posted by Paul

Ruf is not needed to do these conversions, there are much less expensive options out there:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=120386821494&sspagename=STRK%3AMEWAX%3AIT&viewitem=

I think that was a 986forum.com car

The Ebay username sounds a lot like the forum username.


My 18" 5 spokers are factory. Stole them for a song from Ernie's Alloys back in '05.
I think I paid what the Italian replicas go for now. Wheeldynamics.com carry the 30# replicas. I think the price is $1100 now. Was $800 at one point before the Euro took off.

I'm also thinking about picking up a set of 997 Turbo replica wheels for Summer use. I'll need rear spacers though which I'm not crazy about.

[Jake Raby]

Some of the information we have gathered is related to shockloading the IMS sees as the transmission of loads from the variocam is sent upstream to the IMS through the timing chains.

The IMS bearings do not have very much longitudinal thrust capability and these shock loads place a lot of shock on these bearing, a portion of that is thrust.

Don't quote me on any of this, as lots of questions are still unanswered and I am working hard to prove whats occurring as the engine is running with the variocam engaging/disengaging continually.

Thats all I am willing to state now and I reserve the right to change this based on future findings.

[Perfectlap]

Jake,
Just in your experience to date, which cars have you noticed the highest number of IMS failures 97-99, 00-02 or 03-04?

[Jake Raby]

Originally Posted by Perfectlap

Jake,
Just in your experience to date, which cars have you noticed the highest number of IMS failures 97-99, 00-02 or 03-04?

IMS?? These issues generally occur post 99, the pre- 99 engines are more prone to cylinder failures.

After 99 the IMS syndrome is random through all models, none are more or less prone to it.

[Rick M]

Jake,

At appoximately what RPM does the VarioCam engage and disengage on a 3.2?

Thanks,

Rick

[turbo23dog]

I had much the same question and thought...

Attempting to translate Jake's most recent statement into my own words, variocam action is shockloading the IMS and a primary suspect in causing IMS failure.

I don't know exactly how Variocam works, but I assume it does its magic as RPMs increase and probably not in a linear but probably more of a logarithmic function. Higher RPMs mean more Variocam effect...

If I have all this right, then my logic tells me that for daily, around town, stop n go driving, one would have a better chance of avoiding an IMS failure by following the recommendation of the owners manual to use 3K rpm for an upshift point for every gear. I would also assume that conservative, smooth acceleration between shifts would lessen loads as well. Hmmm....

I'd also think that you'd be asking for engine failure by trying to accelerate hard with the transmission in 4th, 5th or 6th gear at 30 MPH or less. Same goes for a tip in manual mode...

[jmatta]

That would be the day I use 3k rpm as my shift point...might as well just drive my Grand Cherokee instead.

[Paul]

Just warm it up and floor it almost to redline, I've been doing this to every Porsche I've owned since 1974 without any engine problems.

My 01 has almost 20,000 stage 1 revs and after 75,000 miles it still uses no oil.

[dennis]

My only confusion when reading all these posts is that everyone praises the car for being both a daily driver and high performing vehcle and I agree with that but if the rpm level is so sensetive I think less people would praise it around town, unless they all have tips?

[Lobo1186]

its not there are all too many failures out there I just think what this thread is trying to say that is IF there is a failure its in car that hasnt been pushed at all and is kept at very low revs.

[sasha055]

Something doesn't add up

1. TIP is not known for IMS failures. TIP usually keeps car at Very Very low RPM's, usually around 1500-2000 RPM's. If we take a driver that doesn't push the car.. it will never go above 4K PRM
-- This is very different from:
2. Driving a manual transmission under 2800 RPM = trouble

Logically.. to avoid IMS failures.. you should start in 2nd and rarely get to 2800RPM.. to simulate TIP.... (and of course don't push hard in low rpms)

am I missing something?

Sasha

[dennis]

I drive a manual by sound more than watching the RPMs....if it feels the engine is ready, I shift. If I'm getting on it, I wind out the gears more, if I am driving casually I shift through the gears quicker and soem times around 2k, if downshifting around a turn, sometimes at 1700