anewman

My approach is to start, wait the 30-45 seconds till initial cat warm up process completes and the revs drop under 1000rpm. When I do this, all is well.
In those seldom times that I just start and go, the oil pressure in the variovalve system hasn't built up yet, resulting in slightly lumpy acceleration at the 3000rpm mark when the variovalve switches over. (When leaving my house I start out going slightly downhill, I tend to shift into 2nd at 3500rpm since there is very little strain on the engine.)
This why I wait the 30-45 seconds, resulting in glass smooth operation while everything is still warming up.
As for emissions, I believe this very brief 30-45 seconds of "while I put my seat belt on and turn on the radio", actually falls within the manufactures definition of "Start up and then drive". (as opposed to going inside for 10 min for coffee).

ZuffenZeus

yes! ✊🏽🙌🏽

BucketList

I'm not finding anything on this. There are writeups about cylinder leak down being a problem, but not enrichment. They are not the same and one doesn't influence the other. Do you have any links to validate your claim you can share?

ZuffenZeus

Jump to the 17:30 mark in the video.


Then, when you have a lot more time, read this technical article from Charles Navarro:
https://lnengineering.com/education/...s-navarro.html

DesmoSD

Go back 2 mins when he's talking about the piston offsets and only have one P/N. I've heard of the piston offset issue being a culprit from the tech at Makellos Classics before this video was made.

Jake is talking about garage kept Porsches where owners start it up, idle for 5-10 mins and then turn the engine off. There are other things to factor in like Lokasil. I don't think a 30 sec idle is going to cause bore scoring.

ZuffenZeus

Reread my original comment that you questioned. I didn't say the sole reason for cylinder bore scoring. I said a contributing factor. The problem is an equation of variables that lead to the sum of cylinder bore scoring. Can I get an Amen in the house? ha!

ZuffenZeus

Jake has mentioned many times that cylinder bore scoring has been the number one mode of failure for M9X cars. He's been working with these car since the beginning of the 996/986 generation. Unfortunately, the IMS bearing fiasco has overshadowed it. It's been the proverbial sleeping giant that is just now starting to eat these cars.

Actually, what came into question was my remark about "cold start enrichment". If you let these cars sit and idle, you do more harm than good which Jake explains very clearly. I wouldn't get wound up about 30sec or 45sec or 1 min. The advice is to get in the car, start it up, put your seat belt on, and drive. The car is better warming up under load than sitting in cold start enrichment.

DesmoSD

We're sort of talking in parallel as I do agree that when you start your car, drive it until it warms up and then drive it well. I interpreted your cold start enrichment post as being one of the main causes since we were on the topic of the 30 sec rich idle.

ManoTexas

I’m going to lose sleep now. I often back out of detached garage and leave car running while I put golf clubs in passenger side. Sometimes sit couple minutes or so while get Waze going and Spotify on the stereo. Never realized P design was so messed up I’m destroying my engine. Always thought getting oil to temp and enjoying the revs would keep it happy. When my kids inherit the car they’ll sue my estate for being an abuser! Hopefully I’ll have spent every dime and all they’ll get is a 997.2 with potential bore scoring for which they’ll live in fear forever.

linderpat

I push my car out in the morning to the road, aim it in the direction I want to go, then jump in and twist the key and accelerate while I close the door and I'm off like a Le Mans racer, without any idling at all ("immediately") and of course I do keep it under 3000 until warm.

Kidding aside, we are simply too wrapped up in all of this silly hysteria. Get in, turn it on, and drive out normally. If that means first putting on a seatbelt and adjusting the mirror or you privates then do so while it idles and then pull out and go. Quit worrying. It is silly.

Scalp_em

3 month new owner here...my routine is get the oil level gauge going, put on seatbelt, adjust what I need to adjust and start up and go once oil reading is done...then i keep it below 3k RPM until i get to 200*F.....then let her rip

Sort of off topic but how long after it reaches oil temp does it no longer qualify as a “short trip”? 5,10, 20 min? That I have not yet gotten a clear answer to despite reading numerous threads on the topic....

ZuffenZeus

Variables in the bore scoring equation:
M9X factory running clearance
+
material composition (i.e. forged piston, Lokasil casting process, skirt coating, etc. )
+
Modern Fuel Blends
+
altered rod (shortened) to stroke (increased) ratio/increase dwell time of piston
+
same piston offset for all 6 pistons
+
cold start fuel enrichment (unburned fuel contaminates the oil, acts as a solvent and washes cylinders, etc.)
+
faulty fuel injectors (e.g. leaks fuel into the cylinder when the car is turned off)
+
car's care environment (i.e. the lack of care) =
________________________________________
BORE SCORING

BucketList

I would agree with that. The paper from Charles was excellent. When discussing topics like this I always think of my car as a reference. I have a .2 so the enrichment process is different for my car and not prone to the issues in the .1 as Jake states. That said, none of us is immune to the other wear items in Charles writeup. Another reason to change oil more frequently. Good stuff, thank you!

Petza914

To your list, for a .1 car, I'd add, climate and the thermostat installed in the car. Bore scoring is more frequent in cold weather climate cars. This from one or both of these reasons - people start them and leave them sitting idle to warm up in the driveway during the enrichment mode and/or the engine itself starts at a colder temperature and with the high temp thermostat, it doesn't begin opening until 180 degrees. This means the combustion process is getting the engine pretty hot before additional coolant starts to flow to bring things into equilibrium. With the 160 degree low temp thermostat, opening sooner, the engine temp doesn't get as high before additional coolant volume starts to flow, so it results in a more gradual warm up and for parts that have different coefficients of expansion keeps pistons from expanding faster than the bores and becoming tight in the bores.

IMO, everyone with a .1 car should be using the low-temp thermostat and the spin on oil filter adapter with a metal canister filter - this gets you a fresh spring for your bypass valve every filter change.

ZuffenZeus

DFI solves one issue and gains another. Watch the video from Lake Speed, Jr. on LSPI.