Prepurchase Inspection
11-02-2009, 12:18 AM
#16
Race Director
Sincerely,
Macster.
11-03-2009, 01:01 AM
#18
Instructor
Thread Starter
My E46 M3 is 6 years old and I have bounced it a few times (1st gear) but not 13. Sometimes the situation is such that you cannot take your eyes off the road to watch the tach. If you have NEVER bounced it, you must be a conservative driver (not a bad thing to be), a short shifter, or you have an extraordinary ear.
11-03-2009, 01:11 AM
#19
That should be read as 13 ignitions and not 13 revs over the rev limiter, unless they did all the calculations from the dme report for you. I don't know the firing pattern of the flat-6 but my guess is that there are 2-4 ignitions per crank revolution.
Those "overrevs" could also occur from bouncing off the rev limiter as well. It's hard even for a computer to control a spinning crankshaft at 7k rpm.
Those "overrevs" could also occur from bouncing off the rev limiter as well. It's hard even for a computer to control a spinning crankshaft at 7k rpm.
11-03-2009, 02:08 AM
#20
Instructor
Thread Starter
You're right, I think, they were not technically "overrevs" because the limiter did it's job. I believe however, that they read this off of the PIWIS. What do you mean by ignitions?
11-03-2009, 04:05 PM
#21
The DME logs that I have seen (from Porsche dealers) record type 1 and and type 2 ignitions. An ignition is a spark plug firing. There are 3 ignitions per crankshaft revolution so if the DME logs 13 type 2 ignition events, then it means the crankshaft made a little over 4 revolutions past the rev limit.
Is that detrimental? Four revolutions over the rev limit is not to me, especially if it occurred just past the rev limit and not at, say, 9000rpm. Unfortunately, the 996 only records type 1 (rev limit) and type 2 (> rev limit) events so it's hard to tell.
Fortunately, the 997 has more type ranges so you can narrow down what rpm ranges past the rev limit that the ignitions occurred in.
Anyway, that is my $0.02.
///Michael
Is that detrimental? Four revolutions over the rev limit is not to me, especially if it occurred just past the rev limit and not at, say, 9000rpm. Unfortunately, the 996 only records type 1 (rev limit) and type 2 (> rev limit) events so it's hard to tell.
Fortunately, the 997 has more type ranges so you can narrow down what rpm ranges past the rev limit that the ignitions occurred in.
Anyway, that is my $0.02.
///Michael
11-03-2009, 07:36 PM
#22
Instructor
Thread Starter
The DME logs that I have seen (from Porsche dealers) record type 1 and and type 2 ignitions. An ignition is a spark plug firing. There are 3 ignitions per crankshaft revolution so if the DME logs 13 type 2 ignition events, then it means the crankshaft made a little over 4 revolutions past the rev limit.
Is that detrimental? Four revolutions over the rev limit is not to me, especially if it occurred just past the rev limit and not at, say, 9000rpm. Unfortunately, the 996 only records type 1 (rev limit) and type 2 (> rev limit) events so it's hard to tell.
Fortunately, the 997 has more type ranges so you can narrow down what rpm ranges past the rev limit that the ignitions occurred in.
Anyway, that is my $0.02.
///Michael
Is that detrimental? Four revolutions over the rev limit is not to me, especially if it occurred just past the rev limit and not at, say, 9000rpm. Unfortunately, the 996 only records type 1 (rev limit) and type 2 (> rev limit) events so it's hard to tell.
Fortunately, the 997 has more type ranges so you can narrow down what rpm ranges past the rev limit that the ignitions occurred in.
Anyway, that is my $0.02.
///Michael
That's interesting. So the number "13" is actually more innocuous than it may seem. Four revs over the limit sounds like one overrev "event". I feel even better. Thanks M-D, I'm learnin'. I knew what an "ignition" was but wasn;'t sure how you were using that term. Now I understand what you were saying.
11-03-2009, 07:55 PM
#23
That's interesting. So the number "13" is actually more innocuous than it may seem. Four revs over the limit sounds like one overrev "event". I feel even better. Thanks M-D, I'm learnin'. I knew what an "ignition" was but wasn;'t sure how you were using that term. Now I understand what you were saying.
FWIW, one 996 GT3 I was looking at a few months ago had 1 type 2 ignition.
So no worries (IMO).
Are you going to keep your E46? I came from an E46 M3 as well. Loved it, but then I got an E36 M3. I figured I wanted to diversify so I sold my E46.
///Michael
11-05-2009, 02:09 AM
#24
Instructor
Thread Starter
Yeah, it sounds like to me that the DME recorded some type 2 ignitions while the engine probably hit the rev limiter.
FWIW, one 996 GT3 I was looking at a few months ago had 1 type 2 ignition.
So no worries (IMO).
Are you going to keep your E46? I came from an E46 M3 as well. Loved it, but then I got an E36 M3. I figured I wanted to diversify so I sold my E46.
///Michael
FWIW, one 996 GT3 I was looking at a few months ago had 1 type 2 ignition.
So no worries (IMO).
Are you going to keep your E46? I came from an E46 M3 as well. Loved it, but then I got an E36 M3. I figured I wanted to diversify so I sold my E46.
///Michael
11-05-2009, 06:26 PM
#26
Instructor
Thread Starter
12-13-2009, 03:47 AM
#27
Track Day
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I'm also in the market for an 07-08 TT, and assume that the one that finally draws me in, will also be out of state. Since I'll also be looking for one with low mileage and under original warranty, what sorts of problems should I be watchful for that wouldn't be covered under said warranty? Would a 6000 mi. engine with a compression problem not be covered under warranty? How can a car fail a PPI for a mechanical issue if it's under warranty (or if it fails, couldn't it be fixed under warranty)? I thought I should be more worried about prior body damage, repaints, flood damage, etc. Thank you for any advice.
12-13-2009, 02:50 PM
#28
Race Director
I'm also in the market for an 07-08 TT, and assume that the one that finally draws me in, will also be out of state. Since I'll also be looking for one with low mileage and under original warranty, what sorts of problems should I be watchful for that wouldn't be covered under said warranty? Would a 6000 mi. engine with a compression problem not be covered under warranty? How can a car fail a PPI for a mechanical issue if it's under warranty (or if it fails, couldn't it be fixed under warranty)? I thought I should be more worried about prior body damage, repaints, flood damage, etc. Thank you for any advice.
A problem with an engine with a "compression problem" is based on the warranty fine print it may not be a "problem". The low compression may be classified as a condition that is *not* addressed under the warranty.
You need to know. Or maybe you don't.
Why bother? If car has a compression problem let some other buyer deal with it. There is always another car.
As for the issue about mechanical problems is that you have to trust the PPI to catch any and all of these.
Sure, a tranny hanging out of the bottom of the car is clearly a mechanical problem.
But a noisy engine or one that burns an excessive amount of oil may not be caught or noted during PPI check out. Also a transmission that jumps out of gear may not be caught.
The PPI check for my 03 Turbo failed to note the battery vent hose not correct. In fact worse than not correct, someone had made some half-assed attempt to electrical tape a hose to the battery with the end of the hose close the vent opening in the battery. If a PPI fails to detect this -- which granted would require the removal of the two cowl panels -- a few seconds each -- what other things could a PPI fail to turn up?
You really need to spend some time with the car to learn how it starts from cold, warm and hot, how the engine idles in all cases and how the car runs, drives, shifts, behaves. And how the car looks.
If you are unable to do this, then you are putting a lot of faith on the PPI.
Generally, only when you have found no reason to reject the car then you have a PPI done. Ideally you want to note what you have found and see if PPI turns up the same things. If the PPI fails to turn up what you have found then the PPI is at best just a superficial one and you have nothing to show for the PPI other than experience in knowing the place that did it is not a place you want to use ever again. And you still are faced with not knowing enough about the car.
But if you are not able to pre-inspect the car yourself and possibly reject the car for obvious or not so obvious things (but things that you're knowledgeable enough about to spot yourself -- for instance bad paint work or mis-fitting body panels, etc. -- then you are going to have to heavily rely upon the PPI.
And the warranty the car comes with.
Sincerely,
Macster.
12-13-2009, 03:47 PM
#29
As I'm going threw a simliar experience in shopping for a 997TT so let me share a couple of things, I've learned.
1. The Porsche CPO warranty check-out, doesn't including running an "Over Rev report".
2. You can purchase a car with a CPO warranty, only to find it has been mechanically overreved.
3. Anything which appears to be caused by abuse, will not be covered. This is ill-defined, and at the liberty of the covering dealer. Don't assume anything, unless explicity listed in the warranty.
If a car has a compression issue, and is covered under warranty, have it repaired under warranty BEFORE taking delivery. Make it a pre-delivery requirement. Best of luck on your search.
1. The Porsche CPO warranty check-out, doesn't including running an "Over Rev report".
2. You can purchase a car with a CPO warranty, only to find it has been mechanically overreved.
3. Anything which appears to be caused by abuse, will not be covered. This is ill-defined, and at the liberty of the covering dealer. Don't assume anything, unless explicity listed in the warranty.
If a car has a compression issue, and is covered under warranty, have it repaired under warranty BEFORE taking delivery. Make it a pre-delivery requirement. Best of luck on your search.
12-13-2009, 04:36 PM
#30
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Thank you Macster for the advice. I'm talking about an 07-08 that would still be under the original 4yr factory warranty. The way I understand a CPO is that it would be an extension of the original so it wouldn't start until 2011-2012. I know most CPOs and 3rd party warranties aren't as comprehensive as the original, which is a prime motivator for me looking at 07-08 models. The benefit I see of a CPO is that the dealers are picking what they see as the best of the cars to put into the program. It lessens the risk of getting a problem car, but surely doesn't eliminate it. Unfortunately, I assume my inspection of a prospective car will be limited. I'll fly in and do what I can, but I obviously won't have the luxury of of spending too much time with the car. I'll rely on a PPI. Is it customary for a Porsche dealer selling a car to automatically provide a PPI as many do with a carfax?
Vaino - good advice on the CPO report not including a DME "over rev report"
Vaino - good advice on the CPO report not including a DME "over rev report"