Porsche Boxster reliability -- let's get better info
 

A few owners have contacted me, asking to include the Boxster in the reliability survey conducted at TrueDelta.com. The key question: how common are IMS failures? In response, I've made getting the Boxster into the survey a top priority.

Here's how the research works: an email goes out once a month. If you have a repair, report it. If there have been no repairs, just report an approximate odometer reading at the end of the quarter--takes about 20-30 seconds four times a year.

We promptly update results quarterly, to closely track cars as they age.

Models are included in the survey once 25 owners sign up. Currently the 2000, 2005, and 2007 are each about halfway, and other years aren't far behind.

To encourage participation, free access to all results, not just those for the Boxster, is provided to everyone who signs up to participate.

Details:

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Sounds like a great idea. would you data include a repair history? Also, why not come out of the gate with the most grievous offenders; late 98's-early 99's ?

Regards, PK

I saw it on Babblers and signed up yesterday.

He needs 25 of each MY to have significant statistical data. I used to use 35 data points as minimum, but not sure which method he is using. And one of my colleages said 35 was not always required.

He didn't ask for any info I considered too private.

I'd love to have information on all model years. At this point, it's up to you guys. Whatever years we have enough data on, we'll provide results for.

It's possible to post repair histories even before a year is included in the main survey. There's a second survey with no minimum for simply posting repairs to the site. In the Repair Histories section responses to both surveys are merged.

The 25 number is a bare minimum for a reasonably stable result (one not likely to change much from update to update). You do have very wide confidence intervals with a sample of just 25. More is certainly better. We have sample sizes of 100+ for a few models, and a sample size over 230 for one.

With the Boxster and Cayman, we currently have 131 for all model years. Most for any year is 21 for the 2000. Up from about 75 when I first posted this thread, but we still have a way to go.

Details here:

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166 Boxsters and Caymans now signed up. A very good start considering the sales volumes. Thanks, guys.

But more remain needed if we're going to properly cover all model years. So far three model years are included in the main survey, and those are still close to the bare minimum sample size.

For the details, and to sign up to help get your year included:

Car reliability research

200 Boxster and Cayman owners now signed up. We hope to have some initial results in August, followed by some full results in November, but it's going to be tight. Six model years now either just above or just below the minimum sample size.

Car reliability research

Can you please explain to me who your are and of what value to you is this information. Is for a reliability study which is to be sold for a price or is it for your own information and the good of the Boxster community? Is anyone funding this research and what is their reason for funding. If these questions are answered I bet a lot more people , like myself , will be willing to participate. If it is a financial investment don't you think that offering some incentive of true value is appropo as we have what you want. Information has a value. Just my oponion. Ed

Sorry for the late response--the notification must have gone into my spam folder.

I conduct this research primarily for those who participate in it. Participants receive access to the results for all cars, not just the Boxster, for free--something that other reliability surveys do not offer. I do hope to benefit the Boxster community in general, so any reliability stats for the Boxseter will also be posted here.

I have been funding this research out of my own pocket. I justify it to my wife by saying there will eventually be some financial return, but we're not nearly there yet. My primary motivation has always been that I felt a need for more frequently updated, numeric reliability stats, and no one else was willing to provide such information to the general public. Sometimes if you want something done you need to do it yourself.

There are now 220 Boxster owners signed up to help. It looks like we'll have the first partial results in November. We will need larger sample sizes to provide stats for specific failure, like the IMS.

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Maybe it could be used in a class action lawsuit( that is if my engine ever implodes) :D

To be honest, I'd rather avoid this application, if only because it provides an incentive to distort the results.

244 Boxster and Cayman owners now signed up. Four model years are now in the survey, and another four are close to the minimum sample size. A good start, but more are needed to provide precise results for all model years.

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Where's Porsche?
 

I signed up. Went to "Car Reliability Comparisons" and found no entry for Porsche in the drop down menu. What's up?

I had the same issue, couldn't find Porsche anywhere. I guess I am tarded.

What's up is that we can't post any results in that area until we have enough people who've been participating for 3+ months. There's an inherent delay built into the survey process. To avoid possible sources of bias, it only collects data going forward.

With 273 owners signed up so far, we should start having results for some model years in November. The 1999, 2000, 2001, 2002, and 2005 are already in the survey, and the 2003, 2006, 2007, and 2008 are all close.

To sign up:

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To view repairs reported so far (not all of these will be included in the analysis):

Porsche Boxster repair histories

I saw the results yesterday for the 2001 Boxster...I knew the cars had maintenance issues but jeez. According to the number of times in the shop the Boxster is one of the worst. Good thing is I also own one of the most reliable, a 2005 4runner. I am going to try and get the IMS updated after the cold season.

You saw a preview of the November results that were only for participants in the survey.

The preview is based on data that has not been entirely cleaned, and responses are still coming in. We won't have an official result until November, and the figures could change.

I have not checked yet, but I doubt that many of the reported repairs have been for the IMS, or are even serious mechanical issues.

Also realize that the sample size is, as I type this, about 70% what we require for a full result. So even the November result will be a preliminary result. We should have a full result in February.

It is common for high reported repair rates to come down as the sample size grows. So I wouldn't get too wound up until we have that February result.

I do hope more owners will participate--the larger the sample size, the more precise the results will be.

We have our first reliability stats for the Boxster that include owner experiences through September 30, 2009. In terms of repair trips per 100 cars per year:

2005: 138, worse than average

2001: 189, worse than average

2000: 163, about average

1999: 91, better than average

In all four cases the sample sizes were a few cars short of the minimum needed for a full result, so these are asterisked and visible only to members on the site itself.

The result for the 1999 is clearly inconsistent with the others.

A big thank you to everyone who has been helping. We'll have more data and thus more precise results with the next update, in February. The more owners sign up and participate, the more precise these results will become.

Porsche Boxster reliability comparisons

Interesting.

Good job.

:cheers:

Thanks for the compliment, I appreciate it.

Updated results next month. I hope to have more consistent results this time. Much will depend on the number of participants. 317 owners signed up so far. A very good start, but clearly more remain needed.

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Later this month we'll have full results for four model years and partial results for two more.

The goal: full results for all model years.

Not yet signed up? Details here:

Car reliability research