I am trying to get a PPI done in a P dealership near the car in MN. The dervice dept' said Compression test is $600 and leakdown is $780. This sounds very high to me. Should I have this done as part of PPI or skip?

 

Hi Brian:

You need to find someone else to do these tests for you; those folks are not honest.

It takes about 6 hours to perform a compression & leakdown test on a TT. They are not easy to get to.

I would not buy any car without those test results in hand.

 

The whole PPI shouldn't cost $500 including R&R to do tests. I found one local shop that even pulls valve covers (on normally aspirated cars) during their PPI (!) so it's a matter of you deciding on the work and the documentation you expect.

It (compression or leak-down) is time-consuming and it involves removing all the junk on top of the engine to get at the plugs. It's also incredibly time-consuming to get to the front plug on the passenger side. I suggest you instruct them to strip down just the driver side, test that bank and then abort if there's any sign of real problems and go for another car.

Most of the time is in R&R. The tests can be done in about two minutes per cylinder once you've reached the plugs. I had a race shop do tests while I was shopping. They knew 993 Turbos and wasted no time on having the right tools and the right size weaponry at hand.

If you're buying locally, I suggest using the PPI to begin the relationship with the shop that will be the long-term service for the car. You really have to find a 993 Turbo expert to inspect it and then to look after it long term.

I've never found anyone that knows a Porsche-documented number on the actual compression of their engines, just the ratio.

The most important thing is to see all the numbers balanced and consistent on all cylinders.

Please post back with the test results. I'm always interested to hear data points on various engine condition factors for given mileage and usage.

Cheers,

 

Thanks for the info. I am not buying the car locally, its in MN. I am in CT. A couple of people have recommended www.auto-edge.com who I will probably use. I will let you know the results.

 

Carrera GT, sounds like you're happy with your shop. Who is it?

 

I used www.theracersgroup.com -- it's not their core business by any means, but they did well.

To clarify, Carrera Motors in San Mateo is the shop that pulled a valve cover on a Carrera during the PPI.