[BiturboS4] Turbo change in pairs - can someone explain me why ?

[jysap at cs.com]

I would also recommend that u UPGRADE your turbos when replacing them, if possible. The additional 'out of pocket' for a turbo that can more than handle the load, it worth it in the long run (if u plan on keeping your car for 100,000+ mi like me). I kinda feel left out - I have not had a PEEP out of my turbos and my car was built in 1999 (Nov - yes - it's an early S4). I could be in for trouble when I chip the car but I will take all the necessary precautions to lighten the load on my turbo after chipping. My Porsche (951-Turbo) is chipped and has 125k mi - she still pulls strong - but I did make other adjustments to make sure that the engine was not strained (incld keeping the boost level around 12-13 psi).


jy
00 S4
86 951


Steven Lin <steven at juniper.net> wrote:

>David  writes:
>
>> Ok, I understand that if your car has 100 000 miles, and one turbo dies,
>> chances are that the second one will follow in a short time. I understand
>> that and old turbo will have maybe less efficiency than a new one, and
>> mixing them would - maybe - corrupt the balance of the work of the 6
>> cylinders. But if you have the one which fails fixed, and the other one
>> carefully checked, by a specialized workshop, what's the problem ? That's
>> what I'm planning to do, and it should be much cheaper than changing both of
>> them.
>
>The conjecture is that the second turbo was likely
>shouldering the workload of both turbos when the first went out.  How
>much are you willing to gamble on that second turbo?  It's the
>opportunity cost of a second, future turbo replacement versus a second
>turbo.
>
>Besides, in one of their study guides, Audi recommends that turbos be
>replaced in pairs.
>
>Steven
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