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      03-28-2019, 09:43 AM   #7
Asbjorn
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Drives: Z4 N54 DCT (VTT GC lites)
Join Date: Mar 2012
Location: European in China

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So what I have read is that the dct oil is good up to a certain temperature. If it overheats, it starts to loose its original properties. You want to avoid that. When you serviced your DCT did they add new oil, and how much, or did they reuse the old oil?

I have posted several transmission temperature logs over at spool street. My build thread is also over there. I use MHD and my logs are here

www.datazap.me/u/asbjoern

But to summarize, the DCT might go to 100C during normal street driving (with DCT cooler off), but never exceeds 90C on track (with DCT cooler on) (EDIT: correction, it does go above 90 and even 100C on track if the weather is hot enough)

I run an SSP DCT oil cooler that I can turn on and off within the cabin. This because I go on track all the time for time attack and practice. So far I have not had issues with the DCT at all. And mind you that I have killed turbos twice due to my application. I am at 120,000kms, and have already replaced the DCT oil with new oil twice during its lifetime.

Unfortunately the Z4 does not have an DCT oil cooler from factory like the M3 did, so if you want to get into serious track driving, you might want to look into aftermarket DCT coolers. In fact even M3 owners do this, and know that the only cooler that was upgraded between the M4 and M4 gt4 was the DCT cooler (taken from the M6 on the GT4).

Last edited by Asbjorn; 09-26-2019 at 01:52 AM..
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