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New Gearbox oil specified for Renaultsport - time to change

Posted: Fri Apr 18, 2014 5:42 pm
by AlexB
Hi guys! This is to let you know that a new oil is now specified for Renaultsport gearboxes (PK4...). This new oil is thin synthetic with potassium borate nanotechnology. It reduces friction considerably, which leads to more power at the wheels. If someone doesn't know, gearbox losses are 15-20% of the engine power. Cut a few % from here, and this will equate to quite a few horse forces at the wheels!

The oil in question is Tranself-nfp-75w80, which replaces TRX. It is suitable for RS-Cup LSD as well. The nanotechnology spec appeared only in 2011. If your car is older, then change the oil!

How do you think RS250 became RS265? If only they chose to use Miller's nanotechnology engine oil, then it would have become RS270!

Re: New Gearbox oil specified for Renaultsport - time to cha

Posted: Thu Jun 19, 2014 9:20 am
by AlexB
Received a question in PM...

To choose a right gearbox oil is more difficult than engine oil. This is because of conflicting requirements for the synchronizers and hypoid gears. You need friction in the former and no friction in the latter. Then comes the temperature range, which is a challenge, because the gearbox does not have a thermostat. Then wear, etc.

The top models come equipped with an LSD of gear type; these are tuned to have some particular friction under certain slip rates and load. Change the characteristics of the oil, and it will become detuned! So, upon experiments I came back to the OEM oil in my rs250 cup, just switched to the latest OEM spec oil as detailed in the earlier post.

Re: New Gearbox oil specified for Renaultsport - time to change

Posted: Sun Sep 01, 2019 10:18 am
by ChrisStark
:hm Hi there! I'm new here. Just began reading. Now I wonder. I got a 2005 225 Lux (no cup). Should I change to the oil in your first post or not. What if I upgrade to the r26 gearbox (with LSD)? Sorry I'm from germany and I don't fully understand your posts if you recommend changing the oil or not... Thx mate :grin