Oil question, sorry in advance, Im confused, DT40 or DI40??
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Instructor
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From: Greenville, SC
Oil question, sorry in advance, Im confused, DT40 or DI40??
So Ive read that the DT40 was developed specifically for the M96, but also read that DI40 is better, from seemingly knowledgeable people on the subject! So which is it?!?!
My vehicle is a 2000 911 C4 manual with 163k miles. Engine rebuilt at 137k. I live in SC, I drive it hard, daily driver, but I dont track it.
My vehicle is a 2000 911 C4 manual with 163k miles. Engine rebuilt at 137k. I live in SC, I drive it hard, daily driver, but I dont track it.
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Here you go.
Driven DI40 / DT40 & pca Video - Rennlist - Porsche Discussion Forums https://share.google/987yaol0BuXRYr6Wh
Driven DI40 / DT40 & pca Video - Rennlist - Porsche Discussion Forums https://share.google/987yaol0BuXRYr6Wh
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So Ive read that the DT40 was developed specifically for the M96, but also read that DI40 is better, from seemingly knowledgeable people on the subject! So which is it?!?!
My vehicle is a 2000 911 C4 manual with 163k miles. Engine rebuilt at 137k. I live in SC, I drive it hard, daily driver, but I dont track it.
My vehicle is a 2000 911 C4 manual with 163k miles. Engine rebuilt at 137k. I live in SC, I drive it hard, daily driver, but I dont track it.
https://lnengineering.com/products/driven-racing-oils/
Burning Brakes
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From: Parkland FL
Last edited by allcool; Apr 22, 2026 at 01:34 PM.
Thread Starter
Instructor
Joined: Mar 2013
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From: Greenville, SC
I know, and Ive seen that. The fact that Porsche recommends a 50 weight and an oil that was designed for the M96 is a 40 weight is hard to square. I guess Im back to square one. I dont know what to run.
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From: Washington DC
Newer to 996 ownership so Im sure Im missing something obvious, but just curious where you heard that the Driven 40 weight oils were designed for the M96? Going on the Driven website, I didnt see any specific mention of Porsche other than DI40 has an active following in the Porsche community. DT40 page just says its used for German, Italian, British sports cars and Chrysler 6.4L hemis, as well as for European turbocharged engines. I have definitely heard about the many positive benefits of the oil in our engines, but was just curious about the designed for comment as would think it would be specifically called out on the website. Thanks!
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From: Illinois
Newer to 996 ownership so Im sure Im missing something obvious, but just curious where you heard that the Driven 40 weight oils were designed for the M96? Going on the Driven website, I didnt see any specific mention of Porsche other than DI40 has an active following in the Porsche community. DT40 page just says its used for German, Italian, British sports cars and Chrysler 6.4L hemis, as well as for European turbocharged engines. I have definitely heard about the many positive benefits of the oil in our engines, but was just curious about the designed for comment as would think it would be specifically called out on the website. Thanks!
Watch the video I attached early on in the thread. It will fill you in.
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From: UT
Lake Speed who was the tribologist at Driven worked with Charles Navarro and Jake Raby to develop DT oil for the M96. Later the DI oil was developed which many of us prefer. Both are excellent high moly, high viscosity oils. DI can be run on both the street amd track, whereas DT is for the street.
Watch the video I attached early on in the thread. It will fill you in.
Watch the video I attached early on in the thread. It will fill you in.
I dont usually drive my car that hard but once in a while it gets the old Italian tune up.
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From: Illinois
DI is more expensive would be the only downside. I run DI50 on both street and track. If I didnt track my car I would still run DI. FwIW, if you live in a cold weather town amd want to drive your car during the winter, you may want to consider running DI40 in the cold weather months and then switch to DI50 in the warm weather months. DI50 is higher viscosity than DI40 and will improve the oil pressure.
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From: Momence, IL
Newer to 996 ownership so Im sure Im missing something obvious, but just curious where you heard that the Driven 40 weight oils were designed for the M96? Going on the Driven website, I didnt see any specific mention of Porsche other than DI40 has an active following in the Porsche community. DT40 page just says its used for German, Italian, British sports cars and Chrysler 6.4L hemis, as well as for European turbocharged engines. I have definitely heard about the many positive benefits of the oil in our engines, but was just curious about the designed for comment as would think it would be specifically called out on the website. Thanks!
However, if you do contact Driven regarding Porsche applications, they just forward those inquires to us as they don't have any European specialists on their support staff. I myself deal directly with the person in charge of formulations.
Jake and I did the testing for Driven in Porsche engines way back in the day. In subsequent years, Driven purchased a Boxster and did extensive OTR testing on that platform to back up our results.
Although Lake may not be at Driven any longer, he still drives a Boxster. LN's in fact, with a 3.8 with plasma sprayed bores that has been on the road since 2019.
All this aside, just look at the used oil analysis results shared by other forum members with their use of DT40. There really isn't any other reason to use any other oil in your street driven Boxster, Cayman, or 911.
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Joined: Apr 2025
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From: Washington DC
The Driven website leaves much to be desired. I have brought this up to them on several occasions.
However, if you do contact Driven regarding Porsche applications, they just forward those inquires to us as they don't have any European specialists on their support staff. I myself deal directly with the person in charge of formulations.
Jake and I did the testing for Driven in Porsche engines way back in the day. In subsequent years, Driven purchased a Boxster and did extensive OTR testing on that platform to back up our results.
https://youtu.be/Ca2UbzBzBNw
Although Lake may not be at Driven any longer, he still drives a Boxster. LN's in fact, with a 3.8 with plasma sprayed bores that has been on the road since 2019.
All this aside, just look at the used oil analysis results shared by other forum members with their use of DT40. There really isn't any other reason to use any other oil in your street driven Boxster, Cayman, or 911.
However, if you do contact Driven regarding Porsche applications, they just forward those inquires to us as they don't have any European specialists on their support staff. I myself deal directly with the person in charge of formulations.
Jake and I did the testing for Driven in Porsche engines way back in the day. In subsequent years, Driven purchased a Boxster and did extensive OTR testing on that platform to back up our results.
https://youtu.be/Ca2UbzBzBNw
Although Lake may not be at Driven any longer, he still drives a Boxster. LN's in fact, with a 3.8 with plasma sprayed bores that has been on the road since 2019.
All this aside, just look at the used oil analysis results shared by other forum members with their use of DT40. There really isn't any other reason to use any other oil in your street driven Boxster, Cayman, or 911.
Rennlist Member
Joined: Apr 2025
Posts: 34
Likes: 14
From: Washington DC
Lake Speed who was the tribologist at Driven worked with Charles Navarro and Jake Raby to develop DT oil for the M96. Later the DI oil was developed which many of us prefer. Both are excellent high moly, high viscosity oils. DI can be run on both the street amd track, whereas DT is for the street.
Watch the video I attached early on in the thread. It will fill you in.
Watch the video I attached early on in the thread. It will fill you in.
Thread Starter
Instructor
Joined: Mar 2013
Posts: 228
Likes: 124
From: Greenville, SC
Burning Brakes
Joined: Jul 2022
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From: Parkland FL
Was this 'rebuild' on oem @163k miles Porsche lokasil cylinders, or on previously built sleeved niksil or steel cylinders...?
Last edited by allcool; Apr 24, 2026 at 11:39 AM.