Boulder GT3

There was a thread a few days about which Mobil1 to use on the GT3. FWIW, I just got off the phone with Redline and here is their recommendation with some commentary:

They said to use 75w90 NS in the GT3 transaxle. There will be noise from the LSD in tight turns. If it is a pure street application and the noise bothers you, add friction modifier up to 1% of the fill. This will quiet the LSD and not leave the oil so slippery that the synchros don't work well which can wear them out prematurely.

Redline 75w90 does have friction modifiers in the ratio of 5%. They don't recommend it with synchros. I was surprised at how much additive there is compared to what is recommended to quiet the unit. 5X.

Redline MTL is for gear boxes only and is not thick enough for transaxles.

none of the Redline oils have additives in them that corrode brass or "yellow" parts in the transmission. I didn't know, but the corrosive element is sulpher based which is what that bad stink is you sometimes smell with some hot gear oils.

cincysaab

have you looked into mobil hsc.

9Eleven

This is the post that I put on the original thread, sounds like TPC knows what they are talking about.

This is what I was told by a pretty reputable guy who races in the Rolex series. This is what he put in my car when he changed my gear oil. "We use a mixture that we make with the Redline product. Normally 75-90 oils have a coeffient of friction of 6% modifiers. We have found better syncro control and clutch pack control with 3% to 1%, but 1% is too critical and a syncro can stick, so we stay at 3%."

Boulder GT3

Yes. The problem I've had is getting the right Mobil product near by. They have a range of packaging and as someone said, it's probably all made in the same way at the same plant but it's hard to tell. My first choice is the Mobil factory fill but Redline is very available.

Phokaioglaukos

Check out that other thread HERE , and especially my post HERE with the attached Mobil datasheets on their three oils. They are different, and only the Porsche-spec oil has the copper corrosion inhibitor. You decide how much that matters to you.

For the street GT3 with the copper in the LSD, I'm sticking with the Porsche oils. Were I to change to the cup car LSD which is, I think, all steel, I may well change to the Delvac/SHC oil that others use in those cars.

Boulder GT3

Chris, thanks for the research from the Mobil end. I trust it.

Talk to the dealer about Mobil and I wouldn't be surprised if you get some conflicting answers although again, I trust your data.

I put the post up on the Redline lube largely because of the concern I have about corrosion to any of the soft or what the gear guys call "yellow" metals which includes copper clutch material.

This concern was accelerated when the redline engineer said the corrosion from the wrong additives in the gear oil increases dramatically with heat. Said another way, what may not cause immediate harm on the street is a short term disaster on the track.

I've tracked my car very little but I'm going to send a sample of the oil in and have it analyzed just for grins.

jlasuncion

"They said to use 75w90 NS in the GT3 transaxle. There will be noise from the LSD in tight turns. If it is a pure street application and the noise bothers you, add friction modifier up to 1% of the fill. This will quiet the LSD and not leave the oil so slippery that the synchros don't work well which can wear them out prematurely."

how do i add friction modifier to 1%? is that sold separately and I mix it with the 75w90 NS?