Metal Guru

I have just completed the A-B-A test of Mobil 1 75W-90 Delvac to Mobil 1 75W-90 LS.
$150 later and I can tell you that the LS was is superior to Delvac. While there is a little differential noise with LS the Delvac was so bad I thought my tansaxle was going to lock up and leave me stranded, it was that bad.
Bothoils yielded the same shifting; a little notchy when cold but smooth when warm.
Doing a search will show many that sing the praises of Delvac. I must assume that the formulation has changed recently because I couldn't get it out of my tranny fast enough.

LVDell

I find that VERY hard to believe especially comparing Delvac to off the shelf LS. I run Delvac in my RSA race car and it's the ONLY gear oil Copans would approve in my GT3 to warrant the gearbox and LSD. Sounds like there is something else at play as Delvac is not going to lock up your transaxle.

Metal Guru

Believe it.
The Delvac was not slippery enough. Made lots of scary noises.

LVDell

Do you have a LSD?

bgiere

Something is not right with the synchros then....

ltc

Porsche...Transmissions....Copans
Whatever he says goes IMHO.

Metal Guru

Did I not say shifting was fine?
Yes, all 965's have LSD. Mine was rebuilt 3000 miles ago.
I will re-state: the Delvac was not slippery enough. My LSD clutches were draggy and noisy, big time. Plain old off-the-shelf LS 75W-90 works better in my car. Why is that so hard to believe?
Who the hell is Copans?

LVDell

Nice attitude. Unsubscribing.

Steve Weiner-Rennsport Systems

Hi Paul,

I'd agree with Brant on this: something is amiss,.....

The term "rebuilt" means many things and its sufficiently vague to cover a wide range of services. I'm wondering precisely what was replaced inside your transmission as we've had excellent success with Delvac in our G50's (street & race cars).

I don't think anyone is questioning your experience, but I'd offer its the exception, not the rule.

Brian Copans is a nationally renowned rebuilder of G50 transmissions and is VERY VERY good at what he does.

ltc

http://forums.pelicanparts.com/showt...hreadid=297491

mooty

one of the porsche transmission God, so is gamroth.
probably knows more about porsche gearboxes then porsche gearbox engineers.
he can rebuild these things blind folded in 30-45 min and get the cup cars back on track.

i have 20 bottles of Delvec in my garage. i have run 75/90 off the shelf mobil 1 before. but delvec is better, at least for me.

Metal Guru

Steve,
The LSD was rebuilt by the P.O. using a local shop. The clutch plates are from the 3.6 as Porsche does not sell the 3.3 clutch plates any longer.
Is it possible that I got a bad batch of oil?
There seems to be a fair amount of variation in the two batches of LS I have used in this short time frame with the latest change being the best.

JasonAndreas

Its not hard to believe at all. I'll even go so far as to say that Mobilube PTX works better than Delvac in a stock 964 gearbox (with non-steel syncros)... The material that your LSD clutch packs are made from is probably different to what is in the GT3 and Cupcars? So a blanket recommendation for one spec of lube might not apply here? There have also been a long list of 964 turbo owners complaining about LSD chatter when the wrong gearbox lube was unknowingly used. So its not hard to believe at all.

Steve Weiner-Rennsport Systems

Jason offers good points; there are differences between street & Motorsport/aftermarket LSD plates. We get the Guard Transmission ones as they are more durable.

Its possible that you received a bad batch of oil; I've never had a VOA done on several batches to see how consistent they are and that might be worth doing. Delvac is used here in the majority of G50's without difficulties and it aids in LSD performance, especially the not-very-robust street 2-plate versions.

bgiere

I did "hear" that some of Mobil's motor oil was "off" due to the disruption caused by Hurricane Katrina..supposedly one of the blending plants had an issue which affected the oils...it's possible the batch was not up to par I suppose.