67King

According to Porsche, it is also an accepted fact that there is no IMS bearing problem.............


Now this thread looks just like every other piece of info I have found out there. There are a LOT of really smart guys who are out there saying you can't do something, it is known........as if it were as common knowledge as teh sky being blue.

But then you have a few guys who have tried doing something against that common knowledge.........and so far, I have not found anyone who has said "Yeah, I tried it, learned my lesson the hard way......"

I guess it gets back to my experience at Ford. Back in the early 2000's, Ford's engines weren't really that competitive. And everyone else out there was making things that our internal experts said we couldn't make, and pass durability. In the Fall of 2006, there was a 30% reduction in engineering across the board, and many of those older guys took early retirement. With them gone, and their common knowledge with them, we were able to do some really cool stuff. I'll point to the 5.0L I worked on. Prior 4V V8 made 315 horse or so. They retire, we are able to bore it, stroke it, run more aggressive cams, and use smaller valvetrain components.......and we made about 425 horsepower (it is underrated at 420), and it has been on the Ward's 10 Best since it came out.

And Scott, that is NOT directed at you - just giving a background on why I am suspicous of "common" knowledge when there is evidence (albeit anecdotal) to the contrary. Like I said at first, I apprecite your input, and I'm trying to learn here. I know you're a smart guy, and I value you input, regardless of whether or not it is what I want to hear.


I would love for someone who has tried both to share their experience. That's one of the reasons I sent a note to the guy I know in England who has run as many of these as anyone. I'm not worried about making one sale - I'm worried about telling a guy to run something, and have it not work, and then me looking bad and losing credibility. In Matt's case, he has a problem that I believe the stuff I sell will help him with.

winders

Look here:

http://www.bobistheoilguy.com/forums...&Number=508604

The "Hayden" text is from Hayden Burvill of Wevo fame.

Do a Google search you will find more........

Scott

Mahler9th

Thanks for agreeing with me Scott. As I said, be careful of absolutes. If the nut behind the wheel works the box as you describe, than there may be benefits of a synthetic like Red Line over say a product like Swepco.

In case you do not know, my favorite transmission builder is... me. I have done it a few times and have been running the Red Line for 10+ years without issue.

The builder to which I think you referred was basically unaware of the Red Line NS product when I spoke to him last on this topic in 2012. I have been using the NS for quite a while.

If the nut behind the wheel does a good job, then there is a case for the extra thermal protection (theoretical as I have not reviewed specs) of the Red Line, especially the NS version as recommend in the link you provided from that rebuilder in North Carolina. Who incidentally seems to recommend dyno lubes, and then somewhat contradicts himself and recommends Red Line's NS product as well.

I would love to know the technical details wrt slipperiness of synthetics, synthetics with friction modifiers (like the Red Line NS product) and dyno products like the Swepco. And of course how that relates to our 915 synchro system. And the thermal details. I'd like to be able to decide which trade-offs make more sense. Of course any such analysis has to factor in the nut behind the wheel. So in reality, a carefully-controlled experiment is in order.

Perhaps a decade from now, when you have reached the experience level that I have thus far accumulated, you will have performed this analysis, or someone else will have done so.

In any case, experience can be a good teacher, and application-specific choices can be beneficial. And it could be beneficial to understand the difference between theory and practice.

Matt Romanowski

Hmmmm...didn't realize that gear lube was the same as head restraints, engine oil, and politics.

I've been a guinea pig before and think I might try it again. Sometimes it's fun to do what people say can't work.

winders

Matt,

It really comes down to how much you want to baby the 901 when shifting. If you are going to rely on the synchromesh system to match the speed between the gear and the input shaft, you really need more friction than synthetics allow. If you match revs on down shifts, even better if you double clutch, and are patient on the upshifts, it's not so important.

I'd go with the cooler and Swepco 201 or 210 based on the problem you are experiencing. Again, Woods and Anderson found that Swepco solved the 935 R&P problem they had. Swepco 201 is still used extensively in the trucking industry because of how well it works.

Scott

Scott

Matt Romanowski

I'm not really concerned about syncro or dog tooth wear. I've run synthetic in my other track car without problems or extra wear (well over 150 track days).

With the cooler and spraying the ring and pinion, I think things will probably be ok regardless of which lube I use. But, I don't really car to do it again, so I'm open to trying something new.

67King

Matt, heard back from Martyn at Millers. He indicates the factory fill oils were plenty slippery, and that the "avoid synthetics" thing out there is a "wife's tale." Like I had said earlier, he's a Porsche guy, though his current one is a 964, so it won't be affected by this discussion. I don't mean to say that his opinion should trump that of gearbox builders, only offering the chemists point of view relative to the properties of different types of oils. Still waiting to hear back from some other places, notably the guy I mentioned in England who has a race shop devoted to the ealry 911's. I did note that GBox recommends the Posche oil, which will be Mobil 1, and I suspect synthetic. http://www.gboxweb.com/faqs.html

That said, Millers offers applicable conventional GL-5 gear oil that matches pretty closely with the Swepco, so it is not a case of a dismissing something because they don't make an appropriate product. This is not something we have in inventory, but I may get some in case we have any calls for it. http://www.millersoils.co.uk/automot...ector=Classics

winders

Well, here you go. It's not a wives tale. Look at post #35 again. The Factory fill was not "plenty slippery" since it was a conventional oil made in the 1960's.

Scott

Matt Romanowski

67King - You would suggest the CRX 75w90 NT then? I'm going to try it and then I'll know if it works or not.

67King

Yes, that's what I would try if it were my gearbox.

But I also run 18's on my 944 against Porshce's recommendation.

winders

If you have an LSD, the Miller web site says to use CRX LS 75w90 NT.

Here something else the Miller site says: "Recommended for modern transmissions where fully synthetic oil is specified..."

Good luck.

Scott

Gary R.

I use Kendall, that way my garage floor only has one color puddle...

67King

Most oil suppliers recommend LS additive for limited slip applications. On our website, we elaborate a bit, and devote some space in our FAQ to it.

Thanks for your conitued contribution. Your objections are noted.

bgiere

I have nothing to add other than I just filled up my zero hour 996 cup gearbox with Millers 75w90NT...I am going to run it for 15 hours and take a sample. It was filled with Delvac after the rebuild, I drained it into a 5 gallon jug and kept it on the shelf. Never had an issue running Delvac but thought I'd give Millers a test run. Seems to me that some teams have saved themselves some money by using it. Oil discussions are mostly anecdotal...I pull samples and gather data but that can take years to draw conclusions from.

winders

Brant,

I suspect that the Millers 75w90NT is a perfect choice for your application. Then again, you do have a modern transmission using Borg-Warner style synchros.

Scott