GBoxguys

I just wanted to make sure that everyone had their questions answered for the operation of this differential?

Let me know if I can be of any help here.

Erik Johnson
GBox LLC

IcemanG17

There is NO doubt that my discs are on the "worn" side of the spectrum.....my plan for now is to limp this trans until winter when I will install a freshly rebuilt one with a tighter LSD.......then send this one out to be rebuilt.....so I always will have a fresh trans-LSD around in case a break something..... The good part about running G28-03's is they are quite common and fairly cheap to find......I have 2 with LSD and one open already

IcemanG17

sorta related comment....

My Scion FR-S has a "torsen" LSD I think....and I gotta say when applying throttle mid corner it really helps it "jump" off the corner......Toyota-Subaru really did a great jump tuning this diff.....granted a 151ftlb car thats 2750lbs with tiny tires is much easier than a race 928.....but damn does it work well.....

Roy928tt

Dunno guys, if I could fit an OS Giken LSDiff I'd have no qualms about fitting it, It's what the Fully Sic Drift Puppies use and they know diffs....Gotta be better than a 30 yr old Porsche part.

Carl Fausett

Their reputation is stainless. All you have to do is Google "OS Giken LSD" to get stories from all over the globe from users and magazines. I'm in.

brutus

Top pro drifters use a sprintcar style quick change rear and run a spool no differential at all ! Both rear wheels always spin the same speed causes massive understeer but only until they get on the gas and break the rear tires loose then it is ALL OVERSTEER. They literally steer with the gas pedal.
Understanding handling and car setup which includes how tight you want a slip to be is not an easy task. Porsche went to the computer controlled units in1990 and newer 928s to allow the car to perform better over a wider range of situations.

GTgears

Carl,
Just a point of fact, but Eddie has been trying to get that quote pulled off the internet for 6 months now. He broke 3 OS Gikens LSDs in a row in under 100 days and then came to us. What he had been running previously was an OEM Porsche LSD when he spun out. Within the last 30 days he set a new world record in the 1/4 mi with our LSD in the car. Call him up. He'll tell you that he will never ever put a Giken differential in his car ever again.
In his own words in post #60:
http://forums.pelicanparts.com/911-9...-1-4-mile.html
And the world record run:

http://forums.pelicanparts.com/911-9...le-record.html

Not trying to start a GT versus Giken debate here, and I am sure that they will deliver you guys a good product for your cars. I'm just saying Eddie Bello should not be held up as an example of Giken's success.

Carl Fausett

Good to know. Obviously, I pulled that quote from Giken's website.
You would think that the quote was good if it was on the parent company website, right?

I have to apply the same caution to your statements too... as you work for the company you are promoting.

Still, happy to have your input.

Thus far, I have only 3 of these LSD's "pre-sold" so it would appear the level of interest will not warrant the manufacturing of the product. I need to make a batch of 10 if I'm going to make it at all.

Will your firm allow a smaller batch quantity? Send your contact info to me at carl@928motorsports.com if you are interested in working with me on this project.

GTgears

Carl,
I appreciate your interest, but I've already partnered with Greg Brown on this project. A GT 928 LSD will get made. It's just a question of competing priorities and whatnot that will determine when it actually comes to fruition. However, I decided some time ago that I would make a 928 LSD without putting anyone on the hook for initial buy in. It might not be until next year, but I'm going to make one.

Mike Simard

GT, I'd love to see some LSDs be available and would be glad to help with dimensions if you'd like. I have the basic dimensions measured and parts lying around. You'll need to consider the ring gear face to CL dimension that's presumably from adding a big-pinion 2.20 gear to the lineup in '85 and the carrier needing 3-4mm more room.

Speaking of LSD diffs, what the heck is it with 915 diifs being extremely rare? I've kept my eye open for a year and only saw one come up for sale, one!

GTgears

Mike,

Thanks for the offer. Greg's got me covered. I've got an early one here and when the time comes, Greg has a late one he's going to send over.

Regards,

Matt

Carl Fausett

Ah. Now your post becomes more clear. You crapped on OS Giken because you want to build up interest in your competing product that might someday appear.

Good luck with that.

GregBBRD

Actually Carl, although it is obvious that this is the way your mind automatically works....we couold care less and encourage you to go ahead and build "your" units from Gilen.

However, if you'd done your research properly, you'd have found that many of the Giken differentials have failed when used in Porsche high performance use. As a matter of fact, it is kinda tough to find anyone, in the Porsche racing world, that much very nice to say about them, at all, except that they do seem to offer replacement differentials when theirs break. Of course, when the ring and pinion and transmission cases are ruined by the differentials going bad, they don't replace that stuff.....

Like Matt suggested....call Eddie and talk to him....before you accuse someone of doing business like you do.

You will find out that Matt is just making a truthful statement.....no more, no less.

BIG 928

i read that eddie bello had broke 3 os gikens in a short period of time when they was mentioned on the cup car forum not that long ago. as i run a hollinger in my cayman racecar i was reading up on cup car gearboxes/diff options to cope with the 993 gt2 evo motor i run in the cayman.
everyone should remember the car that broke the os diffs had 1200 bhp. i guy i race with in the porsche open in england runs a os diff in his 997 cup and has never had a problem in 5 seasons of racing plus 2 24 hours at silverstone so cant be that bad.

im reading this as my old gts racer has broken some diffs in the past(or is that my driving?)

regards mark

GTgears

Carl, if you knew anything about me, you would know that I have only owned Guard Transmission for 3 years, but have been embedded in the Porsche community, specialising in gearboxes, for the better part of a decade. I am like the Norelco guy. I believed so much in the company that I bought it. Not the other way around.

Six month ago, I would have agreed with your point. Previously, all of the Porsche based failures that had come to my attention were cars like Eddie's. He's got 1200 whp. He broke 3. All of the half a dozen or more EVOMS customers that broke Gikens that I know of have 800-1000 whp.

But then just last week I got a call from someone with an RS America. It's a stock car. What is that, 275bhp? 2 years of DE usage and he broke the drive gears in the Giken. Is it an exception? Does he have one of the set of "defective" drive gears that Giken has publicly talked about? They didn't warranty his LSD and he bought one of ours instead. His installer, whom I will not name because I don't wish to embarass him, installed the unit free of labor charges.

Carl can cast any aspersions that he likes. I only encourage any potential 928 LSD buyer to do their homework. GT supplies the likes of Ruf, 9FF, Champion, Sharkwerks, TRG, Bullet Racing, BGB Motorsports, and Alex Job Racing with product. I don't give anything away for free. Any of the above mentioned companies that run our products in their cars paid for it. We didn't give it to them just to say that they were our customers. And if there's anyone out there that is reading this that has ever blown up a GT LSD, send me your email address. Show me pictures and send your LSD to me. I don't take failures lightly. I'm not going to tell you that the LSD is warrantied but the rest of the gearbox is your own damn problem like has been done with more than several Giken customers. If my product failed prematurely and took out your gearbox, I wil do right by you. Even after 2 years drive gears shouldn't self destruct. In 2 years, a racecar can wear out clutches, but unless there's a serious cooling issue with the gearbox and it's running insanely hot, drive gears should not fail. Drive gears are not a standard wear item. We rebuild LSDs 2 or 3 times before we replace the drive gears. And 2 years is way too soon for a weekend track toy to be eating drive gears.

The question I encourage any potential LSD customer to ask to the vendor they are buying their LSD from is how much power can it take? I heard a rumour that Giken recently re-rated their G50 LSD to only be able to handle 400whp. What is that at the crank, 500bhp? If you don't make that kind of power, then maybe this product that Carl is promoting is ok for you. If you make more than that, you might want to look further for a solution to your traction problems...