Final drive gearing

According to Jim, it was a special Dinan differential he managed to get hold of in his travels, and I believe had Brett at Koala MS install a Quaife unit. IMO the optimum setup,

Martinw, Keep in mind that Jim has almost 500Hp to push those gears.

Martin, you have the option of swapping the LSD and new final drive ratio into your diff case so the cooling issue isn't really a problem, leave it on if you want to.
There's always plenty of diffs around and it's just a case of getting on the phone, it's only a matter of time before you get lucky, for example (a couple possibles on Ebay right now);

http://cgi.ebay.co.uk/BMW-535i…geNameZWD1VQQcmdZViewItem
Potteries Vehicle Recylcling (Stoke-on-Trent, 07805 989237) it's an F reg' 535i they want a ton for the diff so it's worth a call (it may or may not have a LSD but if they don't know and it has that can only work in your favour, if they've got it off the car it's got to be worth checking).

http://cgi.ebay.co.uk/BMW-E34-…geNameZWD1VQQcmdZViewItem
Midland BM (0121 544 9444), it's not got an LSD in it but it could be the ratio you want and at 90 quid could also be worth a call.

Martin, not having a CSI I never paid attention to the cooling system you have and seeing it looks interesting indeed. In looking at the setup you have from RealOem HERE and looking at a differential that should work on your car HERE it appears to me that the case does have the inlets or at least blanks in the casting that could be tapped.
FYI, I got a quote yesterday from that outfit on the west coast that would build me a custom unit with my choice of gears (3.45) and THIS option for $1200 shipped and no core charge (!). A step down from the Quaife ATB I'd like to have but a good alternative I think. Hope this helps

Zitat von martinw

Thanks for the info on Jim's 3.45 ...
Can see the need for a modified unit with 500hp ....

The ratio itself (3.45) or something in that range is still a possibility with my standard 380hp.

Still got this unanswered problem with the CSi diff cooling system, and compatability (tappings for the inlet/outlet pipes) to diffs from other cars.
As other 8s seem to manage ok without the cooling system, if I can't get over this problem, suppose I could just disconnect the cooling system, cap it off and leave it in place for reconnection if I want to reinstall the standard diff ? (or remove the whole cooling system, but keep for later re-installation).

Please repair and keep that cooling unit, I want to ad it so bad to my cars this summer, I've been asking around specifically to CSi owners and they say the 3.15 and the 3.25 is a awesome set up for your car, The 3.45 is the hottest set up if you don't mind a little more shifting! 1st gear is useable and Your 6th gear would be at 3000Rpm's at 80Mph! Here's some reading from users who have done it already below, You are on the right path, Just depends on the amount of shifting you wanna do. There's a lot of info at the link below if you do a search from experienced diff changers in US and Euro CSi's.

http://bimmer.roadfly.com/bmw/forums/e31/5363330-1.html

Martin, I had a talk today with Jake at Metrix Motorsports and we spoke of your desired application. We both have 210mm cases and he said no problem to tap that case for your active cooling. The 210mm variable lock is in stock (just hasn't made it to the website listing) and he has the 3:45 gears in stock (M grade gears)as well. Shipping to England (?) would be around $225US. He hinted that building essentially two identical units at once could benefit us both pricewise. Shoot him an email and tell him you were referred by Randy with the 840 and see where it goes for you. I'll help all I can.

M/turbo
You're in Cali too right? Unless you absolutely want stock factory CSI cooling
like Martins (850 Jim had a less than favorable opinion of them) Jake had a much simpler solution he had done on one of his project cars you might want to consider.

It should be said that I have no affiliation with this outfit whatsoever. We've talked and I like his philosophy about innovation and that BMW performance work need not be super expensive.... my kinda guy

rcrad6653, Thanks for the info!

Marv,

Thats just it.... pricing includes the differential. According to Jake there are a lot of them in southern California (Cali is a huge car state). I have the option of sending him mine but he gets them so cheaply that the weight and cost of shipping them clear across the country and back doesn't make sense to me to disable the car for that long.

Jim In NYC aka the e31 undertaker jim@e31parts.com writes

Your wasting you money with the cooler unless your at the trac
I will hunt around for a 3:45 i do have a 2:96 in my euro car if your interested Thats not to far from the 3;15 it has 44,000 miles on it

He's in New York Martin, and I'm currently right across the river in south Jersey. Now that we're up and running again in the New Year I'll do a followup with the west coast guy. There is an associate of his that has a couple 3.15s in our case style that could be converted. He wanted about $500 US for those. I plan to call him today and I'll try and find out definitively if the case can be tapped for your cooling unit. Although not applicable to me I tend to agree with you about retaining the unit whether necessary or not because it's so damned cool.

OK some updates that may be of interest to the 850 group.

New genuine BMW 3.45 gearsets are available here, around $750 US plus shipping. Although targeted for the E39 M5, the 210mm internals are the same. These are not the Dinan marketed gears. Authority* has it that Dinan uses gears not guaranteed against noise. (more on that if requested)
Martin, bad news I'm afraid on the tapping of a non-CSI differential case for your oil cooling system. The case castings are different and though it could be done wouldn't be as strong as OEM. The casting blanks simply aren't there. Swap the internals with an LSD and gears you want into your case or use another with the cooling system disabled is about it. I'd wager that the way that car is driven the same cooling efficiency could be gotten by polishing the gears. (about $200 US during a build)
3.15 LSDs are fairly common here with original 25% lock when new, and down to perhaps 20% locking if higher mileage. The rebuilders start at 40% lock and up if you go that option, or with the variable ramping up to about 75-80%, then to the Quaife. Said authority recommends a refresh of a standard LSD as these aren't track cars and the difference even with spirited driving would be negligible if noticed at all.
Labor prices are all over the graph here with a budget rework of about $1300 US , to near double that.
*previously unamed authority: Brett Anderson of Koala Motorsport

Zitat von martinw

Maybe we should move onto PM ? - unless there is general info of interest to everybody.

I for one am interested in the whole diff ratio/LSD discussion as I intend doing my 840 ci Sport so would prefer to keep the info in the public area if that is OK.

Thanks

Alan

I for one can vouch that a upgraded LSD Diff is a big Plus, Night and day experience, So much nicer when entering a corner too fast! It's will be one of your best upgrades. A LSD for the 8 is also the easiest item to sale if your disappointed with it, You want lose either way...