Diff ratio change in E38 - QUICK opinions please!!

[m5james]

Hopefully I can get this answered this morning, bit I have the option or replacing my stock 2.93 diff with the following as my pricing and options:

DAN with DIFFONLINE
3.45 lsd for $2400
3.64 lsd for $2045 - he recommended this for real fun!

Koala Motorsports
3.15-3.64 lsd for $2750-2850

VAC - rude on the phone, wasn't very helpful
3-15-3.45 lsd for $2500 +/- 200

Now, seeing that I am coming from a 91 M5 to this vehicle, the speed, handling, and and rear drifting of the car is completely different. Without giving me crap for the size of the car, I would like to be able to slid the back out every once in a while, do burn out's like I was able to before, and not be a one legger either. Since I have done the motorwork to the car, I have no bottom end anymore (personal opinion) and would like to regain that and more. Going to the stock 3.15 that comes in the 740 Sport/M5 would be fine for most...which is why in this heavier car I feel fine won't be enough. I don't mind losing gas mileage or topend as my bike will get 40mpg and do 180. I wanna stomp people on the streets, have a daily driver, and be a total sleeper for now. In yours guys opinions, what would be too aggressive or just right for the person who wants a fat ass luxo barge, but is still trying to be sensible also. Thanks alll!!

[Jfstu]

Go with the 3.64. Should be in the 13's in the quarter with the engine mods you listed. Have fun!!

[m5james]

Thanks! These are the kind of responses I am looking for, instead of being attacked for wanting to make a 7 series fast and more capable of powerslides. I don't drive the car like a sheep, and quarter mile is another consideration in changing the ratios! Thanks for your opinion. That is 2 for 3.64.

[Skipper5]

it sounds like you want the 3.64 more than the 3.46 heck, who wouldn't. how high does your motor rev? you'll love it i'm sure. go for it!

i'll probably do a 3.46 in my upcoming 540 but thats only because i'm a sissy

oh, and the 5er board has some tools posting on there. don't worry about them, hehehe.

[m5james]

I sit at like 26-2700 at 80mph, but I find myself always in sport mode to keep the sweetspot of the motor. I want the powerband of an EVO 8 and the comfort of driving a BMW 7...not too unrealistic right?

[bmwtecandy]

DEF. go with the 3.64 it should be more than enough to satisfy your street dominating, tire burning desires. My opinion might be biased though, im the diff builder at diffsonline.


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[ibew595]

Since gas milage is not a factor what about freeway driving? I would hate to have to keep it at 3k+ rpm for hours since your at ~27k now. If you aren't making those kind of trips.....paypal Dan and show us pics
Good luck!

[The Shadowchaser]

Alright call me crazy, but I was considering a 3.73:1 ratio. Dinan offers this for my car on the S740 supercharged version. I figured they are putting over 400hp at the crank with this diff, which I assume they have extensively tested. My brothers E39 528i pulls harder than my V8 and its got a 4.10:1 ratio. For obvious reasons you can see why I cannot allow this. I am just worried about highwway speeds with the rpm range. I do alot of highway driving. If there is a group buy count me in. Man I am pissing away more hard earned money on my car quicker than I wanted too. Damn her, damn her to hell.

[m5james]

Weird thing about these cars.....your 95 can upgrade that high of a ratio, but then when I look at the 98, they recommend the 3.15 up to 3.45. Well...3.64 it is!! . Gonna figure out if the ratio is gonna make 1st gear useless when I convert to 6spd, but otherwise I am staying with that for now.

[bmwtecandy]

Diffsonline can do the 3.73 also, its a little more expensive as it is a rare gearset. Dan's M5 is running the 3.64 with some mods and 1st gear is quick, but still usable. It can create tire spin anywhere in the powerband so it requires a little bit of throttle modulation to keep it hooked up. I wouldnt even think about switching his ratio back down as the car is waaaaaay to fun (completely sideways in first and second when asked).


-Andy

[The Shadowchaser]

Diffsonline can do the 3.73 also, its a little more expensive as it is a rare gearset. Dan's M5 is running the 3.64 with some mods and 1st gear is quick, but still usable. It can create tire spin anywhere in the powerband so it requires a little bit of throttle modulation to keep it hooked up. I wouldnt even think about switching his ratio back down as the car is waaaaaay to fun (completely sideways in first and second when asked).


-Andy

Thanks for the info Andy. Any idea of how much 3.73 will affect my revs at highway speeds? And how much more would something like this be for my 95 E38 M60 740i? Thanks.

[ny-sevens]

Weird thing about these cars.....your 95 can upgrade that high of a ratio, but then when I look at the 98, they recommend the 3.15 up to 3.45. Well...3.64 it is!! . Gonna figure out if the ratio is gonna make 1st gear useless when I convert to 6spd, but otherwise I am staying with that for now.

So your going w/a 3.64LSD right?? I'm watching this closely, as I have a 98' as well. I wanted to do a 3.45LSD but now this thread have me scratching my head thinking.

[JLe38]

So your going w/a 3.64LSD right?? I'm watching this closely, as I have a 98' as well. I wanted to do a 3.45LSD but now this thread have me scratching my head thinking.

I am going with a 3.64LSD. BTW, there is a LSD Group Buy coming up in about a month or two. PM me if you need more info.

JL

[immaculate]

I am going with a 3.64LSD. BTW, there is a LSD Group Buy coming up in about a month or two. PM me if you need more info.

JL

you've got mail James!

aaron

[JLe38]

you've got mail James!

aaron

You got PM back, Aaron

James

[m5james]

Diffsonline can do the 3.73 also, its a little more expensive as it is a rare gearset. Dan's M5 is running the 3.64 with some mods and 1st gear is quick, but still usable. It can create tire spin anywhere in the powerband so it requires a little bit of throttle modulation to keep it hooked up. I wouldnt even think about switching his ratio back down as the car is waaaaaay to fun (completely sideways in first and second when asked).


-Andy

That's what he was saying on the phone. I just had a little flashback of my 91 MR2 Turbo, which first gear was useless after boost mods...but I couldn't do anything but bogdown in second. Just for S%&$ & giggles, can you tell me at what mph 1 gear tops at...I'm too lazy for a calculator and tryng to figure out transmission gear ratios. Thanks, and I look forward to having you guys get my diff built and sent to me. Eastside Bavarian called today and said the pinion in my diff sheared off, causing the failure.

[Md750]

well for those that are not looking to upgrade (just replace a diff), i still have my diff from my 98 750 that i need to get out of the garage.

[m5james]

Sorry for the delay on the update, but here goes. I will tell the story A-Z.

Called around about diff pricing, and decided on DiffsOnline after getting a much better response that others. Called around to various shops in the area about doing the work. There was some indy in Marysville, but never got a return call or anything, even after two messages left on his machine. Car Tender wouldn't do the work unless payment was recieved up front, which I was not about to front myself. After speaking with Eastside, who has worked on my diff before who flushed and filled it when it started its initial clunking that eventually forced its replacement a couple months later. Spoke with Ken on the phone, told him of my plan of upgrading the diff to another ratio with LSD, gave him the appropriate pricing of the diff, which happened to be the best and cheapest priced on the market. Car was towed to their shop on 5/16 after all agreements were made about what was to be done. Adjuster for the warranty company finally came out and confirmed that the diff was in fact broken and covered, and the ball finally started to roll. All this time I had been speaking with Dan discussing and deciding on which ratio to build and just waiting for the green light start the diff assembly. About one to two weeks passed, with calls between the warranty company, Eastside, and Dan. Things started getting ugly when come to find out Eastside had instead told them the price of a rebuilt diff through their own vendor instead of using Dan because Eastside was determined to convince me that the custom diff was not a bolt in item, and that at least an additional two+ hours would be needed to change over the half shafts. BS, confimed by Dan himself, who's own special manufacturing process makes the custom diff a complete drop-in item. At this point, the warranty deemed that the amount for the diff supplied by Eastside's own vendor would cost roughly $1500, plus $400 for labor...all rough estimates. Ater getting angry with Eastside, I tried flexing other options to continue with my plan of getting my custom diff, all which were tossed out the window thanks to Ken at Eastside, and apparantly the owner who has no flexibility nor enough excess money to float $1200 for a week. I asked Ken to continue ordering the diff from Dan since they were already getting a check from the warranty company for the parts and labor anyways, and just float the difference until I came to get the car. The only reason why I went this route is because that is the same thing BMW of Fife did for me with the motor swap and mods, and then I just had to pay for the difference of the mods and my deductible minus the warranty check to Fife when I took delivery. Ken said they couldn't do that for me on such a large amount, so I offered to give them the difference in cash upfront, have them use the check for the warranty to pay for the remainder, and the labor would stay the same as confirmed. I once again got my goals shot down, as floating the total amount minues my $1200 up front would apparantly bankrupt Eastside while the waited for the remained of the money from the check that was in the mail. Fuckin rediculous!! The icing on the cake was when Ken told me that even if they were to do the aftermarket diff, they would have to charge me additional fees for using an outside vendor, causing an arguement betwen Ken and I...he had NEVER mentioned any additional fees for outside vendor parts, Fife didn't charge me for outside vendor parts...so all total bullshit from Ken and Eastside Bavarian. Once the vehicle finally got the rebuilt diff put in, I received a call telling me it was done. Unfortunately I was not able to get the vehicle on that Tuesday because they couldn't release the car until they recieved payment. I asked how long that would take, and was quoted up to a month or two!! So these shits wanted to keep my car even longer! At this point I was furious, but the check arrived within 1 week. I finally got the car back from Eastside Bavarian on 6/22 around 5pm. The car was still on the lift even after I told them I was coming, battery was dead, and the car was dirty covered in dust and finger prints. I get into the car to find that they broke the side panel on the seat that holds the position controls, the harness had popped out, not allowing to move the seat back off the steering wheel from the 5'1" guy working on it. I get the harness conected after pulling it off the lift and out the bay to move the panel out of the way to squeeze my fingers into, and as I look up...they broke my radar detector mount that was mounted next to the rear view mirror! No explanation for the seat or why they even had to touch the radar detector in the first place, no offer to fix the seat, and a half ass apology for the condition of the parts inside. All in all, I will NEVER go there again. SIGH....so if anybody wants to buy a new stock diff, let me know so I can offset the cost of buying the diff that was supposed to be installed in the first place. Sorry for the rant.

[JLe38]

.....The icing on the cake was when Ken told me that even if they were to do the aftermarket diff, they would have to charge me additional fees for using an outside vendor.....

Not cool how they left your car in subpar shape. I think Ken was pressing for the rebuilt diff. because he gets to make a few hundred dollars from that rebiult unit. Common practice and income source for auto repair shops. Just like many business do reselling parts. However, since Ken was aware you were interested in the LSD, he should have been upfront with you about the extra fee for third party unit. Too bad you didn't get to try the LSD. Was looking forward to hear the actual changes.

There is a guy with the call sign "JP" in DFW area that supposedly has bought a 3.64 LSD from KMS for his 01 740iS. I believe he only post at RF. Tried to contact him sevearl times, but aside from knowing he likes it, there has been no reply from him to the new stats.

JL