3.45:1 Dinan Differential - United Bimmer Community

**dinan540** · 01-16-2006, 06:58 PM

So I was looking in the classified adds and found a Dinan M5 3.45:1 differential for $950.

My 540i does not have a LSD and I am interested in having this upgrades.

The stock ratio on my 540 is 2.81:1.

Questions:

1. Would this Dinan M5 differential work for my 540i without much fussing?

2. What are the advantages of having LSD?

3. Is this price high? I am assuming it is used, but not sure.

4. What are the benefits of changing the gear ratio?

Thanks in advance,

Paul

nick_318is · 01-16-2006, 07:16 PM

I can help a little but can not answer all of your questions:

2. The LSD will put power out to the slipping wheels. In this case the rear wheels, when you turn one wheel will have more grip then the other, and the limited slip will put more of that power to the wheel with the grip.

4. The change in the ratio will cause you to accelerate faster compared to your current diff.

**xsperf** · 01-16-2006, 07:59 PM

your car is a 6 spd? i have a question, what makes it a "dinan" differential, dinan makes diff's now or what?

**devinwwu** · 01-16-2006, 11:17 PM

aight paul. here's the difference... i won't be able to toss you on 45th and univeristy way in front of a bunch of UW frat boys and sorority girls... hahahahaha. just kiddin man. the diff will lower your top speed with the ratio change but you will be able to reach that top speed much quicker. the gears will feel shorter but faster. and you will have much better traction throughout each gear. i have a lsd in my ride and love it to death. 950 doesn't seem too bad to me. i spent 400 on a locker for my off road truck so for a bmw to have the same type of traction i could see at least $1k. where are you gettin this info??? pm me a link or somethin. i've done a bunch of differential work and i could most likely help you install it as well if you wanted

**dinan540** · 01-17-2006, 09:53 AM

Quote:

Originally Posted by xsperf

your car is a 6 spd? i have a question, what makes it a "dinan" differential, dinan makes diff's now or what?

xsperf, my car is a 6 speed. And yes, Dinan also makes differentials for some cars.

It is probable manufactured by another company, but they put Dinan on it and charge more. This is what they do when they sell their big brake brembo kit. The calipers are brembo, but say Dinan.

**dinan540** · 01-17-2006, 09:58 AM

This is what I found on the Dinancars.com site under the E39 M5

3.45 Limited Slip Differential
Driveline Tuning

Part #:

Price:
D773-0390
$2499.00

Labor Units: 62.0
Required Products: Dinan Performance Engine Software is recommended for increased rev-limit.
Special Notes: The 3.45 differential is sold on an exchange basis; $1800.00 refundable core deposit required.
Point Value: 2

The shorter 3.45 gearing takes advantage of torque multiplication, lowering the stock 3.15 ratio for a 9.5% increase in torque delivered to the road. The improved acceleration comes with only a minor increase in engine speeds at cruise and no effective reduction in top speed potential. The 3.45 ratio was selected in order to enable the car to attain a speed of 60 mph without introducing a second to third gear shift, which would otherwise slow down 0-60 mph times.

The Dinan 3.45 Limited Slip Differential delivers what is perhaps the greatest "bang for the buck" in terms of improved and more immediate acceleration from the M5.

**devinwwu** · 01-17-2006, 11:56 AM

sounds pretty sick paul. i'd email the guy and ask him how much shipping would be. maybe ask mileage on it, what year car it came off of,any known issues. considering there is a core charge of 1800 and the total cost is 2500 that means you get the thing for $700 once you return your original diff...assuming those numbers are correct.

**dinan540** · 01-17-2006, 12:33 PM

So, it is coming off of 2002 E39 M5 with 20K miles on the diff. The info from the dinan site is for the M5 3.46 diff. They don't make a 3.45 diff for the 540i manual. Dinan only makes a 3.15 diff. for the 540i manual and it costs $7000. I think that the M5 stock diff. is different than the the 540i stock diff, hence the huge price difference for a 540i Dinan diff. and a M5 Dinan Diff.

**gold panda** · 02-18-2006, 02:28 AM

Hey there!

I see you have some very nice Dinan mods as well! What do you think about them overall, since you've had them a bit longer than mine?? Fyi, recently went the full Dinan route on my E60 545i Sport! Any info greatly appreciated. Really interested in learning about the reliability aspect in particular. BEST REGARDS ALWAYS

Storamin · 02-18-2006, 10:57 AM

On a brand new BMW, I think you made a very good choice going Dinan.

That's some nice mods.

**Numark318i** · 02-18-2006, 11:14 AM

Quote:

Originally Posted by gold panda

Hey there!

I see you have some very nice Dinan mods as well! What do you think about them overall, since you've had them a bit longer than mine?? Fyi, recently went the full Dinan route on my E60 545i Sport! Any info greatly appreciated. Really interested in learning about the reliability aspect in particular. BEST REGARDS ALWAYS

Its good to hear that some people in the Bay Mod there BMW's and care for them. doesnt seem that many people do around here.

sorry about hijack. **

**gold panda** · 02-19-2006, 06:59 PM

Thanks for the note! So you believe having those Dinan performance mods are better on the newer BMW's vs. the older platforms? Why is that? Is it the overall refinement and state-of-the-art? BEST ALWAYS.

**gold panda** · 02-19-2006, 07:03 PM

Its good to hear that some people in the Bay Mod there BMW's and care for them. doesnt seem that many people do around here.

Thanks! I think it's definitely about passion and loving BMW's in general. But to each their own, you know?? Everyone has different priorities in life and we certainly can all respect this.

BEST

Storamin · 02-19-2006, 10:56 PM

Quote:

Originally Posted by gold panda

Thanks for the note! So you believe having those Dinan performance mods are better on the newer BMW's vs. the older platforms? Why is that? Is it the overall refinement and state-of-the-art? BEST ALWAYS.

It's because Dinan has a nice warranty. Well, they offer a nice warranty. They don't always back it, but at least it's there.

**///M Power** · 02-20-2006, 12:20 AM

Quote:

Originally Posted by dinan540

So I was looking in the classified adds and found a Dinan M5 3.45:1 differential for $950.

My 540i does not have a LSD and I am interested in having this upgrades.

The stock ratio on my 540 is 2.81:1.

Questions:

1. Would this Dinan M5 differential work for my 540i without much fussing?

2. What are the advantages of having LSD?

3. Is this price high? I am assuming it is used, but not sure.

4. What are the benefits of changing the gear ratio?

Thanks in advance,

Paul

1. Dont know
2. An LSD maintains power to both wheels despite which wheel has more traction through a corner and even in a straight line. For example if you peel out right nwo one wheel will spin and one will gain traction. With a LSD both wheels will have power and spin.
3. price seems fair for a e39 diff.
4. Faster acceleration. Quicker shifting required.

The disadvantages are you will be cruisign at higher rpms with the shorter gearign per mph. So that means if you cruise on the freewa at 80 mp at 2700 rpms now, you could be cruisign at 80 mph on the freeway with the shorter gears at maybe 3300 rpms. This is turn means slightly more gas consumption. 3.46 seems reasonable since you do have a 6 speed.

6 speed e46 m3s use a 3.46 lsd aswell I believe.

$7000 is really steep for a diff. You could get a custom one made for your car for like 4500.