Newest mod: 3.46 w/ 40% lock

[Sam L]

got it from diffsonline.com

man this thing feels niiiiiiiiiiiiiiiiiiiice

my mechanic commented how this car was totally MADE for this diff.

car seems to handle better, and now i have a much more accessible power band (i'm always in the right gear !)

first gear is rendered somewhat useless, but man....2nd gear PULLS.

i'd highly recommend one. =]

Sam

[jmargo]

How does it run on the HWY ? ie revs at cruising speed ?

[Rito Smooth]

Also interested in rev's? How noticeable of a difference was it?

[Brent_Vino]

3.46 is kinda too high without having a 6th gear.


if i can find and get a good deal on a 3.38, i will definately do it.

[coldfusion]

Originally Posted by Brent_Vino

3.46 is kinda too high without having a 6th gear.


if i can find and get a good deal on a 3.38, i will definately do it.

I see no need for an overdrive with the 3.46, and I do quite a bit of highway driving... ABOUT TIME SAM!!! How long have I been telling you to get one?

[///MDex]

Originally Posted by Brent_Vino

3.46 is kinda too high without having a 6th gear.

Don't beleive it. The 95 has what, a 3.15, and going to a 3.46 is barely a 10% jump.

I went from my OEM of 3.23 to 3.73 which ~15% jump, and it is absolutely the best deal going for biggest felt improvement in all around driving. And cruising, I only lost ~400RPM up top.

[coldfusion]

Originally Posted by jmargo

How does it run on the HWY ? ie revs at cruising speed ?

I turn ~3800rpm @ 80mph

[potomac]

Really? I'm up higher than that and I'm running the factory 315 what gives?

[coldfusion]

Originally Posted by potomac

Really? I'm up higher than that and I'm running the factory 315 what gives?

When my '95 had a 3.15 I turned 3500rpm @ 80mph. I also ran 255/35/18's in the rear which should slightly raise the final drive ratio.

[Mpty3]

A 3.15 to a 3.46 is a jump and a half... do you even have a 1st gear anymore?
5th gear 80mph cruise...what are your RPMs at?

Guys with 3.38s that replaced 3.23s... what are your RPMs like at 80mph in 5th gear?

A while back, I wanted to swap diffs on my 96 M, but after doing highway cruising, i think RPMs would be way too high for a long period.

I guess diffs are sweet for the strip only, but for people who highway cruise a lot... I would never swap it out.
M3s barely have a 1st gear to begin with.

[Sam L]

80mph is around 3800 as matt said.

matt- this thing rocks man

btw guys...the day after i got it installed, i drove 6 hours down south on highway 5 at 80mph constantly...didn't bother me at all. car feels more torquey because of it.

mpty: 1st gears no fun anyway!

[Mpty3]

Originally Posted by Sam L

80mph is around 3800 as matt said.

3800 on 3.46? you mean on a 3.38, right?

You guys with the 96-99 M3s (with 3.23s) that are running 3.38... whats your RPMs at 80mph in 5th like?

Originally Posted by Sam L

mpty: 1st gears no fun anyway!

It is with some juice

[binh]

my friend just blew up his 3.46 at the dragstrip tonight..it was 2 months old from bmp and he's not a very happy camper...

still in first gear on a hard launch and BOOM!

his car rips mine though from a 2nd gear roll on pretty nice.

i'll personally be getting a 3.38 though because of hte price factor

[DocWyte]

3.38 yields 85mph at 4000rpm, 80 mph is 3750 rpm.

[pimpscls]

Originally Posted by binh

my friend just blew up his 3.46 at the dragstrip tonight..it was 2 months old from bmp and he's not a very happy camper...

still in first gear on a hard launch and BOOM!

his car rips mine though from a 2nd gear roll on pretty nice.

i'll personally be getting a 3.38 though because of hte price factor

Hmm what would cause it to blow?

[badmonkey]

Love my 3.46 40%, though at times reach for a 6th gear that isn't there...


?

[slcook54]

I'd be interested in seeing a run with a stock 5 Speed M3 with the 3.15 vs. an M3 with a 3.46, you should obviously have to shift more in the 3.46.

[binh]

Originally Posted by pimpscls

Hmm what would cause it to blow?

we have no idea...maybe the track was extra sticky and he launched it pretty hard...

i think the m5 clutch just grabbed real good and there was nothing else to break but the driveshaft

[Mikey52]

Originally Posted by badmonkey

Love my 3.46 40%, though at times reach for a 6th gear that isn't there...


?

Heh, I used to do the same thing with mine. While you do turn ~4000 rpm at 80mph, it was still the single best mod I ever did to my M3. My car had the UUC 8.5lb. flywheel so 1st gear was even more useless but it would also make me chuckle at how silly fast the car would accelerate.

I decided against the 3.38 because you cant know what kind of condition it's in (since theyre all used obviously) and I see people selling them for 800-900 bucks, too steep in my opinion. Either way, you cant beat diffs for $/performance.

Edit: Oh and with my setup (diff/flywheel/ 222 rwhp) my M3 kept up with my Vette until about 50 mph.

[diffsonline]

Sam,
Glad to hear the diff is working out for you.

Just so everyone knows i build 3.46 40% differentials for 1400 exchanged. Here is a chart of your RPM/MPH with 245.40.17 rear tires and a stock 5 speed...

3.46 Gearset

1ST 2ND 3RD 4TH 5TH
0500 RPM 2.4 4.1 6.1 8.4 10.3
1000 RPM 4.8 8.1 12.3 16.8 20.5
1500 RPM 7.3 12.2 18.4 25.2 30.8
2000 RPM 9.7 16.3 24.6 33.6 41.0
2500 RPM 12.1 20.3 30.7 42.0 51.3
3000 RPM 14.5 24.4 36.8 50.4 61.5
3500 RPM 17.0 28.5 43.0 58.8 71.8
4000 RPM 19.4 32.6 49.1 67.2 82.0
4500 RPM 21.8 36.6 55.3 75.6 92.3
5000 RPM 24.2 40.7 61.4 84.0 102.5
5500 RPM 26.7 44.8 67.5 92.5 112.8
6000 RPM 29.1 48.8 73.7 100.9 123.0
6500 RPM 31.5 52.9 79.8 109.3 133.3
7000 RPM 33.9 57.0 86.0 117.7 143.6
7500 RPM 36.4 61.0 92.1 126.1 153.8

and here is with a 3.15
3.15 Gearset

1ST 2ND 3RD 4TH 5TH
0500 RPM 02.7 04.5 06.7 09.2 11.3
1000 RPM 05.3 08.9 13.5 18.5 22.5
1500 RPM 08.0 13.4 20.2 27.7 33.8
2000 RPM 10.7 17.9 27.0 36.9 45.1
2500 RPM 13.3 22.3 33.7 46.2 56.3
3000 RPM 16.0 26.8 40.5 55.4 67.6
3500 RPM 18.6 31.3 47.2 64.6 78.8
4000 RPM 21.3 35.8 54.0 73.9 90.1
4500 RPM 24.0 40.2 60.7 83.1 101.4
5000 RPM 26.6 44.7 67.4 92.3 112.6
5500 RPM 29.3 49.2 74.2 101.6 123.9
6000 RPM 32.0 53.6 80.9 110.8 135.2
6500 RPM 34.6 58.1 87.7 120.0 146.4
7000 RPM 37.3 62.6 94.4 129.2 157.7
7500 RPM 39.9 67.0 101.2 138.5 168.9

and lastly a 3.23
3.23 Gearset

1ST 2ND 3RD 4TH 5TH
0500 RPM 2.6 4.4 6.6 9.0 11.0
1000 RPM 5.2 8.7 13.2 18.0 22.0
1500 RPM 7.8 13.1 19.7 27.0 33.0
2000 RPM 10.4 17.4 26.3 36.0 43.9
2500 RPM 13.0 21.8 32.9 45.0 54.9
3000 RPM 15.6 26.2 39.5 54.0 65.9
3500 RPM 18.2 30.5 46.0 63.0 76.9
4000 RPM 20.8 34.9 52.6 72.0 87.9
4500 RPM 23.4 39.2 59.2 81.0 98.9
5000 RPM 26.0 43.6 65.8 90.0 109.8
5500 RPM 28.6 47.9 72.4 99.0 120.8
6000 RPM 31.2 52.3 78.9 108.0 131.8
6500 RPM 33.8 56.7 85.5 117.0 142.8
7000 RPM 36.4 61.0 92.1 126.0 153.8
7500 RPM 39.0 65.4 98.7 135.1 164.8

Any questions differential wise I can answer I would be more than happy to. As far as quality, I stand behind my diffs with a 3 year warranty on workmanship. I have differentials behind high HP turbo cars, where other people's didn't hold up, if that says anything about the time we spend putting each one together.

[///Mracer]

I just installed a 3.38 into my 95 M3. This is a nice little jump from a 3.15 and should have done this mod first, about 3 years ago. The car is just a lot more fun now. I cannot imagine going to a 3.46 and up

[Brent_Vino]

did u have someone machine you a 3.38 or did u buy it used? how much?

[///Mracer]

Originally Posted by Brent_Vino

did u have someone machine you a 3.38 or did u buy it used? how much?

bought it used for $850

[Mpty3]

diffsonline do you have any 3.38lsd right now? if so, whats the going price and mileage on them?

[///M3ryder NY]

Sam, approx. how much did the 3.46 run you?