Euro Trans / 3.46 Diff - S14 Diff opinions

[keefy6]

Ok.

So I've been looking for a 3.46 diff for over a year now. Found more 3.25 ratios than any off of euro E30s. A little too long in the tooth for me...

My original was an open 4.10 that was great with the US trans after the swap and I changed over to the dogleg, I was like wtf?

So then I bought a 3.91 LSD which is great, but the gas average suffers along with the fact that the ratio itself isn't much off of a 4.10

Seeing that I couldn't find an OEM case I just bit the bullet and bought the 3.46 gears to swap in.


Holy. S@#!


Does anyone else have this setup? I mean the car was pretty quick and although I don't have as many revolutions spinning the wheels ...its seems so much faster!! plus of course 5th gear is an actual cruising gear now

Interested in anyone else's feedback

[diegom6]

I have my stock 3.25 diff and dogleg trans. I think the US M3 (I had one) was more fun to DD it as it will spin the tires more easily and rev up from the low end faster with more "torque" over my euro M3. I did once put the 4.11 in my euro M3 and was horrible, worse than a Jap specs Subaru STi gears (too close, too many shifts to make every second) and wouldn't develope enough speed vs longer ratio in an acceleration.

Sometimes my euro m3 feels sluggish in 1st gear specially in the corners that want to slide the car a bit for fun, although it does it, but you need more revs or speed to achieve it like th US model.

How much does it cost the ring & pinion of 3.46 new from BMW?

[keefy6]

diegom6 totally agree. I had the original non-LSD 4.10 in after the swap and BEFORE the dogleg trans and it was great although a non-slip!

I didn't factor in and do my homework of the gear ratios of said dogleg AFTER it was installed..and subsequently bought the 3.91. Although better, it still was a significant decrease in MPG, highway speed etc.

Reason why I bought the gears was I simply could not find a euro diff with that ratio after searching a little over the year, and although the 3.25 was the ratio from BMW for the evo(2.5) motor i still wanted a few quicker revolutions. Outside of buying the engine itself it's the second best upgrade i've done. $400 but i didn't buy it from BMW.

[gte175x]

I thought lower gears would put more power down at higher speeds, because engine would spin 3.X times vs. wheels @ 1 times....so engine says in lower RPMs until speed gets up. But all the power is up in the high RPMs, which you would want down low for a more streetable set up. Seems that 3.46 would be worse than 4.10. Am I confusing something?

[keefy6]

^ not going to retype again lol but,

in general you give up the partial 'quickness' as a result of more revolutions of the wheels in using a higher ratio.

"But all the power is up in the high RPMs"..i don't know what engine you have but my S14 and its power is immediate...in ANY gear and pulls the car harder and faster the more the throttle bodies are pulled open. Unlike the M52 in my E39 where you could have the gas pedal pressed all the way down and it moves when it gets ready.

"Seems that 3.46 would be worse than 4.10" You don't take into consideration that the trans is a direct drive configuration not a US gearbox which has an overdrive gear. Using a 4.10 with it is willingly deleting 1st, 2nd and half of 3rd gear. Matter fact, euro E30 M3s had a 3.25 and 3.15 diffs from factory.

[LJ851]

^ not going to retype again lol but,

in general you give up the partial 'quickness' as a result of more revolutions of the wheels in using a higher ratio.

"But all the power is up in the high RPMs"..i don't know what engine you have but my S14 and its power is immediate...in ANY gear and pulls the car harder and faster the more the throttle bodies are pulled open. Unlike the M52 in my E39 where you could have the gas pedal pressed all the way down and it moves when it gets ready.

"Seems that 3.46 would be worse than 4.10" You don't take into consideration that the trans is a direct drive configuration not a US gearbox which has an overdrive gear. Using a 4.10 with it is willingly deleting 1st, 2nd and half of 3rd gear. Matter fact, euro E30 M3s had a 3.25 and 3.15 diffs from factory.

Deleting 1st,2nd, and half of third? Sorry, but you don't know what you are talking about. Look at the actual ratios for the CR gearbox and you will see that they are barely different from the OD box. Staring out in first gear at 3.7 vs 3.8 is NOT a big difference.

It is basically a 4 speed with 5 gears. The only major difference is the rpm in top gear since the CR 5th is the same as OD 4th.

Close ratio
1st..... 3.717
2nd.... 2.403
3rd..... 1.766
4th..... 1.263
5th..... 1.000

265 Getrag
1st..... 3.822
2nd.... 2.200
3rd..... 1.398
4th..... 1.000
5th..... 0.813

[keefy6]

tha fuck? I have both the US transmission , the Euro dogleg transmission , an open 4.10 diff, a 3.91 and now a 3.46 ratio LSD and have all used each in various combinations and have driven with ALL OF THEM and "I don't know what I'm talking about" ???

Don't attempt to lecture me on anything in regard to differentials when I've experienced the drivability of every single part that I just mentioned in the very car I've owned now for the past 2 and a half years. I've done my homework over the last 2 years in and out of my car and am quite happy. Go somewhere else to stroke your imagined ego/intelligence or better to S14.net and tell them "they don't know what they're talking about" of whom the advice I've received in regards to my drivetrain, I hold in high regard for..obvious reasons.

[LJ851]

tha fuck? I have both the US transmission , the Euro dogleg transmission , an open 4.10 diff, a 3.91 and now a 3.46 ratio LSD and have all used each in various combinations and have driven with ALL OF THEM and "I don't know what I'm talking about" ???

Don't attempt to lecture me on anything in regard to differentials when I've experienced the drivability of every single part that I just mentioned in the very car I've owned now for the past 2 and a half years. I've done my homework over the last 2 years in and out of my car and am quite happy. Go somewhere else to stroke your imagined ego/intelligence or better to S14.net and tell them "they don't know what they're talking about" of whom the advice I've received in regards to my drivetrain, I hold in high regard for..obvious reasons.

Lol, don't get your panties in a bunch. Care to explain mathematically how you lost 1st, 2nd, and half of 3rd with your CR/4.10 combo? I posted the transmission gear ratios for you, so it should be easy. Your defensiveness tells me you are unaware of what you are speaking about.

I have owned and run all of the transmissions and rear gears you speak about plus many,many more, would you like to start a pissing contest?

I think your internet recommended 3.46 is a good choice and is what i would run behind a stockish 4 cyl/CR combo from my personal experience.

[keefy6]

Still trying to 'educate' me. Good for you:)

[LJ851]

^Nah, just trying to get you to show your ass a little more.

[keefy6]

Oh, that too? Anything else:)

[M-technik-3]

3.46 and a CR is not a bad combo. I use a 3.46 and zf 24V set up. That being said talk with JimmyP over on s14 he has a variety of setups he uses. When I had plans to put a cr in mine he told me the 3.46 was the way to go.

3.25 is good for Europe where speeds are faster and it keeps the 4 more in the torque range on the autobahn and on the faster B roads.

[keefy6]

3.46 and a CR is not a bad combo. I use a 3.46 and zf 24V set up. That being said talk with JimmyP over on s14 he has a variety of setups he uses. When I had plans to put a cr in mine he told me the 3.46 was the way to go.

3.25 is good for Europe where speeds are faster and it keeps the 4 more in the torque range on the autobahn and on the faster B roads.

Totally agree; I did in fact correspond with him and he along with others recommended this setup to me as well. Worked out great, a wealth of knowledge over there.

[gte175x]

Below are the estimated road speeds using the gear ratios provided and final gears @ 6000 RPM...

Close ratio .........4.1 ..... 3.46
1st..... 3.717 ..... 28 ..... 33 mph
2nd.... 2.403 ..... 43 ..... 52 mph
3rd..... 1.766 ..... 59 ..... 70 mph
4th..... 1.263 ..... 83 ..... 98 mph
5th..... 1.000...... 104 .... 124 mph

265 Getrag
1st..... 3.822..... 27 ..... 32 mph
2nd.... 2.200..... 47 ..... 56 mph
3rd..... 1.398..... 75 ..... 89 mph
4th..... 1.000..... 104 ....124 mph
5th..... 0.813..... 126 .... 149 mph

To me, the 4.10 seems much more streetable than the 3.46, in 2nd gear I'm already exceeding most speed limits on surface roads. Maybe it has something to do with longer pull to 2nd, or something about the feel. To me, it just seems that I would want to be in the higher RPMs at a lower road speed generating more torque. But I have never tried any of these - My s14 is a relatively low mileage example, maybe there is some wear or maintainence I need to take care of but I can't imagine it not being fairly tight. I always thought my M20 would pull off the line much better, or at least it felt that way....and I felt a taller rear ratio would be better. Maybe I'm way off...

[keefy6]

The 4.10 when I had it is streetable using it with the US overdrive transmission, it really isn't a viable option for everyday use with the CR however. At 65-70~mph I was close to 4500 rpm on the highway.