I'm trying to figure out what LSD I am going to buy for my 1989 325i. I hear the 4.10 is nice, but is it going to be to high of a ratio? I plan on being in Auto X and joining the BMW CCA after getting more experience under my belt. I will also be turboing the 2.7 L, but that wont be till the end of the year. Thanks for the help :-D
-
-
I assume is a 5 speed. If you're going to drive it on interstates/freeways then 3.73 is the way to go, if you just drive around town or plan to only track the car then go with the 4.10.
Sarcasm is a body's natural defense against stupid.
When a man talks dirty to a woman, it's sexual harassment. When a woman talks dirty to a man, it's £3.95 per minute.
"My mother never saw the irony in calling me a son-of-a-bitch." Jack Nicholson"
Old age and treachery will always overcome youth and skill.
-
Comment
-
It's a fairly big difference. You will notice the acceleration difference, but the M20 is really more of a torque motor compared with the M42 and the s14 that got them factory. 80 mph in my car is about 3700 RPM. First gear is more or less useless because it is so short. If your future turbo kit yields any major hp gains, you're going to want something even longer than 3.73.Comment
-
If I remember right it should be an approx 12% increase in rev's and torque multiplication at the wheels. I'll be going to a 4.10 shortly to see if I like it.
If I were going turbo however, I'd be looking at like a 3.25 or so.Need parts now? Need them cheap? steve@blunttech.com
Chief Sales Officer, Midwest Division—Blunt Tech Industries
www.gutenparts.com
One stop shopping for NEW, USED and EURO PARTS!
Comment
-
So your saying the 4.10 would make acceleration better or just make the top speed better? Or is it a combination of the Both? I mean, turbo is a little ways off. It will take a lot of time and tuning cause i want to do it right and not spend cheapo like a JDM drifter.Comment
-
Did you ever have a 5 speed or 10 speed bicycle?? The rear diff ratio is nothing magical, it's the ratio between the number of times the driveshaft (input) turns to the number of times the axle shafts (output) turn.
In general terms, the higher the number, the quicker the car will FEEL because it's easier for the engine to get it moving- but the top speed will be lower, because it runs out of revs due to the high ratio. If you have a lower number ratio diff, it takes more work for the engine to get the car up to speed, but it will have a higher theoretical top speed.
Think of it in terms of a 10 speed bicycle in the lowest gear (1st)- how easy it is to pedal but how even when you pedal like crazy you're still going kinda slow VS. a high gear (like 10th) and how it's really hard to get going from a standstill, but once you get going, each push of the pedals really makes you move forward- and if you pedal really fast, you're going pretty damn fast. This is the effect of different gear ratios.
No one can answer your question because neither one of those diffs is "better" than the other, they're both a compromise in one way or another.Comment
-
If you are going to get a 4.10 then get one from an ix they are built in a larger case(stronger) unlike in my 91 318is which has a small case 4.10 well did before i blew it up.
1986 325es (69k) Garage Queen Buy It Now 10k;1986 325es (track rat) 2.7i How-To & 1.1/1.3Motronic UpGrade
1991 318is (daily driver) 1991 318is M42 Maintenance How-To;1989 325i (parts car)Comment
-
This is like explaining sex to a virgin.
EDIT: No offense to the the readers or writers of this thread but picking a differential ratios is purely personal preference. You can only make a decision by the numbers.
Last edited by tjts1; 06-06-2008, 07:54 AM.
Comment
-
QFU (Untruth)....
The ix diff is not any bigger than any other 6 cyl E30 diff.
One more time:
all 6 cyl E30's plus E30M3 have the "medium case" diff
all 4 cyl E30's except E30M3 have the small case diff
The ix diff is LSD, but it's a viscous type vs the clutch type found in 99% of other BMW LSDiffs.
And yes tjts1, I agree with your comment about how explaining this to some people is like explaining sex to a virgin. You either get it or you don't.Comment
-
Just go 4.10 until you go turbo. Its not bad at all for daily driving. The gas mileage is effected a little bit its a small price to pay when the car gets moving faster from a stop. The 4.10 gives you better acceleration at lower rpms so it should work well for auto x.
E30_FiendNeed a performance chip for you BMW? Shoot me a PM and I'll get you taken care of!!
Taylor- Follow me on Instagram @e30_fiend
Comment
-
a 4.10 isn't going to lower the top speed on an E30. your engine will run out of breath and you'll hit the aerodynamic wall way before you hit the redline.Comment
-
Comment
-
That was a lot of info to take in. Hmmmm, From the sound of it 4.10 sounds good. But if i go 3.73. Getting a 4.10 from an IX sounds kinda expensive? How much do those usually run for? Thanks for your help guyzComment
-
DON'T BOTHER GETTING A DIFF FROM AN IX.
(got it?)
A 410 LSD from an E30 325i/is with automatic transmission will be easy enough to find- there were tons of them. All 325is autos made after ~6/88 (I'm sure someone will correct this date if it's wrong) had 410 LSD's and many 325i autos had them too- just need to look around a bit.
I've seen them advertised for ~$100-600, but you should be able to find a decent one for $250-300. BTW- don't pay a premium for a 410LSD "M3" diff, it's the exact same diff that came in those auto 325i/is'..........
Bret.Comment
Comment