2.91 diff to 3.46 upgrade
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crisp - go to my330i.com; if you look in the garage section, there is a gearshift calculator that is pretty accurate as far as gear and speeds go.
With my 3.46 diff, I do 80 mph and about 3700 rpms. Both our cars have a 1:1 5th gear, so cruising speed in 5th should be about the same, assuming your tire circumference isn't significantly different from mine.
I would worry about the 3.46 with all your other mods though - first gear is going to go by in the blink of an eye. Acceleration would be sick though. You're looking at 18% more power to the wheels; can't beat that.
With my 3.46 diff, I do 80 mph and about 3700 rpms. Both our cars have a 1:1 5th gear, so cruising speed in 5th should be about the same, assuming your tire circumference isn't significantly different from mine.
I would worry about the 3.46 with all your other mods though - first gear is going to go by in the blink of an eye. Acceleration would be sick though. You're looking at 18% more power to the wheels; can't beat that.
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I am currently driving SimSima325's car putting some mileage on our differential install while he waits for his license to be re-issued. I must say, 3.15 to 3.46 diff is NICE!!! Brendan, short of something drastic like FI, i think you should leave the car how it is. You will see what i mean when you get it. Get exhaust and software and your car is one of the quickest 325s i've driven.
Vince, the jump frmo 2.9x to 3.46 is drastic but I am planning on that same jump. I currently have 3.23LSD and am going to a 3.73LSD... acceleration will be insane and top speed will be not so insane. I spend more time doing runs to 60, 80, 90mph than I do cruising at 140... i don't think i am going to miss my top ened.
Brendan, the car just pulls and pulls. 5th gear seems like 3rd gear since i last drove the car prior to the differential. I would say this is perhaps THE BEST performance mod for the money. $275 got Brendan and Vince their diffs... given that i'm installing theirs for free, $500 would not be bad for a total package.
Edit:
Dboffa! haha! Its jon with the E34 yo! haha whats up man. I think Vince's biggest trouble will be 1) Traction 2) Traction Control (more on that) 3) Shifting fast enough.
Traction control light can be seen lit solid in Brendans 325 from shifting into 2nd and pretty much all the way through 2nd gear. I took traction fully off (or as fully off as an E46 will allow) and found it much improved thanks to Brendans rear tires being nothing short of slicks. The traction control was sensing tire slip going into 2nd gear and was cutting power, which even then was pretty sick. Now, though, it just rips 2nd gear. Vince may have some trouble with this seeing as though he has extra horsepower and is going much shorter in the ratio. Oh well, we agreed we're just going to put it on and beat on it and see how bad the rear wheels give out. If it's too bad... 2.9x back on
By the way, you guys NEED LIMITED SLIP SOOOO BAD. Haha feels so different.
Vince, the jump frmo 2.9x to 3.46 is drastic but I am planning on that same jump. I currently have 3.23LSD and am going to a 3.73LSD... acceleration will be insane and top speed will be not so insane. I spend more time doing runs to 60, 80, 90mph than I do cruising at 140... i don't think i am going to miss my top ened.
Brendan, the car just pulls and pulls. 5th gear seems like 3rd gear since i last drove the car prior to the differential. I would say this is perhaps THE BEST performance mod for the money. $275 got Brendan and Vince their diffs... given that i'm installing theirs for free, $500 would not be bad for a total package.
Edit:
Dboffa! haha! Its jon with the E34 yo! haha whats up man. I think Vince's biggest trouble will be 1) Traction 2) Traction Control (more on that) 3) Shifting fast enough.
Traction control light can be seen lit solid in Brendans 325 from shifting into 2nd and pretty much all the way through 2nd gear. I took traction fully off (or as fully off as an E46 will allow) and found it much improved thanks to Brendans rear tires being nothing short of slicks. The traction control was sensing tire slip going into 2nd gear and was cutting power, which even then was pretty sick. Now, though, it just rips 2nd gear. Vince may have some trouble with this seeing as though he has extra horsepower and is going much shorter in the ratio. Oh well, we agreed we're just going to put it on and beat on it and see how bad the rear wheels give out. If it's too bad... 2.9x back on
By the way, you guys NEED LIMITED SLIP SOOOO BAD. Haha feels so different.
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3.38m330 said:
Jon, i think u saved me from doing a Review of the diff on a 325
gonna have the car thurs if it kills me
i cant wait!!!!What up Jon!
Nice to see you're breaking in the diff for our friend. :lmao:
The diff swap is the sh*t; other than forced induction, it's the best thing you can do for your car in terms of power, especially for the price. And it sure as hell is nice to get tire chirps in 2nd gear :thumbup: Just sucks when traction control steps in and cuts power because I've forgotten to turn it off.
Brendan - have you driven the car at all yet?
Nice to see you're breaking in the diff for our friend. :lmao:
The diff swap is the sh*t; other than forced induction, it's the best thing you can do for your car in terms of power, especially for the price. And it sure as hell is nice to get tire chirps in 2nd gear :thumbup: Just sucks when traction control steps in and cuts power because I've forgotten to turn it off.
Brendan - have you driven the car at all yet?
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havent driven the car dave, thurs is the day
but i just realized its the 3rd, i am legal to DRIIIIIIIIIIVE now!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
so happpyyyyyyyyyyyyyyyyyyyyyyyyyyyy *(#*&$*(#@&[email protected]*([email protected]*#([email protected]*$***%$&[email protected]()#*[email protected](*#)@(* WOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
but i just realized its the 3rd, i am legal to DRIIIIIIIIIIVE now!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
so happpyyyyyyyyyyyyyyyyyyyyyyyyyyyy *(#*&$*(#@&[email protected]*([email protected]*#([email protected]*$***%$&[email protected]()#*[email protected](*#)@(* WOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
im a noob too here.
could someone tell me the logics of a diff. i think it was like if the number is higher, the top speed is lower, but accel is quicker.
anyone know what diff does a 323Ci 5spd have? which diff would get my car to reach 60 in 2nd gear?
...and where do you buy diffs from? how much are they (uhh, lets say brand new)
could someone tell me the logics of a diff. i think it was like if the number is higher, the top speed is lower, but accel is quicker.
anyone know what diff does a 323Ci 5spd have? which diff would get my car to reach 60 in 2nd gear?
...and where do you buy diffs from? how much are they (uhh, lets say brand new)
i went up to 3.38 with 5spd before, the gears were all too short..
1st gear goes by literally in 2 seconds and you can't hit 60 in 2nd unless u have incresed redline to 7000rpm
i have a 3.07 now, i would recommend it to anyone especially with FI, you can definately feel the power better.
1st gear goes by literally in 2 seconds and you can't hit 60 in 2nd unless u have incresed redline to 7000rpm
i have a 3.07 now, i would recommend it to anyone especially with FI, you can definately feel the power better.
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what is stock in a 328ci 5spd....
id like to do the diff mod, and have always thought about it, but was never too sure on which diff to get...
i think the 3.46 would be too much on a manual. The amount of tire spinning these guys with step are doing, i think it would just be way to insane, and shifting way too mcuh to quick.
Plus since im on the road to FI this summer, i think the added power would just blow my rear end off....
so maybe something less drastic that is going to give me some mad acceleration increases would be awesome.
anybody have any suggestions???? and what is cost on a LSD, even a used one for that matter????
also anybody do a diff swap with a lightweight flywheel????
id like to do the diff mod, and have always thought about it, but was never too sure on which diff to get...
i think the 3.46 would be too much on a manual. The amount of tire spinning these guys with step are doing, i think it would just be way to insane, and shifting way too mcuh to quick.
Plus since im on the road to FI this summer, i think the added power would just blow my rear end off....
so maybe something less drastic that is going to give me some mad acceleration increases would be awesome.
anybody have any suggestions???? and what is cost on a LSD, even a used one for that matter????
also anybody do a diff swap with a lightweight flywheel????
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409 Posts
yea our 328s already have the 3.46 diff, at least theres something good about it huh? only bad thing that happened when they upgraded to the 330 was the diff
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crispvx said:
Let's try the 3.46 vince, it's not that bad to pull it back out. Plus we can sit there and insult one another. 3.07 seems like too little of an increase. 2.9x - 3.07? Not worth the hassle in my opinion. All or nothing! You guys really need to Petition BMW for Limited Slip options though, I am appalled that these things don't even have an option! Same with E39. Non-M's of course.
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