325i Sports Gearbox

[E30BM]

Manual Whats the difference between a normal 5 speed & a sports 5 Speed Box ?

[wildeian]

Sport box has better acceleration in first 3 gears

[reggid]

are you sure about that?

Ratios std (sport)
1st 3.83 (3.35)
2nd 2.20 (2.03)
3rd 1.4 (1.36)
4th 1.00 (1.00)
5th 0.81 (0.81)
Reverse 3.46 (3.20)

the gear ratios suggest otherwise but i may be

[Richy325iTouring]

irst 3 gears on the sport are closer

to be honest there is hardly anything in it having put a normal 325 against a sport the difference is negligable

[E30BM]

Thanxs 4 the comments guys, its just my gear box is has a machanical fault, it is stuck in reverse gear. I was thinging if may need to replace it & was told to put a Sports gear box in it as it has higher revs in five gear. £200 for the Sports gearbox, it that a good price ?

[Richy325iTouring]

sports box has same ratio as a normal box in 5th
its the diff that will alter the revs at top end

£200 for a sports box is a it steep imho

try about half that

[E30BM]

Whats the difference with my diff & a Limited Slip Diff ? Or could I go for a better diff ?

[Richy325iTouring]

ratio is the only difference
and 25% lock up on the lsd

early spots had a 3.64 lsd late sports had the 3.91 lsd

the higher the number the better the cars acceleration

[wildeian]

Just sold a sport box for £100

[E30BM]

OK Guys Nice 1 4 that ! Big up your selfs 4 the knowledge & educating me. I will keep that in mind.

[reggid]

irst 3 gears on the sport are closer

to be honest there is hardly anything in it having put a normal 325 against a sport the difference is negligable

what are the ratios of both? The data i have doesn't seem to agree with this

[Andyboy]

are you sure about that?

Ratios std (sport)
1st 3.83 (3.35)
2nd 2.20 (2.03)
3rd 1.4 (1.36)
4th 1.00 (1.00)
5th 0.81 (0.81)
Reverse 3.46 (3.20)

the gear ratios suggest otherwise but i may be

"what are the ratios of both? The data i have doesn't seem to agree with this"

I think you answered your own question. 3.35 to 1.36 is closer that 3.83 to 1.40!
The 325i Sport have 15 inch BBS wheels which with the tyres used present a smaller overall rolling radius than the stock 195/65x14 tyres. Therefore first gear is taller to avoid undergearing the car and 2nd+3rd are bunched up to keep it on the boil.

Easy.

[Zaho49]

For M20 have a same gearbox with M3. I am trying to explain that first gear is in the bottom, it is same as normal gearbox's second gear.
Does anyone explain to me what is it. Because I know that sport gearbox is same like that.

[reggid]

are you sure about that?

Ratios std (sport)
1st 3.83 (3.35)
2nd 2.20 (2.03)
3rd 1.4 (1.36)
4th 1.00 (1.00)
5th 0.81 (0.81)
Reverse 3.46 (3.20)

the gear ratios suggest otherwise but i may be

"what are the ratios of both? The data i have doesn't seem to agree with this"

I think you answered your own question. 3.35 to 1.36 is closer that 3.83 to 1.40!
The 325i Sport have 15 inch BBS wheels which with the tyres used present a smaller overall rolling radius than the stock 195/65x14 tyres. Therefore first gear is taller to avoid undergearing the car and 2nd+3rd are bunched up to keep it on the boil.

Easy.

i see what is meant by closer (not shorter which i was confusing myself over) but the acceleration won't be better in 1st and 2nd gear in the sports box unless you get the diff from the sports aswell

[Andyboy]

As explained, the Sport has wheels and tyres with a smaller o/d than the standard set up, thus lowering the final drive. But only a poxy amount; the o/d of a 195/65x14 is 609mm, that of a 205/55x15 is 606mm. The road speed in 5th gear with a 3.64 diff (used on standard 325i and 325i Sport Tech 1) is 24.2mph and 24 mph respectively - so bugger all. The Tech 2 had a 3.91 diff and the speed was reduced to 22.4 mph - and the close ratio box with it's taller first gear is more use on these. Either way, the 325i always had a slightly low first gear and a taller first even on a standard car with 3.64 or 3.77 diff just works better. The 325i motor has big enough teeth to pull it.