E30 Zone

can anyone tell me what the ratio is for "87 320i standard open diff? thanks

3.64 upto 9th/1987 after 9th/1987, 4.10

torquey wrote:3.64 upto 9th/1987 after 9th/1987, 4.10

Not quite.

320i 9/85 to 9/87 came with either 3.64 or 3.91. My late 86 320i had a 3.91.

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Thanks guys i must find out the exact month and year of the car so it mite make it easyier to work out the ratio, dont want to strip the mans diff down and then say its not what i want if i can help it,

Mines a 87 320i, with a 3.64 diff... Found out the other day so looking to upgrade it to a bigger one like the 4.10 or larger

Jim320i wrote:Mines a 87 320i, with a 3.64 diff... Found out the other day so looking to upgrade it to a bigger one like the 4.10 or larger

is it small case or medium case housing?

E30SPORTMAD wrote:

Jim320i wrote:Mines a 87 320i, with a 3.64 diff... Found out the other day so looking to upgrade it to a bigger one like the 4.10 or larger

is it small case or medium case housing?

Jim's is a small case diff mounted behind an autobox,what Jim wants to do(I think)is make his car a bit faster at the traffic light GP,so he's looking for a small case 4:1 or possibly a 4:27.

Thanks Malc.

Small like Malc said pal. But its on an auto, also like Malc said.

Mine was manual and small case.

clarko74 wrote:Mine was manual and small case.

Now if you were to want a slightly taller 3.64,and Jim would settle for a slightly shorter 3.91,all you have to settle is the difference between Leicester and Kent....

Jim320i wrote: Thanks Malc.

Small like Malc said pal. But its on an auto, also like Malc said.

I think m40 tourings (auto) had something like a 4.45

daimlerman wrote:

clarko74 wrote:Mine was manual and small case.

Now if you were to want a slightly taller 3.64,and Jim would settle for a slightly shorter 3.91,all you have to settle is the difference between Leicester and Kent....

Note that I said 'was' in my post. I changed it to a 3.64 medium case lsd when I put my 2.5 lump in.

took the 3.91 down the tip in the end, couldn't give it away, tried selling on here, then on ebay (some fella bought it for £5, paid and then never collected it as he wanted a medium case one), then tried to give it away without any takers.

whats it like with a 3.64 compared to a 3.91, my 3.91 has just blown up so need a new one was thinking of swapped ratios.

damageandyy wrote:whats it like with a 3.64 compared to a 3.91, my 3.91 has just blown up so need a new one was thinking of swapped ratios.

Which engine do you have?

Chome bumper E30 up to the introduction of the 325i all had small case diffs,325i brought the medium case diff into E30 use.

Small case diffs have 6 bolts holding the rear cover,medium case diffs have 8 bolts here.Medium case diffs are bigger,hold more oil and have bigger bits inside to make them stronger....

3.64 ratio;

73mph at 3000rpm

4.1 ratio

65mph at 3000rpm

(fiqures for manual 'boxes only)

Never tried a 3.91,but it will fall between the above quotes.