LSD ratio help

[E30LI]

Hi guys,

Bit of a novice when it comes to LSD's and understanding the ratios. Just wondered if anyone could help me figure out the best ones to look out for.

My E30 is running a Nissan SR20DET engine, pushing about 260bhp, with an aim to hit around 330bhp by the end of the year.

The LSD i've seen up for sale is one from a 325is and is 3.73. Would that be suitable? I'm not looking to use the car for drift, i'm after more usable road power and like to take it up the strip on drag days etc.

I'm still currently running the 316 standard diff so need to sort an LSD out before I chase more power.

Thanks for any help guys,
Oli

[HairyScreech]

I think the big question here is what gearbox you are running?

[E30LI]

Hi there, it's a standard 200sx s14a gearbox!

[Motorhole]

I found the following ratios online for the 200sx box - although not sure of the reliability of the source:

1st: 3.321
2nd: 1.902
3rd: 1.308
4th: 1.000
5th: 0.759
Reverse : 3.382

From the same source, factory final drive was 3.692 - so that would suggest a 3.64 or 3.73 BMW diff would be ideal. However it does also depend on wheel/tyre size. According to a handy spreadsheet I've built, with those ratios and with 215/45/16 tyres, you'll easily be making 60mph with just 1 gearchange and doing 70mph in 5th at about 2900 rpm, assuming a 3.73 diff. That's about right for a daily driver with the power you're talking about, but you might want something a bit taller (3.91?) for track work.

[HairyScreech]

That all seems about right ratio wise.

Just go for a medium case 3.73 then.

[maxfield]

I've driven a couple of S14s and always thought they were very long geared.

I'd be tempted with a 3.91.

[Motorhole]

You will deffo want something shorter if you're running 45 profile 17s or bigger too.

[E30LI]

Thanks for all the replies, that helps massively. Going to look at a 3.73 this weekend so will give that a try and see how I get on with it, as it's mostly road use that it'll be getting used for, but will try a 3.91 if i'm not happy with it.

Thanks again!

[DCe30325i]

Hello Peeps,

Please can you give me some advice on the best LSD to use on a 325i E30 (1989) switchable auto Gearbox.

Could I use an LSD from an auto Z3 or E36?????

[Superleggera]

Hi Oli

Any chance I can have a chat with you ? I'm looking at doing a sr20det swap and had some questions and for some reason my PM to you doesn't send. If so please PM me back.

Thanks