which diff for m30 and is it ok to weld?

[shanehaward]

i have an m30'd e30 and its still got the 318i diff. 1st gear and most of 2nd gears are wasted. im after a lower ratio diff but not sure which one to go for? i dont fancy paying £250+ for diff that needs rebuilding aswell tbh. would a 3.64 be better? i also hate the idea of a number one and badly need a number 11 does anybody know where i could get it welded up when i get one? thanks shane

[Baurluvva]

I have a 525e open diff that fits onto an e30 (need to swap backplate to e30 and e30 shaft flanges)
2.93 iirc - I was going to use it on my old m30 swap!!

[johnl320]

I have a 525e open diff that fits onto an e30 (need to swap backplate to e30 and e30 shaft flanges)
2.93 iirc - I was going to use it on my old m30 swap!!

Same here 525e diff but 3.07 ratio, not welded it though makes first useable and get 68mph in second gear.

[shanehaward]

I have a 525e open diff that fits onto an e30 (need to swap backplate to e30 and e30 shaft flanges)
2.93 iirc - I was going to use it on my old m30 swap!!

Same here 525e diff but 3.07 ratio, not welded it though makes first useable and get 68mph in second gear.

that sounds ideal for what i want

[MJJ_ZX6RR]

I have a 2.93 in my 335, and it is nigh on perfect for road use. Lovely refined cruiser, surfing that M30 torque and perfectly able to potter along in 3rd at 30mph.

On the track however, it could be a lot better. I barely need more than 3rd gear (5th is geared for something daft like 210mph), and there is a vast chasm of a gap between 2nd and 3rd which makes a lot of 50 to 60mph corners a bit of a pain. IIRC, 2nd runs to about 65mph, 3rd to something like 100.

Just my 2p. I'd go more like 3.64 I think if track work was a priority.

Martin.

[Grrrmachine]

Welding's very popular over here with the "diffin" crew, but they are NOT for a street car; you'll be rubbing the tyres at every roundabout, and going through rubber at a terrific rate. So if it's your daily driver, don't get it welded.

It's also a prosecutable offence if you're caught with one, but that's another story.

[be11]

iv been running a welded diff on my touring and my 200sx for years. You get used to it and tyre wear isn't even slightly as bad as people make it out to be. If your planning on welding your diff your obviously planning on doing some skidding so you shouldnt be bothered about a bit of extra tyre wear anyway.

I'm running a 3.91 on my m50 touring at the moment and have just bought a 3.64 to replace it.

[shanehaward]

yeah im not that bothered about a little bit of extra wear tbh. im going to do it just need to find sombody to weld 1 for me