Gearbox + LSD

All the info you need to race E30's

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invader
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Tue Apr 20, 2010 9:25 pm

I've just got my first E30 that im going to use as a road going trackcar.
Its a 320i ,and i've bought a e36 m52 328 sport engine + box .
I just want to know would the M20 or M52 box be best for the track .
And also which ratio LSD would i need for Which box ?

Thanks steve
e301988325i
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Sun Apr 25, 2010 11:12 am

The normal easily availble M20 boxes are 0.81:1 5th (overdrive, prop faster than engine), you'll want the close ratio m20 box if you go down that route, standard on tech 2 sports (i'm not certain on tech 1's) and availale as a cost option on 325's,
M5* boxes are 1:1 5th,
diffs depend on user requirements of course, but many are available, search for, diff table or similar
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Can anyone suggest how to test if the boot lights are staying on with the boot shut?

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lock the wife in there
Jhonno
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Sun Apr 25, 2010 11:54 am

I would use the 328i box with a 3.25 diff
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danxs
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Sun Apr 25, 2010 8:03 pm

i have a m20 box (unsure of sport or not) and a 3.91 lsd and i think it would be nice for a track, it pulls nice out of corners. dont know if it would be too short with a 328 in though
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invader
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Mon May 03, 2010 8:46 am

Thanks for all the advice .

think i will fit the 328 box.
DmcL
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Mon May 03, 2010 12:47 pm

whats the difference between M20 box and tech 2 sport box? unless my first manual box just happened to be from a sport i cant tell a single difference between the current box i have that came out of a tech 2 sport and the last one that died (was assuming it was a boggo M20 box). far as i can tell same engine speed in 5th at 60mph, 1st, 2nd, 3rd all felt the same, etc.

im thinking the first one i found on its own in the scrapper may have also been a sport box if there should be a noticable difference between M20 and sport boxes.

diff im running is, i believe, a 4.10 as the car was a 4 speed auto that i converted. havent ever checked the tag if there even is one lol

with sport box at 60mph in 5th the engine speed is slightly behind the road speed. best guess somthing around 0.8 to 1? what diff ratios should give me that? car pulls well, really well for only having basic bolt on mods + a chip. hasnt even got a full exhaust system just standard no cat system with a scorpion box out back. also cant crack 60mph in 2nd, runs up to about 55-56ish before the rev limiter cuts in at 7000rpm.
Last edited by DmcL on Mon May 03, 2010 12:53 pm, edited 1 time in total.
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Mon May 03, 2010 12:52 pm

Jhonno wrote:I would use the 328i box with a 3.25 diff
Agreed. I'm using the 328i gearbox with my 2.8 and i much prefer the "feel" of the gearbox over the m40 gearbox i was using with my m50 engine.

I'm using a 3.64 diff at the moment but i wouldnt really recommend it. Its a great laugh but it revs way too high at motorway speeds and it has trouble putting the power down.
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