bmwe21.net forums

Hi guys,

Coming from the VAG world, they share alot of parts throughout the range, and therefore upgrades from later vehicles can retrofitted, such as bigger brakes, suspension, engines etc.

My housemate has an E30 cabriolet (325i) which he is converting to a V8 with M3 running gear, so alot of his parts will be surplus.

This is where my questions come in.

1) The brakes on my e21 are awful, the front discs are warped, and the brake fluid needs renewing. Will the e30 325i calipers bolt straight on to the e21 hubs? Are the hub mounting points the same?

2) Rear brakes - I had read for disc conversions, people use the 323i rear trailing arms complete, now I can imagine this is sought after upgrade, and therefore the trailing arms are probably in short supply. Can the e30 rear brakes be bolted to the stock e21 316 trailing arms, or can the complete trailing arms from an e30 be used.

3) The original solex is due a strip-down and clean, I would rather keep the original 318 1.8 m10 engine, but unsure whether to bolt some bike carbs on (done a couple of conversions on my poloes in the past with much success at minimal cost) or is there an OEM route to convert to fuel injection?

If anyone has any threads bookmarked that covers these, please let me know.

Failing that, once I have finished doing some jobs on my mk1 golf, and can get it back into daily action, I will start having a play with the e21, and will try, by trial and error to see what fits and what doesnt - I will document anything that works, for future reference.

Thanks
Saf

Hi Saf,

Unfortunatly the E30 is completely different, so the answer to question 1 & 2 is no. This doesn't mean it is impossible to convert an E30 rear axle to an E21, but this means a lot of work including some welding.

The rear axle of an 323i has good availability in Holland, so I think that's the easy way to go. For the front the conversion to Wilwood (using brackets) or Volvo 4-pots (straight fit) is the most common option. Try searching that on the forum.

The 318 was later build with injection, so the conversion should be possible. I think the hard part will be finding a 318i

Good luck with the project!

As for the brakes, depends on what engine you are aiming for but for a 100-120 BHP setup the stock brakes will be good enough. But then you have to do a full rebuild on the front calipers. Rebuild kit costs peanuts, it may be good to replace the hoses as well, get some decent pads and of course refresh the fluid. After that, you won't believe the difference. Pedal feel will always be so-so on RHD cars because of the extension that is used to connect the pedal up to the brake master.

You can do a conversion to vented which basically means vented discs and spacers between the brake caliper halves. A kit from a 323i bolts right on.

I'm pretty sure the warped discs are caused by either normal wear (getting too thin) or because of seized brake calipers.

Rear drums are good enough but check for wear and leaks.