The LS swapped E30 inherently has to ditch the vacuum assisted brakes. Directly bolting the factory master cylinder to the firewall causes a large increase in pedal effort that isn’t acceptable. For this reason, the brakes cannot be left alone. Here are several options that I’ve researched and extremely generalized numbers to go with them.
Hydroboost is an assist method commonly used in diesels and trucks/vans. Diesels don’t make vacuums so the regular vacuum booster wouldn’t work. Hydroboost systems generate their assist based off of a fluid pump. Sikky makes a hydroboost kit based off of an E350 booster (IIRC) that is driven from the power steering pump.
Pros – No other modifications are necessary to your brakes. Plug in the kit and have factory feeling brakes back.
Cons – Some people don’t like the pedal feel and consider it “squishy”. If you drift and left foot brake, it completely changes how the pedal feels. There is added complexity to the engine bay but it’s not too bad. My only issue was that my track use overheated the unit and caused the brakes to stick.
Cost – The full kit from Sikky is ~$1200 with booster. But that’s it, plug in and go!
Wilwood Pedal box
He’s one I’m not super sure about. This should be another solution where you install it and go about your life. It replaced the clutch and brake pedal box with a proprietary pedal set. Garagistic makes a pedal box adapter so placing the pedal set in the car is simpler.
Pros – wilwood quality and adjustment. Allegedly still should keep the factory feel and function.
Cons – This looks like (again I haven’t done this) it would require a good amount of fabrication and work to fit into the car.
Price – The pedal adapter is currently $125, the pedal set is $200, and another ~$300 for 3 master cylinders. Plus miscellaneous fabrication and fittings. So I figure ~$800 all done.
Manual brakes and BBK
RX7 front brakes are a common cheap upgrade to the front of E30s. But they aren’t a complete solution. Massive makes an adapter bracket to physically remove the booster. But those two mods alone won’t give back the factory braking effort. I tried using a VW beetle (17mm) master cylinder. The car does stop better but now the pedal is squishy and still no where near factory levels of braking.
Pros – Cheaper of the solutions (but not by much). Fewer parts to worry about and requires little to no fabrication (just the pedal pivot relocation).
Cons – Doesn’t give great braking feel/force. But it works ok.
Price – ~$300-600 depending on what parts you pick up
Manual Brakes With Wilwood Calipers
This is the same as above but using wilwood brand calipers. The calipers are about $120 each for the front and $100 each for the rear so that and the welding needed to attach the calipers puts this around the $1,000 mark.
Pros – Better (possibly) factory feeling brakes. That cool wilwood logo.
Cons – Requires a GOOD welder as I haven’t found anyone making bolt on brackets for these. As I haven’t tried this, it’s possible braking still won’t be up to par with the factory.
Price – ~$1,000 depending on how much you can do yourself.
Manual Brake With 5 Lug swap
The biggest issue with the wilwood calipers is that the small factory rotors become the limiting factor. Larger diameter rotors give better braking (overly generalized). Swapping to full M3 E36 calipers (or E46 330 or any other swap option) will give better braking with the manual braking setup.
Pros – If you were already doing a 5 lug swap, this isn’t an issue. Retains factory parts. Very well documented swap.
Cons – Still might not give you factory braking (don’t quote me on that). Requires you to get 5 lug rims/tires/etc. And there’s 80 ways to go with the swap that might not give better braking performance. I think the E36 318 rear brakes aren’t as good as the Z3 rear brakes.
Price – $1200+
Brake Booster Relocation
Here’s a link to the basic setup. Essentially, you pull all the parts from an E32/E34 and fab it to fit an E30.
Pros – Mostly OEM parts. Retains the booster so it’s all factory.
Cons – Probably one of the most involved setups but not by much. You need to be able to weld and do brake fittings. This deletes the ABS unit and shoves all the bits in there. More parts in the engine bay and theoretically more parts for failure.
Price – ??? No one sells a kit and you’ll have to pay whatever the junkyard prices are. I honestly think this could be the cheapest of the “good” options.