So you want to modify your e30?
So you want to modify your e30? Here is a quick beginners guide I’ve decided to write to help some of the guys who are looking for some guidance on what to do to their e30. The mods I will be covering are usually commonly excepted amongst e30 enthusiasts and I will try to cover as many options as I can.
The first thing to do is always maintenance. There’s no point in having a cool or fast e30 if its unsafe and unreliable. On the M20 its worth doing the timing belt and water pump right away if you don’t know the last time it’s been done. Its better spend a couple of bucks and an afternoons work doing the timing belt than rather risk the belt snapping and causing a lot more damage. It’s also worth changing the fuel filter and swapping out the old air filter, spark plugs, distributor cap and rotor, fluids, and an oil change. I always try to use OE parts, or reputable OEM parts. Stay away from cheap Chinese parts and companies like Uro. They have a reputation of not fitting or failing, it’s not worth jeopardizing your vehicles reliability or safety to save a couple of bucks.
Car Recipes: Here are some basic set ups to get you started. I will go more in depth later and cover a lot more, but this is just to get you started.
Daily Driver: Shocks/Struts: Koni STR.T; Springs: H&R OE Sport; Sway Bars: Front; Convertible/Rear; ix, Bushings: OEM Rubber; Brakes: Brembo Blank Rotors, StopTech Pads, Rebuilt Calipers
Performance: Shocks/Struts: Bilstein Sports; Springs: H&R Race; Sway Bars: Suspension Techniques; Bushings: 95a Poly Bushings; Brakes: Brembo Blank Rotors, StopTech Pads, Rebuilt Calipers, Stainless Steel Brake Lines
Chassis: The early model e30s are much lighter than the later models so if your goal is a light weight e30 this might be the chassis to start out with. Regardless early or late model it’s a good idea to reinforce as much as you can. Garagistic sells some great reinforcement parts that will make sure you have no problem with sub frame cracking or tearing.
There are many options for springs in the e30 world, but the two I will be covering are H&R Race and H&R OE Sports. H&R OE Sports are just a step above e30 M3 springs. They give a 1-inch drop and provide a slightly stiffer spring rate than stock. H&R Race springs give a much stiffer spring rate and provide a 1.5-inch drop. Although they are stiffer they are perfectly fine to use on a daily driver. H&R does offer a middle man between the two with the H&R Sport springs.
The two main shock manufactures for e30s are Koni and Bilstein. Bilsteins are known more to be a tad bit stiffer and don’t absorb bumps as well as Konis, but both a great shock manufactures and both will improve you e30s handling.
Coilovers: Coliovers are obviously the best option for your e30, but come with a big price tag. They come in different spring rates and allow you to control the ride height. Ground Control is the go to for coilovers, but if you are on a budget CA Tuned is another very comparable option.
-OEM: Obviously for the best comfort use OEM bushings, but that doesn’t mean that they are bad for performance either. Your bushing material is going to be a personal preference, but OEM rubber is always a good go to.
-OEM+: There are some OEM upgrades you can pick from when doing bushings. E30 M3 offset Control Arm Bushings, Z3 M Roadster Differential Bushing, and e46 Shock Mounts are all options to get a little performance out of the car without giving up OEM comfort.
-Poly 80a: A soft poly option that is often compared to the same feel as an OEM ride.
-Poly 95a: A little stiffer bushing and is probably the most used poly bushing grade. Great for a car built for performance or track days.
-Poly 70d: The stiffest poly grade and should really only be used for track cars or those who are willing to sacrifice anything for performance.
-UHMW Condor: Definitely the harshest bushing option, Condor makes great bushings and tests them on both their personal race cars and professional.
-OEM: Convertible front and ix rear makes for a great combo for the street. It’s also the cheapest option out there. You can also locate the front sway bar end link attachments to the strut tube to help reduce body roll.
-After-Market: There are several after-market sway bar options, but Suspension Techniques is by far the cheapest and is why I recommend them.
-Manual Rack Conversion: If you’re looking to ditch the power steering then Garagistic sells a block off plate that turns any e30, e36, or e46 steering rack into a manual rack.
-E36: One of the most common rack swaps around and gives the e30 the steering rack it was meant to have.
-E36 M3: A little bit quicker than the regular e36 rack and is a progressive ratio.
-Z3: Possibly the quickest steering rack ratio that you can swap into your e30 and turns your 1980’s car into a little go kart.
-OEM: OEM Brakes are great, the e30 actually has pretty adequate brakes for its stock form. Unless you are tracking the car or have more power than stock you shouldn’t really need more brakes.
-Performance: StopTech pads are a great upgrade along with stainless steel braided brake lines. Brembo rotors and rebuilt calipers will give you all you need for your e30. A 25mm Master Cylinder from a e32 750i will give you a much firmer pedal feel, but won’t actually improve stopping distance.
-RX7: A cheap BBK that’s been done several a million times. Definitely the cheapest solution and probably the go too, but there are other better options out there.
-Massive Street: Massive Lee provides a street kit that will reduce unsprung weight and give you more stopping power. All at a much cheaper price then some of the other options out there. Massive also has full track BBK packages too.
-UUC: More expensive than the Massive Street kit, but comes with a light weight rotor to help reduce unsprung weight and rotational mass.
-Bolt On: Headers, 19 lbs injectors, M30 AFM, SSSpuid Chip. This recipe will give your M20 a little more oomf and is easy on the wallet.
-Stroker: There are two good stroker options for the M20, the 2.7 and 2.8. To build a 2.7 use an eta bottom end with a i head. This will result in a low compression motor great for boost. To build a 2.8 you can use a M52b28 crank, eta rods, and i pistons. Paired with a 272 degree cam and headers you’ll have a great motor for the e30 chassis.
M30: Arguably the greatest motor swap option out there. Also been called the motor that the e30 should have had. A period correct motor that has low end torque and has no problem taking boost is perfect for the e30.
24v Swap: Probably the cheapest and most popular option. It gives the e30 a lot more power and better fuel economy all in its stock form. People have called it the best mod they’ve ever done to their car and should be highly considered.
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