If you have been following along with our blog for the past year, you have seen plenty of ‘best mods’ articles about some of our customer’s top-choices for performance cars. Some of these, I’ve had to do a bit of research to speak about. I’ve had to bother our product specialists, brand teams, and engineers to find out what it is that enthusiasts want for those vehicles. Fortunately, those have resulted in some accurate, concise, and informative articles. This week, I finally get to write something from the perspective of an expert. Settle in, because this is the outline for the best mods, upgrades, changes, and maintenance you can do to get the most fun out of your BMW E30.
First of all, the E30 is a broad topic. Spanning coupes, sedans, wagons, convertibles, baurs, and the coveted M3 designs, and featuring about twelve different engine, suspension, and interior combos, the E30 generation of the BMW 3-Series is a broad topic. Naturally, we’re going to have to narrow it down. I have, as a long-time E30 owner, written many articles about E30 mods, upgrades, maintenance, and what to know before you buy one of your own. If you are new to E30 ownership or interested in picking one up before they skyrocket further in price, I suggest you look at some of those that I linked above. For this article, we are going to focus on the 325i/is a coupe, sedan, and convertible models. Everyone else will have to wait, but some of what we discuss here today will apply to all variants.
If you just purchased, or are looking to purchase, an E30, then you already know these are 30+-year-old cars. They will need pretty much everything. How you go about that maintenance, though, will depend on what your plans for the car entail. This article won’t be so much about what to do, but how to plan what you want to do so you are efficient and conservative without having to do things twice. Let’s begin.
After your purchase, or before you begin to dig in, you need to decide what you want from your car. Really, there are two avenues to explore: a factory-fresh restoration with your own flair, or and all-out build that is done to your specs. So this article is going to be two how-tos in one. First, we’ll cover the factory M20 straight-six family of engines. Then, we will explore what to do if you don’t plan on swapping your E30 with a bigger, newer, or possibly non-BMW engine.
The M20 route:
If you don’t want to swap and prefer the straight-forward, classic, not to difficult M20, you’re a discerning fellow. While they aren’t the most powerful, they are dead-nuts reliable and still provide tons of fun. What you’re going to expect going into one, though, is a full overhaul. I’m not one to take a seller’s word for what they have completed. With my E30s, engine maintenance has been as follows:
If BMW cooling systems are notorious weak points, the E30 may be the poster child for this stereotype. Completing your E30 cooling system service is paramount and it will require some attention regularly during your ownership. Some common failure points include the surge tank, radiator, thermostat, water pump, and hoses. Basically, the whole system. It’s a good idea to start with the amount of water being moved around your system. You can check your E30 radiator flow with it removed by running distilled water through it. If it is clogged, you’ll want to replace it with either an OEM or an upgraded aluminum unit. It should be noted that early model and late model engines are most different in the coolant line input and output locations, as they are switched. The expansion tanks are on the opposite sides, driver’s side for late model, passenger for the early model. The Late Model tank is ‘preferred’ but mostly for swaps. Really, just make sure your radiator has flow.
The water pump, coolant temp sensors, thermostat, gaskets, and hoses should all be replaced as well. Unless, of course, you have definitive proof they have been done fairly recently. Either way, it’s smart to inspect everything for leaks, seeping coolant residue, or potential cracking. The E30 water pump is a regular maintenance part that should be replaced every 60k miles, along with the coolant and thermostat, so be sure to look for signs of possible failure when you have everything out for inspection. At any rate, all of the major E30 cooling system parts you need can be found at ECS.
while you’re in the cooling system and pulling all that out, you should also go ahead with your timing belt service, intake manifold gaskets, exhaust manifold gaskets, valve cover gasket, valve timing service, and ignition service. All of this will have to come apart to do the timing belt, which should always be done when you buy one of these cars, and will be easy enough to deal with since it will all be accessible as you work your way down to that belt. One thing I like to do is replace wearable parts with new/like new versions as I pull them out, and clean as I go. Many covers will be caked in dirt, grime, oil, and whatever else. Give everything a solid scrub-down and replace your spark plugs, ignition wires, distributor rotor, gaskets, belts, and sensors as you pull everything apart. We also have handy E30 ignition system service kits that have everything you need to refresh it all at once.
You should pick your direction for your stance ahead of time, because there isn’t much crossover between parts here, so you need to decide upfront. If you want bags, don’t waste your money on any other suspension parts. Just get the bag setup on the front end because that will require new front housings/hubs, the bags replace your springs, and the struts will come with the Air Lift kit. That said, you should go ahead with the E30 Front and Rear suspension refresh kit to get started, regardless of what you plan to do. If you do want to retain stock performance and feel, we have all the E30 suspension parts you’d need to restore it available as well.
If you want to go static, you have two and a half options. Option one is a ‘cup kit,’ which is basically new top mounts, struts, shocks, and springs. While you’re in there, go ahead and replace your wheel bearings, control arms, FCABs (I like Turner Motorsport Monoballs) and rear trailing arm bushings. Really, all bushings need to be replaced. The next option is a set of E30 coilovers that use a true coilover design upfront but retains the separate shock/spring setup in the rear. Lastly, there are some companies that make true coilover setups for the front and rear of the E30s. This is a great setup, but you will need to reinforce the rear shock tower mounts, as those have a tendency to blow out with this kind of setup.
Finally, just remember you will need to do all your bushings, mounts, and ball joints. Control arm kits from us are a great start. If you choose to go five lug, though, you will need to get specific parts. Short of re-writing it, this guide by CalvinZero I have used is your best bet to know exactly what to buy. Basically, you can go with E36 96+ spindles and a z3 rear end, or E30 M3 hubs all around. The guide I linked will take you through it all easily. The rear diff mount, center support bearing, and giubo all need to be replaced as well in most examples.
Unless your interior is mint, which it probably won’t be, I suggest buying what you want, not buying the stock stuff. If your dash is cracked, buy a dash cover and send it. Otherwise, you will go through about a day of pain to swap it out, which I can tell you from experience is worth it, but not fun. If you can be ok with just a cover, go that route. For seats, RECARO classic seats are your best bet and SCHROTH harnesses will keep you safely pinned to them. That said, a budget-minded build may include E30 seats like those offered by Corbeau.
For shift knobs, the Condor Speed Shop shift knob and Z3 short shift kit are your best bets. I absolutely love mine and will always recommend them to any new E30 owner.
Other than those bits, you’ll just want to do maintenance. A full E30 brake service is likely in order, which should include pads, rotors, sensors, fluid, and possibly brake lines. You’ll also want to replace all the E30 fluids and filters, looking for signs of leaks along the way. The valve cover gasket and pan gasket are common culprits, but after 30 years, you should be prepared to change all your E30 gaskets and seals.
Ok. You want to double your horsepower, stay OEM, and don’t want to fool with a turbo, at least, not upfront. Then you need an M50, M52, S50, or S52. There are pros/cons to each of these engines, but again, you’ll want to decide upfront rather than re-do it, since it can get pricey. First, you need to decide if you want to go 5-lug or stay 4-lug upfront since most of the above maintenance will still apply. Your suspension, brakes, and hub setups should be decided before you get started.
M50 – the most affordable and easiest to swap, the OBDI M50 offers a basically drop-in solution for a good horsepower increase without worrying about additional electronics. With a set of Condor Speed Shop swap mounts, an E36 ZF transmission (or G260 with Condor Speed Shop swap trans mounts/brace) is a great way to go. These are also healthy for boost, so keep that in mind.
M52 – probably the most work for the least amount of reward, the 2.8 liter, OBDII E36 engine offers great power and torque, can rev quite high with the S52 cams from Schrick, and is a great NA option or ready for boost. This does mean, though, that you will need the full harness, ECU, keyring, EWS module, transponder, and original key to wire in for the car to work. It is a lot of effort, but worth it if you don’t want to spend more than $1,000 on your engine, trans, and harness setup.
S50 – the easiest way to swap a powerful, ready to rock, and reliable engine into your E30 is with the OBDI M3 engine. The 3-liter straight-six offers tons of potential but doesn’t require a bunch of wiring changes to swap.
S52 – basically the same as the M52 but with bigger cams, more displacement, and a higher price. If you want the best the US E36 generation has to offer out of the box, this is the way to go. If you want boost later on, however, I would encourage you to go with the M52 and a set of cams to keep your budget low and maintain reliability since the cylinder walls in the iron block 2.8 are thicker than they are in the 3.0 S52. Not only that, but this is also OBDII, so the same wiring/ECU/EWS struggles apply.
We could really go down a rabbit hole with 24v swap upgrades, but that will be another article. What you need to know about an E30 is that they are amazing cars from the factory. With some drivetrain bushing/mount upgrades, maintenance, an engaging shifter setup, and competent suspension, you are well on your way to the most engaging car you could ever own. Of course, there are tons of wheel options for the 4-lug set up, and more for the 5 lug setup, but we will leave that up to you. Just remember to have fun, make your E30 all it can be, and do your research. Whatever E30 parts you may need, you can find them here. Don’t forget, use this article as a starting point, not your bible. I could write for days, maybe weeks, about everything you need to know about an E30. Realistically, this is the jumping-off point for you. So go out, get started, and enjoy the ultimate driving machine.