I’m a BMW E30 fan. I wear E30 BMW blinkers with pride. For me, it’s one of those classic shapes that will never be repeated.

Ask a kid to draw a car and you might find it will resemble this three box coupe. Yeah OK, the E21 was the first of the 3 Series breed and perhaps the purest form, and the 2002 certainly broke more new ground, but it’s the E30 that has my heart. The community that surrounds these cars is incredible. I’ve never owned a car that is so well followed the world over.

For me, there’s no one thing that sparked this obsession. It’s more the culmination of factors.

This side of a Volkswagen Golf MK2, I don’t think there is any car so well supported by the aftermarket. You can get anything you like for these things and they come apart so easily. I’ve just about changed every part of this car and even gone to the dealer for new parts. It is crazy to think that BMW still stock items for a model that is 30 years old.

Aside from that, there are so many OEM variations to choose from; hundreds of rare and niche items from BMW themselves to keep you up all night on eBay. There is so much to learn about trim levels and model differences. This, plus the motorsport heritage, coincide to give me just about all the avenues I need to occupy my busy brain.

The base model E30 was already a competitive Group A race car in 325i form, long before it spawned the legendary E30 M3. This close link is perhaps the most tantalising prospect when getting into an E30 project; the tinker-ability factor is off the chart. The E30 M3 is a true evolution of the base platform, and this allows you to take inspiration and even bolt up M3 parts to your car. The combinations are virtually endless.

That is exactly what I have set out to do: Take a base E30 and manipulate it into my own vision.

I originally wanted to find a 318is, as that model’s four cylinder engine could make a great homage to the M3. Every car I saw was either too expensive or too rotten, though. That was until I stumbled across this 320i on Facebook Marketplace.

It wasn’t too far away, so I headed to take a look. Ten minutes of conversation later and I ‘accidentally’ owned an E30. I didn’t really know much about the ‘baby six’ variant, but you better believe I got up to speed pretty quick. There’s nothing quite like Googling what something is the moment after you have bought it.

The 320i is the smallest of the M20 six cylinder-powered cars and was pitched as a bit of a small-engined, smooth cruising, executive saloon. It is neither here-nor-there in the E30 line-up, sitting hidden and desirable in the middle.

What is cool about my car is that it’s actually a 320i SE, a standalone, low numbers model with ‘SE’ on the logbook. They came packed with extras like pop-out rear windows, electric mirrors, electric windows and sunroof, plus servo-levelling headlights and an on-board computer built into the headliner. I knew none of this when I bought it, however.

What wasn’t so cool was the interior it came with – tatty, beige leather seats with a cream carpet. Luckily a friend, Tom, donated a set of Tech 1 325i Sport rear door cards to the project, and I set out to find the rest. It took another three interiors to make up the full factory Recaro set.

I would tell you that the rear bench is really special as it has both headrests and a fold-down centre armrest, and this coupled with the houndstooth fabric makes it exceptionally rare. I didn’t say that though, because that’s the sort of fact that gets you labelled as a nerd at dinner parties.

Having a six cylinder M20 as standard, it also would prove the perfect base for me to create a 325i M20 Group A car.

I have an M20B25 engine waiting in my garage, earmarked to create a blueprinted ‘monster’ engine. I say monster, but I mean monster for the 1980s. I’m undecided on keeping the stock capacity or stroking it. It’s simple to build a 2.7-litre, 2.8-litre, or even larger capacity engine to make 230+bhp, but do you need that much?

Before getting stuck into the engine I did what any sensible person would do and tackled the rest of the car. Top of the list was to try and work out the chassis, brakes and cooling system. The 2.0 six (M20B20) does not benefit from the external oil cooler that the 2.5 engine does, so it made sense to upgrade to the factory cooler. But at this point, any original oil cooler is at least 25 years old, which means their fins are virtually dust.

As an avid E30 fan, I was aware of CSF Race‘s involvement with CAtuned and their inspirational E30 builds. Cue a quick chat with Ravi at CSF about the requirements of my build and the idea to fit an E36 328i radiator plus a CSF Race M20 oil cooler was spawned.

Before any cooling upgrades could happen, I wanted to know what difference my changes would make – I’m a sucker for data. This car was made in 1989 though, one year after me. I felt that adding logging or gauges would not be in keeping with the theme, so sought another solution.

Step up Liam, also known as Bavarian Auto Developments. I got linked to him by a mutual friend and ‘E30-head’ Corey Morgan. I knew straight away that I needed some of these retro gauges after seeing them in Corey’s car. They slot directly into the spare switch spaces in the E30 dash, and come complete with printed loom plugs, wiring and temperature senders.

I took one for oil temp and one for water; fitting them was a doddle and they can be turned off at the touch of a button for ultimate stealth. A temperature probe in the thermostat housing and one in the oil filter housing measure the respective temperatures.

With stock temps read, I could crack on with the upgrade. The size difference between the CSF radiator and the OEM item is huge – it’s a wonder how it fits into the E30. But I need not have worried; Ravi assured me that the E30’s front end is equipped to take the huge E36 radiator.

A simple rejigging of the OEM mounts allowed the E36 radiator to sit snugly on the OEM rubbers and still clear the viscous fan. Regal Autosport were kind enough to lend me a slither of workshop space to work in, but truth be told, this is an easy driveway job.

A cool feature of the CSF radiator is the bleed nipple on the side of the aluminium end tank which makes it easy to bleed the system. On an M20 you usually need to do it at the thermostat housing, which isn’t always effective.

CSF uses B-tube technology to increase core efficiency by some 20% over conventional cores, and this coupled with the increase in size takes care of heat rejection nicely.

The oil cooler itself is a ‘drop-in fit’. This means that CSF has designed it to work with the OEM oil lines and body mounts, so it slots right into place. All I had to do was retrofit the 2.5 oil filter housing to my 2.0 engine and it bolted straight up.

CSF supply this cooler with AN adaptors too, so at a later date I can upgrade the lines to braided AN on my 2.5 ‘race’ motor. You can’t deny that seeing AN fittings screams race car.

The verdict from behind the wheel is impressive. I’ve seen a 20°C (68°F) drop in oil temperature, and similar results for water temp in brisk driving. The biggest difference has been with wide-open-throttle pulls. The stock M20B20 only makes 127bhp, and with the modifications I’ve made it pushes this to just about 140bhp. To reach any great speed it requires commitment with the throttle and a bit of time. This translates to heat.

With the stock radiator the temp gauge would fly round the clock after sustained 5th gear wide-open throttle-pulls. Now with the CSF oil and water combo the dial will not budge, no matter how hard I drive. Water and oil temperatures are regulated perfectly by the OEM thermostats, and the additional cooling capacity allows the engine to run at optimum temperature with lots of headway.

The radiator not only increases the cooling capacity, but it has totally changed the way the engine bay looks too. I’ve changed nothing else in the images above, just the cooling cores. It makes such a difference to have a bright aluminium radiator in the engine bay rather than the rusty old item. That in itself is a good reason to upgrade.

You’ll notice in Scott’s pictures that the wheels on the car have evolved from 318is BBS RA into fully-fledged BBS RS. These took me just over a year to build from the point my friend Rob dropped four freshly re-drilled centres off to me, to bolting them up. So long in fact that I’d forgotten the offsets and worried that they wouldn’t fit all over again.

They say good things come to those who wait, but the truth is, I’m just a bit of a let down and took absolutely ages to build them. I’m glad I took my time on them, though. I decided to restore the original BBS paint finish rather than blasting the patina to smithereens and re-coating in a soulless new shade. It took forever. It’s a romantic thought, but maybe I’m plain lazy.

Either way, the car is really starting to take shape and I cant wait to get into the nitty-gritty of the engine build. I feel like it’s a great place to get carried away. Don’t worry, I’ve still got the 318is wheels and AD08R tyres for track use. This isn’t a show pony, it’s built to be used.

Ryan Stewart
Instagram: 7.nth
ryan@speedhunters.com

Additional Photos by Scott Paterson
Instagram: scottpatersonphoto

This story is brought to you in association with CSF, an official Speedhunters Supplier