- BMW E30 318is Specs
- The 318is Engine – M42B18
- E30 318is Review – Living With One
Commonly referred to as “the baby M3”, the BMW E30 318is has earned its place in the hearts of E30 heads and general modern classic car enthusiasts.
This article covers the hard information of E30 318is specs and shares the ownership experience of a 318is in the modern day.
The BMW E30 318is is pretty much a run-out model for the E30 platform. The plucky M42B18 4-pot engine found under the bonnet is the most technologically advanced engine BMW ever offered in a normal 3-series at the time.
Testament to this is the fact the following E36 model 318is came with the same unit bar a few tweaks in later production, noted as M44. These also have a similar cult following lately.
The E30 318is was offered for a very short period of time towards the end of production between 1990 and 1991 for around £14,750 base price (which is about £32k in today’s money), despite this BMW still managed to sell 41,234 units of the 318is.
Therefore, only 1.86% of E30s ever made were 318is’, and with many 318is making their way to scrap over the past decades, they are now relatively rare cars to come by.
BMW threw together some its best E30 parts, along with this new and exciting little motor to make it happen.
BMW E30 318is Specs
Compared to a lot of E30 models, the 318is came pretty well equipped as standard.
Available only in coupe (2 door saloon) format and with a couple of 318is only parts, it was special. It adopted a lot of the go-faster parts found on the 325i Sport models at the top of the spec hierarchy as standard too. Here’s a list of items fitted as standard on a 318is.
- Suspension Struts – 51mm front struts with firm Boge dampers from the 325i Sport
- Suspension Springs – Lowered roughly 15mm front and 17mm rear, with similar spring rates to the E30 M3.
- Front 20mm & Rear 14.5mm Anti-Roll bars from the 325i Sport
- Disc brakes all round
- Rear decklid Lip Spoiler – 318is exclusive
- Front Splitter – 318is exclusive
- M-Tech 1 steering wheel & Gear Knob
- Dark anthracite headlining from Sport models
- Sports seats
Aside from this standard equipment list, there were quite a few other spec options to choose from for the BMW E30 318is when they were originally available to purchase from the dealership. Find out more about what the options were further down in this article.
Before we get to that, it’s worth noting that in this era, if you were prepared to pay for it, you could twist the BMW dealers arm and request a special order of pretty much any available spec items or trim you fancied. Due to this, it’s not uncommon to see E30 318is cars with “factory fitted” M-Technic II body kits.
While I love the look of those kits, I personally feel like they’re a bit of a departure from what the 318is is all about. To me, that’s lightweight and simplicity.
Available BMW 318is Spec Options
As far as options go for the BMW E30 318is, prospective buyers had a few key choices available to them when looking to make the car their own.
318is Factory Bodywork Options
E30 318is Paint Colour
The most obvious option when it comes to the body is the colour.
The BMW E30 318is was available in a limited range of colours, albeit some of the nicest ones available at the time. Here are those colour choices:
- Lazurblau Metallic (Laser Blue Metallic)
- Sterlingsilber Metallic (Sterling Silver Metallic)
- Diamantschwarz Metallic (Diamond Black Metallic)
- Brilliantrot (Brilliant Red)
- Alpineweiss II (Alpine White II)
These colours vary quite a bit in desirability, but all of them are attractive colours and suit the E30 body shape.
The most common to see is probably Brilliantrot which looks great so no surprise, the most unusual one is probably Lazurblau Metallic. Among hundreds of 318is’, I’ve only seen a 3 or 4 cars specced colour, one of which I owned.
It’s a difficult colour to represent unless you can see it in person too, on a dull day it’s a rich navy blue, on a bright summer’s day it’s a bright metallic blue with striking purple highlights.
BMW E30 318is Side Skirts
A common source of confusion for buyers is the side skirts. Technically these are not “318is side skirts”, which they are often referred to as.
They’re actually BMW E30 SE side skirts and were available to be specced on standard couple models. So they are not a standard factory fit for the 318is, although an encouraged option.
Although I think the SE side skirts are an essential option to complete the E30 318is look, from my observations, more E30 318is’ don’t have them than do. So if you’re looking to buy one and they aren’t there, it’s not necessarily that they are missing from the car.
You can always add them to the car, although they’re getting hard to track down as lots of people had the same thought.
E30 318is Interior Options from Factory
Like the exterior colour choice, the E30 318is had a limited number of options to pick from in terms of interior.
The good news however, is that all E30 318is’ came with the sports seats as standard. These are commonly referred to as “E30 Recaro seats” however they are not built by Recaro, these are BMW’s own design seats.
Although they do bear a striking resemblance to Recaro seats of the period.
The available interior colour/pattern option combinations are listed below:
- Black Leather – Black door cards – Dark Grey carpet
- Anthracite Check Cloth – Black door cards – Dark Grey carpet
- Silver Check Cloth – Silver door cars – Light Grey carpet
- Indigo Check Cloth – Blue door cards – Dark Grey carpet
- Natural Check Cloth – Beige door cards – Beige carpet
The majority of 318is seem to have come with one of the check cloth options. Probably a sign of the times and the fact it stands out as a bit more interesting than the more luxurious leather.
Anthracite check, silver check and black leather are the three most common. Natural check cloth seems to be extremely rare and I can’t say I’ve ever seen one in the flesh. Although personally it’s not for me, it’s a sporty pattern in a luxury colour which doesn’t go.
I had a silver check in my E30 318is. Although I felt it complimented the external colour well, I always wished it was anthracite to break up the grey.
I’m more a fan of dark interiors and anthracite’s darker door cards, seat-backs and carpet would have been my personal preference. It would have also matched the 318is’ factory fit anthracite headliner.
Indigo check is very similar to Anthracite but with a blue hue to it, I wouldnt say its rare, but it’s definitely less common.
E30 Rear Headrests
Another commonly discussed interior option available with the BMW E30 318is is rear headrests. These we’re a factory option and you could get rear headrests added to any of the interior options.
E30 enthusiasts have differing opinions on whether they look good or not. Personally I like the look and I think E30’s look better from behind with rear headrests equipped. Although technically the E30 318is is a lightweight fun car and you’re probably not going to be hauling 4 people around if you own one these days.
The rear headrests can be easily retrofitted if you have the inclination and can find headrests that match your interior.
E30 BBS Wheels
If you purchased a BMW 318is from the dealership, you were faced with two wheel options. Standard BBS style-5 basket weave wheels in 14”, or BBS style 5s in 15”.
The 318is did not come with 15” style 5 wheels as standard despite what many people say. These were an option available to the buyer at the time. Although many 318is were equipped with the 15” wheels, I’d say it’s around a 50/50 split.
Quite a few have been since fitted with the 15” variants of the wheels which look better in my opinion. The only issue is the rarity of the centre caps when they inevitably go missing.
BMW E30 318is Chassis Specs
Arguably where the BMW E30 318is’ shines is in the chassis department. The lightweight design featuring the best of the performance parts developed for the heavier 325i sport E30 models made the 318is particularly sharp in the handling department compared to its peers.
One of the lightest E30 models available, the E30 318is’ curb weight comes in at 1125kg (2533lbs) which is actually 175kg less than a comparable 325i Sport.
Often touted as 50:50 weight distribution, the BMW E30 318is comes in very close with 53% front and 47% rear split making the handling of the car excellent and predictable in the corners without tendency to under or oversteer.
The wheelbase of the 318is matches that of its 3-series siblings at 257cm (101.2”). The body size and wheelbase of E30s from the factory remained very consistent between the models.
For the size of the car, the wheelbase is a good compromise, it’s short enough for the car to feel agile and light on its feet, but not so short that it’s twitchy and feels as though it wants to swap ends on you all the time.
The BMW E30 318is was only available to purchase with a 5-speed manual gearbox. There was no automatic option available to buyers, even in the US.
The gearbox in question was a Getrag 240/5 unit, the internals of which are shared with the E30 320i 6-cylinder car, but the propshaft end of the unit is a different length making them not interchangeable.
E30 318is Differential – Open or LSD?
Differentials are an interesting talking point when it comes to the 318is, and another common point of confusion.
The gearbox ratios for all 318is’ is consistent, and only one final drive ratio was available from the factory as standard which was 4.10.
However, the characteristics of the drivetrain and how the car delivers its power can be altered quite a bit by swapping the differential final drive ratio for a shorter 4.27 ratio from one of the lower powered 316i or 318i models.
It’s worth noting that the 318is E30 uses BMW’s small case differential size rather than the medium that was standard with the larger engined 325i cars, and due to the size of the driveshafts they are not interchangeable.
Despite the modest power output of the M42 engine, the E30 318is was available with a limited slip differential from factory if selected. These LSDs are quite rare to find these days as most of them made their way into E36 compact race cars over the years, and there weren’t many to start with.
During my E30 ownership I was lucky enough to be able to purchase a genuine 4.10 small case limited-slip diff which I was keen to fit and try out.
When I initially fitted it I came away disappointed realising that the diff I’d actually removed was a 4.27. I can confirm that the M42 engine feels like it delivers power to the ground more urgently with a 4.27 final drive as opposed to the factory equipped 4.10.
As far as the limited slip factor goes, the car was keener to slide when provoked in the wet, but I’d be hard pressed to state any performance gains in real-world spirited driving scenarios. Maybe on a track day it would have been a lot more obvious, needless to say I removed it and sold it on.
The 318is Engine – M42B18
As previously mentioned, the M42 motor is the most technologically advanced powerplant to grace the engine bay of an E30 3-series from the factory.
A real world description of the M42B18 engine is a plucky rev-hungry engine that despite modest power output is very rewarding to work hard. It’s also very good on fuel for an engine of this era, returning around 35mpg average.
318is M42 Power & Torque Figures
The M42B28 engine is a 4-cylinder 16-valve unit with chain driven dual overhead camshafts and 10:1 compression ratio.
At the time, it was also one of the first engines to use coilpack ignition and utilise a twin-valve throttle body.
The engineers at BMW also got creative with their combustion chamber design and the twin-concave design they came up with proved to be extremely efficient making it economical to run but with good power output.
The redline for the M42 engine as standard is 6300 rpm and peak power is produced towards the top at 6000 rpm. Peak torque kicks in around 4500 rpm and the torque curve is quite flat giving the feeling of linear power delivery right up to the top of the rev range.
See below key stats for a E30 318is equipped with this M42 engine:
- 318is M42 Horsepower: 136 hp
- 318is M42 Torque: 175 Nm (129 ft-lb)
- 318is Top Speed: 129mph (with 4.10 final drive)
- 318is 0-60 Time: 9 Sec
- 318is 0-100 Time: 26.2 Sec
These figures initially don’t seem like much to write home about but at the time they were remarkable from a 1.8L engine with good performance numbers that was so economical to run.
The M42 engine has also developed somewhat of a cult following over the years generating a considerable amount of aftermarket support. It turns out that this engine was very robust and gave opportunity for further tuning and performance gains.
Many M42 enthusiasts have built stroker engines to increase the engine displacement, fit a more modern coil-on-plug conversion to the ignition system, swapped out to individual throttle bodies with a carbon fibre plenum and remapped accordingly to see strong gains.
It’s also possible to turbocharge these engines and make considerably more power than standard.
E30 318is Review – Living With One
When I first became passionate about BMW E30’s around 2014, nice BMW E30 318is examples were quite affordable to purchase and seemed much more available than they are now.
Being a foolhardy young man at the time, I decided to go against better judgement and take the plunge. I exchanged my otherwise reliable and frugal diesel daily driver for a lovely 318is in attractive Lazur Blau (Laser Blue) and silver check cloth interior.
The car in question was a 1991 car with a 135000 miles on the clock, and had recently undergone a restoration making it great to look at.
I was initially after (as many people are) a BMW E30 325i Sport coupe, preferably with an M-Tech 2 body kit. However, I was a little bit too late to the party on that, and values had started to climb beyond my reach for good ones.
This along with the fact insurance and running costs for the 325i were more or less double that of a 318is. Thus, I decided to compromise and pick up the 318is.
Hungry for a more interesting and prestigious 6-cylinder car at the time, I initially felt that this compromise was an unfortunate one, but as time went on I really started to build a rapport with my E30 318is and understand what makes it special in its own way.
When compared to the 325i, the BMW E30 318is with its light engine is a beautifully balanced car with pretty much 50:50 weight distribution. Due to this the handling characteristics when pressing on are excellent and you can really have some fun hurtling down twisty roads, even at modest speeds by modern car standards.
Ultimately I came to understand that the 318is can pretty much keep up with its bigger engined 325i brother on the straights too. It’s only down around 30hp compared to the 2.5 M20 engine, and to partly make up for it, the 318is car is a little lighter on its feet.
The 6-pot engines are lovely to hear and produce great torque, but in their stock form they’re definitely geared up more for cruising the autobahn rather than anything too racy.
The M42 4-pot of the 318is however is a lot more free-revving and while there’s a distinct lack of low down grunt, the top end makes up for it bringing a very engaging driving experience.
Amusingly the 318is stands up to the 325i while using only half as much fuel.
Even when thrashed my high mile M42 engine returned 32mpg, and with day to day driving it returned 37mpg (with a 4.27 diff too). I’d say that’s good for a 1.8L engine even by today’s standards, so BMW were ahead of their time.
Spirited driving aside, living with an E30 of any description as a daily driver comes with its pitfalls compared to modern day cars.
My BMW E30 318is came without any driver aids at all, not even ABS.
Using the car to do my rural commute to work even in snowy conditions certainly produced some buttock clenching moments. However, once the car reminds you that you’re on your own, and you drive accordingly with that in mind, you can have a whole lot of fun.
Through the summer months, the car was an absolute pleasure to drive, despite the lack of air conditioning. Cruising in that greenhouse of a cockpit, with the windows down, sunroof open, and shades on is always going to be a pleasurable experience on a summer’s day, and one we miss out on completely in modern cars.
I can’t say the car was 100% reliable, and I was plagued by a small list of problems, some I solved as they occurred, others that plagued me throughout my ownership. But for an old car being used daily through all weathers, it was as good as you could expect.
- Misfire – this turned out to be the HT leads, twice
- Clutch slave cylinder failed – I was lucky to get home locked in a gear with this one
- Hot starting issue – Never figured this out, engine really struggled to start hot
- Window fuse kept blowing – Never solved this either, just kept replacing the fuse
I enjoyed the car for over a year and the main reason I decided to part ways with it was seeing a couple new rust bubbles appear on the body.
This was quite an over reaction, but knowing the car had been restored to almost perfect, I knew using it as a daily driver on salted roads would only see it deteriorate more rapidly and I couldn’t bear to see it.
Also, I’d saved up enough to make another bad decision and jump into an E46 M3 to see what that was all about.
I sold that lovely BMW E30 318is for a bit more than I’d paid for it, despite adding nearly 10k miles to it and using it for a whole year, but I often regret selling it knowing it was a good one, especially seeing where their values have gone over the past few years.