Welcome to my world, my world of turbos, tyre smoke, and tuning...
Tuning cars, driving cars, testing parts, and complaining about everything. It's my job, and a the majority of my non-work life too...
You may think the title of this feature is a big claim, but I'd say it's fact, and in fact this car is FAR crazier than what 99% of people who know this car even think it is!
As you may have seen on THIS recent post on the Stav-Tech Facebook page, I personally think, especially from an engine tuning point of view, 80s and early 90s Rallycross is THE most insane motorsport there ever has been, even more than Group B rallying.
BUT the thing is, it's all pretty unknown to most current tuning fans, and there's VERY little detail out there that explains how crazy the cars were- Even most retro rallycross fans know very little about the cars back then. I've asked these 'fans' many times what engines were in certain cars etc, nothing complex, but people rarely even know that much!
I’m sure that if only people today realised how insane these cars were, they'd be more legendary than even Group B cars are, and I'm determined to find out the details for YOU guys.
While they're pretty unknown to most, their specs and their performance are exactly the kinds of things you love, and totally relevant to your own tuned cars of today.
Anyhow, the first car I've managed to source the long-lost info of is a car that's always been my favourite rallycross car, despite even myself not knowing that much detail about it, and it's this- Arild Martinsen's E30 BMW M3...
I'm not a massive E30 M3 fan normally if I'm honest. I've driven a few, standard and modified, and while I think they're cool cars, they've never been a car I've wanted to own, but this one, well shit the bed, this one is literally my DREAM CAR.
Well why? Well, before I give you all the details, I'll let this absolutely incredible video (From 30 years ago!) below do the talking, check it out...
Watched it yet? Did you say "Holy shit!" and "Fuck me!" loads of times while seeing that 700bhp four wheel drive E30 M3 fly around the track, sideways everywhere, accelerating like a rocket, and chucking flames out the side exit exhaust? Well yes, that's the pretty normal reaction, as that thing is flippin' bonkers.
Funnily enough though, that's one of the VERY few videos out there of this car, as it actually wasn't hugely successful in rallycross, as while it was insanely fast and generally awesome, it just didn't have the traction to match. But it's performances have made it a favourite with many to this day- Including me!
The thing is though, that video is pretty much as far as most people's knowledge of this car goes, and it was only relatively recently I'd even seen an engine bay pic of the thing myself.
But as I love the thing, and I knew you lot would too, I decided to do some serious research (Not just Googling, as there's fook all on the net about it- Believe me, I've looked!), which has enabled me to do this feature you're checking out right now.
Starting with the engine under the lightweight Kevlar bonnet, the common story is it's a modified E30 M3 engine, ie the S14B23 2.3ltr 4cyl lump, fitted with a turbo off a BMW Formula One car.
Well, that's NOT true, in fact it's WAY wilder than that!
The engine is in fact the BMW M12 race engine, ie an engine that's never been in any production car, and has been used in it's various forms and capacities, in Touring Car Racing, Formula 2, and was also the legendary 1.5ltr turbo BMW Formula One engine from the 1980s that was alleged to produce as much as 1400bhp in qualifying form.
This particular version isn't the 1.5ltr F1 lump, but is a modified version of the 2ltr turbocharged lump used in IMSA racing in the USA, used first used in the late 70s BMW 320 Turbo IMSA race car, making 650bhp at 9000rpm, then used in 1985 and 1986 in the BMW/March IMSA GTP race car, making 800bhp at 9000rpm.
Here's some pics from the engine in an original BMW 320 Turbo IMSA car...
Clear pictures of the later IMSA GTP engine are harder to find, especially as the engine was hidden under bodywork at the rear, but here's the car and some spec...
After the GTP car stopped racing in 1986, Arlid Martinsen, with the help of BMW Norway, managed to source one to use in his insane new rallycross build for 1987, and here it is...
Looks like it was made to be there eh! Fits lovely. Here's some closer up shots...
What we have here is, as said, an M14 IMSA GTP lump, 2ltr, heavily turbocharged of course, and in the spec in Arild's E30, it made 650bhp at 2bar boost, and was capable of 2.5bar boost if he wished, which although never measured, was without doubt going to be 700bhp+..
Internal spec was pretty typical as you'd expect for a full-on race engine, though one particular thing to note was Titanium conrods- Now that's flashy.
In 1987 the engine was 2ltr built by a famous Norwegian engine builder, but word is (from a good source too) in later years a 2.3ltr version was built for him by a Swiss engine builder.
As the pics show, it featured a big air-to-air intercooler, carbon fibre inlet plenum, twin scroll tubular exhaust manifold (everyone ran twin scroll back then- Madness not to as it really helps spool), HUGE single external wastegate (same one they used on the F1 etc engines), and a BIG single Schwitzer turbocharger (Schwitzer are now what's called BorgWarner Turbochargers, and they actually invented the ETT Extended Tip Technology compressor wheels before they became BorgWarner- In fact the entire BorgWarner S-Series of turbochargers, and therefore the majority of parts in SX, SXE, and EFR turbos too, use what was originally Schwitzer turbo parts).
Yep, Jubilee clips and rubber hose at 2.5bar boost... ;)
Perhaps what's MOST INTERESTING, and different, in fact pretty much unknown to most people these days, is this car ran FIVE throttles! In fact, so did the insane 1400bhp Formula One version of this engine too.
So yes, I can hear most of you already... "Five throttles? What the fuck are you on about? It's only got four cylinders". Well, do you want to play "Spot the throttles" on the next pic? Check it out...
Spotted them all? Well, it's not easy, but they're there! The first four are in the typical place for a race engine- Ie it's running individual throttle bodies, one per cylinder, right at the inlet ports of the head. So where's the 5th one? Well, look at the throttle cable, it comes over the strut brace, to the ITBs, then continues forward somewhere and disappears. But to where? Well look at the bottom right. As well as a big cone filter, what's that in front of the turbo? Yep, throttle number five!
Confused? Well I better explain then eh, that's what Stav-Tech is all about after all.
Well, it's a form of anti-lag that was used before anti-lag as we know it existed. And while it's not as effective as what modern ALS can potentially be (ie full boost all the time), and has issues (unless you have a specially modified turbo, you'll be sucking oil in to the compressor side badly when off the throttle, filling the entire inlet system with oil and making the exhaust smoke badly for a start), but done right it really is very effective- It was used in Formula One after all.
How does it work? Well, in essence it's the same as when you put your hand over the inlet on a vacuum cleaner, blocking the airflow. What happens? You can very audibly hear the motor speed up as it's doing less work, that's what.
On a turbo, the compressor side is the equivalent of the suction fan on your vacuum, and the turbine side is the equivalent of your vacuums electric motor.
With no airflow the fan/wheel has nothing to do, it's literally spinning in a vacuum doing no work at all, no air to push, and therefore the motor/turbine can turn far faster for any given power input to it (ie the electricity on the vac, or the exhaust gas on the turbine).
On a vac it serves no purpose, BUT on a turbo, if it's spinning far faster when off throttle, it also gets up to speed far quicker when you're back on the throttle; in fact potentially it's already at the required speed!
This is exactly what modern anti-lag does, ie keeps turbine rpm as high as possible even when off throttle, just done in a totally different way.
In related news, I want to test this setup for StavTech, as while it's got issues, A- I think I may have a solution to that, and B- I want to see, and show YOU, how effective it is!
Anyhow, back to the car...
While as I mentioned previously, details on these Rallycross monsters is scarce, but thanks to one of the top motorsport photographers from back then, the legend that is Eddi Laumanns (who took many of the pictures in this feature too!), I got hold of a feature on this car from a German car magazine when it was first built in 1987, and it has some VERY interesting details, in fact some of them can only really be described as pretty fucking insane.
The car was tested in the feature by Jochi Kleint, works rally driver for Opel, Ford, VW, and others in his career, and driver of the Golf Bi-Motor, the twin engine Mk2 Golf that VW entered in the Pikes Peak hillclimb in 1985, 1986, and 1987, with as much as 650bhp!
In the feature Jochi not only says the car feels at least as fast in a straight line as the Golf Pikes Peak monster, but he says it's very tractable, no need for 1st gear even in tight hairpins, and FULL BOOST is by just 4000rpm! A ~700bhp 2ltr turbo engine, making peak power at 9000rpm, but full boost by 4k! That's a 5000rpm+ power band, ie HUGE, far far more than 99% of cars even today, and this was 1987.
Like I've said before you can have all the new technology you like, but a correctly specced and set up engine even with very old spec parts will still wildly out-perform most stuff.
We've pretty much covered engine performance, so to finish this section off, and to go nicely on to the next bit, here's a great pic of the underside of the car, showing the big intercooler and 4inch exhaust system...
Anyhow, as bonkers as the engine is, the TRANSMISSION is probably at least as wild!
For a start, the gearbox is by possibly the best known brand from rallycross- Xtrac. What makes this special, especially for 1987, is not only are they ridiculously strong and capable of handling huge power and abuse, but they had in-car adjustable front to rear torque split, which on this car was meant to be between 28F-72R, right down to 50F-50R.
In the magazine testing Jochi stated he felt the car was fastest at 40F-60R.
The transmission had another setting too, again selectable from one of the buttons within reach of the driver, and I don't know if this was a 1-off for this car or a feature of other Xtrac transmissions of the time, but it's deffo the first time I've ever heard of it- It had a BOOST OPERATED four wheel drive!
Yes, you read that right. One of the settings this car had made the car 100% RWD until boost pressure hit 3psi (0.2bar), and then the 4wd would kick in! Clever as hell, especially 30 years ago!
In theory I can imagine an advantage on turn-in off throttle to eliminate understeer, as chances are this car had a pretty serious plated LSD front diff, but according to Jochi in the magazine feature, he felt it was faster when in permanent 4WD mode.
Away from all that madness, the clutch was a Sachs triple plate item, the front diff was based on the E30 325iX setup, the rare factory 4wd version, and the rear end and diff was full Group A E30 M3 setup. This is a pic of the rear end actually...
And here's the front suspension setup..
The interior of the car was pretty sparse as you'd expect from a race car, but notice the bank of switches, most of which within reach of the driver to adjust the trick 4wd system settings, not to mention the all important boost pressure.
For cooling, the car had what has become a bit of a trend for drift cars and even some Time Attack cars in recent years, and that's a rear mount radiator, and you can see the holes and ducting for it in these pics...
As well as the radiator, there was two other things in the boot of this car, two VERY unusual things, something to mental that if it wasn't for me reading the words in this very sensible and technical German magazine who tested and reviewed the car when it was brand new, I'd be 100% they were joking...
It had the alternator and A MOPED ENGINE in the boot! Seriously! It really says that! It says it has a small moped engine mounted in the boot that has the sole job of spinning the alternator, which in turn gives the electricity for all the trick parts this car runs. Crazy!
So, I've already mentioned that, despite it being absolutely incredible and hugely spectacular, this car wasn't actually very successful in rallycross.
According to Jochi Kleint in the feature, the car was almost undrivable as it simply had TOO MUCH POWER for the tyres and suspension to handle, even with the trick 4WD system, and he felt on loose surfaces a well-sorted 200bhp FWD Golf would be as fast if not faster.
The feature also says the owner/driver, Arild, was having to change tyres after every race, which wasn't normal for rallycross, and was due to the combination of massive power and running hugely soft tyres in an attempt to get decent traction.
There's another alleged issue too, which does tally up with the fact the car always seems incredibly tail happy, and it's said in recent years his son has talked about the car and stated the 4WD system or the front diff at least wasn't actually working like it should, making the car far more rear-bias than it was meant to be.
Either way, win or not, the car has become a bit of a legend and deffo my fave car, and even Arild himself is said to be incredibly surprised people now, 30 years later, still talk about the car. He will probably be a lot more surprised if he sees this feature!
.ANYHOW, that's about it for this feature on this insane and amazingly interesting car, and I hope you've liked reading it as much as I loved writing and finding out about it.
There's a LOT more incredible cars from this era of rallycross, and as long as you guys want to hear about them, and as long as I can find out the long-lost info about them, you'll be seeing more features like this in the future!
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Hi, I'm Stav...
You may or may not have heard of me, but I've spent the last 15 years working full-time in the tuning scene, and the last decade or so writing for various car magazines.