And more than under-rated, it's genuinely fun to watch, and by far the most relevant to UK tuning fans of any motorsport.
Formula One is world famous and has the biggest budget of any motorsport, but is it exciting to watch? Not really. And it's all so secret that any possible relevance to the tuning we all do we either won't know about for decades, or never will.
WRC cars in 2017 will be the most powerful than they've been since the GroupB days, but it's still not a great spectator sport, despite being hugely famous and featuring wild cars.
BTCC is hugely popular in the UK, and as circuit racing goes, it's pretty badass, but in my eyes it's not even a patch on Rallycross, and strict rules make things quite samey too.
If you haven't watched any before, go check some out on YouTube or something. 600bhp 700lbft 2ltr flame throwing anti-lagged 4wd turbo cars door to door, sideways everywhere, on a twisty track which is a mix of tarmac and gravel. As the races only last 5 laps (It was usually 2.5 laps in the 80s/90s), so unlike most racing, it doesn't have boring parts where they're trying to save the car, or tyres, or engine- It's flat out from the start to the end.
Anyhow, as I love tuning (and presumably if you like Stav-Tech you love tuning too), the main reason I love Rallycross is the insane acceleration of these things, and that's because the engines are fucking MENTAL...
Things did vary country to country, year to year, but for example, in the late 80s early 90s in the UK, the 4ltr class, which mostly consisted of 2.3ltr turbo engine cars (turbo or supercharged meant a multiplication factor of 1.7, and 2.3x1.7 is a touch under 4ltr), had a 1100kg minimum weight limit.
Cars in this class were things like Will Gollop's Metro 6R4 which was the V6 de-stroked to 2.3ltr then twin turbos added, giving it 750-800bhp, and other similar crazyness, such as the 4wd Turbo E30 BMW M3 of Arild Martinsten which also had 750bhp+
Due to the various weight vs capacity classes, it was common to see 1.4ltr to 3ltr+ cars all in the same race, and due to the lighter weights and the fact almost everyone had BIG turbos fitted, everything was, just like it is now, fucking mental fast.
You'd imagine maybe that everyone would be aiming for the 2.3ltr turbo engine for the maximum power, but this wasn't actually the case, as these were days before seriously effective ALS systems, so power was always a trade-off with lag, and also, when it boils down to it, on a slippery gravel surface with few straights there's not much grip or opportunity to use big power.
It was often said that around 550bhp was the maximum usable power, and many ex-GrpB cars either stayed at, or were even de-stroked to around 1.8ltr, which was enough for their 550bhp power goal, but allowed them to be much lighter than the 2.3ltr turbo cars.
Having said this, there were some cars with MUCH more power, 750bhp+, but if you watch old Rallycross videos on YouTube it was spectacular but unless they were in the lead it was very little use on the twisting tracks, and usually have about a 2second oppertunity of full power per lap!
Here's a few older rallycross engines. I say a few, as despite the wonders of the internet, it's not a time machine, so despite some pics being uploaded from the 80s and early 90s, there are literally NO pics around of some of the greatest, wildest, and most interesting rallycross engines ever made.
Gollops twin turbo 6R4 lump? Nope. Martinsetens F1 Turbo M3 lump? Nope. All the countless Group B 205 T16s, Delta S4s, Audis, etc made better than ever that ran in Rallycross? Nope. Unfortunately there's very few pics out there on internet land, which really annoys me, but here's a few...
Another mega successful and popular engine in the 80s and even 90s were turbo'd versions of Ford BDA lumps, often built by Zakspeed, from 1700cc upwards, and pushing out well in excess of 500bhp.
EDIT!!! You might think the above acceleration sounds mad, and it is, but according to one of our helpful Finnish readers (who can read the above words, unlike me lol), those times were not only done in the WET, but the cars stop speed is 206kmh and hit it by just 260m, so did the last 140m just bouncing off the rev limiter in top, no more acceleration!
So if it had the gearing for it, and a dry surface, that car is easily in the 2s to 60mph, 4s to 100mph, and running 9second quarter miles.
In 1984, and not remotely a straight line drag car. Crazy shit right there.
Rallycross is also where you see the engines that, while we all NOW know are massively tunable, have often been tuned to 600bhp+ for decades already. But as most people don't notice race engines, and just look at tuner cars for inspiration, people never realise. Like Saab lumps...
I mean, look at all these engines so far, they are ALL stuff you'd recognise from typical big power tuned engines we love to see in road/drift/timeattack cars, but frankly, these are usually done far far better, and cleverer, by people who know what they're doing rather than just pretend to.
Not many parts on Rallycross engines are bits you recognize as the big money off the shelf tuner parts everyone likes to fit to their road cars though, as funnily enough, despite the hype, those bits are rarely, if ever, the best designs.
That to me is a big reason why I love Rallycross- The engines are something I know, understand, relate to, agree with the design, and more to the point, they're my inspiration when tuning- Not some nobhead with a lockup who calls himself a tuner.
THESE are the engines you should look up to in my eyes, not some shiny shit you see on FB, but more on this later...
ANYHOW, moving on to the '00s to present day, Rallycross top classes around the world mostly changed to a 2ltr turbo class with an inlet restrictor (This was in 1997 if I remember right in Europe, and maybe 2003 in the UK?) to hold back power to vaguely sensible levels as things were getting ridiculous (and frankly, with today's tech, a 2.3 non-restricted turbo engine like the old days, would now have about 1200bhp, and costs would be fucking insane), though this 'vaguely sensible' level is still about 600bhp and 700lbft, which frankly is insane fast, like '0-60 in sub 2sec on tarmac' sort of fast.
This is the usual 45mm turbo inlet restrictor fitted...
The engine performance difference ALS makes is an incredibly hard thing to imagine unless you've experienced a really seriously good working system yourself, but the difference between it being on and off is like two different engines, and the difference between being competitive and not in Rallycross.
Realistically, the 2ltr turbo engines of current cars, without ALS activated, are going to have a powerband of 4000rpm+ and not the most responsive things when on and off throttle either, as the turbos fitted are BIG.
A small high rpm powerband and poor throttle response is NOT ideal for Rallycross, which is incredibly close and tight, on and off throttle constantly, and where a whole lot of the cars steering done with the gas pedal rather than the steering wheel.
Basically, if you switch the ALS off on a Rallycross car they will get left for dead by the other cars with it active; you just can't compete without it.
With ALS on (and Rallycross ALS is mental, like full boost all the time regardless of revs and throttle position style, proper fucking mental), the cars are totally different animals, like driving an 12ltr+ naturally aspirated engine that somehow also revs really high, rather than a typical 2ltr big turbo engine- Basically you get BIG torque and instant response constantly, regardless of revs.
Some more pics, all with Tibuc ALS setups, as almost everything had/has it...
But again, variety has always been key, I mean, here's a Mitsubishi 4G63...
This particular ALS system isn't actually new though, the earliest versions of this were used on the Audi Group B rally car in the mid 80s.
This ALS system is the valve at the front by the exhaust manifold on the below pics, and the small bore pipes from it is feeding air to each exhaust runner.
I'm not saying copy them exactly, as I dunno about you but I sure as shit can't afford to build a 700bhp/700lbft 4cyl turbo crazy thing, but what I mean is check them out, check out what they do and often DON'T do, as you can be sure as shit they do or don't do it as they know what's best.
Not sure what I mean? Well...
For example, people often get all giddy and excited telling the world about their amazing boost pipe clamps that cost them about 50quid each, and those same people tell the world jubilee clips are shit and don't hold under high boost, etc etc, usually despite the person saying this having a car that don't even run a lot of boost.
WELL, let's look at some Rallycross engines shall we? Money is NOT an issue for them, they are mega spec, the best of the best. The engines often run 3bar+ peak boost. But what holds the vast majority of their hoses on, from the early 80s to the present day? Yep, that's right, normal Jubilee clips.
YES, shit twisty soft Chinese shit fake Jubilees are junk, but proper ones are strong as hell, can be done up mental tight, and hold a fuck sight better than most the wide Mikalor etc etc ones people like to shout about loudly on the internet.
What about massive fuckoff inlet plenums like so many people pay big bucks for on their tuned road cars with barely 200bhp per litre? Well, these Rallycross cars are 300bhp/litre+ and do they have massive plenums? Fuck no, as there's nothing good to gain from it at all, and plenty to lose in response. A better than standard plenum? Yes. But IMO 80%+ of aftermarket plenums are just some badly designed, often oversized, shiney shit that does no good barring lighten your wallet.
I've mentioned it in the past, but what about big cone filters in the engine bay? If you listen to internet car experts, they suck in hot air and kill ruin performance, seemingly oblivious to the fact ENOUGH air matters 100 times more than COLD air. Thankfully Rallycross people aren't keyboard tuners, and as the pics show, they put a massive air filter where ever it fits best.
Oh, here's a good one you can see in these pics that everyone in the tuned road car world ignores, fucking TURBO HANGERS.
On the internet you can't fail to read people constantly crying as their turbo manifold has cracked, or the bolts have worked loose, for the 20th time this month.
What gets me is peoples solutions, or advice, are all kinds of crap, such as fancy bolts and fasteners, different exhaust designs, even fucking welding the turbo straight to the manifold like they're auditioning for fucking Roadkill or something.
But despite all this, never do they have the sense to look at pretty much ANY proper race car and notice they fucking ALL run turbo hangers, taking the weight of that bloody turbo off the exhaust manifold, off the exhaust system, off the exhaust nuts, and bolts, and studs, and gaskets, and everything else that fucking breaks. And lo and behold this stops them breaking.
Dunno if I ever mentioned it before on here, but on my old Cossie (they have a form of turbo hanger fitted as standard, nothing fancy, but they have them) I ran 2 years no issue at all without anything blowing, leaking, cracking, anything, despite 30psi boost, anti-lag, and serious abuse. THEN my turbo hanger got a bit tired looking so I removed it to sort it out, presuming it'd be fine without it for a bit (this was like 2002, I knew no better), and within a WEEK it was blowing at a join due to loose bolts, and from then on it would loosen bolts or blow an exhaust gasket within a few days of doing them back up.
Refitted the hanger a week later and it never happened again.
That taught me a lesson for sure, but despite telling people for about 15 years since that their issues would be solved with a turbo hanger, does anyone listen? Do they fuck, you still never see 'em.
And the above are just a few examples of the many many many things just checking out some proper race car engines, and ignoring typical shitty tuner cars, will teach you.
And ignoring teaching you anything, go watch some fucking Rallycross, it's mental! There's tons of 80s, 90s, and current Rallycross all over Youtube, and in fact, if you wanna see the craziness of modern ALS on Rallycross cars, find some vids of the Gymkhana Grid Championship finals in Greece from last weekend (ie end of October), there was various Rallycross cars in that, most notably Liam Doran's Citroen. The finals was at night, so it's flames galore, and by the end of a 1min run the entire exhaust, right to both tailpipes, was glowing red hot- Properly amazing looking.
So yeah, Rallycross is awesome, and Rallycross engines are surprisingly educational AND awesome. Check them out...