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...
As we all know and have experienced, the car world is a hive of bullshit and excuses, as people can never admit anything is their fault, so either blame the car or someone else.
From people blaming poor performance on a misfire when it's actually shit driving or them lying about how quick their car really is, to companies not honouring a warranty by making some kind of excuse to blame it on user-error- Excuses are a 'car thing'.
The inspiration for this mini-feature was hearing one of the most ridiculous excuses I've ever heard, and something that I'd not heard for about 15 years, and even back then it blew my mind someone supposedly respected had the balls to claim this...
Step back to 15 or so years ago, and the first example of this was about the Skyline GT-R RB26DETT engine, and most notably the ceramic turbine wheels the turbos have, which are known to snap off the shaft or shatter to many pieces.
While the above is an unfortunate and common fact, one of the big name tuners of the time used to convince their followers they needed an engine reubild as soon as this happened, as bits of the turbine wheel will have been 'sucked' in to the engine.
Some of you right now might be thinking "Well can it?", and some others are thinking "WTF?", so let's break it down in to a way even a tuning novice can understand...
Fast forward to today, and I heard a very similar thing, used as another bullshit excuse, but actually even more far-fetched in my eyes.
The basic story is an engine has severe pitting (IMO severe detonation, but that doesn't matter for this) on the squish/quench pads on all cylinders on a turbocharged engne, and on the exact same opposite areas on the pistons too.
No marks anywere else- Untouched bores, untouched centres of pistons, untouched valves, untouched combustion chambers- Basically only the areas most affected by det.
Certain people (And to make it even more stupid, these people AREN'T the tuner either! This is honestly people just trying to defend him off their own back, despite it not being strictly blamed on him- Retarded or what) flatly refuse to see it as detonation, and claim it's FOD (Foriegn object damage), and back that up by the fact ONE of the cylinders has broken a piece of valve guide off in an inlet port.
My comment was "Even IF somehow it can only damage areas either side of the piston/chamber without touching the center or the bores, how can FOD in one cylinder account for the same damage in all the others?"
The reply was "Doesn't matter which cylinder was damaged, if one goes they're all going to get damaged as the metal will travel back up the inlet manifold and in to the other cylinders"
Again, some of you are already thinking "WTF", as it's probably even more far fetched than the first, despite being said by a bit of a hero of the tuning scene, so let's once again break it down...
So yeah, more utter shit.
The WORST thing about all this kind of crap is though, is that this isn't words of random idiots, the 2nd example wasn't even from a tuner making an excuse either- This is coming from RESPECTED names in the modified car world, 'FAMOUS' names some might say, and because they're "Somebody", people blindly believe them, despite it being insanely far fetched.
My question of it all is, do they BELEIVE what they're saying, or are they LYING? Either way it is REALLY fucking bad considering they're influential, aspirational, whatever the fuck you want to call them, names, in this stupid hobby we all have.
And this is exaclty why I'm hugely skeptical of what even 'Big' names say, partly by being untrustworthy, partly by not knowing as much as you think (or they'd like you to think) they'd know.
It's terrible really, being a skeptic or having trust issues isn't a good thing, and it'd be amazing if this tuning world was just people being honest and helping, but instead the kind of people and the kind of advice in the tuning scene is a big reason why so much of it is fucking awful and so slow progressing.
You have 2 choices, you can either listen to these people and be one of the crowd getting ripped off or having mediocre stuff, or you can take everything you hear with a pinch (ok, a fucking huge road gritter full) of salt, and fact check stuff from even supposed big and trustworthy names, which should, while it's a lot of work, get you a seriously good car.
While it's popularity and media coverage is increasing in recent years (Yet it was on prime time TV on in the 70s and 80s- A long way to go before it's back at this level!), Rallycross is, in my eyes anyhow, the most under-rated motorsport there is.
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.
I've seen people talk about Rallycross like it's fucking Grasstrack oval racing, in fact I've seen the same people go "If you want to see a real mans sport, check out BTCC". FUCK knows what they've been watching, but it sounds like they've never seen Rallycross in their lives.
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...
In recent years engines in the top class are restricted to 2ltr (turbo, of course!) and with a 45mm inlet restrictor, which keeps power back to around 600bhp and 700lbft of torque, though previously there was no restrictor as such, but instead different minimum weight classes depending on engine capacity.
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...
In the 80s Renault Gordini turbo engines (Which are, in essence, the Renault 5 GT Turbo engines, but with a better, crossflow, cylinder head), from 1.4 to 1.6ltr were popular and used in both Renault and Volvo rallycross cars, often pushing well over 350bhp, and as they were fitted to cars that weighed well under 900kg, it's fair to say they went like hell.
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.
Beetles were popular in 80s rallycross too, with all kinds of specs, including 4wd turbo versions, like this one that's still around to this day...
Most interesting about this one is the engine, which is still a VW block, but as Rallycross rules allow any heads to be fitted, it's got Subaru heads...
One thing I'd like to know, and I've yet to see pics or info confirming it, is turbo position on this Beetle. Going by what I can see, I'd say it's mounted inside the car, where the rear seats would normally be, which is pretty cool. In fact I 'think' you can just about see it through the hole in the bulkhead on this pic...
Rallycross gave a new lease of life for the Group B cars after they were banned from rallying too, showing what they could have been like with more development, making them wilder than they ever were in rallying. Check out this Citroen BX4TC. They were rubbish in GrpB due to lack of development, a total disaster, but in rallycross it got it's chance to be as mad as it should've been, and they were fucking weapons...
If you're wondering how batshit crazy fast these cars were, even in the mid 80s, check out this article from 1984. No it's not in English, but enough of it is written in words we understand to get the rough idea of the 1984 spec of Rallycross legend Matti Alamaki's Porsche rallycross car...
So this is 1984, and this Porsche 930 has 4 wheel drive, a twin turbo 3.2ltr flat six pushing out 750bhp and 6200rpm, and weighs, well, 1130kg I think? Check out the old-skool timing gear wheel on the back in the main pic too! Now page two...
0-62mph in 3.1sec (so 3sec dead to 60mph), 0-100mph (160kmh) in 5.7sec, and 10.5sec quarter mile time. And this is 1984, 32 bloody years ago!
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...
Or the Opel/Vauxhall C20XE...
Rallycross is amazingly unknown by tuning fans in the UK, and to me I find that fucking bizarre, as frankly, the engines are THE most relatable to the shit they do of any motorsport; just usually way, way better.
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...
Though at least once a twin turbo setup was attempted, which meant two smaller restrictors instead...
One other big advantage the newer (and by that I mean in the last 15yr or so) engines have, despite less power than some of 80s ones, is fucking everything has something very noticeable fitted, usually a setup made Swedish company Tibuc...
What the above is, well, the 2 blue hoses coming from the box on top of the plenum to the box after the throttles, is the electronic adjustable air bypass valve, a fucking big air bypass too, for the anti-lag system. And ALS is, if you speak to most Rallycross drivers these days, is THE most important part of the engine.
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...
As the above pics might hint, Cossie YB engines dominated Rallycross from the late 90s until recent years, as despite what the Jap fanboys etc like to think, if you wanted a 2ltr engine that could bash out 600bhp/700lbft and win you races, the YB was the one to have. How many SR20s have you seen in Rallycross? I can think of one tbf, in Finland, in a Mazda RX7..
But again, variety has always been key, I mean, here's a Mitsubishi 4G63...
And here's a VW lump...
Going bang up to date now to the present day, while the engines are the same principle, some of the ALS systems are even more advanced, more like mega power versions of current WRC engines, and now the airflow bypass isn't just past the throttles (though it usually is too, via fly-by-wire throttles now though more often than not), but it's direct in to the exhaust manifold via a valve and a series of pipes, which is more efficient.
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.
Anyhow, regardless of age, the fundamentals of turbo Rallycross engines hasn't changed in 30odd years, and they're still fucking awesome and even the oldest ones should be the inspiration to most of us tuning turbo cars in my eyes.
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...
"Oh Emm Gee, my car does 0-60 in less than 4.5sec, it's almost a supercar, your car is way slower, it's 0-60 is 6sec" says all kinds of clowns with pretty standard 4wd turbo cars, usually to people with cars with far more power; almost like they've never raced a car in their lives.
In fact 0-60mph sells cars- A whole lot of people seem to choose their car by its 0-60, which frankly, is retarded.
The fact is though, when the fuck is the official manufacturer 0-60mph figures relevant in the real world? Pretty much never, that's when.
Even if the situation arose, how many owners are able to hit the factory 0-60 figures? Not many, that's for sure, and for lots of reasons too.
First up, the majority of factory figures are done by GOOD drivers (and truth be told, most people can't drive for shit), after countless attempts, so a typical owner can't usually get within about a second of it. And I mean REAL times too, not a speedo and a stopwatch.
Secondly, how many owners do full on, and I mean REALLY full on, max revs, clutch dumping, launches, especially in transmission destroying 4wd cars? Again, next to none.
I've had hundreds, maybe thousands, of impromptu races off the lights over the years, and the amount of cars I've came up against who's actually done a full-on launch I can probably count on my hands- Most just fanny off the lights gently and then nail the throttle a second later; even highly tuned cars racing to big speeds.
People might like to think they're straight out of Street Outlaws, but more are more like Driving Miss Daisy.
Thirdly, and maybe most importantly in the UK at least- This ain't Fast And The Furious or Street Outlaws, so a VERY small % of races happen from a standing start; it's almost all roll racing, so your 0-60mph time means cock all.
I think some of it, the bit that's not total blinkers/pride in their own shit, is that some people really think 0-60 acceleration corresponds to acceleration at other speeds too, but it doesn't, at all. 0-60mph is ALL about the launch.
I've timed tons of cars over the years due to my work, and it's fair to say, aside from really, truly, fucking ballistic things that also have great startline traction, and that's rare, 0-60mph does not tally up with rolling start acceleration at all.
The old Dragon Performance FD RX7 drag car was a great example of this. Fuck yeah it launched well compared to most cars, but it still was often hampered by it's first 60ft or so, hence doing 160mph by the quarter mile, but still running low 9s, despite some 'slower' cars in the 8s despite only hitting about 150mph, due to being able to launch off the line like a bullet out of a gun.
In fact, I had some timing data from a run where due to wheelspin the 0-60 time was 3.5seconds, which is still ridiculously fast, but 1 whole second slower than the legendary Bugatti Veyron.
But DESPITE being 1sec slower to 60mph, it still got to 150mph two seconds FASTER than a Veyron- That means it did 60-150mph THREE FUCKING SECONDS faster than the 1000bhp 4wd mega bucks Bugatti hypercar.
So in the real world, ie a typical rolling start race, despite the 0-60 time being way way slower, the RX7 would absolutely fucking annihilate the Veyron, which illustrates my point nicely.
It's just as relevant with standard production cars, especially now with so many hot hatches having 4wd and twin clutch DSG boxes; both MASSIVE advantages on the 0-60mph sprint.
Lately all I see is people wanking off about the new Golf R and A45 AMG with their 4wd and twin clutch boxes, and saying they're sooooooo much faster than, say, the new Civic Type-R for example, purely going from the 0-60 times and various "Race" videos on the internet from the likes of TopGear etc.
Fuck yeah they're much faster to 60 from a standing start, as the Civic just wheelspins when launching hard, and like most manual cars, it loses about 0.5sec on the 1st-2nd gearchange, compared to almost no time for a DSG box. BUT...
BUT... Look at the times at the end of the video, the 0-60 and 0-100mph figures they achieved, and then subtract the 0-60 time from the 0-100mph time, to calculate the real world, and relevant, 60-100mph time...
The Civic is actually 0.1sec FASTER from a rolling start, and that's despite the advantage of the DSG box in the Golf.
So there you go, unless you REALLY do standing start racing, and REALLY do zero mechanical sympathy hardcore transmission destroying launches, 0-60mph means fuck all, so if you're gonna do anything with it, use it to subtract from your cars 0-100mph time to see a real world acceleration figure.
Overall... STOP FUCKING QUOTING 0-60 TIMES! YOU SOUND LIKE A MORON!
Who originally said this shit anyhow? I've seen it attributed to Carrol Shelby, Enzo Ferrari, and Carrol Smith, but did any of them really say it? And if they did, it must have been taken massively out of contact, as frankly, it's a load of rubbish.
Fuck it, as there seems to be no proof who said it, I'm starting a new rumour of who made it up, maybe that'd stop people quoting this shit...
You know though, I'm sure it's a mis-quote, and I think I know where it comes from...
Imagine you had a car with BIG bhp, but a tiny peaky powerband, and a gearbox without close ratios. So every time you changed up a gear, you dropped out the powerband, killing your acceleration. So despite the big peak power number, a lesser tuned car, which was less peaky so didn't drop out the powerband, and no doubt had more low/mid torque, would actually be faster; especially on tighter tracks.
In the old days, where this quote seems to originate from, this would be even more of an issue, especially with heavy "muscle" cars running 4, 3, or even 2 speed gearboxes, which means powerful but peaky cars would easily drop out the powerband and be shit slow compared to torquey but low power cars.
But these days, where you tend to have to either totally fuck up the spec to make it mega peaky, and even peaky engines have closely spaced 5/6/7/8 speed gearboxes, the likelyhood of even a road car being driven properly falling out the powerband is slim, and literally no chance on a well built race car.
That's my theory anyhow- This quote is out-dated and taken out of context.
Anyhow, this quote, almost always used by butthurt turbo diesel owners, low power V6 and V8 owners, and anyone arguing with a Honda owners, just makes people who are trying to be clever just sound clueless, like they've never had a proper race or even driven a performance car in their lives. I mean seriously? One tear up with a lower torque but higher power car would tell them their argument is pretty retarded.
When most people talk about torque, what they really mean is low/midrange grunt, and while it's great (I LOVE torque, it makes cars much more fun to drive, in fact it's why I love big boost turbo engines), and it's certainly something any performance engine, road or race, should aim for the maximum of, providing they've got the traction to make use of it, it's not what wins races, power is.
BHP is just Torque and Revs combined. It's a tricky one to explain in words, it's far easier to experience in reality by driving various cars, but torque is the "Strength" of your engine at a set rpm, but the faster your engine is spinning the bigger effect torque has on performance, so torque+rpm = POWER, which is key to how fast your engine can accelerate (providing it can stay in the powerband though the gears, that is!).
First up on the explanation list, a BMW F1 engine dyno graph (allegedly) from the a 2007 2.4ltr F1 engine...
So, what do we have here? Well, it's about 740bhp, and a pretty tiny 230lb/ft of torque.
So 6lb/ft less than a Golf TDI. And with about 150lb/ft at 6500rpm, it's got about the same torque at that RPM as an EP Civic Type-R, which frankly, isn't a whole lot- People make fun of Type-Rs for being torqueless, but F1 engines are no better.
Next up, a standard BMW 335D, 3ltr twin turbo diesel engine...
The above dyno is at the wheels, so I'm going to add about 30bhp/30lbft to these numbers, which about tallies up with the official 282bhp and 428lb/ft figures.
Either way, say peak torque is 428lb/ft, that's 200lb/ft more than a Formula Fucking One engine. And a remapped one is something upwards of 500lb/ft if I remember right, over DOUBLE what one of the modern V8 era F1 engines were.
Does that mean Formula 1 teams are stupid and they should've just used a 335D engine with a £150 plug in remap and be shitloads faster? Fuck no, as only retards think that.
Fuck, even comparing like for like cars, 335i vs 335d, and the 335i is plenty faster, despite "Only" having 20bhp more than the diesel, and about 130lb/ft LESS. Basically, it's not true.
The above picture is about the predictable thing every "Torque wins races" person says next... "But, but, but, WRC cars only have 300bhp but like 700lbt/ft, and they're mega fast, they win races" YES, but they've not got '300bhp' by choice- That's all they can manage because the rules dictated an inlet restrictor to prevent power going higher.
With no option of more power, no issues with traction due to 4wd and sticky tyres, AND a style of motorsport that involves a lot of very slow corners where instant momentary punch of acceleration is a big advantage, you'd be out of your mind not to go for maximum torque to go with the limited bhp you're stuck with.
But for next year the rules in WRC are changing once again, inlet restrictors bigger than ever, allowing more than 400bhp if I remember right. So will they still go for maximum possible power, if it's "Torque that wins races"? Fuck yes they will, as it's power that's the no1 performance enhancer.
Another argument by these people are "So, if torque isn't important, why do drag cars run big V8s?". Err, mostly as they're the easiest to get POWER from you clowns. The above car is Larry Larson's S10 10ltr twin turbo V8 pickup truck. Yeah it's got fucking shitloads of torque, but the reason it runs 5sec quarters at over 240mph is because the bloody thing has upwards of 3000bhp!
Torque is a BAD thing for him, and because of this he deliberately launches at just 8psi of boost, as at full boost it'd make so much torque it'd just smoke the tyres. In fact it's only ramped up to full boost (50psi!) by most the way down the track and he's already doing over 180mph! "Low RPM V8 Grunt" is literally no issue on fast drag cars either- Larry's car never sees under 8000rpm for the whole run after 1st gear!
So once again, power wins races, and in fact, torque can slow you down if you've got more than your tyres can handle...
Why do so many really, really, fast drag cars run centrifugal superchargers, despite turbos giving far more power, and positive displacement superchargers give far more torque? Because turbos and positive displacement superchargers give TOO MUCH torque for the grip, meaning too much wheelspin for any given power level, making them slower overall. Centrifugal chargers increase boost linearly with rpm, giving LOTS of power, almost as much as turbos, but adding only a little extra torque, especially at low and midrange rpm, so they are FAST due to the big power, but still don't wheelspin due to the lower torque.
It's the same reason a lot of the fastest FWD track cars run centrifugal chargers too- FWD is grip limited, and they need big power to "win races", but don't want too much torque or it overpowers the tyres, and thanks to the power delivery of the centrifugal charger they can use more throttle more of the time without it being wasted in wheelspin.
It's the same reason many production turbo cars, and most the fastest turbo race cars, run lower boost in lower gears and lower rpm, compared to in higher revs and rpm- To limit torque so they've got more traction, making them far faster overall.
It's also why naturally aspirated 2wd rally cars are often as fast, or faster, than the 4wd turbo rally cars, on grippy dry tarmac surfaces (where 4wd was no advantage), despite having the same power and often well over 400lb/ft LESS torque- Because its POWER that's the number one performance enhancer, not torque. This happened a lot in the late 90s, with the 4wd turbo WRC cars vs the N/A FWD F2 Maxi Kit cars...
"So, is torque totally pointless then or what???"
Fuck no! Torque is awesome! Generally, I fucking hate cars with no torque! Surely, if you've any experience of driving at all, you know torque is great, but despite all this, it's not the key need for pure performance.
Low/midrange torque makes for a nicer, easier, car to drive, especially in slow/fast/slow/fast/slow driving, saving you constantly rowing the gearbox to stay at high rpm where the power is. It's why things like Type-R Hondas need driving hard and dropping gears constantly to be fast, and a Golf TDI just needs the throttle planting in almost any gear to go fast- But ultimately, the Honda, with more power, despite loads less torque, is the fastest if both are driven on the limit.
I drive like a dick and love drifting, so LOTS of torque to smoke the tyres is great for me too. I actually find a lot of drift car setups bizarre, as they ideally want torque but the engine isn't tuned/specced for it.
And regardless of drifting, I like BIG boost, as boost = torque, and torque = fun to drive, BUT if I wanted to go as fast as possible, while I'd want the MOST torque my tyres could handle- I'd not want more than that, as it'd be pointless.
TORQUE = GOOD.
TORQUE IF YOU GOT THE GRIP FOR IT = FAST
BUT FAST? = POWERRRRRRRR
RWhen it comes to modifications of turbocharged engines, one of the first things that come to mind with a lot of people are blow off valves, or dump valves, depending what you like to call them (same thing!).
They've been around since at least the 1970s on race cars (though pretty much disappeared on turbocharged works race cars after the early/mid 90s...), factory fit parts on most turbocharged petrol engines from the mid 80s onwards, and from around the mid-90s onwards aftermarket ones became THE thing to have- It was, and to some extent still is, the first engine mod people do to a turbo car.
But what DO they do? What are they REALLY for? Well this is where the confusion/bullshit comes in, not only thanks to the internet, but thanks to the fact most the things said about them to sell them, in the past at least, were lies too.
Christ, the "Blowoff Valve" Wikipedia page even talks total and utter shit about what they do, and why, and how, and whatnot...
THINGS THAT PEOPLE SAY DUMP VALVES DO...
"Reduce turbo lag"
No. They increase it if anything. Turbo shaft speed drops far more with a BOV fitted than without. That's their true purpose, to prevent surge and overspeeding when you shut the throttle. Honestly, anyone with a turbo speed sensor will have seen this, and I've done tests with timing equipment a few times now, that shows, even if it's not noticeable seat of the pants, it makes it worse, not better. This IS fractional though, don't expect a big, or even noticeable difference on most engines- Really depends on the application.
"Prevent your compressor wheel from slowing/stalling (or going backwards)"
No, they actually SLOW a turbo down, that's their actual job, they're a safety thing, to prevent overspeed and surge on a closed throttle, which in some extreme situations can damage the turbo. Honestly, watch a turbo with a turbo speed sensor fitted, the RPM drops far far more with a BOV than without. The 'spinning backward' thing people say is fucking retarded btw.
It's the AIRFLOW that stalls, not the turbo, something I'll explain further down...
"Help prevent compressor surge"
Yep, they do this, but only off-throttle compressor surge, which isn't that damaging or sustained to turbos, as there's no load on the turbine off-throttle. It's on-throttle surge that can be hugely damaging, and it does nothing to help that. "Certain" turbo manufacturers and their badly mis-matched compressor/turbine combos are the main cause of on-throttle surge...
"Help stop turbo damage due to (whatever)"
Well yes, this is the real reason they're fitted, and can be useful for this, but their need is often hugely over-stated, and how they help prevent it is ass-backwards too. The usual bullshit myth is they help prevent turbos stalling, and the sudden slowing of the turbo is what damages them. NO. They help SLOW the turbo, as without them turbos can overspeed when the throttle is shut, and surge all over the shop, and in certain applications that can damage the turbo.
"Help MAF sensor equipped cars run right (recirc ones ONLY)"
While it's indeed true many engines with MAF sensors run like shit off-throttle if you fit a vent to atmo dump valve, the common info that you HAVE to run a recirc with a MAF is bollocks too in everything I've ever experienced.
Running no BOVs at all is absolutely fine almost always.
It's possible there's a car where the MAF sensor does shit itself, but so far I've not found it. I've heard a whole lot of rumours, I was told by countless people without a shadow of a doubt it'd cause the 2.7TT (ie S4) Audi engine to run like shit and so on if removed, but I tried it, and it's fine- Turned out, as ever, none of these people had ever tried, just 'heard' it did.
EDIT- Now I think back, I do recall a time when it made the MAF go crazy for a second, but that was a BIG aftermarket turbo on BIG boost on a small engine, and that was the only time it happened. Generally, no issue at all.
"Makes that cool chatter noise"
I know most of you know better, but it's rare to see a video of a car with decent turbo chatter without at least one comment saying it's the BOV making that noise, or asking what BOV it is as they want one that makes that noise.
IT'S NOT! HAVING NO BOV AT ALL IS WHAT HELPS MAKES THE NOISE!
Fuck, when I was 18 (1998!) even I at first thought the same, as MAGAZINES TOLD ME SO. In fact these "expert magazines" told me that it was HKS SQV valves did that noise, and though they were about £350 back then, and I wanted that noise SO BAD I would've paid that.
In fact, after a tuned MR2 Turbo came past and chattered like fuck one day I rang Torque Developments (they were the only HKS dealer back then) to order one. THANKFULLY, the sales persons tone of voice and choice of words made me very suspicious, while also accidentally giving me some hints that helped me research what REALLY made the noise (No internet back then!), so I thankfully didn't get skanked out of £350...
THINGS DUMP VALVES DO THAT PEOPLE DON'T TALK ABOUT...
"Help suppress noise"
The main reason they're fitted to OEM vehicles is as noise suppression devices, in fact that's the exact name they're given in many official workshop manuals. The noise I mean is turbo chatter, which is a lot harder to silence with an airbox than the ptschhh of a dump valve. We might like chatter noises and induction noises, but your average Joe new car buyer doesn't. In fact back in the day I worked at a dealership and an Impreza STi we had in on a P/X that we then sold was returned to us by the customer due to "Funny noises" it was making, as it had slight chatter as it had an induction kit on it.
"Help slow the car when in limp home mode"
A lot of new cars also use a system that holds the BOV(s) open, preventing boost/power being made in case of an issue that puts the car in limp home mode. Useful as an OEM.
"Leak like bastards, causing underboosting and turbo wear"
I know they're not meant to do this, but this is a major and common issue, and often impossible to detect unless looking for it. A dump valve is another potential leak point, and split diaphragms and/or weak springs means they leak surprisingly often, especially OEM and cheapo ones, and even if your turbo is still making full boost, a leak can cause a slower boost rise, and a turbo (and therefore entire engine) working far harder.
Confused? Don't be. I'll clear your mind (a little) in this next bit...
""SO! I was always led to believe that turbos stall with no BOV, and now you're telling me turbos SPEED UP?
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.