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...
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This is the never ending myth that comes up almost every time someone asks about fitting big intercoolers on forums and so on. You can be assured a knowitall, who no doubt has zero experience of it or he'd not say it in the first place, will tell you long boost pipes and/or massive intercoolers will make your car laggy, especially if you have a small turbo. Well, let me say, that's TOTAL BOLLOCKS. In THEORY, and it is fucking basic, primary school, narrow minded, short sighted, theory, the longer the boost pipes, and the bigger the intercooler, the longer it takes the 'boost' to travel from the turbo to the engine, and the longer it takes the 'boost' to pressurise it all before it pressurised the engine. In REALITY, airflow out the turbo travels at fucking HUNDREDS of miles per hour, and airflow in to the engine consists of HUNDREDS of litres per fucking second, so how in God's name do you really think adding even 10ft and 10litres (and that's massively unlikely) to the pre-throttle intake length/volume will make a car laggy is beyond me. In reality, and I've tried it over the years with really bloody extreme examples, with poxy little turbos and ridiculously big intercoolers and pipe lengths, it never ever feels 'laggier' or 'less responsive' or 'slower boosting' or any other way people want to say it, and usually (Imprezas are a great example as they have insanely long intercooler pipe lengths and massive front mounts) they actually are noticeably MORE responsive and have MORE low down power than before, as low intake temps are far more effective for performance increases than any theoretical response improvements. Almost all top mount setups, and most v-mount setups too, usually have pretty horrendous inlet temps compared to a decent front mount, and with no real response improvements, giving up lower inlet temps just to shorten boost piping is a terrible plan in reality, which brings me neatly on to this car... What we have here is an MR2, with a mid mounted 2ltr (2.1 maybe, can't remember and it doesn't matter) 4cyl engine. But the turbo is REAR mounted, a good couple of feet from the engine. That alone is enough to make Pistonheads forum nobheads cry 'LAAAAAAG' in some dweeby middle class voice. BUT hang on, where's the intercooler? Well, it's at the FRONT! Yes, this mid engine car, with a rear mount turbo, has a front mounted intercooler, and at least twenty foot of boost pipes connecting it all up!
Seriously, I've literally NO doubt if this car was created by some random lad in this day and age, not only would it get fucking slaughtered on whatever forum he made the mistake of posting it on, but it'd end up going viral on Facebook etc etc as the hordes of internet 'experts' ripped the absolute shit out of it for being a ridiculous stupid idea, despite none of them having any experience at all with anything even close to it. I can picture the unfunny memes about it now... I'm sure, even now, even after everything I've wrote, a lot of people are looking at the pics above and thinking "Fuck me, that must be horribly laggy and useless". Well, no, no it's not, in fact the above car won the GT300 JGTC (Ie Japanese Touring/GT championship) in 1999, vs RX7s, S15 Silvias, Porsche 911s, Imprezas, and more. I'm not 100% as I've not found enough detail to be sure, but the same setup in different livery might have won the 1998 championship too (MR2s with the same drivers did), and I think the 2002 GT300 winning MR-S (below) looks like it might've been a similar setup too, but can't find enough pics to be 100% sure... I actually wrote this for Banzai Magazine last year, but it's still very, VERY relevant, so I'm gonna put it here too...
You know what makes me cringe in the car scene at the moment? Well, a lot of things actually, but at this very moment, as I write this, it's certain peoples obsession, no, expectation, of sponsorship for their cars. Some people seem to think being sponsored and blagging free stuff is a main goal for their project, in fact many see it as a expectation, and they deserve it just because they've got a nice car. Well let me tell you, sponsorship isn't like that, it's not a charity, it's a two way thing, and unless they get their money's worth out of you, they're either not going to give you sponsorship in the first place, or you'll ruin it for everyone else by short-changing them; putting them off doing so in the future. While it seems pretty obvious when you think about it, a lot of people don't 'get' the concept of car sponsorship, so let me spell it out for you. First of all, it's not a charity, it's not like asking your Gran to sponsor you for a charity bike ride, there's no “Tuners In Need” fundraising events, and it's certainly not some free stuff you automatically get by having, or indeed thinking you have, a cool car. Car sponsorship is simply exchanging goods, services, or maybe even money, for advertising, and a big problem is people seem to grossly overestimate the advertising value of their cars. Sticking a few stickers on a car almost nobody sees isn't value for money advertising unless you've been sponsored to the tune of 50p. Competing in some race or drift championship, or going to a lot of car shows doesn't automatically make you a media darling either; like it or not, 90% of competition or show cars are almost never stand out from the crowd enough to get serious amounts of coverage. Fact is, unless your car is truly special, and by that I don't just mean a nice car that's popular in your local area or club, but truly something stand-out and world-class that has a serious following, it's unlikely it can justify any serious amount of sponsorship over a company simply spending the equivalent amount of money on conventional advertising. Unfortunately this sponsorship craze has become such a big deal to some that it's become a badge of honour, to the extent that some will happily plaster their cars in company logos in exchange for 5% off an exhaust and a free T-shirt, but in reality they mostly want 'sponsorship' so they can try and show off about being a big shot sponsored car/driver to anyone who will listen. If people spent more time truly working out how to make a good car, rather than mass emailing badly written begging letters to companies for undeserved sponsorship, the tuning world really would be a better place; especially as so many 'sponsored' cars are far from as good as they could be, as instead they're just a clothes horse for a companies products, no matter how unsuitable they are... The title says it all really, and that's not opinion, that's cold, hard, fact.
They're not useless, in fact they're a handy guide if you have them, but the only tell a tiny part of the story when it comes to how useful a turbo is. For this reason, basing your turbo choice on what you see on a compressor map is ridiculous, and just shows that you, despite no doubt feeling smug that you understand how to read a compressor map, also shows you don't really know how engine tuning works... I've actually seen a whoooole lot of people choose not to buy a turbo because there's no compressor map publicly available (or just doesn't exist). And considering pretty much no aftermarket turbo has a map available, and not even all OEMs publish theirs, this is pretty ridiculous. The fact that the vast majority of the fastest and most powerful tuned turbo engines on this planet runs turbos with no compressor maps available for them is a hint at how "Think they're clever but in fact are stupid" (what's a good term for that, barring dickhead?) so many people are. So what are compressor maps good for? Well, lots of things. They tell you the maximum (roughly, it's not gospel, most can do a bit more) airflow of a compressor. They tell you the maximum (roughly again, most can do more) pressure they can achieve. They also show you what sort of pressure and boost they're most efficient at, though if you're aiming for the most efficient point you'll be giving up both spool and power compared to a different spec turbo, which is a bit daft. As the above sounds useful, why am I saying they're not that important? Well, while it's not as accurate as a compressor map, compressor wheel inducer and exducer sizes are a fairly good indicator of these things too. How much a compressor will flow is indicated by how big the inducer diameter is, and how much pressure it's happy to push is generally indicated by a bigger exducer diameter compared to inducer. The another big reason you can't rely on them is because, as mentioned, the vast majority of the worlds best turbos simply don't have compressor maps available (Only some Garrett, some BorgWarner, and very very few from others), so you'd be likely hugely missing out on the best turbo for you if you went purely by maps. Also, and this is a biggie, thanks to the wonders of the internet, plus the experts who create and sell these turbos, you're hugely unlikely to be venturing in to uncharted waters by using a turbo, and a bit of research can almost always find out how much they flow, how much boost they can produce, even without seeing any hint of a compressor map. And this brings me on to the main reason Compressor maps aren't that important- ALL they show is the compressor side, HALF the turbo, and on most applications the less important side... Compressor maps don't show, in any way, shape, or form, the number one question for 99% of people- How a turbo SPOOLS. Not only that, but it also doesn't show if the turbine side is far too small for the application; something that's often ignored, but is a HUGE factor on reliability and power. An overly big turbine side won't spool well, or indeed at all- Compressor size has very little effect on spool. An overly small turbine side not only can restrict power and usable rpm, but high-pre turbine backpressure causes huge reliability issues that wouldn't happen with a correctly sized turbine- What goes in has to come out! Check out my earlier feature HERE regarding backpressure for more info on this... So to sum up... Compressor maps = Useful yes, but vital, hell no. Choosing a turbo via a compressor map = Stupid, as ignores all the main factors. About a year ago I was in the market for a new daily driver and part time drift car, and thanks to E46 BMW prices being absolute rock bottom at the moment, an E46 330i Sport was the winner. The 330i is powered by the 3ltr M54B30 engine, and it was ok, but less revvy than I expected; feeling a bit dead beyond about 6000rpm. That turned out that was because the stock ECU is deliberately holding the engine back, partially closing the electronic throttle at high rpm. A remapped ECU totally wakes it up- Making it pull strongly to 7000rpm+ and feeling like a different, much better performing, engine. I presumed BMW did this to make the M3 seem much more special, and maybe that's part of it, but there's another reason too- When you rev these things they explode in a fucking massive, engine wrecking, nothing worth salvaging, kind of way. Ever wondered why 325 and 328 engines are cheap and common and 330s cost so much more despite being so similar? It's because most of them are fucking broken! My engine was running great, totally reliable and great, being both my hard used daily driver and used on drift days all over the UK with no problem. Then one day, at 6700rpm in 5th gear, the oil light came on, and stayed on, and it sounded like a bag of nails. I knew this meant game over for the engine, and seemed likely the oil pump failed. But I didn't know why. Well, it turns out it's because of this... You know what that is? That's the nut that holds the oil pump pulley on! It turns out it's a VERY well known problem with 330i engines revved hard on track, and basically the harmonics of the 330i engine shakes it clean off, even though it's reverse threaded. The other, smaller, M54 engines don't suffer from this anywhere near as much; it's mostly a 330i thing. So what happens? Well, the nut falls off, which then means the chain and pulley falls off, so the oil pump stops, meaning instant zero oil pressure, which as you can imagine, writes an engine off pretty instantly. If you catch it super quick and at low rpm you'd likely get away with rebuilding the engine with new bearings etc, maybe a crank polish. That's debatable if it's worth doing over buying a good used engine, but mine fell off at 6750rpm and 3 figure speeds, and I likely didn't notice for at least 5 seconds, so it was deffo game over. I limped it 5 miles home, and then thought 'fuck it, I'm not rebuilding it' so limped it as far as I could to my mates garage 10 miles away. Amazingly, it made it! Well, it got to about 200m away before it expired, and I coasted it the rest of the way. What was the damage? Well, this... Ever seen a cam worn down so much you can see inside it? No me neither, but it's pretty cool. That's a hole in the sump from a conrod in the 2nd pic. 3rd pic is the oil pump with the pulley that had fell off. 4th pic is the alternator bracket with a hole in as the conrod went flying through the block and that too. 5th pic is, among other things, a very bent and broken rod. And 6th is the remains of a cam bearing cap after being ran with zero oil for about 15 miles! So what the hell fuck can you do about it? As it's mega common, and pretty flippin' disastrous lots of people have looked for a solution. There's a few expensive things that 'seem' to fix it, and a few cheaper things that seem to just delay the inevitable... So, 'fixing' it. Well first up, BMW clearly knew of the problem, in fact to the extent they fitted a different nut to later engines (bottom right) which basically just seems to have thread lock on it. This supposedly helps, as it seems almost any M54B30 you take apart, even low milers in good nick, will have a loose nut, and earlier ones are worse regardless of miles, BUT it will still happen in the end, threadlock or not. Another 'solution' is lockwiring the nut in place (top left). You can even buy kits for this, but again, it delays it, not fixes it. The entire pulley ends up shearing off. Next up is almost the same solution and same 'in the end' fail, spot welding the nut in place, as the top right pic shows. A better solution is a modified pump with a 4 bolt pulley, as per center bottom. Shame it costs about 750quid, which is nearly twice what a used engine costs. Because it's crank harmonics that cause it, an ATI crank damper (bottom left) supposedly helps too, but again, it's big money, which turns most the appeal of a 330i in the UK (ie they're cheap as chips) down a little. Best of all, but serious money that would certainly make you wonder why you didn't buy an M3 in the first place, would be a dry sump setup (top centre). So what have I done on mine? Well, I picked up a low mile engine for £450, got the nut spot welded in place, which deffo isn't the full solution, BUT I hope it lasts a long time. Finally, partly as I wanted one anyhow for performance reasons, and partly as it's entirely possible it will change the damaging harmonics to a different RPM that it's no danger any more (but literally no way to know, it's SWAG- Scientific Wild Ass Guess, but a hopeful one) I've got a super lightweight flywheel to replace the fucking mental heavy dual mass setup they come with. WILL IT LAST LONG? FUCK KNOWS! But the theory is fairly sound, I'll pray to He-Man that he can help it hold together, and one thing's for sure, I'll have fun until the time when it does happen again, if it happens.
If it does fail, I'll let you know! The one thing I miss since becoming a freelance writer, is the fact I miss out on the new cars manufacturers send magazines to test. I miss it not because they're amazing cars, as tbf my own cars were usually faster and more fun, but I genuinely do enjoy testing cars, seeing how they really drive, and see if there's the potential to actually make them awesome with a few modifications; especially as most reviews I read sound like someone who's had a 30min jaunt around the streets, sat back down at their computer, and made up a load of cliche filled crap they think the reader will want to hear.
Some cars we were sent disappointed me, in fact most cars did, but some were a surprise, and one of the biggest was the then-new Corsa VXR. I honestly HATED it for the first few hundred miles, and didn't like the Astra VXR I tested before it either, and that was much faster... While they look pretty decent in press photos (it was a red one, exactly as above), in the flesh it looked much taller and bulkier than expected, and from behind the wheel, despite the badass Recaro seats, it felt like the car and seating position was about a foot too high, which is a huge negative point for driving in my book. For the first couple hundred miles I still didn't warm to it. Yeah it went well for a standard hot hatch, with decent torque from the turbo, all the VXRs do really, though it also had a very noticeable performance drop with sustained hard use that felt to me like the standard intercooler was heat-soaking. The main killer of enjoyment was the fact it still felt like I was sitting on the roof due to the seating position and tall thin chassis, which made it feel, well, far worse than any actual timed performance shows it is. While the car was certainly capable, it didn't stand out at all compared to countless other cars I'd tested, and just like most standard cars, any real fun or feel was sucked up by the fact the manufacturers try to make a refined car that will stop your average Joe from either hating it for being too unrefined, or crashing it. But I'm not Average Joe, I'm Stupid Stav, so it just felt a let down, too normal- Until I started driving it like a loon that is... As the miles piled on (I had a lot of shoots to do that week, and I did about 250 miles a day in the thing) my frustration with it feeling a bit numb and crap made me chuck it about far more than it initially felt capable of, and then, well, something just clicked. It turns out, while still a bit too 'standard' for my liking, was actually bloody good when driven on/over the limit; not at all like it felt when driving at 7/10ths. When driving in maximum attack mode it almost shrank around you, and was in fact incredibly adjustable with both the steering and throttle, to the extent you could get lift-off oversteer at will, and a friend I gave a lift to, after about 10mins of saying nothing and just holding on tight, suddenly goes "So is this thing rear wheel drive then?". I've never tested a car that look me this long to like it, but once I did like it, I really, really didn't want to give it back, not because it was amazing, but as standard cars go, it had the potential to be one of the most hilarious modern hot hatches there is. Just a few basics, lower seats, lower ride height, better intercooler, and a more audible exhaust, and I felt the car would be the same hilarious fun it was at 11/10ths, but unlike when standard, it'd still be almost as fun at less licence losing, car crashing, speeds. Funnily enough, a few months later Vauxhall sent us the Corsa VXR 888 edition, which was lower, stiffer, faster, and noisier (to the extent of pretty loud pops and bangs on the over-run), and that pretty much confirmed what I thought it'd be like after driving the standard one; great fun, and stupid enough to not get bored of quickly. Honestly, if I was in the market for a modern-ish hot hatch to tune (and I'm not), while it's not the 'best' one, not the fastest, for me driving is about fun, and I'd get a Corsa VXR... Turbos are amazing things, they're a big reason the vast majority of the worlds fastest cars in almost every discipline are as good as they are, and for us tuning obsessed idiots it means we can go a whole shitload fastest for our money than we could if they didn't exist.
BUT, and this is something a lot of people either underestimate or seem to be totally oblivious to- They're not fucking magic! You can't just throw a turbo at a pile of crap and expect it to work as well as proven results elsewhere, you need to do things properly... Some people are just plain stupid, and I mean the ones who wonder why they've not instantly got the same 800bhp another engine with the same turbo has, despite the other engine being of a totally different spec, running twice the boost pressure as them, or not even being the same fucking engine. But forgetting people who shouldn't be allowed near a turbo in the first place, it's the smaller, but almost as drastically important changes, that most seem to miss. There are literally hundreds, but this is some of the most common... PORT MATCHING- Christ, the amount of people I see who copy someone elses turbo and manifold spec, spend well over a grand on some fancy 8Boost/Part-Race tubular job, but just slap them together and think that's going to work great is unreal. Look at the pics at the top of the page- Just because something has a T2/T3/T4 bolt pattern flange DOES NOT mean the port sizes are the same, in fact they're almost always far, FAR smaller than the manifold ones. And that flippin' massive flat step between the manifold and turbine is a killer for flow, and a good way of buggering up how fast your turbo spools, and if you're anywhere near it's limit, even what peak power is coming out of it. A lot of BorgWarner 'T4' flange turbos have typical T3 sized ports, so the step is huge, and to be honest even most T3s, especially things like twin scroll Holset ones, the ports are far smaller. It's an OEM thing too, look at the top middle pic, that's a Skyline GT-R turbo, R32, R33, and R34 ones are all like that- T2 flange, but the port only goes 2/3 the way along compared to a typical manifold/gasket, leaving a 5cm by 1cm flat plate for the exhaust gasses to smash in to, causing all kinds of flow destroying turbulence. Do what do you do? Well, you port match it. You don't have to be an engineering genius, it doesn't need to be perfect, and you certainly don't need to open up the entire port, but if you can use a Dremel, die grinder, even some files, and turn these big flat edges in to smooth transitions from the manifold port size to the turbine port size, you can drastically improve flow and performance. TWIN SCROLL TURBOS- Fair play, twin scroll turbo setups can be damn good. A good example of how good they are is a little 2ltr engine with a big Holset HX35 12cm on it. Even using the standard Cosworth YB 2wd exhaust manifold (that big cast iron rusty thing centre bottom of the pics above), which is twin scroll, a HX35 12cm (a big, journal bearing, cast wheel, 600bhp+ proven turbo, not exactly a new design either) is well proven to hit 25psi boost by just 3500rpm. Same results on Mitsubishi 4G63s with twin scroll setups. Awesome when you consider a single scroll setup with a similar size turbo, even fancy BB core ones with £1500+ price tags, tend to not hit full howl until upwards of 5000rpm- That's a whole different world of drivability. The thing is, twin scroll manifolds are expensive and relatively uncommon, so a lot of people can't run them, certainly not as easily as they can find badass twin scroll turbos. That's not the end of the world, as while a lot of people ask me if it's possible, I can assure you you can 100% run a twin scroll turbo on a single scroll manifold. Of course it won't spool like a twin scroll setup, but done right it's as good as the single scroll version, so yeah, go for it- Thousands of people do with huge success. BUT, just like the port matching mentioned earlier, the divider on the turbine inlet flange is a big ol' turbulance creating flat plate when ran on a single scroll manifold- So again, smooth it off rather than just bolting it on. TBF you really don't need to fully knife edge it like the one pic at the top, that's a whole lot of work and super thin metal is asking for it to break off and take your turbine wheel with it, but massaging it from a flat plate to a nice smooth curve is well worth the 15min work it will take to do. POXY LITTLE DOWNPIPES- Just like I explained in THIS feature the other day, the first few feet of exhaust after the turbine wheel is by FAR the most important part, especially for spoolup. Unfortunately people often don't realise this, so fit god awful 2.5in downpipes despite the turbos being 600bhp+ beasts, and then they wonder why their spoolup sucks ball. Some make the excuse of "Well, the turbo outlet is 2.5in, so why would I need bigger?" Because reasons, that's why. Honestly, it makes a huge difference, even swapping to a big downpipe on a 2ltr engine fitted with little 350bhp turbos can make a big difference to spool, never mind turbos twice the size. To be honest, to get the best out of a lot of turbos even the standard turbine outlet needs modifying. Good examples of this are most Holset HX35s and HY35s, which have a 2.5in outlet which is cast as part of the housing for the first 4inches or so. People have seen VERY noticeable improvements in spool, over 500rpm, by chopping off the back section and welding a 3-4in v-band right from as close to the turbine wheel as possible. OIL FEED AND RETURN- I'll finish this off with a non-performance one, but one I get asked all the time, and that's oil feed and return sizes. I've lost count of the times I've seen people buy a brand new turbo, fit it, it smokes its tits off, and they remove it crying that it's broken already and it's completely shit. No mate, it's you that's shit. Of course some turbos are faulty and oil is pissing past the seals through no fault of your own, but that's pretty rare as the oil seals are a design that just don't wear or break easily. 90% of the time it's because whoever has fitted it has fitted too big a feed, or most commonly, a comedy small oil return. "Oh I fitted a dash12 billet anodised alloy amazing one I found on eBay, it must be fine" they say. Until you ask how big the internal diameter is. And they don't know. And then they look, and it's 10mm or something, hence the oil can't get out fast enough, and it's forced past the bearings instead. The fact is, oil returns need to be BIG to work well, most turbo manufacturers specify 19mm internal diameter minimum, and changing a little pipe to a big one usually stops the smoke. So bin the fancy looking but restrictive aero fitting and just use a normal but big metal and rubber return line that actually works properly- It's not as if anyone can see it anyhow... Oil feed is similar, but a bit more complicated- Too big and you can get oil flooding past the seals again, but too small and you'll starve it of oil and kill the bearings in no time. Why it's complex is all turbos are different and engines have wildly differing oil pressures. Almost all manufacturers state a maximum oil pressure, but as this is measured at the turbo inlet, almost nobody checks this, so just guess- often wrongly. A rule of thumb I tend to have luck with is non-BB turbos use a -3 line with no restrictor, the more common -4 can be too much for some, which leads people to use restrictors, and they they fit one way too small and run the bearings dry. Then cry a lot and blame the turbo even though it's their fault 100%. BB turbos always in my experience have manufacturer recommendation on oil feed and restrictor size, so that's rarely an issue unless you can't read. But most of all- Make sure the bloody oil return is big enough, has no kinks, and ends above the sump oil level. A great flowing oil return can usually counteract a slightly overkill oil feed in my experience... Exhaust backpressure on turbo engines is one of the most misunderstood aspects in tuning to many people, but it's pretty simple- It's not good.
On non-turbo engines backpressure is a single issue, the pressure in the exhaust system, but on a turbo engine it's actually two issues, pressure in the post-turbo exhaust system, and pre-turbine backpressure in the exhaust manifold. A lot of people still think turbo engines 'need' backpressure or they lose low down power, but that's total crap, in fact the opposite is true- The BEST post-turbo exhaust system would be no exhaust system at all. Bigger really is better for both spoolup and power, especially directly after the turbine wheel, and it's why fitting a big downpipe to a turbo engine makes a massive difference to spool especially, much more than the rest of the system; in fact some new very high performance production cars turbo have amazingly big turbine outlet elbows for this very reason. I'm not one for going in to the science of why things are how they are, as in the real world it usually doesn't matter, but a big part of why a turbine spools is the pressure drop between the inlet and outlet, the bigger the pressure drop, the better for spool, so having as little as possible in your post-turbo exhaust is what you want. But post-turbine backpressure is only part of the story, pre-turbine backpressure is one of the biggest, yet totally invisible, killers of tuned turbo engines, and is also a massive reason certain engine setups don't make the power they're hoped to either. Pre-turbine backpressure is inevitable, it's just a turbo engine thing, one of the things that spools your turbo, and a worthwhile exchange for acceptably fast spoolup for your application. Unfortunately, too small a turbine, be it the wheel, housing, or both, can cause too much backpressure, which in turn means exhaust gas struggles to leave the cylinders, huge EGTs, higher cylinder temps, diluted fuel/air mix in the cylinders, and so on, which in turns means hugely more susceptible to engine-killing det, not to mention general reliability issues and power restriction. Some well specced, huge turbo, drag engines, actually do have lower backpressure than boost pressure, and this 'holy grail' of scenarios actually makes for an engine that makes amazing power and hugely det-resistant. Unfortunately, these sort of setups just won't spool fast enough for 95% of applications, so tend to be found on high-end drag engines only. In the real world, most engines can be expected to have up to twice the backpressure as boost, but more than that, and some engines do have a LOT more than that due to peoples obsessions with tiny turbine housings (and a great many badly specced turbos with overly small turbine wheels compared to compressor size), which causes a lot of reliability and performance issues, and with no way to know what backpressure they've got, most don't even realise this is the main culprit! You often find that if your pre-turbine backpressre is more than about twice what the boost pressure is (and some engine setups can be 3 times or more!), changing to a bigger turbine housing, or ideally a bigger turbine wheel, will not only drop the backpressure, but hugely increases power and reliability per psi boost, and actually not slowing your spoolup at all despite the bigger turbine; in fact in some situations it speeds it up as it was so strangled beforehand. So yeah, BIG exhaust is good, a backpressure gauge is good to see if your turbine is strangling your engine, and don't be afraid of a bigger turbine- It may well transform your engines performance in every way... I love going sideways. For me the adrenaline rush of being beyond the limit but still in control is more fun than anything else you can do in a car. Like it or not, oversteer, powerslides, drifting, whatever you want to call it, often isn't the fastest way around a corner, but it is the most fun way around, and from a spectator point of view it's certainly what's memorable and gets the crowds excited.
Despite my love for it, there are some aspects that drive me flippin' mad, some because they affect everyone associated with drifting, and some purely because so many more people, even people who are already part of it, would enjoy things much more if things were a little different... While I'm not a JDM fanboy by a long shot, one thing the Japanese have pretty much 100% correct is their drift scene, and if we, as drivers, as fans, as organisers, could have the same attitude to it as they do, things would be a lot better. My problem mostly boils down to peoples reasoning for why a car performs as it when drifting. In Japan they rightly say drifting is 90% driver skill, 10% car spec, and they embrace this in every aspect, from practice days where it's normal to see low power basic spec cars drifting with absolutely mind blowing skill, to high end competition, where the cars are surprisingly low power and basic compared to UK competition cars, but the action is so much more impressive to watch, and the driver skill is so much more apparent . In the UK however we've got a huge tendency, whether it due to over-confidence or simply ignorance, to blame the cars specification for everything. Because of this, massive spec cars being driven in hugely mediocre ways is the norm here, and even newcomers to the drift world have it in their heads that before they even get behind the wheel, a car needs big power, huge amounts of lock, and a hydraulic handbrake. Well let me tell you, you're wrong. Lower power lower spec cars entering corners at huge speeds using massive Scandinavian flicks, like you see in Japan, is a whole lot more fun both to do and watch, not to mention cheaper, than seeing a big power car doing a skid on the handbrake, then smoking its tyres around the track with just a lazy stab of the throttle. It's a good job there's no UK versus Japan drift events any more, as if we went by their rules, our top cars would be hugely embarrassed by cars with half the power and specification, but driven by guys who truly push them to their full potential... While it's less common now, as there's countless cars out there proving it's a load of old bollocks, you still see people commenting that they can't/won't/shouldn't/couldn't use a certain turbo because it's a "diesel" turbo, and their car is petrol. But do "Diesel" turbos exist? Well, maybe back in the day, but in this day and age? No, not really. Turbos that are the wrong wheel/housing spec to suit a certain engine? Yes, 100%, but what fuel the original engine it was designed for is not the issue here. Frankly almost all turbos, yes, even the most high-end aftermarket ones, have at least 'some' parts originating on a commercial diesel engine, and many, many, consist of parts that almost all OEM on some diesel engine of some description; they simply consist of choice parts of various diesels to make a good spec one for a typical tuned spark ignition engine. In fact there's tons of OEM turbos that work straight out the box as fantastic performers on tuned petrol engines. A whole crapload of 'famous' BorgWarner S200/S300/S400 turbos people use on some of the worlds top tuned cars are also OEM on various things, in fact a lot of them John Deere (yes, farm machinery!) engines. Yep, awesome spec, even billet wheel, Borgs are fitted to tractors, combines, generators, and more. And things like the 12cm Holset HX35 is hugely popular in the tuning world, and proven ridiculously capable on tuned petrol engines, despite being fitted to countless diesel 'things', even diggers. Much the same for the 10cm Holset HY35, which is mega popular on things like 1JZ engines in the UK, proven 520bhp+ and 500lbft+ despite hitting full boost under 3000rpm, but they're OEM fitment to various DAF engines among others. OEM 'diesel' turbos may not be THE best turbos in existence, but the sometimes amazing performance combined with reliability and a low price often makes them THE most value for money. The problem with 'some' diesel turbos being great for tuned engines is some people go to the polar opposite of the people who think diesel turbos are the car equivalent of Ebola, and instead think they can fit any old diesel turbo to their engine and expect it to perform well. WRONG. Fact is, as good as some are, most of them aren't suitable for performance petrol applications. Most have a FAR too big turbine side to work well on small capacity engines, so unless you know it will work, or actually understand turbo sizing and what turbo you're looking at, don't do it. Obviously business is business, so big aftermarket turbo sellers will slate "Diesel" turbos 'til the cows come home, even going as far as to tell bare faced lies, as they don't want people to buy them instead of their own, even if many of theirs are barely changed over an OEM diesel unit. Like it or not, the fact is, there's a LOT more money to be made in OEM than in tuning, which is a tiny % of the turbocharger world, and for that reason the top OEM engines get the best, most high-tech, turbos, long before the general aftermarket. Christ, even normal, low power, 4cyl Mercedes Sprinter vans now run twin compound turbochargers, both with billet compressor wheels. The only things they don't get vs the aftermarket are gimmicky or unreliable things- OEM is built to last... ;) DON'T GET ME WRONG- The best turbos, the most powerful and fastest spooling turbos, are not OEM, they are aftermarket ones, but you will be paying the premium to get these, and only you can decide if that money is better spent elsewhere (Hint- Usually). Honestly, aside from very very few, literally mega-bucks, Pro drag units, and of course things like proper WRC/Rallycross/LeMans race turbos like Garrett TR30Rs, they're all based on OEM "Diesel" units to some extent, be it just a turbine wheel and housing, or much more... Let's face it, standard cars are boring. No matter how fast they are, they have to cater for the 'average user', so they're safe, they're easy, they're, well, a bit too sensible. This is a big reason we tune cars, not just for more performance, but for more feel, more involvement, more excitement. And as the years roll on, the bar of what's considered high performance is ever rising, so it's rare for an 'old' car to be very fast either.
Well, welcome to a rare exception to the rule, the Lotus Carlton, one of the VERY few production cars I've been hugely impressed with, and certainly the only unmodifed car from two and a half decades ago that's impressed me in modern times. To be honest, most people I know who've driven them don't like them as much as they expected they would, usually moaning about it being geared too long to use the performance, the car not being as fast as they imagined, or the transmission being hard work, feeling old fashioned, but to me that just says they're pussies who can't drive... First up, the car IS long geared, but not in a way that detracts performance if you know how to drive it, and being in too high a gear is why most think it's not as fast as it is. It's not a turbo diesel, you can't plant the throttle at 1500rpm and expect it to rocket off down the road, as the engine loves to rev, that's where the performance is, and thanks to the long gears you're at least one gear down compared to most modern cars. Unusually, 1st gear is actually usable in performance terms, good for almost 60mph, and things get even longer at higher speeds, so while 6th is a cruising gear, 3rd and 4th is for hard acceleration at motorway speeds, and 5th is for doing hugely, ridiculously, illegal speeds; and yes, it's very, very, easy to see the claimed top speed of 177mph... In all honesty, and I'm very rarely impressed by a cars performance, I was hugely impressed by how these things go even compared to their modern rivals, and the driving experience is leagues ahead in my book. Cars are about fun, and this thing is fun. I like rawness that other seem to dislike. The heavy duty 6 speed gearbox is clunky and slow, and the clutch is similarly heavy, but from a driving experience, that just adds to it in my eyes. The total lack of driver aids seem to scare people off too, but I loved it, being able to feel everything and having to do everything, which along with huge acceleration, and the grunt to easily spin the wide rear tyres at motorway speeds, it was the experience you get in a good tuned car, but this was standard. Having said this, it's not some kind of wild beast, and as long as you're not deliberately being a dick, as long as you have a decent understanding of car control, it just squats down and rockets off down the road far faster than I expected, and in roll races versus most it's much newer, but much heavier, rivals, they're left wondering just beat them. Considering the standard car was the kind of fun you normally only get from a well tuned car, I'm 100% with some well thought out mods (Standard inlet temp is 60degC so the standard chargecoolers would be first to go!) it was be absolutely ridiculous fun. If I had to compare it to any more modern car, it wouldn't be a BMW M5 or AMG Mercedes, in fact it wouldn't be any standard car, as this car doesn't feel 'standard'. The Lotus Carlton feels a lot like driving a well tuned Toyota JZX100, and that includes the fact that as well as the stupidly quick acceleration for a big obscure four door, it drives and handles far better than you'd expect, and can be seriously chucked around corners. Unfortunately, the cars and their parts are rare and expensive, so that's very unlikely to happen; the one I had was very kindly loaned to us from the Vauxhall museum! And as the picture top right shows (Top left is on my driveway!), they also let Richard Hammond 'test' the very same car for TopGear... |
Hi, I'm Stav...You may or may not have heard of me, but I've spent the last 20 years working full-time in the tuning scene, and the last decade or so writing for various car magazines. Archives
March 2024
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