In defense of Ford's CHT engine?

Ford failed in Brazil a lot of times due to the lack of a long-term planning for its engines range to meet the local market conditions, and the Escort Mk.3 which was the first one introduced officially to Brazil had to rely on the Renault-designed Cléon-Fonte engines to which it had access after merging with the Brazilian branch of Willys-Overland with whom Régie Nationale des Usines Renault had a partnership at the time. Even though that was even better than Ford's own Kent engine fitted to some entry-level trims of the European Escort by then, it ended up being one of the most underrated engines in Brazil as competition from Chevrolet and Volkswagen evolved to the OHC layout. Even though Volkswagen's EA-827 engine series mostly known in Brazil as "AP" and more frequently referred to as "Motor Audi" in Argentina and Uruguay is often highlighted as the holy grail for reliability covering displacements between 1.6L and 2.0L while also being reasonably affordable when it comes to tuning, the good old CHT which was better known in the 1.6L displacement range even though 1.3L and later even a 1.0L variant had been available had even better reliability despite its more conservative power and torque figures often blamed on the chain-driven OHV valvetrain receiving much criticism.

It's not unusual to claim the CHT engine is the one to blame for the Escort XR-3 not having been taken so seriously as a sports car in Brazil until the AutoLatina joint-venture with Volkswagen provided Ford with the AP engine, yet the unsuitability to expand the CHT over 1.6L was much more of a real issue. Ford really got a hard hit from the '73 oil crisis in Brazil due to bad planning, including the usage of the F-Head Willys Hurricane engine in Brazilian versions of the Maverick instead of the Thriftpower Six which was available in Argentina powering the Falcon and the F-100 which used to rely only on the V8 engines in Brazil until the Lima OHC became available in Brazil only in the 2.3L displacement and also resorting to natural aspiration and carburettor while export-bound variants could be had with EFI and even turbocharging. In trouble, the Brazilian branch was saved by a combination of engine exports to the United States, the creation of the F-1000 which was basically a higher-GVWR F-100 with a Diesel engine available (while the Argentinian-sourced Thriftpower Six was not so sought after), and naturally the Escort to which the CHT engine already on the parts bin was a reasonable option not requiring the expenses of a tooling update to manufacture the CVH engine fitted to its European and American counterparts.

A cheap engine to manufacture, and nearly indestructible while also quite easy to overhaul due to its wet-sleeve layout, the Renault Cléon-Fonte on which the CHT is based was successfully tuned to high power and torque ratings in Europe, being widely used for rallying and other demanding motorsports even behind the Iron Curtain where some derivatives were made by Dacia in Romania before it merged with Renault. Even though it's often pointed out as "inferior" and "outdated", mostly due to the lack of an aftermarket support so focused on performance enhancements, the CHT engine was better than what it's often regarded in Brazil, with its low-end torque still being appreciated despite featuring a lower specific power within the 1.6L displacement range compared to what Volkswagen and Chevrolet had to offer in Brazil during the '80s. Had it not fell so out of favor between '86 and '96 when AutoLatina was in effect, sure the CHT could've proven its worth, and eventually could fare better than the Kent-based Endura-E supplied from Spain from '96 to 2000 in 1.0L and 1.3L variants along the 1.4L Zetec-SE once the Fiesta started being made in Brazil, and then presumably with the fitment of a sequential EFI and other fewer improvements it would not surprise me the CHT could save Ford in Brazil again...

Why could the concept of a single-clutch automated-manual transmission be still relevant?

There were times when a very same car could differ considerably from a region to another regarding the availability of automatic transmissions, even for models with a broader "World's car" appeal such as the Toyota Corolla. At its 9th generation (E120), it resorted to a narrower bodyshell for both the European and Japanese markets, even though the lower demand for automatic transmissions in Europe rendered it more suitable to make an automated-manual transmission available instead. As it retained the coupling through friction from a regular manual instead of resorting to a hydraulic torque converted usually fitted to conventional automatics, gear changes are often more noticeable according to the driver's behavior, which might seem more annoying to a Japanese or American more used to a greater smoothness that a single-clutch automated-manual transmission is reportedly unable to provide.

While both the evolution of conventional automatics, CVTs and the arrival of the dual-clutch automated transmissions could sound like the end of the road for a single-clutch AMT, it retains a foothold on the commercial vehicles segment. Considering aspects such as purchasing price, maintenance schedule and concerns related to the impact of an automatic transmission on both fuel consumption and payload, the simpler layout of an automated-manual seems more appealing to fleet managers and owner-operators in countries such as Brazil where the commercial vehicles market is highly conservative. Even though the rougher operation and usage of a conventional clutch which still needs replacements through the useful operating life of a truck such as the Volkswagen Constellation or a bus such as the Volkswagen 17.230 OD may sound disadvantageous compared to an automatic transmission, maintenance procedures more similar to what most commercial operators are comfortable with is likely to render them more favorable to a single-clutch automated-manual transmission.

It's also worth to remind some claims of longer clutch life due to clutchless gear changes which happen more frequently, and a lower fuel consumption because of the automatic selection of the more suitable gear according to traffic and terrain conditions, at a cost premium not as high as for an automatic and a lower increase to the curb weight of the vehicle. The increased precision of the newer electronic engine management systems has also led to the viability of a more accurated and better integrated transmission control, preventing driver errors such as over-revving which is detrimental to the fuel consumption. It's worth to remind the viability to expand the concept of single-clutch automated-manual transmissions to nearly any vehicle with a modern engine electronic management system, rendering it an effective way to increase comfort, durability and fuel-efficiency even for vehicles which were never available with an automatic transmission, to the point that even modern versions of the classic Lada Niva with sequential port-injection and distributorless ignition could benefit from this feature.

Besides the lower cost comparing a single-clutch automated-manual transmission to both an automatic or a dual-clutch transmission, rendering it a good option for emerging markets where the economics of scale can be favored by sharing most components with the regular manual transmissions on cars such as the Volkswagen Fox, it's also noticeable the failures on single-clutch AMTs is usually more related to electro-hydraulic actuators than to the internals of the gearbox or the clutch pack, while for dual-clutch transmissions it's not unusual to have clutch pack failures which may damage the entire transmission. A simpler approach may not provide all the advantages from its more sophisticated counterparts, such as the claimed seamless and faster shift which rendered DCTs widely praised, but a lower overall cost is worth to consider. So, even though it might not be always understood by the average Joe, the concept of a single-clutch automated-manual transmission is still relevant.

Dettachable refrigerated module for Brazilian car-based trucklets

Mostly due to size and purchase price concerns, car-based trucklets such as the previous-generation Fiat Strada are taken seriously as a work vehicle in Brazil. The agility of a small vehicle on the heavy urban traffic benefits the operation with small loads, however the monocoque body becomes troublesome to fit special load compartments which would handle more efficiently either a slightly larger amount of the refrigerated items or allow a better integration to the stock vehicle. Resale value is also often taken as a priority, and dealing with the removal of a specialized truck body to fit another more appealing to the average Joe is as much as a matter of concern as the cost of the refrigeration equipment. A detachable refrigerated module which fits inside the pick-up box, eventually being titled as an "interchangeable body", makes it easier to address with the needs and preferences of many commercial operators who require a more compact vehicle and are not willing to compromise much of its original features once the time comes for resale.

Volare 4X4 - Brazilian 4WD minibus

Brazilian countryside can be rough, and the same may often apply to the outskirts of big cities or other operating scenarios that may require a more specialized approach for a job to get done. Initially catering to the school bus segment, Marcopolo's subsidiary Volare developed the Volare 4X4 in partnership with Agrale and benefitting from the 4-wheel drive experience Agrale had even before it started producing the Marruá utility vehicle series.

With a Cummins ISF3.8 engine and a 5-speed manual transmission, and a dual-range transfer case, the Volare 4X4 also found its way on segments other than rural school buses, also being possible to spot it on construction sites and other demanding off-road environments. The articulated rear bumper means it can have a rear overhang more similar to a normal 2-wheel drive model, while still allowing a greater departure angle while off-roading.

Possibly the last remaining International KB-1 from my hometown

Took these pictures in August 2011, and since then I had only seen it again a handful of times while passing in front of an apartment complex where it could be seen from the street at the carport.

Pictures don't show it, but it had a Ford steering wheel, which considering how hard it might be to find spare parts for its stock Blue Diamond engine might suggest a repowering with either a Ford 221 "Falcon Six" or some MWM Diesel engine fitted to a Brazilian derivative of the F-Series, even though I have never seen it running in order to identify by the engine sound if it's a gasser or a Diesel.

4 features I consider hard to explain regarding Volvo's T8 hybrid powertrain

I must confess hybrids are not exactly my cup of tea, even though it seems like there is no turning back from them anymore. Some models such as the Volvo V60 now don't even offer a turbodiesel anymore, and it even became more frequent to see a hybrid than a gasoline-only version, which is also leading to an opportunity to take a look at some features that might be hard to explain when it comes to Volvo's current approach to hybrid powertrains. Regarding the T8 rating, which is available only as a hybrid, there are at least 4 features seemingly opposed to the "environmental" approach hybrids are supposed to be all about:

1 - the "twincharger": while the engine-driven supercharger might provide a reasonable boost from launch to around 3500 RPM, and then the exhaust-driven turbocharger does all the job when it comes to forced induction, it's worth to notice the increase on parasitic drag from the supercharger and its drive, which is somewhat more objectionable as it may be desirable to keep the engine at lower load during normal operating conditions driving on the speed limits. Since the presence of the supercharger is not taken benefit to allow the engine to operate within the Miller cycle, which resorts to a longer intake timing advacing through compression stroke in order to emulate the Atkinson effect while the forced induction prevents the charge air intake to escape, eventually it would make more sense resorting to the PowerPulse system fitted to the Diesel twin-turbo D5 engines which resorts to a compressed-air impeller for the turbocharging in order to overcome turbo-lag with the air being supplied through an electric-driven compressor on board;

2 - absence of flexfuel capability: due to the "sustainability" premises, it would make sense to have a provision for the vehicle to be capable to operate on a renewable fuel along the more usual gasoline, with ethanol capability being somewhat reasonable to expect from a modern spark-ignited engine. Not only it has a cleaner combustion process, turbocharged engines fitted with direct injection provide ideal conditions to narrow the efficiency gap per fuel volume between gasoline and ethanol, as they lead to a safer increase on compression ratio while operating with gasoline and easier cold starts while running on ethanol;

3 - keeping the same automatic transmission of non-hybrid versions: while it could either take benefit from the instant torque output of electric motors to get no gearbox at all, enabling them to act as a CVT just like Toyota and Lexus hybrids usually do through their Hybrid Synergy Drive setup, or to use some other automatic or automated-manual transmission more optimized for overall efficiency, it just retains the same 8-speed automatic shared with the non-hybrid T4, T5 and T6 versions. Sure it would be harder to expect the option for a manual transmission, as an automatic leads to a smoothier transition from EV mode to combined electric and gasoline power, but other setups predictably more in line with the usual expectations for hybrids would be more favored by fuel-efficiency and emission regulations;

4 - seemingly lack of motivation to benefit from a Freevalve design: even though the mainstream automakers usually tend to take breakthrough tech with a grain of salt, most noticeably when there is a need for a licensing from a smaller engineering outlet, its hybrid range would be a perfect receiver for the Freevalve technology, not only because it would allow the usage of a simpler port-injection and to get rid of the particulate filter, but also due to eventually making it easier to alternate from 4-stroke to 2-stroke under specific conditions as the presence of the supercharger could serve to provide a more efficient scavenging just like on 2-stroke Diesel engines.

2nd-generation Peugeot 208 made in Argentina: only one engine option doesn't match regional needs and preferences

Released with a delay after its European counterpart, the Mercosur-bound version of the 2nd-generation Peugeot switched the manufacturing base from Brazil to Argentina, relying only on the old EC5 engine in an ethanol-capable flexfuel trim for the Brazilian market while other countries receive it tuned to use only gasoline. Besides the absence of a turbodiesel engine, which used to be much sought after even on compact cars in Argentina, it's also noticeable the fitment of an automatic transmission as standard and only a naturally-aspirated engine with greater displacement than its European counterparts which resort to the smaller EB2 engine available as a naturally-aspirated with manual transmission and turbocharged versions also including the option for an automatic transmission. Considering both the brand perception of Argentinians who don't really see Peugeot as somewhat premium, while in Brazil it tries to recover a prestige it used to get when imported cars flooded the local market in the early '90s attempting to take over the middle and upper-class customers, it would actually make some sense to retain the same EB2 of its European counterpart.

While the higher purchase cost of a turbodiesel inherent to the increasingly sophisticated aftertreatment becomes troublesome for a country with a severely troubled economy as Argentina is at the moment, a strong market for natural gas conversions is more favorable to the EC5 and would also be to the basic naturally-aspirated EB2 due to the usage of port-injection, instead of the direct injection which is fitted to the turbocharged variants of the smaller engine. And since the 1.2L EB2 is slotted right above a more favorable displacement class up to 1.0L for taxation purposes in Brazil, just like the 1.6L EC5 does, it could be at a first glance rendered less competitive against the direct-injection turbocharged flexfuel 1.0L engine offerings from Chevrolet, Volkswagen and Hyundai and unlikely to set a foothold as the higher manufacturing cost of a downsized engine compared to a more traditional counterpart is not so easily amortized through a tax break, even though the Mercosur agreement gives Argentinian-made cars a different tax break in Brazil. It's also worth noticing similar models from other manufacturers which are available in Brazil in 1.0L naturally-aspirated or turbocharged and larger-displacement naturally-aspirated versions only go to Argentina with the biggest engine for the very same reason, as such more favorable taxation scheme is absent there.

While a naturally-aspirated trim of the EB2 could be more valued by Argentinian customers as long as the purchase cost remained lower and a manual transmission would be retained, and some turbocharged variants would be more appreciated in Brazil due to the technology and "sportiness" appeal with a good marketing perspective for the availability of both manual and automatic transmission options, retaining the EC5 and automatic-only becomes an objectionable one-size-fits-all approach. The total absence of turbodiesel options, which could at a first moment sound quite predictable as it's not allowed for cars in Brazil and nowadays seems too expensive for a small car in Argentina, can also be counted as another mistake somehow. Overlooking all the complexity of South American car markets as a whole, ignoring specific aspects of each country in the region and how to better address such conditions, often leads to a poor decision-making which may have a troublesome reflex on the actual marketing perspectives for an otherwise good product, and right now it seems to be what happens to the 2nd-generation Peugeot 208 even though it's too soon to be sure about it failing or receiving a better-adjusted selection of engines.

Would a mild-hybrid version of the 1.3L Firefly engine make sense if Fiat ever brings the Strada back to Europe?

With the recent release of the 2nd generation of the Fiat Strada in Brazil and regional export markets across Latin America, and recent changes in European legislation favoring pick-up trucks, it may sound like a good opportunity to reintroduce this nameplate to Europe. Even though it doesn't feature any turbodiesel engine option anymore, relying on SOHC versions with 2 valves per cylinder of the 1.4L FIRE in basic and intermediate trims with both cabin styles while the Volcano available only with double cab resorts to the 1.3L Global Small Engine a.k.a. Firefly, this may not be so much of a problem. Due to economics of scale, I would expect only one of those engines to fin an eventual Euro-spec range of the new Strada, most likely the Firefly which is gradually replacing the FIRE, and the recent release of a mild-hybrid variant of the 1.0 GSE for subcompacts in Europe may be a sign of what Fiat could do in order to make the Strada available there once again.

Its more utilitarian nature and the aim to budget-conscious Latin American markets may justify the use of sequential port injection and 2 valves per cylinder, in a contrast with the DOHC layout with 4 valves per cylinder and direct injection already fitted to the mild-hybrid 1.0 and the turbocharged versions of either the 1.0 or the 1.3 engines already fitted to Euro-spec versions of other Fiat and Jeep vehicles, yet it could also justify in Europe. Besides leading to a good low-end torque which is more important for it than for a Fiat 500 for example, it's worth to notice port injection leads to a colder charge air intake which is beneficial under the operating conditions it will usually find among professional operators, and not require the expense of a particle filter which is now widespread on Euro-spec and US-spec vehicles with a spark-ignited direct-injection engine. The modularity which allowed the Firefly engines to cover the 1.0L displacement range with a 3-cylinder layout while the 1.3L ones resort to 4 cylinders also leads the process of developing a mild-hybrid trim for the largest one to be quite a straightforward deal, even if it keeps the simpler cylinder head design and injection pattern of the current Fiat Strada.

Ford and the switch to 3-cylinder gasoline engines for the EcoSport: why not a 3-cyl turbodiesel too?

Initially targetting to poor Latin American markets, the Ford EcoSport became a global model with its second generation, which after a facelift started a switch from the 4-cylinder layout to 3-cylinder on the majority of its 2-wheel drive versions, even though 4-wheel drive ones retain the 2.0L Duratec Direct 4-cyl engine. Among the newer engines, there are a turbocharged Ecoboost derivative of the 1.0L Fox and the naturally-aspirated 1.5L Dragon, this one also available as a flexfuel in Brazil. Quite surprisingly, with Diesel engines struggling to remain competitive along the challenges regarding the ever-tightening emission regulations, the 3-cylinder layout is seemingly overlooked by Ford as a viable measure to decrease the cost impact for buyers who look at a turbodiesel engine option as a matter of necessity instead of a luxury.

In a moment when Ford was one of the few automakers with an operation in India that did not stepped out of the Diesel field right after the Bharat Stage-VI norms became effective in April, despite the local market keeping only the Dragon for those who prefer a gasoline-powered engine being supposed to set the price gap more unfavirable to Diesel as the spark-ignited engine with port-injection requires fewer aftertreatment devices which have been blamed for most of the recent price increases on turbodiesels throughout all the markets where they are or at least used to be relevant for light-duty cars and SUVs. A simpler and presumably more affordable engine, even though it could turn out to not attract so much to a broader buying pattern as in the early days of the common-rail turbodiesels when the performance got closer to that of a naturally-aspirated gasser within a similar displacement class, seems likely to offset a cost disadvantage induced by the presence of so many exhaust filters and even one more injector which is quite expensive in an electronically-controlled engine compared to their old-school mechanically-governed counterparts. Considering the recent announcement of a joint-venture between Ford and Mahindra, which manufactures its own engines for many different vehicle classes including a newer 3-cylinder turbodiesel within the same 1.5L class of the current EcoBlue which is now the only 4-cyl engine available for the EcoSport in India, relying on an outsourcing at least for the local Indian market and regional exports would not be so pointless at all.

It's also worth notice the stricter deadline for motor vehicles to remain eligible for a registration in New Delhi and other Indian metropolitan areas, which is also biased toward the engine type with Diesel in a less favorable condition calling for their registration in these regions to expire in 10 years, while their gasoline-powered counterparts can go for 15 years. Even though the newer and stricter emission rules are putting both engine types on par when it comes to limits for the same parameters, this situation is uncertain to become a sign of change in order to grant a similar treatment for all vehicles regardless of fuel type, thus justifying even more the market opportunities for a simpler engine focusing on the core advantages of Diesels when it comes to reliability and fuel savings. So, while gassers already overcame the misconceptions about fewer cylinders rendering them somewhat "inferior", it's time to look at their Diesel counterparts in a similar way.

Could it have avoided GM too much trouble with China if it insisted on rear-wheel drive for small cars?

GM took a quite conservative approach in the '70s and '80s with the Chevette in the American domestic market, and throughout Latin America where in some markets it lasted until mid-'90s. Sure it seems too crude for modern standards, while its persistence in the rear-wheel drive layout when many contenders at the time had already switched to a front-wheel drive and transverse engine configuration might sound like an excessively outdated approach. On the other hand, looking at some present-day Chevrolet small cars and models which had been released in a meantime after the Chevette had been phased out, there is no way to disconsider how rear-wheel drive could have avoided GM a lot of trouble not only in some of its former traditional markets but also at its Chinese joint-venture operation where it gives too much for its local partner for a somewhat unfair return.

Even though it may seem foolish at first to consider the possibility of refraining from fitting a modern car such as the second-generation Chevrolet Onix with any layout other than front-wheel drive, there is at least one main reason why it would've been sensible to consider the rear-wheel drive at least for the Chinese market where the model was premiered worldwide. Unlike the other countries where the Onix is made, namely Brazil and Mexico, the Chinese operation is not fully owned by GM and is tied to the requirement of technology transfer for the state-owned SAIC Motor which is its local partner. Chinese communist dictatorship has a total disregard not only for human rights, but also to intellectual property of the foreign companies lured by its low labor cost akin to the old "coolie trade" system which served the role of a replacement for black slavery, and so its state-owned enterprises resort to the technologies transfered by traditional automakers in order to take over their presence on some overseas markets such as Latin America and Africa.

Considering the Chevrolet Onix still retain a center tunnel, which would clear the way for a propshaft in a hypothetical rear-wheel drive variant, that approach would eventually make sense somewhere else due to some advantages of this setup which are unfortunately overlooked nowadays, but it might seem even more stupid how GM ceded too much and received too little in exchange for its technology transfer. It's worth to consider the way SAIC's subsidiary Wuling benefitted from Chevrolet's traditional nameplate as a way to reach export markets with its microvans such as the Rongguang rebadged Chevrolet N300 in some Latin American markets where it often competed for market-share with products made by some fully-owned GM regional subsidiaries. Factors such as local economics of scale could have been more favorable to an adaptation of the rear-wheel drive layout into a modern front-wheel drive GM platform, allowing some parts commonality which would be able to save GM the expense of giving away modern powertrain technologies to the Chinese dictatorship for free and turn it into a fierce contender in many overseas markets where it now struggles to retain a foothold.

It's worth to notice the rear-wheel drive layout of most Wuling microvans, itself copied from Mitsubishi projects, is actually advantageous on the crowded Chinese large cities as it allows a tighter turn radius due to the absence of front-wheel drive half-shafts imposing a narrower limit to the maximum steering angles. Another aspect which may be relevant is the perception among the average Chinese customers that a 4-cylinder engine, even the much basic ones offered in the Wuling Rongguang, as if they remain inherently better than any 3-cylinder counterpart such as the 1.0L turbocharged which is currently fitted to the Chevrolet Onix. Even though GM was making some huge profit in China that seemed convenient to overlook some deficitary operations in traditional overseas markets such as Australia and Europe, or even India which now hosts only an export operation catering to some Latin American countries while SAIC took over an India-focused production and retail for its own MG brand, another critical matter in recent times has been a slower recovery of sales figures in China for the American joint-ventures than it has been for their Japanese and German counterparts and independent local automakers.

Even though the second-generation Chevrolet Onix was jointly developed by GM and SAIC, it actually had a large Chinese input during the development of its GEM (Global Emerging Markets) platform, so it could have eventually offered a good opportunity to look more seriously into rear-wheel drive instead of being so strict with the front-wheel drive layout. On the other hand, with front-wheel drive being so unnegotiable for other markets such as Brazil where a hatchback bodystyle had to be locally developed to ensure the Onix would remain a best-seller, the investment on modern platforms to be designed from scratch could seem harder to justify at first due to the disregard of an overwhelming majority of new car buyers for aspects such as safety features, but it's worth notice tough riding conditions in Brazil provide the chance to test the vehicles under a considerable amount of circumstances allowing to gather enough data to ensure reliability and balance it with an ease of maintenance much valuable not only among the local customers but also in regional export markets.

The way GM repurposed some front-wheel drive platforms in Latin America, creating models such as the Chevrolet Agile which used to be made in Argentina as a stop-gap during a moment of economical downturn, may actually highlight how foolish it was to privilege the Chinese joint-venture which may now be accountable for some of its misfortunes in other markets in a way harder than the expansion of Japanese automakers in the '70s. Giving too much away for a hostile dictatorship is somehow similar to feeding caviar to a herd of wild boars, as both are too disconsiderate for what they receive. So, probably giving the Chinese a similar treatment as what was done to Latin America would be fair to say the least, with minimum effort for maximum profits in a place with a somewhat strange business environment...

Is a ban on 2-stroke motorcycles an effective option to deal with air pollution?

There were times when a considerable amount of the basic utility motorcycles, such as the Yamaha RD 135, relied on 2-stroke engines due to their low manufacturing cost and perceived ease of maintenance. Even though the lack of a valvetrain and the lube method based on oil consumption along the fuel have led to the perception of an easier maintenance compared to some 4-stroke engines with a chain-driven overhead cam, prompting Honda to respond with the CG 125 with a gear-driven overhead-valve layout which stood better to longer-than-recommended intervals between oil changes. Unlike other third-world countries where 2-strokes remained widely accepted among a broader public in the small-displacement segments, the Honda CG 125 quickly became a market leader in Brazil where it was launched in '76.

While the 4-stroke layout would ultimately become more widely accepted from an utilitarian standpoint and become mainstream, truth be said much for influence of the Honda CG 125 and in recent years all the unlicensed copies from China, the 2-stroke still retained a foothold among users who perceived it as a somewhat sportier alternative for those who value a more spirited riding experience, be it in a basic model such as the Yamaha RD 135 or in a real beast like the RD 350 LC. Tightening emission laws are often pointed out to have pulled the plug on the 2-stroke engine option for conventional motorcycles, in times when carburettors were still the rule instead of an exception, and the nature of 2-strokes which rely on the overlap of the intake and exhaust flows for scavenging renders it even more difficult to deal with. Even with the fitment of expansion chambers on the exhaust pipe, an attempt to retain more of the intake charge for a complete combustion through pressure differences as a makeshift to compensate for the lack of exhaust valves, the porting overlap is even more critical than the valve overlap on 4-strokes.

What may be considered relevant when it comes to the emissions concern as a reason for the phaseout of 2-stroke motorcycles is the Piaggio Vespa PX 150 having been available brand-new until 2016 while being certified into the Euro-3 emission standards and still carburettor-fed, meanwhile electronic fuel injection was already mainstream among its 4-stroke contenders. Sure it would not be rocket-science to fit it with EFI too, either a direct-injection setup which would require a different cylinder head cast or a port-injection layout now used by KTM in some of its 2-stroke enduro motorcycles that are even Euro-4 compliant. Considering the Vespa, naturally a more restrictive porting in order to decrease the loss of unburnt air/fuel mixture through the port overlap was as relevant as the catalytic converter to achieve an emissions compliance, despite being clearly detuned compared to previous model-years not subjected to this very same level of environmental scrutiny.

While any explicit ban on 2-stroke motorcycles has not been enforced in Brazil, and I do hope it never happens, neighboring countries such as Colombia already have such measures in some cities, including Bogotá, sparking controversies not only among many people who used old and beaten-down Japanese motorcycles but also enthusiasts of classic models such as the Vespa who nowadays have a much more leisure-oriented profile in contrast to its utilitarian origins when the austerity of the immediate post-war years called for affordable transportation. Probably some random brain-dead leftie would claim a Vespa owner who could rely on any modern 4-stroke scooter should eventually become liable to extra taxation as some supposed compensation for a claimed environmental damage and eventually fund subsidies for a replacement of 2-stroke motorcycles with newer 4-stroke ones or eventually engine retrofits allowing older models to remain allowed on the streets, but it's an oversimplifying approach which ignores some technical aspects. Besides an eventual usage of synthetic lube oils which decrease noticeably that thick blue cloud often seen from the exhaust pipe of a 2-stroke ride, models not fitted with an automatic lube system through oil injection from a separate reservoir also work with vegetable-based lube oils which even blend more effectively with the ethanol added to the gasoline in so many countries nowadays for example, already leading to a noticeable decrease on particulate matter emissions due to an incomplete combustion of oil and spark plug fouling.

Even though it may seem quite obvious that a 2-stroke carburettor-fed Vespa would consume more fuel and have higher emissions than, lets's say, a Brazilian Honda Pop 110i, and looking at it from a merely economic standpoint the 4-stroke fuel-injected Honda would seem to be better for those who look for a simple and utilitarian approach, but it should be taken with a grain of salt when a so-called emissions enforcement becomes a threat to individual freedoms. Just like recently enacted stricter restrictions on Diesel vehicles in some European cities are technically objectionable somehow, comparable attempts toward spark-ignited 2-stroke engines in Latin America and Asia ignore other measures which could be more reasonable. So, even though it may seem quite simple, a ban on 2-stroke motorcycles is not really an effective option to deal with air pollution as it might seem at a first glance.

5 reasons why Volkswagen's attempts to get rid of naturally-aspirated engines haven't been so effective

At least since May 2003 I remember speculations about Volkswagen eventually getting rid of natural aspiration at its entire range, with some progress on that matter becoming more achievable in the United States and Canada 10 years later in 2013. It's been a while, and some models such as the 6th-generation Volkswagen Polo are now highlighted in some markets such as Europe and Brazil for its 1.0 TSI engine available, but it turned out to not replace some naturally-aspirated counterparts so effectively. It might seem quite easy to justify the comparatively higher cost of a turbocharged engine with direct injection in Brazil and Europe due to the displacement-biased taxation, also highlighting an easier cold start with the direct injection while using ethanol as the 1.0 TSI is offered in Brazil as a flexfuel, but even in these markets the naturally-aspirated 1.0 MSI remains available as a base engine while in Brazil and regional export markets the 1.6 MSI is available as a flexfuel in the local market while in other countries such as Mexico its gasoline-powered non-flexfuel trim is the only engine offered. At least 5 reasons can explain the failure to the all-turbo strategy.

1 - cost: even though in Brazil the Polo has a more prestigious approach than in Europe where it's seen as an entry-level model (disconsidering smaller vehicles which may not be suitable to serve as a family car), both markets are inviting to the 1.0 MSI, while in Brazil a recent increase in demand for automatic transmissions is also favoring the 1.6 MSI which is more affordable to manufacture than the 1.0 TSI. In some countries supplied by the Brazilian-made Polo, not even the hi-tech approach could favor the TSI, as the absence or non-applicability of displacement-biased taxations render it somehow cost-prohibitive compared to the 1.6 MSI;

2 - suitability to alternate fuels: while the direct injection may benefit the usage of ethanol, as it not only increases cold starting ability but also allows a higher compression ratio which otherwise could be troublesome while using gasoline, it becomes more expensive to convert to gaseous fuels. Even though LPG can be injected at the liquid phase through the stock fuel rail and injectors of the TSI engine when fitted with a suitable conversion kit, CNG requires either specifically-designed injectors which allow liquid-phase injection for gasoline and vapor-phase injection for natural gas replacing the stock ones or mounting the CNG injectors bridge at the intake manifold for port injection while a smaller volume of gasoline direct injection is still required in order to keep the stock injectors cooling and lube as they are directly exposed to the flame spread. When it comes to ethanol, the electric pre-heating of fuel became a standard for port-injection flexfuel cars in Brazil as a cold starting aid, somewhat analogue to what has already been done on Diesel engines which relied either on glowplugs located at the cylinder head or grid heaters at the intake manifold;

3 - maintenance: turbocharged engines are still perceived to be more sensitive to factors such as lube oil quality, even though using a lower-grade oil in a modern naturally-aspirated engine is not exactly a good idea too. And even though turbocharging technology also had to evolve at a high pace due to the prevalence of start-stop on newer cars in order to address tighter fuel-economy regulations in Europe and Japan also leading to more demanding conditions for the lubrication system, the higher thermal loads to which a turbocharged engine is submitted are undeniable. A lower cost of replacement parts for the fuel system of a port-injection engine is also valued by budget-conscious buyers;

4 - turbo-lag: nowadays it's not so critical as it used to be when downsizing started to be more closely observed as a step toward a future that didn't materialise, but the turbo-lag is still often pointed out as a determining factor for turbocharging to not become so widespread on entry-level compact cars. On the other hand, models above the Polo and its derivatives now feature only turbocharged engines which may be smaller in displacement than the 1.6 MSI such as the 1.4 TSI yet the low-end performance is not so bad even though it still takes longer to reach full boost in Mexico City than in Cancún due to the lower atmospheric pressure inherent to a higher altitude;

5 - a conservative public: in the markets where Volkswagen failed to promote downsizing throughout its entire range, the acceptance of turbocharged engines remaining more concentrated around models and versions within classes above the Polo, which renders it easier to find out the appeal of natural aspiration for conservative buyers who look at Volkswagen for an all-around commuter instead of some sportier model which would be supposed to require a more specialized maintenance.