For a company that has made a name for itself with progression through gentle evolution, Volkswagen's use of a five valve-per-cylinder turbocharged petrol engine as the bread-and-butter powertrain in its volume models was radical for the mid-1990s.
The engine was actually designed by VAG's premium Audi brand, and the 20V tag was a highly evocative reference to the mighty Ur-Quattro – although achieved by an entirely different cylinder count and valve setup.
A four-cylinder engine with three inlet and two exhaust valves driven off two camshafts, the VAG 1.8 20V turbo first appeared in 150PS form in the Audi A6 then VW Passat B5 and Audi A4, with the ultimate factory version being the 240PS unit that powered the Mk1 Audi TT quattro Sport – but it appeared under the bonnet of no fewer than 16 Volkswagen Group cars, including some that you may have forgotten all about.
Note: There was a 170PS version of this engine produced for the US and some other markets, but this article will focus on the 'European' engine range.
Power (PS): 150, 156, 163, 170, 180, 190, 210, 225, 240
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The Mk4 version of the Polo supermini saw the reintroduction of a GTI model, and this time VW was serious and enthusiasts got excited about a car that could be the spiritual successor to the Mk1 Golf GTI.
It wasn't – soggy handling saw to that – but it had the looks, and it had turbo power in the shape of the 150PS version of the 1.8 20V engine.
To battle more powerful rivals, VW introduced a GTI Cup Edition, which had the 180PS version of the same engine and several sporty add-ons… but no better handling.
Power (PS): 150, 180
Top model: Polo GTI Cup Edition
The Mk4 Golf was a mainstay of British roads and its heartbeat in the pre-TFSI days was the 1.8 20V. The 150PS turbo version was slotted in to create what enthusiasts reckon was the most disappointing Golf GTI in history, but the tuneability of that engine meant modified versions could be the best sleepers in GTI history.
VW even had a go themselves, slotting the Audi TT's 180PS 1.8T into the body-kitted 25th Anniversary edition, finally creating the GTI that we deserved.
Power (PS): 150, 180
Top model: Golf GTI 25th Anniversary
With a name taken from a Maserati, you'd expect the Bora to have an exotic engine, layout and shape. But instead it was a Golf-based saloon with the boggo 125PS 1.8 20V as its bread-and-butter powertrain.
One of the more curious VW decisions with the Bora was to give it the characterful but inefficient V5 engine toting 170PS, but simultaneously offer it with the relatively economical 180PS turbo 1.8 20V turbo AT A LOWER PRICE. Huh? However that car is now a bona fide performance saloon bargain.
Power (PS): 150, 180
Top model: Bora ST 1.8T
Volkswagen's drive towards becoming renowned for efficiency as well as reliability was initiated by the downsized 1.8 20V's debut appearance in the big Bauhaus-n-Beetle-inspired Passat B5.
Although it didn't power a performance version of the family saloon, the engine's easy power and efficiency was integral to this model of Passat crashing the Ford Mondeo and Vauxhall Vectra's mainstream company car party with a premium twist.
Power: 150, 163, 180
Top model: Passat 1.8T Sport (B5.5)
Love it or absolutely loathe it, the New Beetle was certainly a talking point with its cartoonish looks, dash-mounted vase and reliable Golf underpinnings, and it came loaded with some hilariously powerful engines – but only the 150 and 180PS versions of the 1.8 20V turbo.
The more powerful version found its way under the bonnet of the US-only Beetle Turbo S, which is a load of fun in a silly kind of way.
Power: 150, 170
Top model: Beetle Turbo S
One of the most exciting proponents of the 20V turbo VAG engine was the Seat Ibiza. When VW Group decided upon a rally programme for the 6K2 version of the Spanish supermini, sporty road models were required - step in the 1.8T, whose 156 and 180PS versions were enough to turn the Polo-based hatch into a seriously fast hot hatch in Cupra and Cupra R forms.
The replacement 6L Ibiza used slightly updated 1.8Ts (but with no more power - less, in the case of the 150PS version) for its FR and Cupra editions, but were softer to drive. The 6K2 is more fun - and you have as much fun in the lower-powered Cupra as its R brother for less layout.
Power (PS): 150, 156, 180
Top model: Ibiza Cupra (6K2)
The Seat Cordoba was an Ibiza with a boot designed for markets where superminis must be three-box designs, and it gained a reputation for slow sales and elderly drivers in European markets.
However, Seat still made a Cupra version and it had the Seat-only 156PS version of the 1.8 turbo, and its tuneability gives the unloved Cordoba tremendous sleeper ability – if you can find one.
Power (PS): 156
Top Model: Cordoba Cupra
Seat's Walter da Silva-designed Golf-botherer was designed to be sportier than its reserved and refined German cousin, and became Volkswagen Group's budget hot hatch in 20VT form, which was a hugely fun 180PS propelled car.
This wend on to spawn the 210PS Cupra and 225PS Cupra R models, the latter featuring the top-whack Audi TT quattro engine, but struggled to put that power through the front wheels.
Power (PS): 180, 210, 225
Top Model: Leon 20VT
Hard to believe, but Seat's utterly bland booted version of the Leon, the Toledo, also utilised not the 150PS 1.8 turbo but the 180PS one. It didn't help it gain a personality though, but if you can find one on the second hand market
Power (PS): 180
Top model: Really?
By the time the 1.8 20V turbo was 13 years old, it was slotted into Seat's unashamedly rebadged B7-era Audi A4 – and it was past its best.
The 150PS-toting version of the engine has been cleaned up to just about scrape through the latest EC emissions regulations, but it had been comprehensively usurped in Volkswagen Group's engine line-up by the new era of TFSi powertrains and only had a couple of years in it before it was retired.
Power (PS): 150
Top model: Exeo Sport
The hugely likeable Skoda Octavia became a serious proposition amongst enthusiasts for two reasons: firstly, the inclusion of the 1.8 20V turbo in its line-up, but mostly because of the brilliant VRS performance model powered by the 180PS engine.
Added sporting pedigree came via a WRC campaign, but the secret gem in the line-up is actually the lower-spec Octavia 4x4 which is a highly tuneable Audi quattro wolf in sheep's clothing and probably our favourite car here.
Power (PS): 150, 180
Top model: Octavia 20V Turbo 4x4 Estate
The first generation of the Skoda's Passat B5-based executive express was an underrated car but an absolutely giant one in the family saloon class, and the 150PS 20V turbo (and even its 163PS replacement) had its work cut out shifting that bulk and a decent lick. Still, outright pace is not what this big smoothie was about.
Power (PS): 150, 163
Top model: Superb 1.8T Elegance
Audi's premium remix of the Golf has been a huge sales success, and the whole A3 line-up featured 1.8 20V turbos is varying states of tune.
The unsung hero is the 1.8T quattro, which looked much like a base model on the outside but packed the 180PS engine and 4x4 hardware – but the one you really want is the S3, which contained the Audi TT's unit, first in 210PS and then 225PS form, and is already well on the way to icon status.
Power (PS): 150, 180, 210, 225
Top model: S3 (225)
For some, the Audi TT is the true home of the 1.8 20V turbo. Every state of tune of the venerable 20V turbo was available in the TT, but it was the only car in Volkswagen Group to get the most powerful version of the engine.
The 240PS (yes, that's 133PS per litre!) TT quattro Sport (also known as the TT Club Sport) was a limited edition monster that could hit 0-62 in under six seconds and was the final hurrah for a car that helped propel Audi to the stratosphere.
Power (PS): 150, 180, 190, 225, 240
Top model: TT quattro Sport
Audi's volume saloon utilised the 1.8 20V turbo's flexibility to ensure the Ingolstadt company carved a chunk out of the BMW 3 series' domination of this sector.
While the S4 was wooing the enthusiasts with its biturbo V6, the smart cookies knew that the A4 quattro Sport was the one to have, with great performance from its 190PS engine plus the security of four-wheel-drive – and loads of space if you opted for the Avant estate.
Power (PS): 150, 163, 180, 190
Top model: A4 quattro Sport Avant (B5)
The first Audi to wear the A6 badge, the C4 model, only used the non-turbo version of the 1.8 20V, but the C4's fabulous C5 successor added the turbo versions.
This was a brave move from Audi – most executive saloons required six-cylinder power to be taken seriously, but the 20V turbo's combination of power and economy won over buyers, and the A6's Bauhaus-influenced style did the rest.
Power (PS): 150
Top model: A6 1.8T quattro