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The official IMP Engine Thread [V12]

Hello there everybody, this is the unofficial official page for engines I have designed for usage in my main car company, IMP ( just don’t ask what that stands for :wink:). I have built quite a lot of engines since the latest major update, so I will only gradually add a few select “worthy” engines to this thread, and maybe give a little story on my inspirations and intended purposes for said engine.

IMP engines (pre 1981, includes small-displacement diesel engines):

K41: 1946-1955, Inline 4, 1.0-1.4L, 72x85,7mm, “SV” 8V, 28-43hp

BT6-A: 1951-1982, Inline 6, 3.8L, 94,8x96,9mm, OHV 12V, 120-155hp

BT12-A: 1951-1982, V12, 6.6-7.6L, 94,8x96,9mm, OHV 24V, 185-250hp (Trucks only)

A-series : 1952-1972, Inline 6, 2.8-3.8L, 91x96,9mm, OHC 12V, 137-216hp

B-series: 1955-1961, Inline 4, 1.3-1.8L, 81,5x87mm, OHV 8V, 50-78hp

C-series: 1958-1970, Inline 6, 2.0-2.7L, 81,5x87mm, OHV 12V, 78-147hp

D-series: 1961-1974, Inline 4, 1.5-2,1L 90x82mm, SOHC 8V, 75-165hp

E-series: 1965-1976, Inline 4, 1.0-1.4L, 80x74mm, SOHC 8V, 55-115hp

F-series: 1966-1973, Inline 6, 3.1L, 90x82mm, SOHC 12V, 178hp

G-series: 1966-1988, V8, 3.6-4.5L, 96x86mm, DOHC 16V, 197-285hp

H-series: 1970-1987, Inline 6, 2.4-3.0L, 86,5x85mm, SOHC 12V, 124-200hp

I-series: 1972-1973, Inline 6, 3.0L, 86,5x85mm, DOHC 24V, 193-258hp (experimental High-Performance engine)

J-series: 1974-1983, Inline 4, 1.6-2.0L, 86,5x85mm, SOHC 8V, 75-145hp

BT6-HK: 1977-1988, Inline 6, 5.0-5.2L, 103x104mm, SOHC 12V, 166-240hp (Monolith only)

K-series: 1976-1983, Inline 4, 1.4L, 75x75mm, SOHC 8V, 75-85hp

4-stroke diesel:
406DC: 1963-1985, Inline 6, 2.3-2.7L, 81,5x87,5mm, OHV 12V, 63-79hp, Pre-chamber Injection

406DM: 1967-1988, Inline 6, 4.1-4.8L, 99,9x111,1mm, OHV 12V, 108-140hp, Pre-chamber Injection (Monolith only)

IMP passenger car engines (post 1981): [TO BE ADDED GRADUALLY]

Inline 3 (designated with “U”)

Inline 4 (<1.5L, designated with “E”)

Inline 4 (1.5-2.3L, designated with “Z”)

Inline 4 (>2.3L, designated with “F”)

Inline 5 (designated with “P”)

Inline 6 (<2.5L, designated with “K”)

Inline 6 (2.5-3.6l, designated with “J”)

Inline 6 (>3.6L, designated with “H”)

V6 (designated with “Q”)

V8 (<5.4L, designated with “R”)

V8 (>5.4L, designated with “V”)

V8 Flatplane (designated with “N”)

V10 (designated with “M”)

V12 (designated with “G”)

Boxer (designated with “B”)


Starting off my long and glorious line of fictional engines that are utter rubbish compared to anything done by actual engineers is Genesis. No not the band, my first post-war engine design, the very creatively named A-series family of engines (totally unrelated to the engine found in numerous english cars of the era). Some of my engine designs have fairly weird origin stories, and this is one of them.

But first of all, a bit about the engine itself. My A-series is a family of inline 6 engines first introduced in 1951, all with identical capacity of 3781 cubic centimeters, with a bore and stroke of 91x96.9mm. I actually built three variations of the basic block. The first one of which is a 12 valve DOHC high output engine (pictured above) that essentially serves as a development prototype to test out the limitations of the engines bottom end and to spark public interest in the upcoming models of my company. As such it produced 202hp@5100rpm and 334Nm@3000rpm with a fairly mellow cam profile, but a twin 2bbl carburetor setup and 9.0:1 compression ratio running on 98 octane fuel. Unfortunately all that fancy high performance engineering is not at all suited to early 1950s europe, so many changes had to be made for the production versions, which debuted in 1952 and would go on to serve in light and medium duty trucks as well as luxury cars until the mid 1960s. The first production version, designed for commercial applications, exchanged the complex and expensive DOHC cylinder head for a state of the art OHV design and made use of a single carburetor. In order to run on regular fuel, the compression ratio was lowered to 7.0:1, however the bottom end remained unchanged. In this form, the engine produced a much less eye-watering 134hp@3900rpm but a healthy 277Nm of torque at just 1900rpm.

The second production variant entered production in 1953 and was destined to serve in up-market luxury cars and perhaps even a sports car here and there. Like the truck variant, the cylinder head was simplified to achieve greater reliability and lower cost, however it featured an OHC design with parallel valves for more pöwer. This version made a fairly impressive for the time 165hp@4700rpm and 293Nm@2400rpm with a compression ratio of 8.5:1.

Both these engines would go on to develop a reputation for their strength and reliability and remained largely unchanged for most of their 15-year production run, save for a minor revision in 1956 to improve their fuel economy.
Now, on to the origins of this particular engine family, which is the slightly more interesting story in my opinion, it is even kinda sorta interwoven with a number of other engines that I have designed in the 1980s and 1990s (I didn’t). At the beginning, there was a 16-year old me drawing a large 1980s sedan vaguely inspired by the Audi 100 C3. When trying to think of a suitable engine, I for some reason thought of the legendary Buick 3800 V6, particularly the supercharged 3800 Series II with its relatively low power but high torque, so I decided on imagining something similar. I generally prefer inline six engines massively over V6s, though 90° V6s are totally cool in my book, so I went with an inline design. I also gave my abomination a SOHC 12 valve design rather than GMs familiar pushrod engines, because I can. And unlike the Smallblock-derived GM V6 with its oversquare bore/stroke ratio I chose undersquare dimensions and a capacity of 3781cc, because I really like that number for some reason. The final addition was a nice and very 1980s turbo that boosted the imaginary power to 245hp and 450Nm of torque. Eventually I bought myself the full version of Automation and decided to flesh this particular engine out, designing modernized versions with multi-valve heads, even bigger turbos and a lot more power, as well as non-turbo versions and predecessor engines. This is also the reason why my library of engines has conspicuously many inline six engines with roughly the same capacity during the 1980s and 1990s. I have the tendency to become attached to certain of my engine designs, and the 3.8 I6 is definetely one of them.
Good Night.


This week/month/whatever: The 1996 RA engine family.
This is a family of high revving, high output naturally aspirated V8 engines with relatively small displacement designed for high performance applications. It is an all aluminium engine, of which there are two variants available, a 3.5L that features a fairly obvious DOHC cylinder head with four valves per cylinder for a total of 32 valves and develops 326hp@7500rpm and 357Nm@4900rpm, as well as a 3.8L which is generally more aggressive than it’s smaller brother that develops 354hp@7200rpm and 388Nm@5000rpm. Both engines have a redline of 8000rpm. The 3.5L has mildly oversquare cylinder dimensions, with a Bore/Stroke of 84x78.9mm giving a total displacement of 3498cc, while the 3.8 gets its additional 300cc from increasing the stroke to 85.7mm, giving it a slightly undersquare Bore/Stroke-Ratio. To ensure that the bottom end can handle the high rpms this engine has to cope with, the crankshaft and connecting rods of the 3.5 are made from forged steel while the pistons are made from forged aluminium. Due to the increased piston speed the 3.8 features even more expensive titanium connecting rods. Yeah by the way when designing the engine my engineers were instructed to not care about cost at all. Fuel is delivered via a sequential multi-point EFI system with twin throttle bodies for the 3.5 and ITBs for the 3.8. Both engines have a compression ratio of 10.5:1 and run happily on 95RON premium fuel, which is pretty much the standard in europe these days. Over the course of the years the RA series only saw one major revision in 2004, which saw the addition of VVT to both variants as well as ITBs for the 3.5L. Power of the 3.5 rose to 358hp@8500rpm and 364Nm@5000rpm, while the 3.8 is nearing the magical 400hp mark with 393hp@8500rpm and 405Nm@5200rpm. Thanks to the addtion of VVT the fuel economy has been improved as well. The year 2008 finally saw the introduction of the extensively reengineered RA-2, which led to the discontinuation of the RA-38, however the RA-35 got yet another small update with the Direct Injection system from the new RA-2 and an increase in compression to 11.4:1. Horsepower of this variant has been slightly reduced to 355hp@8300rpm, while torque has improved to 382Nm@4900rpm. This variant continues to be in production alongside the new engine, slotting in just below the RA-235.

I’ve decided to make some substantial changes to the engine thread, instead of just posting a random engine every now and then, I’ll try to provide a full list of all IMP engines together with download links for them. For now only the pre 1981 engines will be featured, as the changes I’ve made to post 1981 engine nomenclatures make organizing them more difficult.

Does anyone even care about engine threads that don’t involve EXTREMEs?

Anyway I felt it was time for the very first dedicated IMP passenger car engine, designed way back in 1937 for use in luxury cars. This is the “Personenwagenmotor x Zylinder Luxus” family, in short PxL.
The 1930s saw the extensive growth of the german Autobahn network, and with it came the need for manufacturers to make their cars capable of sustaining high speeds over extended periods of time. This mostly resulted in Art Déco streamlined shapes for otherwise regular cars. Since IMPs first venture into making cars was such a huge failure, they decided to do the exact same thing again a decade later, because surely a people’s car would have never been a success. IMP planned a range of luxurious sedans using the most advanced technologies available at the time and capable of not only reaching, but sustaining speeds of over 110mph all day long. At first, a compact V8 engine was designed that should kick the Mercedes-Benz 540Ks ass without the need for a supercharger. In order to get the performance required, a bunch of racing engines were studied and eventually the engineers decided on an engine block cast from Elektron and a cast iron, cross-flow cylinder head with a bevel driven single overhead camshaft actuating two intake valves and one exhaust valve with a 22° separation angle between the intake and exhaust valves, thus also creating a nearly hemispherical combustion chamber resulting in excellent engine breathing at high rpm. The forged crankshaft had five main bearings and the bore x stroke ratio of the engine was square at 88,8x88,8mm, resulting in a total displacement of 4400cc. Power delivery was through three Solex downdraft carburetors and it featured dry-sump lubrication. In 2004 one of them was dynoed by IMP on the original settings based off surviving documents and produced a still admirable 185hp @ 4600rpm and 339Nm @ 2300rpm. This engine was installed in the 1937-1940 IMP L8. 203 units of this engine were built, but only twelve are known to survive, five of them being in posession of the IMP Technologie Konservatorium, with three being in working condition.

The next engine dedicated to the flagship limousine was a V12 that was basically identical to the V8 apart from the added cylinders and a fourth carburetor. It had a lot of power to say the least. This engine was installed in the 1937-1940 IMP L12. It is estimated that 45 of them were built, but none are known to survive, thus the specifications seen here are estimates based on the figures of surviving P8L engines.

In 1939 IMP thought it was a great idea to make a cheaper entry level car using a less powerful version of the PxL engine. What they did was take one half of the P12L block, recast it in cheap, but heavy iron and simplify the valvetrain. The three-valve arrangement was replaced by two parallel valves directly actuated by the now gear-driven camshaft. The dry-sump lubrication system made way for conventional wet-sump lubrication. Other changes include a four bearing crankshaft instead of seven on the P12L and a more restrictive exhaust manifold. The engine was intended to be installed in the unrealised 1940 IMP L6 and produced in higher numbers as its more complex sister engines but the outbreak of WW2 halted those plans. Production continued until 1942 for military usage but the still rather high production and maintenance cost meant the engine was phased out to make space for truck engine production. Over 1500 are estimated to have been built, but yet again it is not known how many survive. Many of the P6L design features were however later salvaged and made their way into the 1952 IMP A-Type engines and therefore indirectly became the foundation for a lot of IMPs post-war successes.


This is a setup post for the first proper IMP UE4 reveal. The IMP KK-Series is the first of the new generation IMP gasoline engines, designed to meet upcoming, even stricter emission standards. It is the exclusive gasoline powerplant of the 2018 Impakt range.

The KK-Series is a small-displacement Inline 6 engine, with a Magnesium engine block and Aluminium-Silicium cylinder head, 76.5x81.5mm bore and stroke and a bore spacing of 87mm. It features 5-valve per cylinder technology, GV2 VVT, IMP i6De III direct fuel injection with 450bar of injection pressure, a variable length intake manifold and fully forged bottom end with a 7 main roller-bearing crankshaft.

The KK-Series replaces the KE-series of small Inline 6 engines on which it is based. The core engine, with 2.25L of displacement remains largely unchanged, the pistons have been changed from forged aluminium to forged steel with graphite coating for lower friction and thermal expansion. The main differences lie in the accessories and the Exhaust system including the Turbocharger. On the KK, the Turbocharger is now a Borg-Warner Twin-Scroll VGT unit, which allowed us to eliminate the electronic Boost Controller. Furthermore the Catalytic converter has been moved directly after the Turbocharger, and all KKs are fitted with a Gasoline Particulate Filter (GPF). The Starter motor and Alternator have been replaced by an Integrated Starter-Generator (ISG) fed by 48V Electrics which can also aid the engine in stop-start traffic, making the Impakt a mild-hybrid. This reduces intra-urban fuel consumption by up to 26%. The 2018 Impakt 225e with 175hp now consumes less than 4.5L/100km. The KK is also the first production engine to meet the Euro 6c norm.

The KK-Series comes in four variants that only differ by engine management and Turbocharger, and in case of the GET also the Camshafts:

KK-22FQT: 175hp, 275Nm, engine redline 7000rpm
KK-22FET: 210hp, 320Nm, engine redline 7000rpm
KK-22LET: 270hp, 380Nm, enigne redline 7750rpm
KK-22GET: 324hp, 410Nm, engine redline 8750rpm

Expect the KK-Series to appear in more future IMP and Monolith vehicles.


How wildgerman is that, god damn


Now you know what the M in IMP stands for.

Inline Magnesium Power.

Insane Mormon Population?

The V12. Unattainable to most, it is unmatched in its smoothness and power delivery, therefore perfectly suited for tough, reliable and long-lived utility vehicles. At least we think so.

[This Article covers the GA line of gasoline V-12 engines and its Diesel derivative, the D12.80]

The first IMP V12 was the P12L of 1937, a 6.6L, 285hp monster, effectively a racing engine tamed for a limousine, only built 45 times. It was also the first and last time an IMP V12 appeared in something other than a body on frame truck.
The next V12 was a totally unrelated 6.4L OHV engine launched in 1953 for medium-duty trucks, later enlargened to 6.6L and eventually 7.1L. This engine was the BT12-A, based on IMPs then new A-Type straight six, which remained in production until the 1980s and also formed the basis for the first GA V12.

The original GA (retrospectively referred to as the GA-1), was a modernized BT12-A with a tall-deck engine block and better cylinder heads, but still a 2 Valve OHV Pushrod engine. With a longer 96.9mm Stroke (shared with the 3.8L A-Type Straight sixes) displacement was up to 7.6L. Nevertheless this engine, designed for the Monolith A-Series Truckand intended for heavy hauling purposes barely revved to 4000rpm and only produced 285hp, but made a staggering 631Nm of torque at just 1900rpm. It was far from lightweight at just under 400kg courtesy of the all cast iron construction. Later variants added electronic fuel injection and a catalytic converter, reluctant concessions to modernity from a design conceived before Germany won its first Football World Cup.

Ironically what was arguably the least sporting IMP petrol engine of them all ended up being by far and away the most successful in motorsports. This came about in 1986 when IMP entered the rallye Paris-Dakar with their Monolith M130 SUV fitted with a triple-carb GA-76R that produced 420hp and 700Nm
1987 saw these engines fitted with the Turbocharger from the S76.15-40 Truck (15L V10 Diesel engine with 410hp) that raised output to 530hp and 900+Nm.
The madness would continue in 1988 with bigger turbos from the S76.18-55 (18L V12 Diesel, 550hp), 670hp and 1200Nm, but the climax would come in 1989 with a displacement increase to 8.6L and more boost, resulting in 850hp and more than 1600Nm of torque.

The Turbocharged V12 was soon outlawed by motorsport governing bodies, but a more wholesome, street legal, fuel injected 7.6L Turbo with roughly the same output as the 1987 Competition engine made a comeback in 1991 for two special editions of the Artisan truck. The last GA-176EII was built in 1996.

The GA-1 is special for many reasons. It was the last surviving member of the A-Type family, which was known as one of the most versatile and long-lived designs IMP ever produced, with a 44 year production run, fitted to almost every type of vehicle short of a small front-wheel drive City car. The 1989 GA-186T also provided a fitting end to one of our most successful decades. Naturally it was the last truly simple engine we built, and while nowhere near as efficient as any newer engines, it remains highly regarded as the arguably most reliable gasoline engine IMP had ever built, which is no small feat. At 1.000.000km this engine is only barely broken in. GA’s have endured the harshest conditions a vehicle can endure, and they’ve come out victorious. GA’s can take unspeakable amounts of abuse, being redlined for hours on end, running without airfilters, fuels of wildly varying quality, driving underwater…
The GA-1 was not just installed in cars, it was in boats, forklifts, as a stationary generator, as a starter motor for far bigger engines and more, bringing total production in 14 years to 1.4 million units, making it the most successful V12 engine of all time, even more so when you include the older and very similar BT12-A, bringing total production of A-Type derived V12 engines to 2.5 milion.

1995 However saw the beginning of a new era that continues to this day. The GA-2.
The GA-2 was based on the modular M92 family that had started in 1982 and also included Inline 3, 4, 5, 6 cylinder engines in petrol and diesel as well as a V6 Diesel. The GA-2 was adapted from this V6, obviously with an elongated block. It was a cutting edge engine design, all aluminium with a 90° Cylinder bank angle and 48 valve DOHC cylinder heads straight off the then new HF-38 inline six, but with the variable valve timing removed for more durability.

It came in two displacements, 6.0L and 350hp and the classic. 7.6L displacement with 400hp and 690Nm.

The GA-2 was only available in the Artisan trucks and the Jupiter and M140 SUVs. Later versions of it reintroduced VVT and eventually peaked at 390hp and 480hp respectively. The GA-2 was succeeded by the very similar GA-4 in 2012. Main differences were the adaption of Direct Injection with twin intake plenums. The 6.0L was up to 470hp while the 7.6L produced 550-630hp. 48 valve GA V12s can be identified by their blue valve covers. The GA-2 and GA-4 are the main variants of this family and currently only available in the Artisan and Jupiter.
The GA-4 has since spawned to new variants of the same basic engine design.

The first of which is the 2016 GA-5 with 5 valves per cylinder. It has white valve covers and produces between 580 and 675hp. It is only available in the high-end Artisan L12 and the Jupiter 760S.

The second is the 2017 GA-3 and is an all-iron brick with four valve SOHC and (yes) VVL. Basically a multifuel engine with indefinite service life for special applications FORKLIFTS it still produces 470hp and 720Nm from 8.0L of displacement. It is distinguishable by its green valve covers.

So far the GA-2 based V12s have sold 500.000 units and counting.


A crazy engine for a crazy car. And yet, it’s hugely effective for more applications than I thought it would.