Tiny cars with huge engines are fun for obvious reasons, but for our readers that are not engineering-minded auto enthusiasts, let's talk about power-to-weight ratios. To calculate the power-to-weight ratio of any car is a simple equation. The weight of the vehicle divided by the horsepower of the vehicle gives you the power-to-weight ratio.
Based on statistics from Road and Track, let's calculate power-to-weight for a 2001 C5 Corvette Z06—a fast, lightweight car with great horsepower and torque numbers. For example, a 2001 Chevrolet Corvette Z06 has a weight of 3,115 pounds with 385 horsepower. This means the power-to-weight ratio is calculated by taking the weight of 3,115 lbs and dividing by the horsepower of 385 for a power-to-weight ratio of 8.09. Sounds good but let’s compare this to a more pedestrian vehicle: a 2018 Honda Accord Sport 2.0 Turbo with a manual transmission. The curb weight is 3,276 and the horsepower is 252hp which means the power-to-weight ratio is 13. This isn’t bad at all but the much sportier car with the better power-to-weight ratio is the 2001 Corvette.
Ok, I can hear the YouTube stars saying, "Hold on, what about the Tesla Model S, weighing in at 4941 and with 762hp? That equals a power-to-weight ratio of roughly 6.5!" Sure, the Tesla weighs more, but it has a ton more power to make up for its greater mass. Also one of the reasons why the Tesla is much faster than the rest of the pack is due to the lack of an internal combustion engine.
So let’s take a look into the simple way auto enthusiasts have made power by checking out 19 tiny cars modded with huge engines. Remember, the numbers are rough estimates and this is just for entertainment purposes. If you choose to do a motor swap, conduct the swap under the guidance of a knowledgeable professional with proper tools, a manual, and a calibrated scale for accurate results.
19 Mazda Miata (V8 Swap)
According to Road and Track, the Mazda Miata in bone stock form comes with an inline-four cylinder engine producing 155hp and 148lb-ft of torque. The curb weight for a manual model is approximately 2,592lbs, resulting in a power-to-weight ratio of 16.7. Now with GM's LS376/525 crate engine producing 525hp and the new weight tipping the scales at 2,660 lbs, the power-to-weight ratio is 5.1.
This is with normal aspiration, no nitrous, no turbo, and no supercharger.
The weight sits in the front but weight distribution is something to be discussed in the next article. There are many other V8 options from Ford even a Lexus V8 but of course the performance depends on the horsepower and weight of the Miata.
18 MG Midget (V8 Swap)
The MG Midget was a small and lightweight two-seater roadster with 65 horsepower. According to the MG owner’s club, an MG Midget weighs about 1,620 pounds—very light indeed, but with only 65 horses, the power-to-weight ratio is 25. The added weight of the engine plus the donor car and a counterweight is approximately 2,458 lbs, and producing the base of 331hp and result in a power-to-weight ratio of 7.4. This combination appears to be a beast, if one can control it. Wider tires and stiffer suspension hardware is a must to compensate for the heavier engine and brute power.
17 VW Beetle (EJ25 Swap)
The VW Beetle is a relatively light vehicle weighing in at 1,600 lbs and producing roughly 40 hp. According to Road and Track magazine, an EJ20 swap was done on a 60s model VW Beetle, with an EJ25 engine (the 2.5-liter, turbocharged flat-four from the Subaru WRX STI.)
The EJ25 produces 305 hp and combining this motor with the Beetle chassis, the power-to-weight ratio is approximately 5.2.
A bit more power can be extracted from the EJ20 motor by converting the motor to run on E85. E85 is mostly alcohol based and grain alcohol mixed with regular gasoline will boost the octane rating of any fuel. The major advantage is that E85 is much cheaper than race fuel.
16 Lotus Esprit (V8 Swap)
I won’t bore you with another hypothetical motor swap conversion with equations because this is not Pre-Algebra class. The Lotus Esprit is known to be super light and adding a General Motors LS3 crate engine, you have 430hp in a small and lightweight package according to Renegade Hybrids. The engine is mated with a Porsche transaxle—due to the Lotus having rear wheel drive and a mid-engine layout—that can handle the massive horsepower and torque numbers produced by the LS3. The LS3 is rumored to be only a couple hundred pounds more than the Lotus turbo inline four, originally rated at 210hp. With custom lines, the air conditioner from the LS3 can even be retained.
15 Porsche 996 (LS Swap)
The Porsche 996 came with either a 3.4 liter or a 3.6-liter flat-six engine, according to Car and Driver. The 996 has been known for an IMS failure, however, which is a critical component that connects the engine timing gear through a timing chain to the intermediate shaft. Once this breaks, it causes catastrophic engine failure where the pistons hit the valves. Tyler Hoover from Hoovie’s Garage (also known as the Grandfather of basket case automobiles) purchased a 911 and did an LS conversion. With prices hovering around $10k+ for a Porsche flat-six replacement, Tyler replaced the flat six with an LS motor with the total bill over $17k USD. The end results is a car that is less than 3,000 pounds at around 430 horsepower and no IMS issues to worry about, ever.
14 MK2 VW Golf (VR6 Swap)
The MK2 Golf is a cute lunchbox-shaped vehicle that is slightly chubby and not bad at all because everyone remembers that slightly chubby girl from high school that blossoms into a curvy beauty queen...anyways back to this MK2 VR6.
It weighs a bit more than some swaps out there but the VR6 gives the Golf the horsepower it needs to move its moderately heavy body.
According to VW Vortex, the VR6 puts out roughly 172 HP and 177 lb-ft of torque. The original MK2 Golf did not touch 170 hp with any of the stock four-cylinder engines, both turbocharged and naturally aspirated.
13 Datsun 240z (V8 Swap)
The Datsun Fairlady Z, also known as the Datsun 240z in the United States, was marketed and named after the 1956 Broadway play “My Fair Lady”. Nissan’s president loved the play so much that he named the two-door sports car after it, but Nissan realized that the name would not be popular in the U.S. so it was called the Nissan Z, according to Motor Authority. The inline six was robust but for serious power over the stock 161 hp, throw in a General Motors LT1 with 370 hp. Do I need to say more? I didn’t think so.
12 Lotus Elise (Honda turbo-four Swap)
The Lotus Elise is an aluminum-framed, fiberglass-bodied sports car built for the enthusiast that wants driver engagement with nothing else. With a stock horsepower output ranging from 118hp to 192hp depending on the engine, a different powerplant (especially with a large aftermarket following) can yield much better horsepower output. According to Monkey Wrench Racing, the 3.5 V6 Lotus Evora engine in this Elise will give one lucky owner 340 hp and 320 ft-lbs of torque. With the naturally aspirated 3.5 V6 found in the Evora, the power is more linear and a bit more predictable.
11 BMW E30 (V8 Swap)
The BWW E30 was built during a time where BMW focused more on the driving experience. The BMW E30 was an excellent handling car which feels like the driver has a tie rod in each hand and with a 2.5 liter inline six mated with a five-speed ZF or Getrag gearbox, you will feel like a racing hero except for the fact that the 2.5 straight-six needs more horsepower. According to Bimmer Forums, swapping a 4.4-liter V8 into the E30 will produce 342 hp with the correct generation of the 4.4 V8. (I didn’t mention the E30 M3 because the car has started to seriously appreciate.)
10 Mini Cooper (V8 Swap and other)
The Mini Cooper in this section is a newer model Mini Cooper. Mini Cooper is owned by BMW due to the purchase of the Rover Group from British Aerospace. BMW resurrected the Mini Cooper by keeping the vehicle small on the outside but large enough for adult passengers.
The range-topping Mini Cooper S produced 163 hp with a weight of 2,513 according to Car and Driver.
A man by the name of Curtis Mowery (also known as the “Fabman”) has shoehorned in a small block Chevrolet 350, however. The Mini has to be converted to rear wheel drive, and power is routed through a Toyota 4Runner rear-end and a TH300 automatic. An automatic transmission is great for drag racing and the driver never misses a gear.
9 Fiat 500 (V12 Swap)
A newer Fiat 500 is a great compact car with Italian history behind its name. According to Car and Driver, the Fiat 500 has a 1.4-liter four-cylinder producing a respectable 135hp. The Fiat Abarth produces 160 hp and 0-60 in 6.9 secs. I used the newer Fiat as an example because the 1970 model is much smaller and has less power than the offerings today. A father and son team put a 580 HP Lamborghini V12 engine into an original Fiat 500, however. According to Super Street, the duo cut and stretched the Fiat 500’s frame and shoehorned in the Lamborghini V12 into the rear. A shortened driveshaft and axles were fabricated and the Murcielago’s AWD system was utilized in this swap.
8 Porsche 944 (V8 Swap)
The Porsche 944 was not the traditional Porsche, due to its front engine design, but it was quicker than the 911 in straight line acceleration. According to Car and Driver, a 0-60 time was about 5.9 seconds which is no slouch. But the timing and balance shaft belts need to be changed every 3 years and or 45,000 years according to Grassroots Motorsports. An LS swap provides the driver with more power and better reliability. The 944 Turbo produced 247hp but after the swap, one can expect 300 + horsepower. Larger brakes are recommended along with an LS-spec clutch to handle the added horsepower.
7 Porsche Cayman (Coyote Swap)
The Porsche Cayman is a fast car with great handling and I would not change Porsche’s formula but when a Cayman’s 300 – 365 hp, turbocharged flat-four engine (or the 295 hp flat-six engine before it) bites the dust, then one could replace the motor with another of Stuttgart’s magic motors.
Either that, or there's always the Ford Coyote V8.
The end result is a lightweight Porsche with 424 hp to begin with, according to “The Drive.” The 5.0-liter Coyote engine even mates up with the stock Getrag 6 speed transmission. Now here is the catch, the large V8 sits in the rear hatch of the Cayman so you may need earplugs and if you are wondering about air conditioning then this car may not be for you.
6 Honda S2000 (V8 Swap)
The Honda S2000 was a fun and fast rocket from the factory and produced a peak 240hp at 7,800 RPM (with a redline of 8,000 and some earlier models even at 8900). The Honda S2000 gives the driver the feel of piloting a four-wheeled motorcycle. Engine Swap Depot found a 7.0 liter, LS7 powered S2000 mated to a T-56 six-speed transmission, all combined with a shot of nitrous. Handling was improved with coilovers and AP six piston 14-inch disc brakes. The LS7 produces 505 hp with 470 lb-ft of torque and this is without the nitrous. You may want a change of pants.
5 Chevrolet Cavalier (4 Cylinder Ecotec turbo and mid-engine swap)
The Chevrolet Cavalier 2.2-liter turbo produced 140 HP stock, while and the supercharged Ecotec could push 190+. Benjamin Wootson from BWC Fabrications took a 2.2 Ecotec and threw a Garrett T3 turbo into the mix and he even relocated the engine to the middle section of the vehicle.
This Cavalier’s suspension uses coilovers and the track has been widened.
The new power numbers are 405 hp with a 2,060-pound curb weight with otherwise stock internals and ECU. A relatively small engine producing big numbers, the impressive part is that this monster is street legal.
4 Ferrari F355 (F12 Swap)
The Ferrari F355 was an awesome looking exotic and can still be seen at country clubs around the world. According to Car and Driver, the F355 came stock with a 3.5-liter, 375-hp V8. Not bad but like Tim Allen would say, “We need more power….” An innovative German by the name of Tim Eckart swapped the 3.5-liter engine out of an F355 and replaced it with a 4.9-liter flat-twelve cylinder engine from the Ferrari 512TR. The end result is an F355 that produces 428 hp, according to Engine Swap Depot. The five-speed transmission was retained and this Ferrari remained pure to Ferrari enthusiasts.
3 Lotus Exige S1 (Ferrari F355 V8 Swap)
According to EVO UK, the Lotus Exige S1 produced 192hp from an 1800cc inline-four and only weighed 1,719 pounds. The Exige is basically a race car right off the showroom floor but an interesting swap found on Engine Swap Depot featured someone swapping in a 3.5-liter Ferrari V8—and not just any Ferrari V8 but a race-prepped engine with a six-stage dry sump system, flat-plane crank, and 5 valves per cylinder with titanium rods. The end result is 380hp. The builder designed a special 34-liter fuel tank made of aluminum. Building a custom and exotic racecar is never easy, but this one looks like fun.
2 Mazda RX7-FD (LS Swap)
The Mazda RX-7 was a revolutionary vehicle equipped with a 1.3-liter twin turbo Wankel rotary engine, according to Top Gear. The Wankel rotary is lightweight and has two spinning rotors instead of pistons, though it fails when the apex seals begin to leak and then it’s time for a rebuild or replace the motor. Gas mileage is poor and the common misconception about rotary engines is that they burn oil but they actually use nozzles to squirt oil into the fuel to lubricate the apex seals and also aid in cooling. Expect 255hp to 280hp with a twin turbo rotary. With an LS swap, on the other hand, expect anywhere from 345hp to 638hp, according to Sikky conversions.
1 Toyota MR2 (V6 Swap)
The Toyota MR2 name is short for Mid-engine, Rear drive, and 2 seats. According to Car and Driver, the second-gen MR2 was a mixture between an economy car and a sports car to get a mixture of both worlds. There is a conversion kit for all Toyota MR2s to accept the V6 from the Toyota Camry and the ES300. The Toyota MR2 weighs 2,599lbs and the stock turbo produces 200hp so the power-to-weight ratio is in the neighborhood of 13. With the V6 3.5 ES300, we can assume this motor adds about 150lbs to the total weight of 2,624lbs and produces 210 hp which results in the same power-to-weight ratio of 12.5. There is very little decrease in power-to-weight ratio but the vehicle is more reliable than the turbo engine without head gasket issues of the turbo four. Also, this swap can be done on a non-turbo model as well.