Swapping A V8 Into A Toyota MR2
Please note: This is the first in a series of articles on this subject. For many years, I have dreamed of owning a mid-engine exotic supercar. Unfortunately, they remained out of my reach financially. I decided that the only way I was going to get one was to build it myself. I have always been fascinated by mid-engine sports cars due to their superior handling, braking, and traction over a front engine sports car --even those front engine cars with a rear transaxle, that have a supposedly optimum 50/50 weight distribution. I like to call them the "dumbbell cars" because their weight distribution is just like a dumbbell--heavy at the ends, and light in the middle. This is decidedly suboptimal for acceleration, handling and braking. Compare this to a mid-engine cars, where if you were to make a dumbell resemble the mid-engine car, the weights would be slid to the center.
Now, if you want to make the dumbell, or the mid-engine car rotate about its vertical axis (called "yaw" in aircraft terminology), it will do so much easier and more quickly. This is because the tire traction does not have to overcome the inertia that a front engine/rear transaxle car would have over each end of the car. The result is that the car will be able to change directions faster, and with less tire wear. The peak G-forces will be much higher in a mid-engine car as well, meaning its faster around the corners. Rear wheel traction during acceleration is superior, since more weight is on the rear wheels. Strangely, there are a lot of "side-effect" advantages to mid-engine cars that the automotive press fail to mention. This means more power. The exhaust system will also be lighter since there is less of it. Dumbell cars have no advantage here.
The rear brakes do a LOT more of the stopping vs. When you hit the brakes, weight transfers to the front wheels. This means that the rear wheels become unloaded. On front engine cars, the front brakes do about 80% of the stopping. This is why disk brakes in the rear took a long time to catch on. They simply are not needed in the rear. A mid engine car has a LOT more of the weight (usually around 55 to 60%) on the rear wheels. When you hit the brakes, weight transfers to the front, so under braking, you might get 50%-60% on the front. Dumbell cars get some of the help that mid-engine car gets, but not nearly as much, because the engine is still in the front and is still far heavier than the trans at the back. Unfortunately, most mid engine cars are very expensive. Ferrari, Lamborghini, McLaren, Zonda, Koenigsegg, Bugatti, and so on. Some of these cars are above a million dollars! Mid-engine cars do tend to be more difficult to work on as well.
Changing sparks plugs on the exotics is a major operation. The McLaren F1 requires engine removal to change the plugs! In the realm of affordable mid-engine sports cars, there are Pontiac Fieros and there are Toyota MR2s. In each case, the cars came with 4 cylinder motors. The Fieros also got V6s, but those V6's were very underpowered, with a whopping 140hp. In 1990, Toyota redesigned the MR2 and upgraded the power as well. Base models got 130hp and the high-end Turbo was 200hp, which at the time, was quite a bit for a car that weighed 2700 lbs. The new body was very good looking, much like the Ferrari 348 at the time. The build quality was also superior as it was, after all, a Toyota. I decided to purchase a 1993 Toyota MR2 turbo in 2005 with the intention of doing a Toyota V6 swap, which up to that point, had been done by many people.
In late 2007, another V8 in a MR2 mark 1 (1st generation) was completed by a guy in Europe. The car was crazy fast, and would do cookies at the drop of a hat. So, I took another hard look at the prior attempts to install a V8 into the MR2 mark 2. What I realized was that they were attempting to "keep it in the family" and use a Toyota or Lexus V8. There wasn't really any valid engineering reason to use this power plant. It did not bolt up to any of the MR2 transaxles, and it was too long. The Toyota V8 used,(engine code 1UZ-FE) is about 26 inches long from the crank pulley to the rear face of the engine, or bell housing interface. This is the critical dimension. Compare this to the stock MR2 engines like the 2.0L 3S-GTE turbo motor which has a critical dimension of 20 inches.