Here’s the next chapter about our Vantage Turbo project. Today, I’ll tell you about the approach we will be taking with the engine itself.
The power level we are aiming for requires the engine to be rebuilt with parts that can withstand more mechanical strength than in stock condition. OEM manufacturers make their engines not only for horsepower, but also for durability, sustainability, fuel economy (yes even on cars like Aston Martin), weight and most of all: production costs.
The Aston V8 engine is no exception to these rules. A lot of the components in the engine are made with low production costs and with low weight, so these engines are not very capable of withstanding the abuse that two turbos can give them. The power of the engine might be stretched another 20% but making the engine produce twice the power as stock (which is our aim), will require us to rebuild the engine with aftermarket components.
Normally, we would remove the engine from the car and perform the rebuild. However, that would leave this beautiful Aston waiting engineless for a few months. We’d rather have fun with it in the meantime.
The solution: use an extra engine!
If we can do the rebuild on an replacement engine, we can still use the car while the rebuild takes place. So we started looking for a spare V8 4.3 engine. However, one day we ran into a seller having a spare 4.7 engine. We decided to go with the 4.7 engine as it is newer than the 4.3 engine and is already a little bit more powerful as it has 2mm bigger bore and 5mm bigger stroke.
While working on the engine at a steady but easy pace, we can have the car in the shop determining things like turbo placement, intercooler core dimensions and other things keeping the car drivable because the engine stays in the car.
When the new engine is finished, we can call the car back in the shop, swap over the engine and get the car on road again within a few weeks.
The extra engine: a 4.7 liter V8
Here are some pictures of the engine we bought:
The engine came complete with wiring harness, intake manifold and power steering pump. Items missing were the alternator, starter, exhaust headers and the ECU. We will adopt those from the old engine
The engine did not look very healthy on the outside. We did not really care about this, as the engine was going to be rebuild anyways. To our surprise the engine was looking almost new and very fresh on the inside! Talk about never judge a book (engine?) by its cover!
The Aston Martin V8 engine has constant variable valve timing on the intake camshaft. This will produce better torque throughout the whole RPM range, as the engine management system will put the valve opening and closing timing as optimised as possible for any certain RPM and throttle position.