What to do with a car over 25 years old?#

At the beginning#

I bought this car — my first car, a Golf MK3 GTI — back in 1996, and I have had a special affection for it ever since. It has taken me on countless trips and given me more than a few unforgettable moments, but now it was time to decide what to do with it. Thinking about it, there were two simple options:

1. Retire it with full honors, in recognition of its years of service.
2. Restore it to showroom condition once again.

The decision came to me during a trip with my daughter to the Pyrenees in Lleida, in August 2021: I would restore it, but with a twist. Leaving it as it was simply was not an option — that would have felt like watching a good friend slowly fade away.

In standard trim, the Golf MK3 GTI makes just 115hp — a reasonable figure for its time, but I have always felt the car was underpowered; in fact, it is one of the most common criticisms levelled at it.

More than once, the idea of swapping the engine for something with a lot more power had crossed my mind — so why not a Golf MK5 GTI (BWA) TFSI engine with 200hp? Those TFSI engines tune very easily: more power, a reprogrammed ECU, bigger injectors and turbo, or all manner of upgraded parts — the sky really is the limit. But let us not get carried away; the goal here is to swap in the original 200hp BWA engine, keeping the car road legal in Spain.

None of this is fast or cheap — buying a second-hand Golf MK5 GTI outright would be far cheaper. As for time, I am already more than 18 months in and still not finished, but I am having a great time doing it.

What is the plan?#

The plan itself is simple: swap the engine and get the car road legal so it can drive on Spanish roads again.

Going into a bit more detail, that means:

1. Swap the existing engine for a 200hp Golf MK5 GTI (BWA) unit.
2. Swap the existing gearbox for a 6-speed 02Q manual.
3. Upgrade the front and rear brakes, suspension and axles.
4. Carry out a complete body restoration, including a full respray.
5. Restore the interior of the car — dashboard and seats.

All of this follows one basic premise: the car has to look as original as possible from the outside, so no body kits or styling modifications.

The first and most important step when starting a project like this is finding a good specialised car engineer who can certify that every change made to the car is road legal, along with a workshop capable of doing the job.

From the beginning, I was lucky to have:

• Sergi Lopez (RH+ Homologaciones), an engineer specialised in car certifications, who quickly and clearly explained the rules of the game for making all these changes road legal. Sergi is also handling all the paperwork required to get everything approved.
• Marc Perramon (Tallers Marc), a mechanic crazy enough to get into this mess, with a lot of experience in mechanics in general and in building custom trikers.

Rules of the game for an engine swap in Spain#

First and foremost, this is neither an exhaustive nor an exact list — the regulations are complex and can change. That is why, as I mentioned before, it is essential to have a specialized car engineer to guide you throughout the entire project.

With that said, here are the basic rules for certifying an engine swap in Spain:

1. The intake and exhaust lines must be those of the donor vehicle.
2. Front and rear brakes (disc diameter and number of caliper pistons) must be at least the same as those of the donor vehicle.
3. The maximum power of the engine installed in the receiving vehicle cannot exceed the maximum power approved for that chassis by more than 30%. In my case, the highest-powered engine approved for a Golf MK3 is the 174hp VR6, so the donor engine is capped at 226hp. This rule basically leaves me with only one choice among the Golf MK5 GTI engines: the 200hp BWA.
4. The engine’s mounting points to the chassis must be those of the receiving vehicle. Furthermore, no changes (bending, drilling, welding, etc.) can be made to the chassis of the receiving vehicle. For example, the donor vehicle’s exhaust line must attach to the exhaust mounting points of the receiving vehicle.
5. No less important are the per-axle weights. These should not change, although there is a certain tolerance — around 5% maximum, as far as I know.

In my case, I settled on the following:

1. 2.0L TFSI BWA 200hp engine from a Golf MK5 GTI
2. 6-speed 02Q manual gearbox from a Golf MK5 GTI.
3. 334x32mm front discs (from a Golf MK4 R32) with 6-piston calipers
4. 310x22mm rear discs with the rear calipers of a Golf MK4 R32.

All of these choices comply with the basic rules listed above. You are surely wondering how the engine of a Golf MK5 gets fixed to the chassis of a Golf MK3 without modifying it. The quick answer is Fabless Manufacturing, but do not worry, I will go into detail on that later.