I think we have all heard that one friend say, “Just engine swap it, bro” as if it is like taking Lego apart and putting it back together. You have probably also heard people say it is a straight fit and bolt-in. But let’s talk about the actual facts. What does it actually take to engine swap a car?
This idea popped into my mind because I seem to have hurt the small-end bearings on my MK3 Supra. With it running the 1G-GTE, it is not the most common engine to find parts for. So the question came, “Why not engine swap it?”
The Popular Options
If you are a fan of the MK3 Supra, you probably know two swaps are the most common:
- The 1JZ
- The 1UZ
Both have compelling arguments for going into an MK3. People say they are “bolt-in” swaps. But is that really true? Let’s break it down.
The 1JZ Swap
From 1990 to 1993, the MK3 Supra came with a 1JZ from the factory. So it should be simple, right? Well, sort of.
Knowing the car once had the motor tells you the original mounting points and engine bay size are fine. That ticks the “drop-in fit” box. But making it work is another matter. You will need to think about:
- Bellhousing adaptor
- Better clutch
- ECU
- Wiring
You might wonder why these are needed if the MK3 came with a 1JZ. The truth is that while you can use the same cooling system (as long as you keep the motor relatively stock), the gearbox is another story. In the 90s, the MK3 moved from the W58 to the R154 (found in MK4 Supras). The R154 handles more torque, but if you keep power under around 500hp, the W58 will be fine as long as you are not too hard on it. You will just need a bellhousing adaptor and an upgraded clutch.
The jump from the 1G-GTE’s 207hp to the 1JZ’s 276hp does not sound huge, but the torque increase will get you. Do the clutch now, or you will be back under the car after your second burnout.
Wiring and ECU
The trickiest part by far is wiring. In the States, companies like Wiring Specialties make this much easier, offering plug-and-play looms. The ECU is where costs rise. You could run a Dictator or Spitronics, but with a 1JZ, you are already investing a lot.
At the time of writing, the cheapest 1JZ-GTE I could find was R45,000 for an unknown import motor. If you are paying that much, you may as well spend more to ensure everything is sorted.
Supporting Mods
When doing a swap like this, think about:
- Brakes and suspension upgrades
- Diff type (open vs limited-slip)
An open diff will be a disappointment when trying to put power down.
The 1UZ Swap
After you have been kicked out of the JDM club, there is another option, the 1UZ. This is one of South Africa’s most common and cost-effective swaps. If you have heard someone say, “Yeah, that’s a Lexus swap”, they are talking about the 1UZ.
It is also as near as can be with slightly different engine mounts and a bolt-in swap, fitting the MK3 bay without issue. Like the 1JZ, it can use the stock W58 gearbox with an adaptor plate and upgraded clutch. It still needs an ECU and wiring, but you can get away with a cheaper management system like Spitronics.
Here is the kicker, you can often pick up a 1UZ for around R25k, sometimes with a gearbox and ECU included. The only real change needed is swapping the original clutch fan for an electric setup.
Why the 1UZ?
The UZ is arguably one of the most over-engineered Toyota engines ever made. It has a forged steel crankshaft, six-bolt main caps, and an aluminium block that actually weighs less than the stock 7M motor. It is also famously smooth. Top Gear once put a coin on an idling 1UZ and revved it without the coin falling over.
Performance-wise, the early non-VVTI 1UZ-FE can handle boost thanks to forged internals. At just 0.6 bar (8psi), you could see 400 to 500hp, which conveniently matches the W58’s upper limit.
The Real Cost
Here is where it gets real. The adaptor plate, clutch, ECU and other parts will cost around R30k, possibly more than the engine itself. Add the price of turbos, intercoolers and other upgrades, and things add up fast.
Final Thoughts
So next time someone says, “Just swap it”, think about the bigger picture before you pull the trigger.
Even as I write this, I am having an internal argument about the 1UZ swap. If parts for the 1G-GTE become truly unobtainable, I might start counting pennies and head to the local scrapyard to hunt for a 1UZ. Or maybe, if the YouTube channel takes off, a sponsor could foot the bill.
For now, the budget Supra will stay budget for a bit longer.