The 702HP lie
You saw the commercials. You watched the Baja 1000 footage. You handed over AED 450,000 for 702 horsepower, 650 lb-ft of torque and a 0-100km/h time of 4.5 seconds. The TRX is supposed to dominate everything.
Then you take it to Liwa. You hit the first big dune. The supercharger whine gets quieter. The power goes flat. By the third dune, you're getting passed by stock Raptors. What happened to your 702HP?
Heat happened. Every supercharged engine in the Gulf runs into it.
The physics problem
A supercharger is belt-driven instead of exhaust-driven, so it compresses air mechanically, and compressing air heats it.
The TRX uses a 2.4L twin-screw supercharger running about 11psi of boost. The air going into the engine starts at 45°C ambient and comes out of the blower at 120°C or more. That's why there's an intercooler.
RAM gave the TRX a liquid-to-air intercooler. In theory, it's better than air-to-air because liquid transfers heat more efficiently. In practice, the heat exchanger (radiator) is mounted in the engine bay, surrounded by a 6.2L V8 making massive heat. In the desert, the coolant temps climb, the intercooler efficiency drops, and your intake air temps skyrocket.
It compounds from there. You hit the gas, the supercharger compresses air, the air gets hot. The intercooler tries to cool it and is already heat-soaked. Intake temps hit 70°C, then 75°C, then 80°C. The ECU sees dangerous temps and pulls timing aggressively. You lose 100+ HP, the truck feels gutless, so you back off and let it cool. Twenty minutes later you have power again. For one run.
We logged a customer's TRX during a dune session. After three hard accelerations, intake air temperature was 83°C and the ECU had pulled 12 degrees of ignition timing. Twelve degrees on a supercharged engine is the difference between the truck in the brochure and the truck he was sitting in.
Why the TRX is worse than the Raptor
The Raptor uses twin turbos. Yes, it heat soaks. But a turbo is driven by exhaust gas that was leaving anyway, and it spends most of a dune run off boost entirely.
The supercharger is belt-driven off the crank, so it is turning whenever the engine is turning and it is compressing whenever your foot is down. The peak pressure is similar to the Raptor's. The difference is how much of the run is spent making it. On a dune session that is nearly all of it, and every one of those pounds arrives as heat the intercooler has to find somewhere to put.
Weight is the other half of it. The TRX weighs 2,950kg, 400kg more than a Raptor, and moving that much mass through soft sand takes constant power. The engine is always working hard and always generating heat, and the cooling system never gets a break.
How to stop a TRX heat soaking in the dunes
Software helps at the margins. The fix is cooling hardware, in three escalating levels.
Stage 1 is software only, and even on stock hardware it helps. We retard timing at high intake air temps gradually instead of taking the stock aggressive cut, enrich the mixture under high load so the fuel does some of the cooling, lower the supercharger bypass threshold so it generates less heat when full power isn't needed, and set the fan and pump speeds for UAE ambients.
The truck still loses power when heat soaked. The timing pull we log drops to roughly half of what the stock calibration applies, and the truck stays drivable through a session instead of falling off a cliff on the third run.
Stage 2 is the intercooler, and it is where we get serious. The stock heat exchanger is too small. We fit a larger one, CSF or similar, mounted where it gets airflow, an auxiliary radiator dedicated to the intercooler circuit, a high-flow pump to move coolant faster through the system, and a thermostat bypass that keeps coolant flowing even when cold.
Logged results: intake air temperature drops from around 80°C to around 52°C under the same conditions, and the timing correction falls with it.
Stage 3 is the complete cooling overhaul, for anyone serious about desert performance. The Hellcat runs hot, so a large external oil cooler goes on. The 8HP95 transmission copes well but generates heat, so it gets a cooler too, and the front and rear diffs get theirs for sustained high-load use. Header wrap and heat shields bring under-hood temperatures down.
What that buys is a TRX that still works on the fourth dune run in August.
What the numbers look like heat soaked
Even with every upgrade, a TRX in the July desert will not make its rated 702HP. Compressed air gets hot and there is no calibration that repeals that. What the cooling work does is stop the ECU from having to defend the engine so aggressively.
Figures below are logged in July desert conditions, heat soaked, on the same vehicle and the same terrain.
| Configuration | Intake air temp | Ignition timing pulled |
|---|---|---|
| Stock | ~80°C | ~12 degrees |
| Stage 2 (intercooler package) | ~52°C | ~3 degrees |
| Stage 3 (full cooling overhaul) | ~48°C | ~2 degrees |
Going from 12 degrees of correction to 2 is the whole point. We publish the timing and temperature because those are measured directly from the ECU. Converting them into a horsepower figure needs a dyno, and a dyno figure taken in a temperature-controlled room would tell you nothing about a dune at 45°C anyway.
The other change is repeatability. On the Dragy Pro, a Stage 3 truck holds its run times across a session. A stock one does not.
The fuel octane issue
Here's something else most TRX owners don't know. The Hellcat engine is designed for 91 octane (US rating), which is roughly equivalent to our 95 octane. But the TRX really wants 98 octane (Super) when tuned.
Higher octane resists knock. A heat soaked engine is already closer to detonation, so the octane margin is what lets us leave ignition timing in the map instead of taking it out.
Run 98 octane in a tuned TRX, every tank. This is an engine safety requirement rather than a performance preference. If you will not commit to Super, tell us before we write the file and we will calibrate for what you will actually buy.
Daily driving vs desert use
On the street, Stage 1 tuning is plenty. The TRX has enough cooling for highway driving and occasional hard acceleration, because at road speed there is air moving through the heat exchanger. You get sharper throttle response, better transmission logic, and a modest power increase on a cool morning.
In the dunes you need Stage 2 minimum, and the intercooler upgrade is non-negotiable. Without it, you're paying supercar money for sports car performance, or worse.
The TRX can tow 3,700kg. But towing in summer generates massive heat. Stage 2 cooling is recommended if you tow regularly in UAE summers.
Is the TRX worth buying in the UAE?
It depends entirely on where you drive it.
As a street truck for Sheikh Zayed Road and JBR, the TRX is hard to beat. The sound, the presence and the acceleration on a cool morning are all real, and highway speeds keep the heat exchanger fed with air.
As a dedicated dune truck, we would point you at a tuned Raptor instead. The TRX weighs 2,950kg, roughly 400kg more than a Raptor, and moving that mass through soft sand keeps the engine at high load continuously. Less power, but lighter, cooler and more predictable in the sand.
The TRX does work in the desert. It works once the cooling hardware is on it and the expectations are set at the right level.
What a TRX owner should actually budget for
The heat is not a defect you can tune out. Compressed air gets hot, the intercooler circuit rejects that heat into an already hot engine bay, and the ECU responds by removing ignition timing. Software can make the ECU's response less brutal. Only hardware changes the underlying temperature.
Do not buy a TRX expecting 702HP in July. Nobody gets 702HP in July.
If you want the truck to work through a full desert session rather than one run at a time, budget the cooling package first and the calibration second. Book it in at one of our partner workshops and we will log it heat soaked before we quote you anything.
