For as long as there are turbo cars, there have been intercoolers and the big shiny aluminum intercooler behind the massive hole gape in the bumper tells everyone that your car is turbocharged, so much so that the Turbo Intercooler Sticker found on the 90s Pajero Fieldmaster is still remembered today.
For most of the Diesel engine’s existence, most make do without an Intercooler because it’s not as needed as a gasoline engine with the diesel as it’s not prone to pre combustion when the intake air gets too hot. It also kept the cost down as diesels are mostly relegated to work horse type vehicles like trucks where power isn’t a priority but torque, which the Diesel engine delivers a lot of at.
Diesels in consumer cars really cane to prominence with VW in the 90s as it rolled out the first electronically controlled Diesel engines that can vary injection volume across the rpm range, across a variety of load applied. Diesels engines also by nature get more efficiency than a gasoline engine engines, and with diesels, just throw in more air and fuel and it will make more power. So turbocharging is the next step in adding more air.
The Philippines is rather unique in that our diesel fuel is significantly lower than gasoline, unlike other places like Europe, there diesel and petrol are same price and sometimes a bit more expensive. But the power and increased fuel economy are definitely worth it.
It’s no wonder that half of all vehicle sales nowadays are diesels, dominated by SUVs and pickups, of which Honda is the poor kid left out in the cold.
A full half of Toyota’s lineup is diesel, Isuzu sells nothing but diesels.
And diesels now are making more power than gasoline cars. Gone are the days of the L300 where it is hirap to reach 80kph and is slow as dirt. 140-150kph is easily attainable even by an old 2006 Innova.
Having and ecu control the engine also opens up a world of improvements for tuners like us to extract more power with modules like Unichip or direct Ecu remap/reflash.
Design wise, SUVs have gone from two box designs (90s Patrol anyone?) to sleek space ship like styling of the latest Montero. Design cues have also evolved, from top mount intercooler of the Pajero Fieldmaster, Trooper and 1st Gen Fortuner to the front mount placement in all of of today’s offerings. And why is that?
The answer is two part: cost and design.
Admittedly a vehicle with a hood scoop screams performance, just look at Subaru, the hood scoop and top mount has been a staple since the 90s. And for the Fortuner, the hood scoop easily distinguishes the more expensive 3.0L from the 2.5L
Cost wise, it’s cheaper to make a top mount system that’s a front mount systems. It requires less parts and is faster to assemble. Plus you rarely get issues like testing hoses like on the current Ranger. And it’s another place to put branding on, with words like INTERCOOLED or D4D emblazoned on the plastic.
So why the shift to front mount and is it better if I convert my top mount to a front mount?
One word: efficiency.
A front mount intercooler that is away from engine heat and has a bigger surface area to catch the incoming air will always be better. As the. Same implies, the job of the intercooler is to COOL. We have taken temp measurements before and after if a top mount and with a front mount system. From cold start both show a 20-30 drop across the intercooler core but that drop quickly disappears from the top mount setup. The front mount setup is able to maintain the temp drop for far longer.
Googling will just confuse you more, as the is the perennial top mount vs front mount debate especially in Subaru forums. These are my 2 cents:
1. All arguments you see are for countries with winter, which we do not have and thus not applicable.
2. Subaru world rally team uses front mount. Enough said.
So will changing to a front mount give me more power? Well no, and yes.
No by itself, there is no power or very little power to be had. Intercooler makes are all about temperature and being stuck in traffic, there is no power to be had as both intercooler a will be hot due to lack of air flow.
But once you hit the highway with sufficient air flow , then the one with the front mount will cool the air faster as compared to the top mount.
Also when the vehicle is tuned, a front mount setup will make power due to the capacity to Cool more air brought about by higher boost levels.
But the biggest advantage of a front mount? It looks very nice.