TMIC vs FMIC | Which One Is Right For You?
We get tons of questions when it comes to choosing a top mount or front mount Subaru WRX intercooler, and it's all in good reason. It's one of the most common mods for 2015-2019 WRX owners who plan to build past the standard stage 2. Truth be told, there is a bit of unnecessary controversy surrounding the two mods, and with the upcoming release of our own WRX top mount intercooler, we hope to lay some of it to rest. The most common questions we get are:
- Does a TMIC have less lag than a FMIC?
- Does a FMIC cool charge air temps better than TMIC's?
- Does a FMIC have better airflow properties than a TMIC?
- I have 'X' mods, should I run 'Y' intercooler?
While these are all legitimate questions, and some you should certainly be asking yourself and retailers if you're in the market for a Subaru TMIC or FMIC mod. Let's discuss!
Which intercooler placement creates more turbo lag, front mount or top mount?
The difference here is dependant on a few factors, most of which relating to the supporting mods also installed on the car. In most cases, most 2015-2018 WRX TMIC's will see less turbo lag given the close proximity to both the turbocharger outlet and the throttle body, whereas a front mount has considerably more distance to travel between both. While you wont feel the difference in the seat of your pants on WOT pull, the difference is measurable with more advanced tools. With that said, the difference is practically negligible, so use the information presented below to help form your buying decisions.
Does a FMIC cool better than a TMIC?
Quite possibly the most definitive question, but still worthy of discussion. A top mount intercooler is located in arguably the hottest position on the car, right above the engine. Thoughtfully, Subaru gave their turbocharged cars a large scoop to take in fresh, cooler air while the vehicle is moving. But this doesn't do much for the car when sitting at a stoplight or staging on the track, where heat soak slowly becomes a factor. Even while moving, if the ambient air is hot enough, a top mount WRX intercooler may not be able to keep up with cooling charge temps when compared to a front mounted intercooler. Add a few performance modifications into the picture, and you've got enough heat under the hood to fry an egg on your intercooler. This is not ideal for performance, so a front mount intercooler gets the nod in this category.
Which Subaru intercooler has better airflow?
Overall, an aftermarket intercooler of either type will have substantially better flow characteristics than the stock top mount intercooler on your 2015-2019 Subaru. In stock form, the OEM top mount has a ton of design flaws that lead to poor airflow exiting the turbo, entering and exiting the intercooler, before finally being put to use at the throttle body.
From an airflow efficiency standpoint, a top mount intercooler will be more efficient than a front mount given the shorter path from the turbo to intake. You'll be moving air quicker. But don't confuse the longer path with turbo lag, as the system is already pressurized. Also consider the use of mandrel bends on a front mount intercooler kit, which is much better for flow than the restrictive factory piping. For most street cars or daily drivers, we suggest running an upgrades WRX TMIC unless you're shooting for more than 500whp.
What Subaru WRX mods work best with either intercooler type?
This is a tricky question to answer, but just like every other modification you make should be made in consideration of your goals. All out track machines will benefit more from a front mount intercooler, where a daily driven Subaru may benefit from either depending on the amount of work the owner wants to perform. But in most cases, a top mount is best paired with cars planning on making less than 500whp.
Front mount intercoolers typically cost more, require modification to fit, as well as additional aftermarket parts. Kits are readily available (we love these Cobb or Perrin Front Mount Intercoolers Kits) which make the process easier, but there is no avoiding the cutting and modifications you'll need to do to get it to fit. When running an aftermarket turbo, we recommend a front mount to handle the extra heat discharged from the turbocharger. However, for most customers, the best bang for your buck is a TMIC Upgrade including charge pipes, designed to be a direct bolt in replacement for your 2015-2019 WRX intercooler.