Tag Archives: ARC

EJ257, STi, Subaru, Tuning, Turbo, USDM, WRX

Coolant use and Cooling System for Subaru WRX/STi

What type of coolant should I run in my car? You can never go wrong by using Genuine Subaru Coolant available through your local dealer.

Subaru Genuine Coolant. To the left Super Coolant and to the right long life coolant.
Subaru Genuine Coolant. To the left Super Coolant and to the right long life coolant.

Is the Subaru coolant pre-mixed or not? They have both kinds, but BE SURE to read the labels carefully as they are nearly identical in appearance except the wording on the package!

Is there a required coolant additive? Yes. Subaru Cooling System Conditioner has recently been required to be added with every coolant replacement to prevent coolant system leaks. This recommendation applies to every Subaru model for every model year.

Subaru Cooling System Conditioner has recently been required to be added with every coolant replacement to prevent coolant system leaks. This recommendation applies to every Subaru model for every model year.
Subaru Cooling System Conditioner has recently been required to be added with every coolant replacement to prevent coolant system leaks. This recommendation applies to every Subaru model for every model year.
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EJ257, Intercooler, JDM, STi, Subaru, TMIC, Turbo, WRX

TMIC basics on a Subaru WRX/STi

TMIC basics on a Subaru WRX/STi:

The primary purpose of a top mount intercooler is to reduce post turbo air temperature prior to entering the combustion chamber via the throttle body.

HP gain is around 15HP. This figure can vary as many TMICs replace the restrictive OEM piping and results can be further enhanced with post installation tuning. This is one modification that is extremely difficult to put a traditional HP figure on as results truly vary from car to car based on tuning and turbo output in terms of CFM.

How much HP can my stock TMIC hold? 300WHP on the WRX and 400WHP on the STi are attainable. That does not mean those power levels are 100% efficient, but that those power levels are attainable with their OEM TMICs. As discussed below though, TMICs are not meant to be HP rated, but rather CFM related, but this is an FAQ so the HP figures are given as a good “bad” answer.

TMIC basics on a Subaru WRX/STi: 04-07 STi oem TMIC
TMIC basics on a Subaru WRX/STi: 04-07 STi OEM TMIC

Which manufacturer is best? This topic is highly debated. There have been no reported consistent “bad” TMICs on the market. Obviously, there may have been bad TMICs sold, but not enough to report as “bad” overall.

I have a 2008/2009 model, any differences? Yes. Your engine bay has an entirely new layout vs. the 2002-2007 models.

TMIC basics on a Subaru WRX/STi: A 2008 STi stock TMIC
TMIC basics on a Subaru WRX/STi: A 2008 STi stock TMIC
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