Unlike most aftermarket turbocharger which feature a down-firing compressor housing, the TD05 housing uses a j-pipe with a 2-bolt flange for the compressor outlet. The intercooler pipes that bolt to this style housing is called a “J-pipe”. There are several different aftermarket J-pipes available for our cars depending on your setup. Most down-firing turbochargers feature a vacuum port on the compressor housing which is used as a boost source for your wastegate. This is the most ideal setup and is where you will want to feed into for your boost controller. Now with a J-pipe style housing you still have options for this. Some feature a bung with a threaded vacuum port. Some just have vacuum ports welded on, and some leave you searching for another boost source or making your own port. Regardless, the closer to the compressor housing the better. It allows the wastegate to see the most accurate pressure and is more efficient overall. One very important thing to look at when choosing a J-pipe for your setup is fitment. Will it clear the stock radiator fan? Which direction is it routed? Just some of the questions you will want to know the answers to when selection your J-pipe. The biggest downfall of a J-pipe is the 2-bolt flange, it requires a gasket and if the threads in the housing become weak it can cause big issues which can range from just the bolts loosening up to actually pulling the threads out of the housing under high boost. In that case you’ll have to either tap new threads or replace the compressor housing.
The factory J-pipe for a 1G DSM is rather small and restrictive, but goes well with the stock side mount intercooler setup. It is routed toward the passenger’s side of the car. it is equipped with a vacuum port from the factory.
The VR Speed Factory or “VRSF” J-pipe is an aftermarket option. This pipe is routed almost straight down making it ideal for their short route intercooler kit. There are many pros to this J-pipe but there have been reports of a not so easy installation due to the fact that the lower bolt hole is right beneath the actual pipe makiding it difficult to tighten the bolt.
The “Ebay” or “CXRacing” J-pipes come in various shapes and sizes and are hit or miss as far as fitment. You really have to pay attention to how you will be routing your intercooler piping before buying one of these J-pipes. Some are setup to go toward the passenger’s side for long route piping or side mount intercoolers. Others are routed straight down or toward the driver’s side making these ones more ideal for short route piping setups. A big issue with these J-pipes is they do not feature a vacuum port. You will need to make sure your intercooler piping has one somewhere or have a bung welded on for a threaded port.
The ETS J-pipe is alot like the VRSF pipe in the way that it is routed. There are several versions of this pipe. As far as i understand all of these pipes clear the stock radiator fan and do not feature a vacuum port.
The Punishment Racing J-pipe is a simple aftermarket J-pipe angled towards the driver’s side making it a good option for short route setups. This pipe also does not include a vacuum port.
The Forced Performance J-pipe is setup for their intercooler kit. It routes toward the passenger’s side of the engine bay. It does not have a vacuum port.
The Slow Boy Racing J-pipe has been said to be one of the best J-pipes on the market before the company went under. If you come across one of these you may want to consider picking it up while you can.
The Extreme PSi J-pipe appears to be a well built unit. It is routed straight down which also makes this a good choice for shorte route setups. It does not appear to come with a vacuum port. It does however clear the stock radiator fans.