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Old 08-26-2013, 03:05 PM   #1
Scooby Guru
Member Sales Rating: (17)
Member#: 261612
Join Date: Oct 2010
Location: Minneapolis, MN
2002 WRX - 750WHP
9.5s @ 150mph

Default xluben's VF39 and GrimmSpeed Crosspipe, Uppipe, and Downpipe Reivew and Photos

xluben's VF39 and GrimmSpeed Crosspipe, Uppipe, and Downpipe Reivew and Photos


These parts went onto my 2002 WRX sedan. When I started it was completely stock and had 185k miles on the factory shortblock and tranny, but it was still working great, so I wanted to add a little more power. The GrimmSpeed uppipe, downpipe, and crosspipe were chosen to free up flow a bit, but I figured I might as well replace the TD04 while I had everything apart, so I picked up a used VF39 to go along with it. This review will focus on the install and overall impressions of the GrimmSpeed exhaust parts.

I got the GrimmSpeed parts used, but they look great. They have cosmetic discoloration from use, but physically they are perfect. All of the parts are made from very high quality materials and have very thick machined flanges. The flex joints are the newer, high quality pieces that GrimmSpeed has switched to. I don't expect to have any issues with them and the flow seems like it would be very good. The downpipe is a true divorced designed for the best leaste turbulent wastegate exhaust flow. The flange has very complex machining to ensure there will be ideal flow.

The first step to installing these parts is to remove the old parts! To gain access you will first need to remove the intercooler. For a stock TMIC this is just a few bolts for mounting, loosen the clamps on the turbo compressor and the throttle body, and then unbolt the two bolts into the BPV. At this point the TMIC should just lift off. Once the TMIC is off you can remove the turbo height shielding. This is held on by several bolts on the top and side. Some can be tricky to find. If it doesn't easily come off, then you probably missed a bolt.

Once the height shield is off you can remove the downpipe. It is held to the turbo by (5) bolts/nuts. Use a 14mm socket and remove the nuts. The top two will also require a wrench on the bolt head. Once this is done, move to the underside of the car and remove the two bolts holding the downpipe to the tranny. Unplug the rear O2 sensor (you can leave it in at this point and swap it into the new downpipe off the car). Lastly, remove the two nuts/bolts holding the downpipe to the cat back exhaust. At this point you can remove the downpipe from the car.

With the downpipe out of the way you can now remove the nuts holding the upppipe onto the car. There are 5 nuts that should all be accessible from the engine bay with the right sockets and extensions. Once these are removed, the uppipe is free from the turbo but it will not move anywhere because the headers are holding it in place. At this stage you can remove the turbo. If you are not doing a turbo swap, then you can skip the next section.

To remove the turbo you will want to slide the upper and lower coolant hoses off. Clamp them before you remove them or you will make quite a mess. You will also have to remove the oil feed and drain. The feed is a banjo bolt on the top of the turbo. The drain is a rubber hose with a squeeze clamp. Simply move the clamp off the flange for now. The hose will slide off when the turbo is lifted. Before lifting the turbo out you also have the loosen the clamp on the inlet. Once it is loose you should be able to lift the turbo up and back and get it out.

Now moving back under the car the headers and uppipe can be removed. To get at the header to head nuts you will have to remove the head shields on the exhaust manifold collectors. I would also suggest removing the nuts/bolts holding the header to the uppipe. They are easier to remove separately. Next remove the nuts holding the header to the head, and then remove the header completely.

This will leave the uppipe completely free, but stuck between the motor and car. Make sure you also unplug the front O2 sensor before trying to remove the uppipe. With the OEM heat shields on it cannot be removed without jacking up the motor slightly. To do this, remove the motor mount nuts and then jack the motor up from the oil pan (with a piece of wood or rubber on the jack to prevent any damage). You should only have to lift it up an inch or two and then you can twist and turn the uppipe out. You can then lower the motor and reinstall the motor mounts.

Once everything is off the car you can swap the O2 sensors into the new parts and start reassembly. Make sure to put gaskets on every location that they are needed. I used all brand new GrimmSpeed gaskets. This is recommended to prevent leaks. All of these parts, including the VF39, are direct bolt on to an 02-07 WRX. There are not too many tricks needed to get it back together. You do not have to jack up the motor to fit the GrimmSpeed uppipe back into place.

Start by installing the turbo. Getting the oil drain, and turbo inlet are on kind of tricky, but not too difficult. Reconnect the remaining oil and coolant lines. Then install the uppipe, then the headers. Loosely attach all the nuts/bolts, until it is all in place, then torque all the nuts/bolts. Then finally the downpipe. Remember all gaskets. Remember to plug in all sensors. Remember to torque all nuts/bolts (but do not overtorque). Last is the TMIC, which is reverse of the removal. Finally, you will need to prime the turbo, then burp the coolant, and then get a tune for the new parts!


Last edited by xluben; 08-26-2013 at 03:53 PM.
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