Category Archives: Turbo

Ej20, EJ257, Subaru, TMIC, Transmission, Turbo, WRX

Motor Mount install for Subaru Impreza WRX/STi

Motor Mount install for Subaru Impreza WRX/STi:

This how-to is based off a GR, but the concepts should be similar to a GD. I’m not sure how different the front subframe is or how it might interfere with the install.

Here is a selection of stiffer motor mounts:

Group-N motor mounts:

Group N Subaru Motor Mounts Set! Legacy Gt, Sti, WRX See Listing for Fitment!

Perrin Performance motor mounts:

Perrin Performance Motor Mount Kit Subaru WRX/STI 02-14

Torque Solution motor mounts:

Torque Solution Engine Mounts: Subaru Wrx Sti 2002-2016

I’m making this as a response to so many people saying that motor mounts are a terrible install. I think they’re cake, and I want to show why. I had originally installed the Tigwerks motor mounts, but their NVH was a little much for my tastes so I went to Group Ns, and that’s where this install was born (my second time through). I’d do it again and could accomplish the whole process inside of two hours with mandatory beer breaks.

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AWD, STi, Turbo, USDM, WRX

Rear Wheel Bearing Repair 02-07 Subaru WRX/STi

Rear Wheel Bearing Repair 02-07 Subaru WRX/STi: This is a write up on how to replace your rear wheel bearing for your 02-07 WRX STi.

DISCLAIMER: WORKING ON YOUR CAR IS DANGEROUS. IF YOU FEEL YOU CANNOT COMPLETE ANY OF THESE TASKS, DON’T DO IT, THESE PARTS HOLD YOUR SUSPENSION AND WEIGHT OF YOUR CAR. THIS IS A REFERENCE ONLY! do not attempt.

Tools:
– 32mm Socket (axle nut)
– 19mm, 17mm, 14mm (suspension, and brake parts)
– Needle nose
– Sockets, breaker bar
– Torque wrench
– Access to a press
– I used a 36mm to press the bearing
– 26-27 mm for the hub

Parts
– Check with your local Subaru dealer
– Or use online sites or vendors!

Parts I Used
– Rear Wheel bearing – #28016PA010
– Oil Seal #1 – #28015AA080
– Oil Seal #2 – #28015AA070
– Rear Axle nut – #28044AA001

Rear Wheel Bearing Install

– First you need to break the torque on your lug nuts
– Get your rear in the air and stable (your going to put some stress on some parts)
– Remove your wheel

Rear Wheel bearing: Remove your wheel and Locate your axle nut and "uncrimp" it.
Rear Wheel bearing: Remove your wheel and Locate your axle nut and “uncrimp” it.

Locate your axle nut and “uncrimp” it. After its uncrimped, make sure you have your parking brake on really well. Either break the torque on it and back it off so its hand tight accessible, or remove it all together.

- Locate your axle nut and "uncrimp" it - After its uncrimped, make sure you have your parking brake on realy good. - Either break the torque on it and back it off so its hand tight accessible, or remove it all together
– Locate your axle nut and “uncrimp” it
– After its uncrimped, make sure you have your parking brake on realy good.
– Either break the torque on it and back it off so its hand tight accessible, or remove it all together
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AWD, STi, Subaru, Transmission, Turbo, USDM, WRX

Clutch replacement for a Subaru WRX/STi:

How to replace a Clutch for a GD Subaru:

This procedure was performed on a MY04 STi with some modifications which may or may not be relevant for the purposes of this How-To. This procedure is only ONE way of removing the transmission and is not meant to be the be-all method. This is a DIY on your driveway process only. If you have access to a lift, this would be the preferred and safest method.

Perform this procedure AT YOUR OWN RISK.

Clutch: STi Transmission
Clutch: This procedure allows you to remove the transmission from a Subaru STI for the purpose of gaining access to the clutch and flywheel system for inspection and or replacement

This procedure allows you to remove the transmission from a Subaru STI for the purpose of gaining access to the clutch and flywheel system for inspection and or replacement.

This procedure allows you to remove the transmission without the benefit of a lift and is meant as a DIY for the weekend warrior. This is by no means a simple or easy procedure and it requires a good deal of strength. IT IS RECOMMENDED YOU HAVE A FRIEND THERE TO HELP. You will need a second pair of hands at times.

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AWD, Ej20, EJ257, STi, Subaru, Tuning, Turbo, USDM, WRX

Flywheel: Flywheels for Subaru WRX/STi’s FAQ

Flywheel FAQ:

How does a lightweight flywheel improve performance? A transmission can be thought of as a fulcrum and lever in a car. First gear has a really long lever; second gear has a shorter lever, etc. The lever represents the mechanical advantage that gears give your vehicle. When your car is moving, you have two factors that are present during acceleration, one is driveline losses, which are constant and the variable, which is vehicle weight and the mechanical advantage supplied by each gear.

Flywheel: SPEC flywheels are CNC manufactured at an unheard-of .001 tolerance, in an industry where the standard is .010. This precision manufacturing process ensures perfect balance and a perfectly flat bedding surface for the clutch disc, both of which also contribute to the ultimate in safety for competitive environments. All SPEC flywheels carry SFI certification.
Flywheel: SPEC flywheels are CNC manufactured at an unheard-of .001 tolerance, in an industry where the standard is .010. This precision manufacturing process ensures perfect balance and a perfectly flat bedding surface for the clutch disc, both of which also contribute to the ultimate in safety for competitive environments. All SPEC flywheels carry SFI certification.

While changing to a lighter flywheel will give the user little to no changes on a dyno, the apparent changes are quite dramatic due to the greater mechanical advantage. Consider these made up figures for consideration: Drive line losses, 45 pounds and vehicle mass (weight) at the driveline (remember your gear’s mechanical advantage reduces your actual car weight). We know that within reason, vehicle mass is a constant.

Now imagine if you reduced the driveline loss from 45 to 35 with the use of a lightweight flywheel. Since the engine has less drivetrain losses to compensate for, this means the “gained” horsepower can be applied to moving the vehicle mass. Using mathematics, one can realize that the higher you go up in gears, the less effect that a lightened flywheel will have to the overall equation.

Are there any downsides to a lightweight flywheel? While the performance characteristics of a lightweight flywheel seem to be the perfect solution, there are compromises:
a. Low end performance is affected. This usually means that higher revs are necessary for smooth starts due to the reduced rotational mass. For drag racers, this can be a BIG issue.
b. Possible missfire check engine light.
c. Possible chatter, like missfire this affects some users and not others.

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AWD, Ej20, EJ257, STi, Subaru, Tuning, Turbo, USDM, WRX

Clutch: Subaru WRX/Sti clutch FAQ

Clutch: Subaru WRX/Sti clutch FAQ

The first impulse when clutch shopping is to get “too much” clutch. This is often a very big mistake, as there will be compromises in the different types and compositions of clutches.

Clutches hold Torque, not Horsepower:
Most performance enthusiasts relate more to horsepower numbers rather than torque, but clutch capacity is measured in terms of torque. Think in terms of a high rpm 250 HP Honda Civic versus a 250 HP Ford Powerstroke turbo diesel. The truck will need about three times the clutch capacity because the engine produces about three times the torque.

Choosing what’s best for you:
It may be difficult to know what clutch is right for a particular application since there are so many different levels of personal tolerance and many variations in design. Some people can tolerate clutch chatter, or noise, or heavy pedal effort, or shorter clutch life, higher cost, or other trade-offs. But why tolerate unnecessary issues if you don’t have to? Get the clutch that suits your needs.

What are the various clutch materials? Other than unique or specialized compositions, clutches are generally comprised of:

1. Organic
2. Kevlar
3. Ceramic
4. Feramic
5. Carbon (initially invented in 1998 by Alcon Components for the Subaru World Rally team )
6. Sintered Iron

Depending on manufacturer specifications, this list also shows the general order of the amount of force the clutch materials can hold.

Organic: Metal-fiber woven into “organic” (actually CF aramid with other materials), original-equipment style. Known for smooth engagement, long life, broad operating temperature, minimal-to-no break in period. Will take hard use, somewhat intolerant of repeated abuse (will overheat). Will return to almost full operational condition if overheated. Material is dark brown or black with visible metal fibers.

Kevlar: High-durability material more resistant to hard use. Engagement is similar to organic, but may glaze slightly in stop and go traffic, resulting in slippage until worn clean when used hard again. Higher temp range in general, but can be ruined from overheating; will not return to original characteristics if “cooked”. Material is uniform yellow/green and may look slightly fuzzy when new.

Ceramic: Very high temperature material. Engagement is more abrupt. Will wear flywheel surface faster, especially in traffic situations. Due to it’s intrinsic properties, ceramic has a very high temperature range. Material is any of several light hues – gray, pink, brown.

Feramic: This unique clutch material is one that incorporates graphite and cindered iron. The result is a friction material that offers good friction coefficient, torque capacity, and smoothness of engagement.

Carbon: Very high temperature material. Engagement is more abrupt. Will wear flywheel surface faster, especially in traffic situations. Slightly more durable and flywheel-friendly compared to other aggressive clutch materials. Material is black.

Sintered Iron: Extremely high temperature material. Engagement is extremely harsh and is generally considered an “on/off switch” both due to it’s characteristics and the clutch types this material is generally associated with. It requires a special flywheel surface. Material is metallic gray in color.

 

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Ej20, EJ257, exhaust, STi, TMIC, Tuning, Turbo, USDM, WRX

Uppipe WRX upgrade FAQ

Aftermarket Uppipe FAQ for WRX/STi

Uppipe: The primary purpose of an aftermarket uppipe is to remove the catalytic converter housed within the stock unit. This serves two purposes: to increase horsepower and decrease turbo spool time.

uppipeaftermarket
Uppipe: The primary purpose of an aftermarket uppipe is to remove the catalytic converter housed within the stock unit.

HP gain is around 10HP. This figure is highly debated as different manufacturers use different dynos with different cars with different levels of mods. Dyno Proof Example. The general consensus for turbo spool time decrease is boost will occur around 500 RPM sooner.

Is an aftermarket uppipe a performance or reliability mod? With regard to swapping over from a catted uppipe to a catless uppipe, it’s both. Need some evidence of the reliability? View this link.

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

What uppipe metal material is best? Uppipes are made from mild steel, stainless steel (304 & 321), cast iron, and inconel. There is no irrefutable evidence that one material is better than the other. Obviously, corrosion levels are higher with mild steel (coated or otherwise) and cast iron. Corrosion on cast iron, due to it’s thickness and material qualities, is more resistant to corrosion damage than mild steel. In terms of heat retention, the best material is inconel.

Which uppipe construction method is best? Uppipes are either solid or flex. There is no irrefutable evidence that one design is better than the other. The thought process is that a flex pipe will reduce the chances of leaking. Practical application has shown that correct installation plays a bigger role than the uppipe construction.

What is the cheapest uppipe? Gut your stock uppipe. Instructions. Gutting your stock uppipe can have the same benefits as using a more expensive aftermarket uppipe. Dyno Proof.

Which uppipe has the best gains? There is no irrefutable evidence that any uppipe has better gains than another. The consensus, if there is one, is they are all within 1-2 HP, gain wise, of each other.

Where do I buy an uppipe?

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

TGV Deletes for Subaru WRX/STi

TGV Delete on WRX/STi’s:

The primary purpose of a TGV delete is to remove the divider bar and butterfly valve inside the TGV assembly to improve airflow to your engine.

TGV Delete: Top is a deleted TGV and bottom is the stock TGV.
TGV Delete: Top is a deleted TGV and bottom is the stock TGV.

HP gain is 12 HP. This figure is highly debated as different manufacturers use different dynos with different cars with different levels of mods.

What is the purpose of TGV Deletes? The are meant to reduce cold idle emissions. Nothing more, nothing less. Once your vehicle is warm, the butterfly valves open fully and remain that way.

Which manufacturer is best? This topic is highly debated with no real winner in terms of performance. There are several companies that offer the TGV delete service as well as purpose built units or Japanese models which are, in essence, hollow units.

Japanese model, what is that? TGV internal assemblies are only used for cold start emissions on US cars. Hence, the Japanese TGVs do not have the divider plate or butterfly valves. Some models are one piece intake manifolds with longer runners that make up the TGV portion and other models are just like their US cousins with no internal plates or butterfly assemblies. Neither units have the associated TGV external motor controllers as well.

Which TGV Delete has the best gains? There is no irrefutable evidence that any TGV Delete option has better gains than another. The consensus, if there is one, is they are all within 5HP or less, gain wise, of each other.

Do TGV Deletes cause a CEL? Yes. By removing the TGV motors, it will throw quite a few CELs. The bad news with this, is the TGV CELs will throw your car into limp mode, meaning unlike some other CELs that you can still drive around with and have no fear, the TGV codes limit boost/RPM operation meaning they must be taken care of in order to drive your car for any reasonable distance.

How do I fix the TGV CEL? You have three methods:
1. Normally, you remove the TGV motors and the rod that holds the butterfly valves in place. You could leave the rod in place (sans butterfly valves) and reinstall the TGV motors. This would allow them to actuate normally making the system think everything is working correctly.
2. APS makes a block that you attach the TGV motors to, this allows them to actuate normally making the system think everything is working correctly. These are not sold separately though, but can occasionally be purchased in the Private For Sale Forum or on eBay.
3. Various engine management systems can remove the associated CELs.

Do I need to perform the CEL fix? Yes. The TGV CEL codes will throw your car into limp mode. This will limit boost/RPM seen by your vehicle. It will still drive, but it should only be driven a short distance with the TGV CEL. Meaning you can drive it across town or a few short trips, but by no means should you drive it as a daily driven car for weeks on end until you get the proper fix.

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AWD, Ej20, ej20G, Intake, Intercooler, JDM, Legacy, Rally, Subaru, TMIC, Tuning, Turbo, UK, wrc

Legacy: 1989-1994 Subaru Legacy (BC/BF) GT/RS

Prior to the Legacy RS turbo, Subaru had never enjoyed the experience of distributing a genuine performance car. Of course, there had been the 4WD turbo RX and Vortex, but neither could crack 10 seconds for the 0-100km/h sprint – although they were very reliable. The RS was the gun version of the first Legacy series released in 1988 and discontinued in 1994. The RS (Rally Sport) model was aimed squarely at world rallying, with many of its components and concepts carried over to the dominating Impreza WRX.

Legacy: The BC/BF is unique in having an Air - Water intercooler with a front mounted radiator for optimal cooling. The bonnet scoop only provides cooling to the turbo. While later model legacy's have all used air to air intercoolers.
Legacy: The BC/BF is unique in having an Air – Water intercooler with a front mounted radiator for optimal cooling. The bonnet scoop only provides cooling to the turbo. While later model legacy’s have all used air to air intercoolers.

The center Viscous LSD on the MT models initially starts out with a 50/50 torque split, front and rear, and will up the ratio towards the end with more traction. The manufacturer doesn’t give a final figure, so the max split is either 65/35, or could even venture as high as 95/5, since the A/T model has a different system that is marketed at a 65/35 maximum split. A higher ratio would explain some of the handling characteristics at the limit. The rear differential is also a Viscous LSD model.

The BC/BF is unique in having an Air – Water intercooler with a front mounted radiator for optimal cooling. The bonnet scoop only provides cooling to the turbo. While later model legacy’s have all used air to air intercoolers.

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