The PERRIN Rotated Turbo kits were originally designed for the customer that needed something bigger and more efficient than a stock location turbo replacement.  A stock location turbo has 2 problems areas that cause inefficiencies, and loss in possible overall horsepower, the Intake path, and placement of turbo.  Both limit the size of turbo, and sacrifice intake path restrictions, again limiting potential horsepower.

Rotated!

The PERRIN rotated kit is just that, rotated! Because Perrin puts the turbo off to the side, and rotate it out of the way of the intake manifold, you can use a larger smoother straighter intake, and pretty much any size turbo you want!  Perrin’s placement of the turbo is in an optimum place to clear 90% off the front mounted intercoolers out there, and of course the PERRIN front mounted intercooler.

Silicone Inlet Hose

Included with the PERRIN Rotated Kits is their silicone turbo inlet. This inlet hose is designed to fit over turbo inlet, and to the MAF housing with out using extra couplers for a nice clean look.  A key difference with the Perrin Inlet Hose is that it includes a BOV (Blow Off Valve) return hose. Where other kits force you to buy a vent to atmosphere blow off valve, this piece allows you to choose to re-circulate your BOV for best drivability, or use a VTA.  The hose is constructed of 5ply high temp silicone to eliminate the possibility of the hose collapsing.  Lastly you will find 2 spigots on the intake to provide vacuum for your crankcase and valve cover breathers. This is another important feature, as with high-powered Subaru engines, you will have extra blow-by cause by excessive boost, and with built engines, having vacuum applied to the crankcase will help with making power.

Because these turbo’s are so much bigger and can flow much more air than the OEM turbo, Perrin also includes a Big MAF intake housing with them. This Big MAF housing has become a standard in the tuner world for making big power. This housing is larger than the OEM intake housing allowing for the ECU to be able to read more airflow with proper calibration. This along with our high flow foam filter, gives you a free flowing, smooth intake path.

You can also remove the MAF sensor completely with Perrin’s Blow-Thru Boost tube to create an even freer flowing intake path.

Uppipe

The PERRIN Rotated Kit uppipe is a TIG welded, CNC mandrel bent, 2” 304SS tube with .500” CNC cut flanges.  The external waste gate is plumbed into the uppipe with a smooth transition to the Tial 44mm wastegate. This is another important feature as that allows for smoother exhaust flow to the wastegate to control boost. The uppipe is also designed to bolt to a factory exhaust manifold, and has a T3 flange on the turbo connection with a new smoother transition from round to rectangle.

Downpipe

Like Perrin’s uppipe, the downpipe is TIG welded, CNC mandrel bent, 3” 304SS tube with .500” CNC cut flanges. A feature that is different than many kits is the fact the vented exhaust from the wastegate is dumped back into the downpipe. Many other kits vent them to the atmosphere, which claim to make more horse power by creating less backpressure in the exhaust system. Besides the danger of fire/melting things this presents, the more boost you run the less the WG is dumping pressure so the less it effects exhaust back pressure. Because the wastegate dump tube sees quickly varying extreme exhaust temps, it is important to use a connection that can move and give. The tight slip fit allows for expanding and contracting of the WG dump tube will still proving a nice seal. This slip fit also allows for easy removal of the downpipe with out having to deal with undoing the V-band clamps, or flange connection on the wastegate.

The downpipe is also designed to bolt up to your OEM catback exhaust. This in turn means most aftermarket catback exhausts will bolt right up to this turbo kit and of course the PERRIN Catbacks all will bolt up!

PERRIN/Tial 44mm Wastegate

This is a key part to controlling boost. Perrin choose the Tial 44mm as this version uses V-band connections instead of flanges. This allows for a more compact install of the entire kit. Tial is the premier brand when it comes to wastegates, and they make nothing but the best. Their high quality NiCrFe based alloy is used for the valve and 347SS valve housing will offer longer product life compared to competing designs.  A 17-7 PH Stainless Steel actuator spring gives consistent pressure at high temperature, resist "relaxing" at temperature to 900F (483C).  The 44mm model is also used as it has a larger diameter valve compared to other kits, which makes for flawless boost control. A 14psi WG spring is included with the kit but many other spring choices exist!

Turbo Time

Because there is a wide variety of people’s HP goals, Perrin offers a wide variety of turbos. The turbos range from 250-700 Wheel Horse Power.  Garrett Ball Bearing Turbochargers are used because of the wide range of choices and because Perrin feels that they are the best turbocharger on the market.  Garrett Turbochargers use a dual ball bearing cartridge as opposed to a journal bearing or sleeve bearing. The ball bearings have many advantages over sleeve type bearings. The largest difference is the ball bearing cartridge has far less drag allowing for 15% quicker spool, and needs much less oil to lubricate. This helps with oil consumption over time.  Also the dual ball bearings cartridge provides far better control of shaft motion when compressor surge occurs, which give the turbo a much longer service life compared to a sleeve bearing turbo.

Surge Ports

Where applicable, Perrin chose a turbo with compressor surge ports.  These are important for controlling surge at low RPM. There are 2 types of surge, surge when the BOV doesn’t work well, and surge when the turbo pushes more air than the engine consumes.  This second type of surge what Compressor surge ports help with. Surge ports are designed to broaden the compressor map at lower airflows, where this surge can occur.

Identifying surge ports on a turbocharger can be described as looking like another intake on the compressor housing. The outer port has small slots machined at the bottom that allow air to enter the compressor wheel.  This allows for air to “recirculate” at low airflow, and in turn pushes the surge limit toward lower RPMs. The GT3076R, GT3582R, and GT4088R turbos the Perrin’s kits use will have these surge ports.  This is another small feature that makes our turbo kits stand out from the rest.

T31 Turbine Housing

The turbine housing is also known as the exhaust housing. This is an important item to understand when picking your turbo as there are different sizes offered.  For a given turbo, Garrett offers generally 3 different size AR’s.  The AR in simple terms is the overall size of the housing.  A bigger number indicates a bigger freer flowing housing. The trade off with going to big is more turbo lag. The larger housings flow more air, but the velocity of the air is lower, which in turn has less energy to get the turbo spooling. But since they flow more air, they will make more power!  The smaller housings do just the opposite. Since the housing is smaller, the velocity of the air is much higher, helping spool the turbo.  But the trade off is top end power.  This trade off isn’t as great as some make it out to be.  Because of the engine displacements we are working with, and power goals people need, Perrin offers 2 choices which cover most peoples needs. These are the .63AR, and the .82AR. The response vs. power trade off can be mixed and matched very well with each turbo they offer.

 

The parts included with the kit are:

And of course your choice of a Garrett GT2860RS, GT2871R.

Simply add your front mount intercooler, fuel system, ECU tuning, clutch, cat-back and you are ready to claw apart the surface of your local racetrack! All systems have a fully recirculated wastegate vent to prevent fire, noise and stench.

 

These kits are not for the faint of heart and it is best to speak to Flatirons Tuning before ordering. Let us cater the exact combination to meet your needs. We can help you choose the extras that make this project successful with ECU plug-n-play tuning, fuel pumps, etc.

 

Fits all STi models 2004-2007

WRX models 2002+ require additional oil lines and fittings. 

2005 STi models may require additional clearance on transmission housing.

 

NOTE: Some systems do require engine modifications for optimum longevity.

To ensure prompt delivery, please call to check availability before ordering.