Nov 182016

About a year ago I got the bug to do something really different for the new 2015+ WRX. With the FRS/BRZ being well established in the aftermarket world, some really well thought out supercharger kits had started emerging. This got me thinking about adding a supercharger on my WRX! Its the same motor right? It should just bolt right on right? I contacted two companies to see about getting a supercharger to test fit to really see what is involved. There were two really high quality kits that I thought would be perfect for my project. Cosworth’s kit was kind of the primo kit out there, it was the most expensive and had really good charge coolers mounted inside the intake manifold. The problem is cost. Cosworth/RallySport Direct (Cosworth USA) wasn’t able to give us much of a discount as their kit was new, in super high demand and not available for a month or more. They were a little leary as the project wouldn’t have benefited them in selling more kits. We were in the same boat as this was going to cost us a lot of money and a lot of time/money and it may be for nothing. Then I found the Harrop TVS1320 kit one day. I fell in love as it just looks sexy under the hood on the BRZ. At the time Harrop was interested to help us out with the project but there was a huge delay on when we could get one. While both Cosworth and Harrop were willing to help, the delay in getting kits really killed the momentum with this crazy project.


Fast forward to this year (2016) and the bug bit me in the ass again. There were plenty of people with bigger turbos and lots of power, but still nothing as unique as a twincharged WRX. I hit up the same two companies to see about helping with the project. This time around Cosworth/RallySport Direct had taken this idea and started down the path of installing it on their SEMA WRX. I thought great, we can do this together… except that once again, the kit was out of stock for a couple of  months. Harrop came to the rescue and was able to ship us a kit within a few days! Perfect and not to knock the Cosworth kit or RSD for not having one, but the Harrop kit was actually my first choice because it looks sooooo good. My only hold ups with their kit was the fact that I had never seen one in person, and the fact very few BRZ guys had them. What makes up for that is their willingness to help us out, their killer water to air intercooler system, and completeness of their kit.


Why even do this? The one thing I have come to love about modding cars is the response you gain from the turbo/engine. Anytime you do something you gain some response or something that makes the car better. This is great for a while until you get used to it and you want more. Well I wanted more! Adding the instant response (boost response) of the SC, along with the midrange power of the turbo, this would make for a killer setup as long as it all worked. Secondly the stock WRX turbo doesn’t hold boost past 5000 RPM and having the SC and turbo working together, this should allow for higher boost at redline. In theory, this had the potential to do great things if it all worked. And if it didn’t work, at least it would look really awesome!

With parts on the way, my excitement grew and was compiling a few things needed to make it work. Since RSD had already been installing the Cosworth kit on their WRX, they gave a few things to have to look out for. In return we offered to help them with the front mounted intercooler needed, the tuning aspect and overall setup. I still had reservations with a few things like fitment, tuning, and would this all be worth some kind of gains we couldn’t get from a turbo. I was confident enough that I didn’t care, and I would make it work one way or another.


What was needed to make it fit? Lots of grinding, and also lots of grinding. I would have made really tall spacers to clear a few of the obstacles, but the kit nearly fits perfect without that. I ended up making spacers that reduce some of the grinding, and added space for the bypass valve, but mainly they were made to create the transition from the BRZ sized ports to the WRX heads. You would think that these engines are exactly the same, but their heads have different port sizes and bolt patterns.


I started out building it in stages working up to the final install. Like installing the WTA (Water to Air) intercooler plumbing and pump. It fit amazingly well behind the PERRIN FMIC and bump beam. Even the custom molded hoses that Harrop includes for the BRZ work pretty well. The pump and harness they include worked very well. As you can see the pump mounted perfectly behind the intercooler pipe, I just had to extend the wires to it.


Once that was all done, the next hurdle was the grinding aspect. The AC bracket required a lot of material to be removed. This was to clear the throttle body and also to make room for the dual port bypass valve. It took about 4 times to get it right and also make it look nice. The throttle body needed some massaging too. Grinding all this down with a proper die grind bit is easy compared to what was next. The clutch slave cylinder was about 3/8″ in the way. The easiest way to remove all the material was to do this on the car, but imagine removing a 1″ x 1″ x 3/8″ block of steel with a die grind tool. Not only is it time consuming, it is soooo messy.

The rest of the install nuts and bolts things. Playing with belts and pulleys to get the best wrap and belt tension was the big hurdle.  As you can see it looks very OEM like.


I was able to utilized 95% of our 15+ WRX FMIC kit to make this all work. That was important as there could be a day that enough people start do this and I didn’t want to create something that is over the top custom. The one custom part of the intercooler was the last charge pipe before the supercharger. With that said, it is setup so that the WRX turbo system is all in place just like it was, but it is feeding boost to the supercharger. The heated and compressed air from the turbo is being cooled by our front mounted intercooler, then compressed again from the supercharger, and cooled one more time by the built in water to air intercooler within the intake manifold. You could call this twincharged and twin intercooled!

The moment I took off for the maiden voyage, it was very obvious (even with the lowest boost pulley) that this would need some taming of the throttle as the SC adds a huge amount of response! I drove on the car with the 95mm pulley at first to understand how this whole system would work. Being that this pulley should create a boost curve of 4.5psi at 2500 ramping up to 7.5psi at 7000, I was hoping to see boost to run about 15psi ramping to 18psi at redline. I was WAYYYY  off!

There are a few factors to why I was wrong. One being that the supercharger is compressing air at a ratio (pressure ratio). The supercharger is taking ambient air pressure and compressing it at a ratio to make boost. Compressing the boost from the turbo at this same ratio ends up multiplying the actual boost pressure instead of adding it up. This means, it should be running more than (turbo boost plus SC boost). The thing is this still didn’t really show what I was seeing, especially at lower RPM.

The other factor (the bigger one) is even with the turbo running off the wastegate pressure only (10-ish PSI), the added energy from the superchargers boost spools the turbo even faster. This created a rising boost curve out of the turbo (18psi verus 10psi), which added to the natural rising boost curve of the SC. I would see 25psi at 4500, and it was still going up! Obviously this is a bit much for pump gas and stock motor. My goal was to be able to a minimum boost level that would  allow the stock ECU safety parameters to function. That way if the ECU sees too much knock or has a legit CEL, it would drop boost to a safe level. So obviously this crazy boost was not ok.

Fast forward to today and after about 4 or 5 versions of control systems, I finally got it dialed.  It is so good that I took it one step further and installed a 10mm smaller pulley to make even more boost down low.  This would not  have been possible without the dual port bypass valve Harrop includes and our EBCS Pro to control it. I can run at little as about 12psi or as much as probably 35psi, all fully controlled by the ECU.




As you can see by the pictures, I have a water meth injection system installed into each runner. I ended up doing this as injecting the mixture into the SC inlet would destroy the coating on the compressor. I have been using the Aquamist HFS-4 for a long time now, and it was a must to integrate this into a high power WRX that can’t run on E85 or run high quality fuel. With the carbon build up issues, blow by from the crappy PCV valve, EGR stuff, and also being able to make power on pump fuel, every 2015+ WRX customer should consider running a water/meth injection kit.


Why did it take so long to show this off? Its actually been running on the car for the last two weeks but there were many things that had to be worked out. Mainly was boost control but other things like oil cooler setup, routing of things, visual appearance, and most important was tuning/drive-ability. I didn’t want to show it off in its testing state with hoses and wires everywhere. Nor did I want to fail at answering peoples questions that I am sure would be asked.  As of two days ago all of this came together to a point where I was willing to show it off, and it turned out WAY better than I expected!


Does it work and was it worth all the effort are two really important questions. Absolutely! The response is amazing at all RPM’s, and the best part is there is virtually no turbo lag. If you are cruising at any RPM there is an instant 6psi of boost on tap. The higher the RPM the most instant boost you have. Even at 2300 RPM, if you go from 0% throttle to 100% throttle, it instantly hits 6.5PSI, and in .6seconds, I am seeing 17psi. At 3500 its even better. And it is even MORE responsive if you are at part throttle then smash the gas (because the boost tubes have some boost in them). So yes… it works and yes, this whole thing was worth

There is only one question that I can’t answer at this time, which is “How much power does this make?”. Dyno time will follow very soon. Every day, I am tweaking the setup dialing it in, working out bugs in order to get it on the dyno. I can say for sure that it absolutely makes power, and it a blast to drive! I will post up some good data with boost curves and things showing where the SC blows the turbo out of the water in the next few days.






 Posted by on November 18, 2016 Project Builds
Nov 192015


One day I was doing some R&D work on our WRX and noticed how sloppy the steering felt when the car was in the air. For whatever reason I was turning the steering wheel back and forth quickly and I could feel a strange rubbery feeling to it. This rubbery feeling drove me to look at the steering rack closer as well as all the mechanisms in the car. What I found was the steering dampener on the rod going from the firewall to steering rack. With the help of an employee doing the steering while I was under the car you could see this dampener squishing a bit and the wheel would go from left to right. After further testing, we found there was quite a bit of deflection when the wheels are locked down. Check out the image below and you can see how bad the steering rack universal joint dampener flexes!


It is pretty obvious that this is moving and deflecting but how does this translate to the driver while on the road? Imagine you turn the steering wheel and the wheels don’t actually turn. That is essentially what is happening here, but not quite as scary as that may have sounded. This dampener is in place to reduced feedback from things like ruts, bumps and vibrations that may translate form the road.

I had never noticed this part on my other cars partly because they were mostly STI’s. These cars do not have a dampener installed on the steering rack universal joint, they are just a straight rod. Obviously Subaru did this to give the driver better feedback, and make the car handle a little better. For this customer base, they wouldn’t mind that additional feel from the road, where WRX (and most all the other Subaru’s) are being sold to customers that are looking for something a little more subdued. The question becomes, does removing the dampener negatively effect anything? We will get to that in  a bit.


Solution, OEM STI Universal Joint?

Why not just install the OEM STI part? First off, it costs more than $150, which is almost twice the price of the part we sell. Secondly the installation for this is not easy. You need to drop the steering rack, and make sure the steering wheel and rack stay aligned during installation. My guess is a shop would charge roughly 3 hours labor to install the OEM STI part. Our part installs in about 10 minutes on the 2015’s! Other cars take anywhere from 30-60 minutes depending on if you do it from the top (removing the intercooler) or from underneath the car. Between the price of the parts and installation, our part could save you almost $300!


How Does Our Part Feel Once Installed?

Things like ruts in the road, bumps, and other things are transmitted to the steering wheel, are numbed by the OEM dampener. Without the PERRIN Steering Dampener Lockdown in place, as you turn the steering wheel there is a delay when the actual wheels turn. Also just the opposite, as  things push on your wheels trying to turn them, the dampener has to flex before transmitting that to the steering wheel. That means your car can steer it self in a direction you don’t want, while the dampener flexes.

Once Installed, the best way to describe it is there is more “feel” to the car. You will notice in situations like the middle of a corner, you might normally make tiny corrections to keep things pointed the right direction, or you don’t correct your steering and the car moves around a bit. With our steering rack lockdown installed, your car just goes where you tell it to. You may even notice how you are automatically correcting the wheel with ruts in the road as you can now feel them and let the steering wheel do it’s thing as you drive over them. It is hard feeling to describe but once you install them, you will quickly find out how much better the car feels. Personally, I don’t think any customer is going to complain about the added feeling.

 How Does Our Part Work?

Instead of making a whole new joint, we created this part that simply locks out the rubber portions of the dampener. This does the same job as replacing the dampener with an STI part, but without all the labor and costs! You can see the before and after in the moving GIF above how it completely removes the flex from the dampener. Without even saying anymore, that picture should sell you on why you need this part! The picture below shows you how both halves comes together during the installation. This not only pulls the rubber pieces together, but also stops the upper portion from rocking back and forth. You can see this motion in the above moving picture.



What Cars Will This Fit?

After designing the part for the 2015 WRX, it was important to work backward with what else it will fit. Essentially every single Subaru model other than STI, has a dampener withing the steering rack universal joint. What we have found is that around 2005-ish, Subaru changed the part in a way that allows our part to fit. Using the picture below, you can see a gap through the side of it. The distance from the bottom of the archway, to the top of the flat surface must match this.


We created this diagram to help determine if it will work on their car, which helps us narrow down the specific models and years to exclude. Currently it’s the 2004-2006 cars that seem to randomly have different dampeners installed. Check out our website for the most up to date list. It is a giant list that grows every day! We would love to hear from everyone that installed this on cars other than the cars we have listed, so please feel free to email us and let us know!

 Email Us!

 Posted by on November 19, 2015 About Your Car, Part Design & Tech
Nov 032015

The Idea

A while ago, a customer said something to me that made me think about a better purpose for the PERRIN Horn Bracket. I mean everyone loves a good horn and loves that look of the Hella horns behind their bumper. But really, who uses their horn enough to warrant that. For a matter of fact, why not just install some red circles behind your grill :)

Ok, kidding aside, while horns are good to have and I loved my Hella horns on my 2015 STI and other 2015 WRX, I wanted to install something that was functional but still looked cool. Why not some LED driving or fog lights?  They would show up while turned off, they would actually allow you to see better, and it would be something I would use everyday (especially in the winter).


I started with researching LED lights that were smaller than 5″ and reasonably thin. There were so many to choose from and after getting a few samples of some high end lights, i found most to be really heavy because how how beefy they are made. Even though our Hella Horn Bracket is really thick 304SS, I didn’t want there to be small vibrations that would cause the lights to jiggle while driving down the road. After doing some digging, PIAA has a bunch of lights that would work. Since they are local to us and we have a nice hook-up there, I was able to test out a few.


I settled on some PIAA LP530’s, but a close second was the RF 3″ cube lights. Both fit perfect, look great, and are pretty lightweight. This is important as many others were about twice the weight and could compromise our bracket over the life of the car.


Everything you need comes with the PIAA lights, and the only thing I did is use my own M8 hardware to mount them to our bracket. Even with the bumper removal, the whole install only took about 1 hour. This was done on my Base WRX, and since it didn’t come with fog lights to start with, I had to install a switch. Had this been on a car with fog lights already installed, this would have been even easier!


What Car Will This Work On?

This works on the 2015+ car because the distance between the bracket and the gill is huge! I would say almost any light that mounts on center with the light will work on these cars (as long as you consider the weight). The 08-14 WRX/STI also has quite a bit of room but its the other cars that won’t work. There just isn’t enough room on the 02-05 cars and the 06-07 cars the grill will cover up too much of the light.


If you are not using a PIAA light, consider the lower profile the light is, the better chance it will fit behind the grill. The lighter they are the better to reduce the amount of bouncing around that could occur. The bracket for the light must be able to mount behind and centered with them as well. Lastly consider the outside diameter of the light and stick with something smaller than 5″.

This whole idea only works, because our bracket is made from heavy gauge stainless steel. Other thinner brackets, ones with a million holes,or ones from aluminum are not going to hold up, and or will cause the lights to bounce around a bunch. We over built ours to be able to handle the heavy Hella horns and it just so happens to work for LED lights!





Lights on…


Lights off…


The idea of installing some LED lights on a PERRIN Hella Horn Bracket is 100% valid, and 100% something we expect people to start doing! Trend started here! At least, I think it was…

It happened to be a nice foggy day during the pictures. It does make them a little grainy, but you get the idea.




 Posted by on November 3, 2015 Part Design & Tech
Oct 302015

See our Poll on NASIOC to help us figure out which style you like!    NASIOC Poll for PERRIN Gurney Flap


How This Came To Life

Like a lot of parts I come up, it starts with something I make just for my car that I think no one else will want, and then it turns into a real part. This is exactly how the Wing Riser Kit for the 08-14 STI Hatchback happened as well. One day I made a bunch of spacers and pieces to raise the wing off the car and next thing i know, people wanted it!

In the case of the PERRIN Gurney Flap, it happened exactly the same way. Adam bought one of the Camaro Z28’s with the Wicker Bill option and it got me thinking about doing that on my car. Just like the factory GM part, it would require drilling, and I was willing to do it as worst case I would just remove my wing. After finding center of the wing I went to town and drilled some holes. At this point the guys in the shop thought I was crazy drilling holes in my new car… I installed the inserts, cut some cardboard then started shaving into shape.


This part is a hard one to figure out because it can be made so many ways. Taller shorter, longer sharper, rounder and different materials. Literally, there are endless options. After lots of opinions and 4-5 versions of cardboard, I made a metal one and drove around for a few days deciding if it was cool or not. So many people actually liked it, that it started to become a potential real product for us to sell. The next step was to have a couple versions laser cut and install them on the car to get customers opinions. As of this moment the project on hold while we seek help from the Subaru Community. What style do you like? What do you NOT like about it? Any reasonable suggestions will be taken into consideration. We would love it if you participate in our polls we have going on social media, your opinion matters!


Product Details

What does this fit? Specifically, this fits any 2015+ WRX with the low profile trunk spoiler option. This comes standard on the Limited and Premium WRX, but it is an optional part on the WRX Base and STI Limited. We have seen the low profile spoiler installed on some of the Impreza Sedans, so there could be a few other models this fits. For now we are focusing on the WRX and STI models.

How does it install? We are currently tweaking the instructions, but quick version is this: Locate your first hole (center of wing), drill and install supplied insert. Bolt on Gurney flap, and use part to locate remaining holes (making sure they are centered vertically on spoiler). Double check measurements then drill remaining holes and install inserts using supplied tool. Bolt on wing and done! Beside being timid to drill some holes in your car, the install should be 1 hour or less.


How does it function? We have not tested this in our wind tunnel yet (we don’t’ have one actually) nor have we done any CFD testing.  Most likely will not go to those lengths until we get a little deeper into the project. At this point the primary function is looks as it adds a nice clean edgy look to the WRX’s and STI’s with the low spoiler installed. For sure this part does add downforce, but the amount it adds isn’t something we are going to provide to customers right away. Until then think of this part as a dress-up/rear deck lid cleaner. You can totally tell that it is working since the top of the trunk lid stays very clean.

Here are a few more pics to help.

gurneyrear2      gurneyrear1

Gurneyside1      Gurneyside2

Gurneyside3        Gurneyside4

gurneyfinal1      gurneyfinal2      gurneyfinal3

 visibility1       visibility2       visibility3

As this project progresses we will post up more info!

Email Me with any comments!

 Posted by on October 30, 2015 Part Design & Tech, Project Builds
Oct 282015

Upon the release of our PERRIN Electronic Servo Driven Gauges, we stumbled onto a perfect part to make, that would compliment them being installed on a 2015 WRX or STI. Something everyone would need and could afford!

In the past, we would have to slit a large rubber boot behind the turbo to fish wires and things through to get from the inside of the car to the engine bay. This was a simple location, but the issue is water and noise. Doing this opened up the door for water getting into the passenger foot well as well as you would hear engine noise a bit more. We just dealt with this on the 2002-20014 cars(as I am sure everyone has), but now on the 2015’s we stumbled across a pretty cool solution.


Subaru was nice enough to install a hole in the firewall just for us to use for passing wires and other things from the interior of the car to the engine bay. I know, they didn’t do this just for us, but we saw a perfect opportunity to make a part that any customer buying gauges, or installing things like water methanol injection or NOS systems would use. You can see the location of the hole in the above picture, which is in the same place on the STI and WRX. There difference is on the WRX, there is a simple plug where the STI has the sound generator tube installed. This is that weird tube that connects to the intake system and pipes sound to the inside of the car.



This hole opens up to the cavity where the windshield wiper motor/hardware resides as well as where the HVAC system sucks in fresh air. Within this cavity is another hole that is perfectly located to run wires and/or hoses completly out of the way of a passenger (or driver if in another country) and down to the frame rail. Just like the engine bay hole, it is covered by a plug on the WRX and on the STI the remaining section of the sound generator passes through it. In both situations, running regular wires through them will leave open holes, let in sound, water, air and look terrible, so we designed the PERRIN Firewall Grommet!

asm-gau-120_01 asm-gau-120_04

The PERRIN Grommet was the first rubber OEM type part we ever made. We have made many previous parts in urethane, but in testing, we just weren’t happy with the way it looked or functioned.  Using OEM type molding methods, we were able to create a part that will perfectly compliment any engine bay. You can see in the pictures below an example of  our plug being used during an installation of PERRIN oil pressure, fuel pressure gauges, and an Aquamist HFS-4 system. There is plenty enough room for 8 separate wires and hoses passing through it. In this example there is enough room to run 4 more sets of wires for gauges and maybe enough a power wire for a stereo system!


You can see in the bigger picture that all that is left to do is snug up the zip-tie and the installation is complete. We felt this was and important feature to ensure the wires were secure as well as relatively sealed from weather and heat from the engine. The


One last thing! If you look at the WRX and STI pictures you will notice that there are two holes! That means there are two places to install a PERRIN Firewall Grommet. While we will be selling them separately, we do expect most customers to buy two at a time. It is such an inexpensive part that there is no reason to not get two :)

We expect this part to do well enough that we will expand this into other sizes and fitments for other popular Subarus. So keep an eye out for more items like this from us!

 Posted by on October 28, 2015 About Your Car, Part Design & Tech
Sep 222014

If you read the entire post from 2015 WRX and STI Exposed article, you would know that the 2015 WRX shifter is one of the things that I feel is terrible about the car. Normally cars that use cable shifters have a very positive feel and provide excellent feedback, but that is not the case for the 2015 WRX.

This all started the first day I drove the car for an extended period of time. I first hated how the shifter felt regarding the distance between gates. It felt like 1/2 gate was really far away from 3/4 gate. Then 5/6 gate was really close to 3/4 gate. This led me to dig into the shifter more and figure out why this is happening. What I discovered was that the shifter is really sloppy feeling when its in gears 1 and 2 and really tight in the 3rd, 4th, 5th and 6th. This gives you the false feeling of the gates being weird. So how can we fix this slop? Easy……


The PERRIN Shifter Stop is the first of its kind for PERRIN as well as any Subaru. This wasn’t something we ever NEEDED to design before since the transmissions generally shifted really well. If you are a past Suby owner, you a probably wondering how sloppy the WRX shifter is, if you are going to notice this, and then how does this thing work. All good questions, and to be answered below.


How Sloppy Is The WRX Shifter?

Using the diagram below, you can see that there is a huge amount of slop in the 1st/2nd gate compared to the others. These measurements are taken in gear at the end of the knob and with very light action moving it left to right. You can add about .25″ to the below numbers if you push on it left to right with a bit more force.  The 1st/2nd gate is so sloppy that it almost feels like its in neutral on a normal car, so when this slop is removed, its amazingly different.  Almost to the point of making the car shift as good as the 6spd STI tranny.


After installing the PERRIN Shifter Stop, you can see how much this tightens up the slop. Going from 1.00″ of loose sloppy feeling in 1st and 2nd, to .12″ is very noticeable. Even people that have never driven the WRX notice how much better this feels just sitting in the car.


How Does This Part Work?

As you can see from the above diagram, there is a varying amount of slop in each gate. The PERRIN Shifter Stop only fixes the slop found in 1st/2nd gate. 3rd/4th gate is already very good because the internal parts of the transmission have very little slop in them. The 5th/6th gate changes because we have you adjust the OEM shifter stop to help tighten things up a little. The OEM shifter stop is mainly used for locking out reverse, but doubles as a shifter stop, lucky for us that it is adjustable!


You can see the OEM shifter mechanism above and how the PERRIN Shift Stop is similar to the OEM part but for the other side. When you place the transmission into 1st or 2nd gear, the shifter has nothing for it to rest against, so the play that exists inside the transmission (shift forks, syncros and rods) all gets translated to the shifter. In this case it’s more than 1″ of free play!

The PERRIN Shift Stop creates a physical stop on the shifter to shift rod mechanism, this controls the amount of slop translated from the tranny to the shifter. When properly adjusted, the amount of free play goes from 1.00″ to about .10″. Not to mention, the feeling of putting the transmission into 1st, or downshifting into 2nd is significantly improved and feels much more solid.


Besides removing the slop found in 1st and 2nd, you will find going from 2nd to 3rd and 5th to 4th is much more natural feeling and much more positive as the slop doesn’t translate into the sort of lost feeling of which gear you are in. One complaint I had before was the distance from gate to gate being different, and that completely goes away after installing the PERRIN Shift Stop.

This part is like many of our other shifter bushings an short shifters, once it’s installed you will wonder why Subaru didn’t just make it like this to start with.


Bonus Fix Included

Another thing I found while coming up with this part is the whole shifter mechanism moves around a bunch as well. The biggest culprit of this is the gap you can see in the below picture. Like with everything, there is a tolerance in what something is made to. In this case, the tolerance between the shifter mechanism parts is pretty large. You would think that the OEM bolts would suck this close, but they do not because they are a shoulder bolt. When they are tightened down they do not actually suck things together. We include some special SS washers that allow this gap to be closed up when the nuts are tightened. This tiny amount of flex translates into a much larger amount of flex the top of shift knob.



One of my favorite things about modifying cars is improving the way they feel and this part is a perfect example that. It makes such a huge improvement and is so noticeable, that it will bring new joy to your driving experience. This will be a mod that everyone will want and everyone can afford. Add the also affordable PERRIN shifter bushing to this same installation and you will be very pleased with the way your 2015 WRX shifts. This doesn’t only apply to 2015 WRX customers, but also 2010-14 Legacy/Outback with manual tranny, and 2014+Forester with  Manual tranny.




 Posted by on September 22, 2014 About Your Car, Part Design & Tech
Jul 262010

Super Steer has been a product we have kept secret since the inception of the company. This simple little part is like nothing else offered for your Subaru STI. Like most car enthusiasts at one time or another you have driven a go cart and noticed the super quick steering they have. You hear from time to time, a car has “Go- Cart” Handling, well now you can make your car handle more like a go cart with the PERRIN Super Steer System!


Its started years ago with the first WRX I had and the one thing it really lacked was quicker, sharper steering. First looking to things like aftermarket steering racks to solve this problem, I quickly found the issue is cost and installation. Subaru made quicker ratio racks as well as a few Rally companies, but at $2500-$5000 a pop plus a lot of work, this just wasn’t feasible for most people. This is what sparked the idea for the PERRIN Super Steer System.

The first prototype was built back in 2003 with intentions of it working on the WRX. Then shortly after the STI came out and it changed the whole project because of two things. One it needed redesign to fit this car, and two the STI craze made us focus our efforts on other parts shelving the Super Steer until a later date. Its now been 2 years into its testing lifecycle and its finally ready to release!

How Does the Super Steer Work?

So how can we make the STI steer quicker without the added cost of an entire steering rack, or extensive installation? Simply be relocating the Steering tie rod connection at the hub. Moving the linkage pivot closer to the center of the hub, requires less input from the steering rack to turn the hub a given amount. Normally when you turn the steering wheel say 90 degrees the wheels turn about 6 degrees. After installing the PERRIN Super Steer System, turn the steering wheel 90 degrees and now the wheels will turn about 8 degrees! Meaning you don’t have to turn the steering wheel quite as far as you did before in order to get around the corner. This, 2 degrees could mean the difference of keeping both hands on the wheel, or having to cross your arms for a turn.


Here is another diagram showing how this change in leverage at the hub effects how much the wheels now turn. This diagram is exaggerated slightly to show the difference.


The heart of the Super Steer is the tie rod bracket. This bracket is what relocates the steering tie rod closer to the middle of the hub. Mounting from the OEM tie rod mount and securing to one of the break shield mounting holes, you can be assured that this over built part will not fail and give you trouble free operation!


Included with the Super Steer kit is new shorter tie rods. Instead of using some off the shelf tie rod we took it up a notch and made custom length tie rods using high quality Teflon lined spherical bearing rod ends. Besides providing superior strength and being lighter than an OEM type, these allow for a wide range of adjustments depending on the application.


So with the wheels moving further with every turn of the wheel, the next problem we faced was limiting the wheels rotation. If left alone it makes for a great turning radius but it with wider tires, you get tons of rubbing! Our Steering rack collar locks control this problem. They fit between the steering rack next to the OEM rack stops. These simple devices create new stops for the steering rack and limit the travel of the rack to accommodate wider tires and even cars with wider tires and PERRIN PSRS installed.



How Much Quicker Steering?

So how much quicker steering does this make your STI steer? Here are a couple graphs to help you understand how the Super Steer works.


This is a comparison of a WRX and an STI and how steering wheel input effects the amount of turning occurring at the wheel. For instance if you turn the steering wheel 90 degrees in your stock STI, the wheels turn about 6 degrees. After you install our Super Steer System, turning the steering wheel 90 degrees now moves the wheels about 7 degrees. The extra 1 degree of steering translates to 23 degrees LESS steering wheel input to get the same movement! That is huge! When turning the wheel 135 degrees(right about where you start to cross your arms while turning) the change is almost 2 degrees which is about 45 degrees less steering input needed!

In simple terms think of a clock. After installing the Super Steer System, the corners where you would turn the steering wheel to the 3:00 position, you’ll now be turning the wheel to the 1:30 position.

Sometimes you here steering systems are rated lock to lock. That is a tough way to compare because sometimes this is affected by the ability for the car to turn a tight circle. So while lock to lock can be a way to describe the Super Steer System, its not an accurate way to describe how much quicker it is. The best way to compare is how much the steering wheel turns in relationship to the wheels turning. Below are some other cars to give you an idea how your STI will compare!


I spent time going around from car to car gathering data from known quick steering cars. While the WRX is not slow steering relative to you normal grocery getter car, its something most STI owners can relate to since most of them had one at one time or another. The WRX steering is the slowest steering of the bunch as is the Lotus. Part of the reason why the lotus is slow steering is that it does not have power steering. But the Lotus makes up for it with Ackerman Angle. More on that later. In our world the EVO is known to have super quick steering compared to the STI. You can see in this example how the STI with Super Steer installed, steers quicker than an EVO! We threw in some steering data from an Ariel Atom to give you and example of how an extremely fast steering car compares to somewhat normal cars.

In these graphs we are showing just one side of the car and how much it turns compared to the steering wheel. What most people don’t know is that both wheels don’t turn the same amount! This angle difference between the left and right wheels while turning is called the Ackerman Angle. The Ackerman Angle is not something that is adjustable on a road going car, but it is something that greatly effects the handling of the car.

Added Features of the Super Steer System

Added Anti-Ackerman Angle

Imagine your car is turning in a small circle in a parking lot. The inside wheels are turning in a much tighter circle than the outer wheels. So naturally the outside wheel doesn’t need to turn in the same amount as the inner wheel to make the circle. Its this relationship from the inside to the outside wheel turn-in that the Ackerman Angle comes into play. A Pro-Ackerman setup is where the inside wheel turns in faster than the outside wheel. An Anti-Ackerman setup is where the outside wheel turns in faster than the inside wheel. Stock car guys and real race car guys will say a Pro-Ackerman setup is better for higher speeds, and an Anti-Ackerman setup is good for short tight courses. A simpler way to think of this is Anti-Ackerman creates some toe-in while turning. is when turning the wheel, the outside wheel is toeing in or toeing out compared to the inner wheel.


In our testing of a bunch of cars and their relationship of steering wheel rotation to wheel rotation, we also gathered lots of data regarding OEM Ackerman Angles. 08 STI and most OEM cars are Pro Ackerman meaning the inside tire turns in further than the outside tire. The only car we tested to be Anti Ackerman is the lotus. Having driven Lotus many times before, you can feel how the steering ratio is slow at lower speeds, but as the car goes faster and faster it steers quicker and quicker. This is because of the Anti-Ackerman angles. One could use this info and determine that the closer you are going to get to an Anti-Ackerman setup the quicker the car is going to turn. The Super Steer system is removes some of the Pro Ackerman angle effects making the Ackerman Angle closer to that of some of the quicker/twitchier steering cars out there.

Ball Joint Extender

A feature that is built into the PERRIN Super Steer is a tie rod ball joint extender. When you lower your car, it changes some of the suspension geometry for the worse. So things like ball joint extenders and roll center kits bring these things back to where Subaru designed them. The Super Steer has a tie rod ball joint extender built into it! This saves you a couple hundred dollars if you ever plan to install a roll center kit. We made our offset such that it suites cars lowered around 1.5 – 2″.


The idea behind the Super Steer is simple. Make your steering quicker by changing the geometry of your front suspension, but do so in a way that it doesn’t affect the geometry in a negative way. We feel we have done this with lots of testing over the last few years. There is one downfall of the PERRIN Super Steer System, when you get out of your STI you will have to settle for boring, slow steering normal cars! Who will want this? Any autocrosser, any racer, any casual track day participant, and pretty much anyone who has an STI and drives it!


We have had a lot of questions come up regarding how strong this part is and also have questioned the Super Steers integrity. These below points are to help customers better understand those concerns. We really hope that this helps customers feel better about the part.

Tapered Bolt is Stronger??

This mentality of it being stronger is a concern for some, but the taper has nothing to do with being strong. Our body is being tightened between two surfaces, the bolt and the hub. Its not relying on the strength of a stud to work against like the OEM part or other ball joint extenders. In the OEM application, the stud is relocating the point of force 1.25″ or so form the hub. This puts a lot of force and deflection on the shaft of this part. This requires that is very strong. Which is why people who make extended versions of these parts have to make them really high quality as you are really starting to add stresses to the shaft as you make it longer. Our part is mounted right to the hub surface making the point of force very low. The deflection all goes into the billet body and carried by the both bolts. Again, very stiff.
The tapered part of ball joint extenders has nothing to do with making its stronger, it only has to do with keeping it tight with all that force trying to work that 1.25″ lever arm back and forth. But in the case of the PERRIN Super Steer, this isn’t an issue.

Will the Super Steer Come Loose??

The idea that it could come loose is valid concern. But if that was the case then what about all bolted connections on the car. Are all connections using bolt and holes loose and or moving within their mounts. Think of strut bolts, control arm bolts, trailing arm bolts, and others where they are under far more stress and all have holes larger than the bolts. They do not come loose because they are tightened properly.

For example, your front control arm forward bolt uses a 12mm bolt (11.08mm on the shank and 11.78mm on the threads), that is in a hole that measures 12.35mm on the arm and slightly larger on the subframe. That is .57-1.27mm of slop. But this bolt doesn’t come loose because its tightened properly (and has way more stress on it than our part does). Same goes for our part. In our case the head of bolt is locked into one side and only has a small amount of slop on the hub side. When its tight its not going to come loose.

But for that matter, there are many applications that use steering tie rod ends with ZERO TAPER to them (VW/Audi’s, Mercedes, Jag’s,Land Rover,..) They use a single sear setup, and are similar to how our OEM front endlinks connect. Some only have a chamfer to make sure its centered over the hole.

I think that with that, there is plenty of info out there for customers to make an educated guess if this is a product for them.


 Posted by on July 26, 2010 Suspension Part Design &Tech Tagged with: , , ,
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