Attention Getters: Go Fast Bits Blow Off Valves & Bypass Valves

When installing a BOV it's important to be aware of the ratio you're venting to the atmosphere. GFB offers a dual port option, so that users have the ability to adjust to different ratios that don't all effect the MAF sensors and require no tune. However, if you have a MAF sensor and you want to upgrade to a BOV that vents to atmosphere 100% it's recommended you get a tune that uses speed density, so the ECU is able to account for the correct air fuel ratio. Without a tune, some of the air that passed through the MAF sensor has already been accounted for and the ECU doesn't know the BOV got rid of some of it therefor the "correct" fuel proportion will be distributed causing the car to backfire.

So NOW we can get to the how to choose what BOV should you get. The easiest way is to go to gofastbits.com and use their drop downs to see what they have for your application. For most of us this will be the easy button we get to use and then we just have to decide to do we want one that's loud? Then GFB recommends their Hybrid or VTA options for all of the BOV noises. Do you want it to be adjustable sometimes loud but sometimes quiet? There are 3 options they have, one is the hybrid that allows for full vent to atmosphere, 50/50 or recirculating. The next option is one that would allow you to adjust the sound without plugging or unplugging hoses, the Respons and DVX. The Respons allows users to adjust venting ratios from 100% recirculating to 100% atmosphere and anywhere between by twisting the adjustment rings. The DVX can be adjusted by moving the lever, the close the lever is to the x that looks like a mute button, the quieter the BOV will be. The further away it is from the x, the louder it is! If you want an even easier way to control the sound of the BOV, then GFB Deceptor Pro II is the way, as it allows you to control the sound from the inside of the car with a remote. Fun fact, almost all of these BOV's you will see listed on their site are bolt ons, making this head turner decision even easier. 

If you made it this far and you're still thinking you rather have something that doesn't make any noise what so ever because you want to be sneaky and look stock, live in California or not get in trouble for turbocharging the car, bypass valves are probably your best bet. GFB does have a C.A.R.B approval on the T9351 DV+, for those of you who live in a state that require that.

Bypass valves are very similar to the blow off valves but instead of releasing the pressurized air to the atmosphere they recirculate it back into the intake after the airflow sensor but before the turbo inlet. With the bypass valve, a huge advantage is you most likely won't need a tune for it since the air that's being measured by the MAF is going into the combustion chamber after being routed back to the intake system unlike where it's blown out by the BOV. Bypass valves still have the pros of holding boost, minimizing turbo lag and that throttle response we loved to have when we're boosted. One thing to note with bypass valves though, is when you start making a lot of horsepower these might not be the best application any longer as they would have a hard time flowing enough air. Typically this happens when you exceed the limits to the factory location turbo , but GFB can help you get fitted with the proper application if/when you reach that point though. 

Some options that GFB offers a few different bypass valves to consider, their SXV, MACH 2 and DV+. The SXV is a plug and play for the plastic OEM “Bosch” style bypass valve found on early European turboed cars and side by sides. It’s made of better materials that don't crack, stays closed until it needs to open, which increases throttle response and eliminates turbo lag. Next is their MACH 2 has all the same benefits and is more for the Subarus and similar platforms. Both of these are performance based and uses GFB's Turbo Management System (TMS), to enable up to 30% faster boost recovery when shifting gears. The TMS is a valve that is designed to keep as much as boost pressure in the charge system between shifts.

The DV+, are for some of you newer 2022+ WRX Subaru’s with the FA24 motors. The DV+ replaces the factory electronically controlled diverter (bypass) valve. The electronically controlled diverter works similar to how the previous BOV/BPV do except these are controlled by the ECU instead of pneumatically. The ECU is what tells the valve to open when the throttle is let off vs the pneumatic versions that are controlled by pressure from the manifold dropping before the valve can open. A con of the ECU controlling the factory diverter is it's very binary to open or shut, as you're on throttle it remains open for about 2 seconds and this delay can cause drops the intercooler pressure. Which can be a problem, especially in a manual because as you're shifting you have no built-up boost, making the response time laggy and not fun to drive. GFB has been waiting for this moment to help the Subaru fam out since 2013, when they first made these DV+'s for other vehicles experiencing this issue. GFB DV+ uses a "pilot actuation" system meaning the solenoid controls a pilot valve opening and closing. The stroke of the solenoid is reduced to a 1mm stroke instead of the stock 5mm one, allowing for a faster operation. So, when the ECU tells the diverter, to open the solenoid, opens the pilot valve allowing the boost pressure to open the piston and then once the targeted pressure has been released the spring then pushes the piston closed regardless of the ECU telling it to stay open. So main improvement is GFB DV+ is able to open and close progressively whereas the factory one is a binary on off style. Fun fact again, almost all of these BPV's you will see listed on their site are also bolt ons, making this stealthy decision even easier too. 

So, all that information was great and helpful right? But you're, still wondering why GFB? Well, I asked their Head of Engineering, Brett Turner, what sets from the competition and some things about their quality assurance, how do they test their products, as well as things they're genuinely proud of when it comes to their process.

The first question I asked Brett was quality related - everyone always says they do QC (Quality Checks), but what makes GFB stand out - how are they ensuring quality products? His reply was first and foremost their in-house design, manufacturing and assembly are all up to ISO9001 certification standards. Which if you don't know, that's a globally recognized standard saying the company has a defined controlled quality process for each of their steps. Brett goes on to share that their products are inspected both for visual and operational quality checks. The critical dimensions and tolerances are tested on every part - Such as for the clearance of the pistons and bores, they're measured with a 3-point anvil micrometer and a bore micrometer and are held to a clearance of 0.0005-0.0011". Their less critical dimensions are batch checked but still do not vary by more than +/- 0.1mm. As mentioned, all products are visually inspected and even products that have something simple as a laser engraving being slightly off is rejected from being sent to the customer. For those of you not familiar with manufacturing processes, it's a pretty big deal that GFB does it all IN HOUSE, which means they have total control and the ability to react quickly if there's a problem in the process and aren't held at the mercy of outsourced work. In house processes are usually the ones that are able to provide the best quality since they're also able to be proactive and continuously improve the way they do things, making mistakes less and less.

The next question I had for Brett was about their testing, how do they test the products to ensure they're working? Do they use customer cars? Dyno runs? Fixtures with air running through them? He answered the prototype parts are 3D printed, then tested on an airflow bench that uses compressed air to run through and evaluate if the product is performing to their desired spec. Next the parts are machined and tested on cars before having the okay to go to final production. Brett brought up a great point on how testing one car alone sometimes doesn’t' mean things will always work out as planned, as different modifications can cause things to respond quite unexpectedly. He used the VA WRX as an example, where they tested the BOV's for the car, it passed, until a customer had stalling issues with a bypass valve. After some research they were able to find the FA20 engine had a 33mm inlet, but the actual valve size was only 12mm and the car had a stage 1 tune with a cold air intake where the MAF sensor was relocated closer to the turbo. Brett's team was able to understand that with that set up their valve vented more air than the factory valve, which helped performance but changed the MAF readings as the engine was approaching idle. Again, since they do everything inhouse, were able to test and find a solution that worked. Brett's team ended up installing a bump stop inside the valve to limit valve travel so the flow would be closer to factory values. This kept the boost holding and throttle response benefits and a happy customer! 

The last and final question I asked Brett was - Is there anything about the design, testing or manufacturing process that you're really proud of and makes GFB unique? His reply was touching on my intro to this whole thing of how they started in the Subaru world in 1998 and were the first ones to make a dual port BOV then to also solve stalling issues for a vent to atmosphere BOV on a Subaru. Brett mentioned how they were also the only company to offer a dual port BOV with a venting bias adjustment. Remember that Hybrid valve we touched on? That's what he's referring to as they were the first ones to offer that in 1999! Brett mentioned another huge plus is they're the first in their field to offer a lifetime warranty. I mean, that's pretty bold of them and speaks for itself on just how good of a product they make and how willing they are to solve any problem that comes their way. 

Thank you guys for reading, hope you learned something, like how cool it is to have a company literally started to make a Subaru better! We will be back for part two when we go over GFB waste gates! For any questions you guys may have check out their website, gofastbits.com where they have how-to videos, guides, and a team ready to help by email or Facebook messenger (Ask for Will though). Be sure to follow along on their social media channels to stay up to date with the latest products they come up with!