For a while now, items like Blow-Off Valve Spacers have been available for the Fiesta ST, and while they make the “BOV” “woosh” noise people want, they’re only getting the sound with none of the benefits of an actual blow-off valve. To me, that’s a tragedy. If you’re going to make the extra noise, may as well at least make the extra power, right?


Turbosmart has finally released their Fiesta ST-specific KOMPACT 50/50 Blow-Off Valve for Fiesta ST, opening the door to a BOV option that delivers sound and actually ENHANCES performance. I’ve been a long time big believer in recirc-valve type BOV systems. I’m a low key kind of guy (as far as noise goes), and extremely performance oriented – since none of the “BOV spacers” on the market offered any performance gain, in all honesty, personally I was against the idea of any Vent-To-Atmosphere type BOV for ST applications – I didn’t see the need or benefit of such a thing. However, thanks to some rather interesting data, Turbosmart has managed to change my mind.

A while back, I wrote a tech piece about the need for a chargepipe and upgraded diverter valves for BMW N54/N55 engines – the difference in power was a whopping 29wtq between stock and a turbosmart BOV – why?
Because the OEM plastic bypass valve and wastegate, being made of plastic and other cheap materials, don’t seal perfectly and as a result, leak boost, resulting in slower spool-up times, reduced low end response and difficulty keeping boost once you make the boost at high RPM.

As most of you probably know, the blow-off valve or bypass valve is the thing that relieves excess intake manifold pressure when you let off the throttle. The wastegate on the other hand is a little diaphragm on the turbo that decides WHEN to relieve excess boost pressure and to stop making boost at a certain PSI. In simplest terms, the wastegate actuator is a device that regulates boost pressure.

Turbosmart replaced the Internal Waste Gate and Blow-Off Valve of their Fiesta ST with no other changes made to the car, and well, check out the difference for yourself.

Pretty impressive, no? The dyno sheet above was enough to pique my curiousity enough to put a set on order for our Project Fiesta ST. While we haven’t yet seen the difference firsthand, we expect that it’ll be noticeable.

On the new 2.3L Mustang EcoBoost, which shares its engine with the upcoming 2016 Ford Focus RS, there’s a ton of power to be had and a quality blow off valve like Turbosmart’s 50/50 Blow-Off Valve for Mustang EcoBoost will help give a tuned Mustang EB the power it needs to embarrass a GT at a stoplight.

If you’ve got a Focus ST and want the same benefits, Turbosmart has you FoST guys covered as well with the option of either a Turbosmart Kompact Dual Port 50/50 BOV for Focus ST or a Turbosmart Kompact Plumb Back Recirc type BOV for Focus ST if you like keeping a low profile while bolstering your Focus ST performance.

Want to get more power out of your ST? Have questions about a Turbosmart BOV or IWG? Need to make an installation appointment at the ModAuto install shop in La Habra? Call 714-582-3330 to speak to our team of Mod Experts who can help guide you to your next upgrade.

Once we fit our ST with our Turbosmart upgrades, we’ll share out firsthand experience – thanks for reading and we hope this has given you some food for thought- see you next time!

Story Nick Gregson
Photos courtesy Turbosmart