StringerStacks Variable Length Velocity Stacks offer a huge performance gain and improved throttle response over stock velocity stacks (or bellmouths as they are also called) that cannot be gained from the installation of any other aftermarket products.
These electronic variable-length velocity stacks transform the bikes we have fitted them to. Our track testers have not wanted to take them back off their bikes!
StringerStacks Variable Length Velocity Stacks are printed using 3D printer technology using a carbon fuel resistant filament and they are delivered as a complete replacement stack kit coupled with an electronic motor and CPU to lift the upper stacks at a set RPM. This approach allows us to create variable stacks like Yamaha, BMW, Ducati do from the showroom and allows us to create velocity stacks that increase power and throttle response at mid and high rpm, not only giving proven gains on the dyno chart below, but this doesn’t tell the whole story, in real-world use – where unlike on a dyno – the ram air into the airbox is properly fed, thus getting horsepower and torque gains and throttle response that cannot otherwise be achieved with bike modifications at this price point.
StringerStacks Variable Length Velocity Stacks are a DIY plug and play installation, Stringer Stacks come complete and ready to install, if you have retained your smog/AIS/PAIR valve system then you should select the airbox installation kit, this comprises a grey rubber bung and a hole cutter to feed the electronics from the CPU to the stacks, customers who have removed the smog/AIS/PAIR system can run the cables through that bunghole.
If you prefer our technician to install the stacks for you at his UK based workshop then this can be done on a time and materials basis, please contact us for a price, to get the most out of the stacks we advise either a custom dyno map using an ECU tuning product such as FTecu and where available ActiveTune to correct the fueling to get the biggest gains and best throttle response from your bike.
StringerStacks are available for the following model bikes
- Aprilia RS660
- GSXR1000 K9-L6 2009-2016
- GSXR1000 L7+ 2017-2022
- GSXR600 2011+
- MV Agusta F3 800
- Yamaha MT10
- Yamaha R7
- Yamaha R6 06-07 2CO
- ZX10R 2011-2015
- ZX10R 2016-2020
- ZX10R 2021+
- ZX636 10-22
- Ninja 400
- CBR1000RR 2020+
- CBR600 2007-2021
- Triumph 675
- Triumph 765
(if your bike is not listed then please contact us as we are looking to add more bikes we cover)
Here is a really nice review by the 2014 FIM WSBK Champion, current Suzuki MotoGP test rider and FIM EWC racer and BTsport MotoGP pundit Sylvain Guintoli
The creator of these products, Ray Stringer from Stringer Race Services as spent the last 24 months developing and testing the stacks on the bench through millions of activations and in BSB Supersport onboard Moto2 bikes for the entire 2021 race season, they are proven to be extremely reliable with zero failures in testing, furthermore, the CPU is enclosed in a vibration and waterproof housing and can be mounted on the fork leg (for ease of access to the test button) or under the seat or tank. We warranty the product to be free of defects on delivery, as they are race products there is a limited warranty, but all parts are covered by a 12-month manufacturing defects warranty.
StringerStacks are intended for high-performance sports bikes, they are intended for race use, Stringer Race Services, nor Bienvenu Motorsports Ltd / Veloxracing do not accept any liability from damage or injury from the installation or use of these performance products.