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Improve Your Yamaha Waverunner Supercharger Reliability with a MACSBOOST Blow off Valve

You can hear the improvement!

Planned obsolescence is a fact of life in 2019. Light bulb conspiracy anyone?

Have a look at the hose clamps in your Yamaha Personal Watercraft. Look at The screws. They are not stainless steel. While the bands are stainless the clamp will only last as long as the screw will. Perhaps it is not a deliberate effort to create a product that will fail right after the warranty ends. Perhaps it is. We will give Yamaha the benefit of the doubt and place the blame on a cost cutting bean counter. Hulls are light weight, but also not as forgiving as those made in the past. Kudos to Yamaha for improving quality in those areas on the GP-1800.

Either way, if you want a factory new personal watercraft you can only get what is available on the showroom floor.

Yamaha’s Supercharged 1.8L engine is a beast. The latest SVHO variant has taken performance to the next level. Then in an amazing feat Yamaha combined their lightweight and stable VXR hull with their highest output engine to create the GP-1800. The GP is an amazing example of factory hod-rodding and the result has been one of the industries best selling PWCs.

This future racer is all smiles on his 2017 GP-1800 with MACSBOOST Blow off Valve

Where are we going with this? Yamaha’s supercharger has a weak link. They incorporated a sprag clutch to reduce the torsional load on their over revved gear driven supercharger. This is different from the clutch pack design from Sea-Doo with its own pro’s and cons. This is a reliable system when used in a boat that never leaves the water, however when used on a PWC that spends a significant amount of time airborne the equation changes. Under extreme conditions such at P1Aquax racing it is not uncommon to need to replace the clutch after 2 motos or 2 tanks of fuel! These boats all run aftermarket blow off valves doing their best to keep their clutches healthy. When the clutch goes the rider typically experiences intermittent full power before it reverts to a docile 0psi of boost. Obviously losing 1/2 of your horsepower is going to knock your off the top of the podium.

Yamaha 1.8l Supercharger with broken shaft, minced gears and grenaded sprag clutch.

So, what can the rec rider do to keep your clutch in good working order? We off a high quality MACSBOOST Blow off Valve kit in a pre-assembled kit with an industry leading price.

What does the MACSBOOST BOV do? When the throttle is abruptly closed the pressure generated by the supercharger has to go somewhere. The pressure spikes until the supercharger stalls due to flow abruptly stopping.. This pressure surge causes the load to spike on the supercharger clutch and causes the most wear and tear on your clutch sprags. How do we reduce this pressure spike and thus reduce the load back fed into the supercharger system? The MACSBOOST BOV uses the vacuum signal behind the throttle plate to open the BOV and allow the air to escape back into the hull.

MACSBOOST Blow Off Valve installed on a Yamaha Waverunner GP-1800

Our kit includes a super high quality blue silicone hose. This hose is manufactured on a true spline curved mandrel to minimize pressure loss and improve fitment. The transition is super thick and reinforced with many layers of polyester fiber. This extra reinforcement ensures our product can take the pounding of marine duty year after year.

You will notice we use an ALL stainless hose clamp on our valve. Not just any clamp, but a gapless euroseal clamp. Our vacuum hoses are oversized and need no zip ties. That means no zip ties to break or fall off. Our T is also barbed and interfaces between the factory MAP sensor and manifold. We make the extra effort to include the highest quality 9mm silicone vacuum line, nylon tee ,all pre-cut and configured. Our valve is held in place by a stainless circlip. We go the extra mile to provide the highest quality product at the best price.

Yamaha blow off valve map sensor connection macsboost bov
No drilling necessary, attach your BOV here!

Don’t wait until you have a dead clutch to wish you had been to first!

13 thoughts on “Improve Your Yamaha Waverunner Supercharger Reliability with a MACSBOOST Blow off Valve


    1. We use a SQV style BOV. It is a custom piece we have made to MACSBOOST specs with marine fasteners and quality internals. We run these on our personal GP1800s and love them.

      1. Will the presence of the BOV void the factory warranty?

        1. It should not void any warranties. However, our kit can be removed in just a few minutes and the factory hoses replaced with no trace of modification.

  2. How does that work with a fizzle intercooler

    1. Our MACSBOOST velocity stack intakes deliver more rpm than the competition. Try one and stay ahead of the rest!

    2. This BOV kit is designed for the factory intercooler or an aftermarket with the same physical shape.

  3. Why do most people say NOT to tap into map sensor hose and recommend drilling the plastic manifold for vacuum hose. Forums go back & forth with this subject.
    Does tapping into the map sensor hose honestly set off ECU with false readings?? I’m only asking bc I rather not drill out my plastic manifold. Thank you.

    1. Fake news? Don’t believe everything you read online. No it does not set off the ecu, nor does it cause false readings. Our setup used custom thick wall tubing and special barbed tees that are designed to not need zip ties. It is the easiest to install and the most secure. Nobody else uses what we do. We ride what we sell!

      1. I appreciate your input, Supermac!

  4. I had no issues with this BOV installation. Installed, then went out and thrashed the GPR. No idiot lights, machine ran great.

  5. Hi, I’m looking for a blow off valve for my Yamaha fx svho 2016 which one would I need and how much is one .
    Kind regards Marc

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