Do you need a Blow Off Valve for your Supercharged PWC?

[@watercraftjournal]

Great video, but there's some key points that were missed: 1. 300 and 310HP Kawasaki engines came/come with a BOV because at peak RPM they generate 16.8psi. The maximum boost generated by a Sea-Doo 300 ACE is 8.8psi. The SVHO is 8psi. These are VERY safe boost levels even when pinned at 7700rpm and dropping to idle. 2. Centrifugal superchargers do not generation positive atmosphere until late in the engine's torque curve. 4,400-to-4,600rpm is when boost gauges begin to register usable psi and deliver extra fuel. 3. When you release the throttle trigger it closes the throttle blades...slowing the engine RPM down, so the supercharger is no longer generating boost at any sort of excessive levels. 4. Unspent/unused boost does not cause (in stock psi PWC) supercharger clutch slippage. Erratic throttle control does. The slippage in centrifugal superchargers is/was originally "baked in" to the design to protect the SC drive. Better throttle management software has made it so OE superchargers require less slippage - but all healthy OE superchargers have slippage for this purpose. 5. Even major aftermarket parts vendors have noted that ONLY watercraft generating MORE than stock OE psi levels require an aftermarket BOV. And no, an ECU does NOT increase psi levels enough to necessitate one. 6. The OE's allow the intercooler and tubing to absorb the unspent psi until the throttle reopens, permitting the remaining latent psi to pass in. Owners of previous 255 and 260 Sea-Doos would feel this surge regularly. 7. Latent/stored psi degenerates rather quickly (3rd law of thermodynamics). This positive atmosphere also does not experience a reversion effect (traveling back up), but expands the intake tubes and contracts as it depletes. (Again, speaking for low boost/stock OE psi applications.) Again, great work! I love your channel. Keep it up.

[@TheShipsLogg]

Thank you and thanks for the additional information!

[@kkutube1972]

Thanks

[@kkutube1972]

@@TheShipsLogg Thanks.

[@t.j.goldwater]

Hi there , I have built a mini jet boat with the svho engine. Bone stock, only ribbon delete. With the S/C in front of the engine, I have the air intake between the seats. When I let of the throttle I clearly hear the thuthutu noise. Isn’t this air blowing back through the S/C?

[@patrickkennedy7756]

I really like how you are professional and factual in your videos not opinionated, snarky and arrogant like a different PWC channel. Not saying any names but I cant stand that guy for those reasons. Kawi... On another note the "clutch" in any vehicle actually is the wear and intended weak point so other more expensive components dont break or wear. So a clutch is intended to be a wear item.

[@silverdollar6548]

I also capt. Frank am not an aggressive rider but will occasionally enjoy the need for speed, with that said, I don’t feel I need this valve installation. Though I do respect the aggressive style I tend not to creat a days work and chance blowing my back out. As always Capt. Frank, excellent vid and thanks once again.

[@TheShipsLogg]

Sounds like you and I are on the same page!!

[@2SHARP4UIQ150]

Great video. Basic explanation of what a Blowoff is.

[@OldGreyBeard45]

I’ve got a 21 RXP-X 300 w/ catch can, 90 velocity stack and scom. I do run wide open but never just let off, I just ease out of it until it’s slowed down enough to let off. My wife has a Spark so I mostly just cruise around at her speeds anyway. Trying to get her to trade it in for a bigger one but she’s small and scared of the big one lol

[@TheShipsLogg]

Smart way to ride. Let your wife know that a bigger machine will be a smoother ride when the water gets rough. Maybe that will do the trick! 😉

[@jajcozucchini5438]

Thank you for the video, It made me understand why do I need 3rd clutch already on my 169 HR SVHO Great educational video ,

[@TheShipsLogg]

Thanks. I'm glad it helped.

[@gerardotorres9963]

Excellent video very well done you explain everything I have 2021 FX SVHO I am not aggressive driver but sometimes I really like to go fast that’s why I bought that machine I put the blow off valve from Riva racing just to be protected because let’s face it we spent almost $20,000 And on my case I am not a reach guy

[@TheShipsLogg]

Thanks Gerardo!! One thing that the FX SVHO does really well, is go fast!! Happy Riding!

[@MrKevcola11]

I really enjoyed this video, I’ve come across your content b4 & yes I’m an aggressive rider who blew his clutch 😂

[@TheShipsLogg]

Thanks for watching. I bet that new clutch was worth it though, wasn't it? 🤣

[@jasonmekush5280]

Yeah im w wcj here no blow off valve needed unless u go to a big wheel motor.

[@antoniosampedro2804]

I don't have one yet just took my permit to be legal in NJ, but I love your videos and you sir are a great teacher.

[@TheShipsLogg]

Thank you! Hopefully you can get some good riding in up there before the weather gets cool.

[@spartacane5904]

Thanks for the info

[@TheShipsLogg]

You are welcome!!

[@lynncampbell8503]

Will this void the warranty. 22 GP 1800 SVHO

[@TheShipsLogg]

It should not as long as the job is done right. Most people probably don't need one though.

[@seadogg404]

Well explained . I need one

[@TheShipsLogg]

Yes you do!! I've seen you ride! 😂

[@1989rrichard]

It needs a blow off valve the same way almost if not every supercharge vehicle or turbo charge need one. If it don’t come wishbone and u put one on it always have a benefit , the reason u need one is because when u are in the throttle and u let off all that back pressure put stress on the turbo or supercharge .

[@TheShipsLogg]

@@1989rrichard It is true that a lot of forced induction engines need them but not necessarily all. It depends on the engine and the amount of boost that the turbo/supercharger can create. That being said, adding a blow off valve when you don't really need one won't really hurt anything so you may choose to do it simply as a precaution.

[@jayppop3333]

Wonder if you can feather the throttle to help release pressure

[@TheShipsLogg]

That does help as it prevents "slamming the door" on the built up pressure.

[@1989rrichard]

It does it will flutter tho

[@scottmurray2532]

Thank u for this video, rxpx owner

[@TheShipsLogg]

You are welcome!!!

[@kupar2095]

So if I understand correctly all that gasoline air mixture goes into engine compartment?

[@TheShipsLogg]

No gasoline. Just the compressed air. The blowoff valve releases any unused compressed air before it reaches the combustion chamber.

[@donaldbell9669]

I am one of them aggressive riders how much does one of these cost?

[@TheShipsLogg]

There are different brands and it also depends on your ski but I would say that you should be able to get one for under $500

[@CrochetNewsNetwork]

Man I’m learning more from your channel than any other! Well done sir. I ride pretty much like you. However I’m not typically mechanically or maintenance inclined , but your videos now give me confidence that I can properly take care of basic maintenance. You as well give me a knowledge base in which I can intelligently speak to dealer, repair shop, and know what accessories I might need. I’m still agonizing over a 2022 Yammy FX SVHO limited and the 2022 Seedoo GTX 300 Limited. Although the Kawasaki has made wonderful improvements for 2022 I’m just not that keen on the style. It looks too busy to me. I wish I could ascertain what hull and seats of these three jet skis has the most comfort. Dealers hardly have anything in stock let alone a test drive. Any advise fro you would be enormously appreciated

[@TheShipsLogg]

As it turns out, I was just having a conversation with. A PWC mechanic yesterday. We were talking about the differences between Yamaha and Sea Doo. We both agreed that Yamaha is a more reliable machine but Sea Doo is more innovative. They do come up with some cool features before anyone else does. My Yammy is very comfortable for me but I know that a lot of people rave about the comfort of their Sea Doo. Hope this helps and I'm glad my videos are helping you.

[@CrochetNewsNetwork]

@@TheShipsLogg - thank you sir for your reply. Your advise is greatly appreciated. What I appreciate is your unbiased fact based information. I will probably go with the Sea Doo GTX 300 Limited as I live up in the Pacific Northwest . Meaning my summers are short, no salt water, and a few local lakes. I agree with you the Yammys are more reliable, but I’m crossing my fingers I won’t have many problems with SEA DOO due to the fact I won’t be riding too hard. We do have a couple large lakes that get quite rough so I’m hoping for a low and wide hull to cut through along with a comfortable seat. At my age I have some back pain and can’t do a whole lot of bouncing around at 45 to 59 mph However when the water is smooth, I’m a full throttle kind of guy:-)

[@TheShipsLogg]

@@CrochetNewsNetwork Awesome! Good luck with your new machine!!

[@Murdoc1511]

what about seadoo gtr 230 can be recommended for a driver that have both agressive and cruise ?

[@TheShipsLogg]

If you have not made any modifications to the machine to increase the power, you should be good. If you have made modifications, you might need to consider it.

[@Murdoc1511]

@@TheShipsLogg thanks 👍 great video btw

[@michaellindon5688]

Interesting

[@irvingonzalez9576]

What PSI should the valve be set to ?

[@TheShipsLogg]

That depends on the system that it is installed on. Different superchargers are designed for different boost values. Setting the value too low pretty much nukes your supercharger while setting it to high defeats the purpose of installing it.

[@scottlovesplayingbass3495]

I agree and I have a GP 1800 supercharge but I’m not gonna drive like that. But I did add a breather upgrade that helps the motor.

[@BaronTeaParty]

did you add a oil catchcan with the breather?

[@Maxrotor1]

Thanks captain. I will have to consider this for my new 2022 FX SVHO Limited.

[@MarkCamo69]

I have the same model, lets face it if you are out with mates everyone races, and i will ride it erratically on throttle most likely as well, most of us do, so that's why i put a Fizzle hose with Turbosmart BOV to fit in with stock airbox, i also use a full Riva (k&N) air filter for stock airbox, and i modified the airbox as well, not sure how to post pics here for you to see what i did

[@arqjavierobregon]

Just install it and forget about it

[@schoolsout2069]

I ride like you for the time being. Have a 2021 FXSVHO with 11 hours (need to do oil change) and extended warranty. Do these addons void warranty? Obviously, tune and other stuff would, but wondering if this is more of a preventative type thing Yamaha wouldn't have an issue with.

[@TheShipsLogg]

It's always best to check with your dealer but I don't think it would void the warranty. As you said, it's more of a preventative measure. Of course, it may give your dealer a hint as to how you operate your ski. 😂

[@Jay_Hall]

It would be very wise to leave all stock for warranty purpose,,especially for the extended warranty. :)

[@TheShipsLogg]

@@Jay_Hall agree

[@Mroswaldo16]

Bov doesnt void warranty. Just keep the stock boot, to swap if you dont feel comfortable

[@mr_lucky_1797]

Will this ruin my warranty if I put one just to play it safe?

[@TheShipsLogg]

No, it will not

[@Dr_Flankensteinn]

Great Video Capt. Frank - can you do one on a CATCH CAN? :)

[@TheShipsLogg]

You are reading my mind Jeff. I have already been thinking about getting one to test. Stay tuned!

[@Dr_Flankensteinn]

@@TheShipsLogg I just had one installed - as a recommendation to keep the intercooler from getting oil buildup/residue

[@TheShipsLogg]

@@Dr_Flankensteinn That is what I have heard as well.

[@Mroswaldo16]

Jumping waves is only.for personal injuries. When jumping waves just let go of throttle, so at the end of the day, yes you need one! Not even 7 hours on my 22 fx & first thing i got was a blow off valve! Then, ribbon delete kit.

[@isaaaldoy]

To get rid of letting go of the throttle just get racing retainers

[@Mroswaldo16]

@@isaaaldoy bov is to get a bit longer clutch life.

[@danav3387]

I consider myself a pretty aggressive rider. I have a bone stock 09 FZR with 350+ hrs and 0 issues with my supercharger. My midshat bearing is bad but no other issues.

[@TheShipsLogg]

That is awesome. Not surprised that you have a Yammy. Yamaha seems to design their machines so they are not overstressed, even if you are an aggressive rider. This helps to ensure that you have many hours of trouble free riding. 😁

[@paulpuglia8480]

On the same note of the blow off valve, the oil catch can is it necessary to get an oil catch can on and on a natural aspirated engine???

[@TheShipsLogg]

Good question. I know plenty of people who swear by them and say they make a difference. I personally have not put one on my supercharged ski and I am not using any oil at all. It seems to me that it may only be necessary if you have modded your machine. I am thinking about adding one as a test just to see if it actually makes a difference on a stock machine. Stay tuned.