v8 jetski gear ratios engine rpm and pump speeds (Ls v8 jetski)

[@komododragon4242]

Your your partner rocks. Keep this build going forward. I'm so glad your not giving up on this project. Always looking forward to what comes next.

[@JetSkiBrothers]

👍👌😁

[@mickotoole4795]

Here we go the guys are on the ball .. 👍👍 getting the V8 back to the water 💯💯🇨🇮🇺🇸🇨🇮👍👍

[@mickotoole4795]

Thank you guys all the positive commenters whot gets the jet ski Brother's bonus points FROM UTUB KEEP ALL THEM GOOD COMMENTS ROLLING IN AND SAVE THE V8 😃😃😃😃🇺🇸🇨🇮🇺🇸🇨🇮👍

[@JetSkiBrothers]

😂👌🍻😁🏅

[@spcneary]

You guys are blowing up! Keep up the great content.

[@JetSkiBrothers]

👍👌

[@cpcassone]

The words “Give Up” do not exist in the Jet Ski Brothers’ vocabulary! Everybody’s else looks at sinking their ski as game over or some kind of tragedy! Reviving sunken skis is nothing for these dudes! In fact…..If you aren’t swamping your machines then you aren’t going hard enough! Another awesome video guys and I’m looking forward to pressing on into the future with this awesome build!

[@JetSkiBrothers]

Thanks buddy! We just go for it and usually something breaks haha 😂 oh well we’re having fun so it doesn’t matter 😁👍

[@vivogarage]

"Classic Jacob" LOL, dude cracks me up! good work getting this thing back together!

[@davidbrennan5]

Very cool project. It was sad to see it sink but sometimes that kind of stuff happens, can't wait to see it run after some improvements.

[@joetris719]

Glad to see you're not giving up!

[@ststele]

You get an insane amount of views for a channel with 20k subs! Very nice! 👍

[@motoman22atgmail]

Love these guys! They actually design and build stuff on the fly, not just assemble sponsored products.

[@JetSkiBrothers]

Thanks 👌🍻

[@daddosjeffery]

Keep chipping away at it and you will end up with one hell of a sled, love the channel and keep it up mate 👌

[@JetSkiBrothers]

👌🍻👍

[@tyleraguinaga2557]

Jacob is hilarious Keep up the great videos guys

[@AwesomeBroStory]

Dude my ski sank after I watched your vid of your v8 sinking 😭 I cried man.. it was my baby.

[@JetSkiBrothers]

Sorry that sucks

[@AwesomeBroStory]

@@JetSkiBrothers your good it was a rxp 215 supercharged! I’m getting it repaired

[@JoelArseneaultYouTube]

I think it's interesting about your gear ratios and the fact that the engine isn't just spinning up to max rpm freely... it means that your pump has way more to offer and you can get a lot more out of this ski by boosting power. Man... figuring out gear ratios is hard enough... then trying to actually say it... that's even harder. I feel ya. I would hope that that cluster is waterproof.... I would be afraid to use it if not... but I'm just paranoid about electronics. I watched your video yesterday on my phone but was super busy and forgot to comment.

[@chrisglassey8585]

Do you know about the piston flip debate between the guys from Engine Masters and Uncle Tony's Garage on you tube? The myth that putting a piston with wrist pin offset in backwards makes more horsepower. It's been claimed by many people for decades but never proven back to back on a dyno. Lots of people tried to explain using math and lots of other techniques why it would make more power. So Richard Holdner and the guys at engine masters actually did it and it turns out it made within a decimal point of 1 horsepower with the pistons flipped around. So the myth is busted.

[@chrisglassey8585]

I think that's what we got with the pump debate here. No one will really know till someone does the jet ski pump vs the bigger jet boat pump test.

[@JoelArseneaultYouTube]

@@chrisglassey8585 I've never heard of that... I know that Yamaha and a few other companies are offsetting the crank shaft to take advantage of the engine peak pressure at an optimal crank angle ... I don't really know enough about the LS or car engines to know if this is a similar idea ... I'm not really understanding the "Offset in backwards" It's interesting though... Many things that work out in theory don't really work out in practice as there are so many variables and you end up changing more than one thing, even if you try really hard to only change that one thing, for testing.

[@JoelArseneaultYouTube]

@@chrisglassey8585 I totally think / agree that a bigger pump just makes more sense. My understanding of pumps isn't the best... I freely admit that. I don't think that the factory pump will be as efficient as a larger pump, when they really start pushing it, but I don't believe that they are stressing the pump yet. I believe that Yamaha would have given themselves a bit of a "buffer zone" in this pump and not had it sized so that it was on the verge of being too small. Based on their approximate impeller RPM and the fact that it is a OEM impeller I have to assume that they can spin it a bit faster and or step up their impeller game and move more / faster water through this pump before it becomes really inefficient and just starts soaking up any extra power. That being said... why did the carrier fail 🤷‍♂️. Based on the numbers the JSB got, I wouldn't think it was close to failure, but maybe it is building too much pressure 🤷‍♂️

[@chrisglassey8585]

@@JoelArseneaultKZbin Most production engines for cars and trucks have the wrist pin offset to one side of the piston just slightly to stop piston slap and make the engine quieter. Some people thought if you put the piston in facing the wrong way it would increase power. That was the myth. I do agree that the pump Josh is using probably still has more to give but it's already spinning 8000 rpm and producing 70mph. How much more does it have in it? Good question. I agree Yamaha didn't put a maxed out pump in that ski, but it was only designed to handle 260hp not 2 or 3 times more. If you take that pump and spin it at 8000 rpm and you take a bigger pump and spin it at 8000 rpm the bigger pump will move more volume of water assuming impeller pitch is comparable. The more water you move the more thrust you have as long as the water speed coming out of the nozzle is of comparable speed and given you are applying the same power into the pump. Thrust = forward movement. It's the same principle as with hydraulics. If you take a 1" diameter ram with 1000psi and take a 6" diameter ram with 1000psi the bigger ram has more power even with the same psi. In this instance the psi is the force being made by the "engine".

[@ianbrown9104]

Jacob was on the money with the ratio, you didn't need the calculator lol.

[@stevejohnson8703]

Right on, right on. Hey Rolex are waterproof man. I would work on a plate to plate heat exchanger with Tstat to get away from salt water to engine. You can use it on new engine also. And its not free money, not at all.

[@NastyMoto]

Good vids, would love to see some more of the BOB build!

[@JetSkiBrothers]

Should have some more videos of the rob coming up pretty soon

[@c4k3t0otz6]

Not sure if those gauges are waterproof, but if they are not maybe look into potting the electronic boards inside the screen (epoxy covering over the electronics keeps moisture out). Ive also seen clear nail polish used to paint over the pcb to make it somewhat waterproof

[@peavyrocks]

LS6 is a 5.7L out of a C5 Z06, LS7 is a 7.0L out of a C6 Z06. My recommendation is a LS3 6.2L

[@keving1774]

Was vibration on the output shaft the problem?

[@Nathan427007]

What's the cam specs with the upgraded cam?

[@nicolashuffman4312]

Is this ski internally or externally cooled? Seems like an internal system might not have enough capacity in the ride plate.

[@AzBigD]

So what snapped? ?? The bolts on the shaft or the shaft itself?? Would of been nice to see the damage in the hull...good stuff Bro👍👍👍👍👍

[@BushmanCanuck]

Last video covers that.

[@SeaDooEric]

What size is the Yamaha jet pump you’re using?

[@chuckingram5966]

Sounds like you're putting the cart before the horse. You've already proven that your propulsion system is inadequate the amount of horsepower you're making. I know you're talkin about making more horsepower does that make sense to you. Love what you've done so far and in my opinion it's time to dive into researcvh and development for a pump

[@timewa851]

yes. failure analysis would be required, or this will repeat. water is incompressible. the shards tell some kind of story........looking forward to the JSB's solve.

[@bansheeman1]

What kind of RPMs was that jet pump running with the jet ski engine?

[@chuckingram5966]

@@bansheeman1 excellent question

[@garrettstevens2232]

I thought it was the OEM coupler that failed? Lest video they talked of getting a billet coupler for the pump side to match the one they made for the engine size.

[@Aquaholic6801]

He said in the video ... 1:1.6 @ 5000 RPMs from the engine 1.6 x 5000= 8,000 RPMs, stock drive lines are capable of handling @9,500 RPMs

[@derekw3554]

You have to remember as well, it's torque that breaks driveline components... aqualine whatever. Using the torque from the engine with overdrive gears will put much more stress on everything as I'm sure you know. Kind of how why you don't let a car shift into overdrive driving up a mountain road

[@Deadfeat]

Jacob, please start your own channel. Ill be the first subscriber .

[@MF11283]

When our boat got water im the oil (to this day not surde why) changed it several times boat shop finally said take it out and boil the water out.. just keep that in mind when you get her running again And the gear ratio i believe would be about .6 not 1.6 but didn't do the math

[@tracylittle4268]

What’s Jacob been drinking? LOL

[@bigdaddy5212]

On a jetski where peak torque is located makes zero difference when it comes to getting the best top speed.The original Yamaha engines make peak torque in the low 8000rpms and the real fast guys turn them way past that between 10,500 and 11,000rpms.For best top speed you want to pitch prop to turn the rpm where the motor makes its peak horsepower.

[@Anthony_Pell]

Please put dielectric grease on all the connections

[@JetSkiBrothers]

Affirmative 👍

[@grnwtr4life]

Is it just me or does jacob sound different?

[@Jacobskibros]

I have an orthodontic device that makes me sound retarded.

[@ericmuhlbeier8023]

@@Jacobskibros thats way cooler that using a jaw breaker addiction as and excuse

[@tngtacticalmiata1219]

You're going to need a proper jet pump..... like from a real jet boat. The puny little jetski drive is just going to grenade again. Then you don't need the gear reduction, either....

[@tngtacticalmiata1219]

Oh, yeah.... 1100 swap one of those Wet Bikes and get it running!!! I love those things... Or.... maybe.... Ya'll wouldn't be interested in selling one of those, would you?

[@chrisglassey8585]

@@tngtacticalmiata1219 I recommended a Berkeley in the beginning and that idea was shot down. I still think it is the way to go. It can handle a lot of power with a stainless impeller and you wouldn't have all that power loss going through the gear box. You could actually use that power. It would be easier to swap than people think as the Berkeley puts it thrust to the floor of the boat and not the transom. The square looking box on the back of the boat is just there to seal up the water from coming in with a big o ring. It's not structural at all. Having said that not everyone has the same opinion and may not wanna go that route. Sometimes people figure out another way to reach the same goal and I'm also interested to see Josh find his own way there.

[@jackdevane2496]

Why would the "puny drive explode" you realize people push 600+hp with those "puny drives" the fastest jetski in the world which is 1000+hp used those "puny drives"

[@chrisglassey8585]

@@jackdevane2496 you think his driveshaft will hold 600 horse as is? It didn't even hold what it has now. There is still no way to use it without losing power through the overdrive gearbox setup which kind of defeats the purpose of putting a big engine in the ski in the first place.

[@jackdevane2496]

@@chrisglassey8585 You think people running 600 horse run stock pump system NO but he was saying run a jet unit off of a actual jet boat when these units can handle power just need to be beefed up and something wasnt right thats why it gave out you realize a 4.8 stock makes like 280 he cammed it and tuned it so it probably is 350 atleast but hp has NOTHING to do with top speed its all rpm and hes running almost same rpm as stock just a couple hundred more thats why hes at 70 and stock goes 67

[@TurboDog73TX]

Do an LS3 for the motor, or an LS2, or even one of the L76 6 liters that are all aluminum.

[@southerndualsport3827]

Once you get this thing sorted out PLEASE MAKE A KIT TO DUPLICATE IT!

[@JetSkiBrothers]

Yeah it sounds like a good idea but I would want to get paid a lot for them

[@southerndualsport3827]

@@JetSkiBrothers I would bet a simple kit with gearbox, exhaust manifolds and some basic instructions would suffice. I gotta believe you could put that together for a few grand no?

[@southerndualsport3827]

Honestly just the gearbox with the bellhousibg integrated would be enough!

[@westmonroe-r1v]

So does a standard jet ski run 1 to 1?

[@michaelholderegger645]

Yes, the crank is coupled directly to the driveshaft with a rubber coupler.

[@JetSkiBrothers]

Yes

[@Driver0808657]

It looks like there's some extra room up front - what about packing the free space with styrofoam? That's what the nose of RC boats are packed with so they won't sink completely

[@kenyz123]

Pump and gear ratio. Called it

[@kylestewart8354]

I would think gearing for max torque would yield more speed 🤔. If you need more RPMs up top, There's always NOS.

[@davidj.platter3555]

Make a waterproof Box for it

[@stevenichols1861]

What the hell is going on with Jacobs speech? Lol

[@Jacobskibros]

I have a dental device that gives me a speech impediment or makes me sound retarded. I think it's kind of funny but it gets annoying.

[@stevenichols1861]

@@Jacobskibros lmao well that explains it, hope it doesn’t keep you from riding and having fun!

[@sledneck182]

I thought he had a lip full of chew

[@stevenichols1861]

@@sledneck182 me too lol

[@mickotoole4795]

You need to watch sum thing elce 😠like paint dry 👍

[@vdrivevideo]

I spin my propeller 48% over my engine rpm. 18 foot flat bottom v-drive with 1500 hp. Gear that thing up! You have a ton more hp and torque than what was originally in there.

[@Aquaholic6801]

Need to get it 2:1...

[@adamr9215]

This is a jet, not a v-drive. With a jet, the design is only efficient within a certain range. If they start spinning it faster then stock, it will just cavitate and stop moving water. They need to ditch the gearbox and just change the impeller pitch.

[@Aquaholic6801]

@@adamr9215 ... There's folks here spinning them at 9500 RPMs

[@adamr9215]

@@Aquaholic6801 That exact pump with the same exact set up? I know that if you have them blueprinted they can be set up to take that kind of rpm, but do you really think their worn out used stuff is built to the max? I don’t. I’ve raced v-drives, jets and outboards, and know enough about them to know that this isn’t going to work how they want without throwing a bunch of money at it. At that point, the cost would be the less to rebuild the pump and pitch it to run direct drive. That would simplify things considerably.

[@TurboDog73TX]

The dash is 100% NOT waterproof, and Y'all will need to build a waterproof case for it. You guys must be running either an HP or Dominator ecm, as the Terminator X and X Max are definitely NOT waterproof..

[@JetSkiBrothers]

Thanks for the info, we are running Holley hp 👍

[@mrbmp09]

The gear ratio is 1:1.6, not 1.6 : 1. Actually 1 : 1.647 or 0.6 : 1 You don't need a gear ratio calculator to figure it out, simply divide the 2 tooth counts. 28/17= 1.647....

[@christianborghi7544]

Leave gear ratio as is just add a cam and rev motor to 8k , at 1.6:1 that’s 12800 pump speed

[@woomdawg]

Put all the modules in a big bag of rice. I am sure you have already thought of it.

[@Skwisgar2322]

Problem is it is salt water, so just drying it out will leave behind salt.

[@woomdawg]

@@Skwisgar2322 WD-40 everything. Fog the cylinders. Everything

[@jackdevane2496]

L92 is the way to go cheap and a lot of performance

[@TurboDog73TX]

Or an L76/77 which are aluminum. L92 is iron block, and I'm sure like Me they would want to save all the weight they can.

[@vinvinn7050]

Rite on rite on

[@nikdipetta]

You mean to tel me you don’t have unlimited funds and time that this ski isn’t running yet!?

[@jasonskibrothers2192]

🍻

[@TheDcianfarini]

150 shot nitrous…

[@davidsmith8048]

I enjoy the content, I dig Josh, but Jacob is annoying af

[@extremeshok7851]

7.2L v8 ;-P

[@marcmacdonald5862]

Lol gear ratio calculator? 🤣 do you just mean calculator? Just divide the drive gear teeth by the driven gear teeth. 1.6:1 would mean for every rotation of the drive gear the driven gear would spin 1.6 times.

[@mrbmp09]

No, 1.6:1 means output would turn 0.6 turns.. 1:1.6 means output will turn 1.6

[@toob247]

Is it wasting the money if you spend it ona dancer? But than you video her on the back of the v8 Jetski and make all your money back.? She can keep your donations. Click bait booty thumbnails, v8 jetskis and dancers. , sounds like success. Murica 🇺🇸

[@chompeyboy]

The ratio is actually 1:1.6 not 1.6:1. Supercharge it.

[@jasonskibrothers2192]

I love math! ➗