Boost Bottle for freestyle?

[yamanube]

Riva makes a boost bottle setup for racing, just saw it in my catalog. I think it was for the GPR12

 

[CARBONX2]

I have the technical paper from when Yamaha developed YEIS
Did some calcs for a sxr motor, basically need 1500cc's for each bottle for each cylinder and at least a 22mm pipe, length can be played with to fine tune the setup over about a 1000rpm range between 3000rpm and 4000rpm
Space is the problem to fit this in

 

[skithis]

"So basically to make a four stroke run like a two stroke you make it unreliable ,peaky and make it smoke.Sounds good so far." hahahaha. Now thats funny.

As for you guys who think 4 strokes are the wave of the future, its true. 4 strokes will eventually most likely be all we have except for free lance pricey engine builders. BUT, you are incorrect as for why we are now seeing 4 strokes. Its not that 5 years ago some designer said, ya know what, I'm going to start building a 4 stroke race engine. IT is however, that the EPA said, your going to have to.:sad6:

As far as outboards go. All the major brands these days are putting out awesome products. Although, in my opinion the best is the mercury optimax. I can count all the problems ive seen with them in the last 5 years on 1 hand. However, the 4 strokes (which are incredibly heavy and bulky) have had 10x the troubles. In yamaha's and mercury's 4 stroke outboards, when the cam belt breaks or skips, and it will, Its a new engine for you. A lot of people will complain that 2 strokes smoke and will fowl plugs...This is because they haven't ran a new EFI 2 stroke. You can idle all day with no issues.

Anybody who sais that 2 strokes have not advanced in the last 10 years has not done their research. I'd have to say that the 2 stroke has almost advanced more than the 4 stroke over the last 10 years.

After all, Do you want to pull your engine every 50 hours to re-shim the buckets? Not I. Have fun when you sink or injest water at WOT.

 

[skithis]

Why does everybody think a 4 stroke weighs so much??...a 250F weights the same as a 450F with almost twice as many cc's, shoot a dang CR125 almost weighs as much as a 250F....you can take a smaller CC 4 stroke that would be amazingly easy to put a supercharger on and have more power than a 10,000 dollar watercrap 1200, I just think people are afraid to think way outside the box.

You ever seen a supercharger compressor after it sucks water?

 

[Polish jet pilot]

I do Love to tinker:smile: Just because no jetski companies manufacture them doesn't mean it is a bad idea, I don't think the 2 stroke motor in a ski is much different than a banshee motor. ATV's are a larger sport than stand-ups, yet still there are only a select few quad related companies that manufacture boost bottles for them (Vito's, Nacs,Graydon,etc.). Why? I think it's because the two stroke is a dying breed. But, for the basic jetskiier It would probably be best to leave it stock, stick to bolt on goodies, or pay an engine builder to get the power out of your motor for you. For those who like to tinker here is an interesting read:http://search.aol.com/aolcom/redir?...dItemPage=1&clickedItemDescription=WebResults

You are absolutely right. Look at snowmobiles and PSI company - jetskis are way behind - boost bottles can work, and they were used in the 80's from my knowledge..

 

[94superjetriverrat]

do you hav a banshee? cuz ur nacs boost bottle had two intake ports?

 

[Polish jet pilot]

Ok so I see that snowmobile engines use boost bottles (not the "NOS") but rather containers that equalize pressure in manifolds and reeds... here is alink:

http://www.startinglineproducts.com...escription&catalogID=3&catID=21&productID=368

I can bet 100usd that a lot of jetski guys use it as well... 2 stroke is a 2 stroke... any pics of such a system on a jetski?? Thank you!

 

[CARBONX2]

Almost done with mine, making individual bottles for each cylinder.

 

[Polish jet pilot]

Please update us on the work.. maybe some pics and some words of explanation how this will work.

 

[CARBONX2]

Prototypes are fitted, will test tomorrow. Would have liked pipe to have been bigger(at 15mm now) but should fine as have set it for 3500rpm(not sure on where the torque dip is, somewhere in the 3500 to 4500rpm range). Main aim is to get better response from just off idle without affecting peak hp and jetting

 

[CARBONX2]

They work, got rid of hesitation I couldn't get rid of with jetting, pulls harder off the bottom too and the best is that I reduced the LS screw from 1,5 down to 1 turn. Still need to swop 16/21 impeller out and put in 16/18. Did some work on my barrell-rolls using only a pre-hop and no wake.

 

[Waternut]

Are those just pvc pipes with caps on the end? How did you connect them?

 

[Polish jet pilot]

cool! Good job! Pretty NEW carbon X2!

So maybe a schematic picture?

Once again congrats! You proved that they do work...

 

[CARBONX2]

I made a new carb plate 30mm thick to replace the 8mm one that came with the manifold, drilled it and tapped threads, used hdpe pipe fittings, 90-elbow to come up vertical, short hose, straight fitting in through a cap. All parts are common hdpe water pipe and fittings. Going with only a 15mm pipe(hose & fittings centreline length is 210mm, the bottle volume became 640cc to work @ 3500rpm.

 

[CARBONX2]

A little update
I swapped the bottles for a pipe joining the 2 manifolds and I picked up more grunt off the bottom(so much for everyone blocking their crossovers). I tested back to back with the individual bottles so I could compare the difference a few minutes apart. Must still measure the total crossover pipe length but it is about 420mm
All this is with 48mm annular discharge carbs which are 44mm at the venturi, so these are big carbs with very little restriction.
Next is to design a bottle that connects both manifolds

 

[Geeshow]

if they work on snowmobiles and atvs then they have to work. when i had a banshee it came with a stock one, took it off and got a cool head, carbs done, tommey pipes and boost bottle and i was hitting over 80 mph. talk to chuck a xscream, old rd 400s have them also.

 

[WFO Speedracer]

These boost bottle thingys cannot possibly work, I mean everyone here doesn't have them on their ski so they can't work right ? :scratchchin:

 

[Schmidty721]

They work, got rid of hesitation I couldn't get rid of with jetting, pulls harder off the bottom too and the best is that I reduced the LS screw from 1,5 down to 1 turn. Still need to swop 16/21 impeller out and put in 16/18. Did some work on my barrell-rolls using only a pre-hop and no wake.

Did you try the new thick manifold plate without the boost bottle installed? Changing your intake track length could have of had as much or more effect that the bottles themselves. Either way, nice to see someone actually trying this theory out.

 

[Matt_E]

These boost bottle thingys cannot possibly work, I mean everyone here doesn't have them on their ski so they can't work right ? :scratchchin:

:lmao:

 

[CARBONX2]

Did you try the new thick manifold plate without the boost bottle installed? Changing your intake track length could have of had as much or more effect that the bottles themselves. Either way, nice to see someone actually trying this theory out.

That is the one thing still to test. I know from the yamaha RZ50 how well a boost bottle works, that's why I built individual bottles. I was impressed by the boost bottle gain but even more impressed by going to crossover pipe.
My pump setup is different now than what I first tested with, but am still using a 144mm Mag. 13/18 with 86mm exit nozzle. A big thanks to Eric Malone for the info on pump setup.