Boost Bottle for freestyle?

[xxx2]

I was talking to a two stroke engine builder (quad) and the subject turned to Boost bottles and I was wondering if one could be used in a freestyle ski. The Boost Bottle and tube provide storage for the fuel air mixture between carb boots (within the intake manifold)while the reeds are closed. The energy (pulse) forces the pre-atomized mixture in the tube from the previous cycle into the adjoining carb boot where the reeds are just opening and ready to receive the fuel air mixture. The boost bottle and tube provide a "boost" supercharge effect to each cycle.
The way it works is it assists in filling the manifold (shorter distance) for a fraction of a second until the carburetor venturi gets enough velocity to fully atomize the fuel. The advantage is that it brings up the torque and horsepower in the bottom of the rpm range, up to where the pipe(s) starts to work ideal for lowend snap.

boost bottles are most effective at lower and mid-range rpm, and, when you are on & off the throttle, Which is why it is not really benificial to allot dirtbikes and 4-wheelers because there is a small benefit at high rpm's because the reeds don't stay closed long enough to fill the bottle. But a freestyle ski is most exclusively off idle to mid (Brap)
Sorry about the essay, It's a little slow @ work:biggrin:
Please post your thoughts on this subject!

 

[yamaslut]

I was talking to a two stroke engine builder (quad) and the subject turned to Boost bottles and I was wondering if one could be used in a freestyle ski. The Boost Bottle and tube provide storage for the fuel air mixture between carb boots (within the intake manifold)while the reeds are closed. The energy (pulse) forces the pre-atomized mixture in the tube from the previous cycle into the adjoining carb boot where the reeds are just opening and ready to receive the fuel air mixture. The boost bottle and tube provide a "boost" supercharge effect to each cycle.
The way it works is it assists in filling the manifold (shorter distance) for a fraction of a second until the carburetor venturi gets enough velocity to fully atomize the fuel. The advantage is that it brings up the torque and horsepower in the bottom of the rpm range, up to where the pipe(s) starts to work ideal for lowend snap.

boost bottles are most effective at lower and mid-range rpm, and, when you are on & off the throttle, Which is why it is not really benificial to allot dirtbikes and 4-wheelers because there is a small benefit at high rpm's because the reeds don't stay closed long enough to fill the bottle. But a freestyle ski is most exclusively off idle to mid (Brap)
Sorry about the essay, It's a little slow @ work:biggrin:
Please post your thoughts on this subject!

I don't think it would fit in a standup, would it???

 

[WFO Speedracer]

That particular setup wouldn't but basically you run a hose to the bottle and mount it where you want it.From the setups I have seen on dirt bikes the hose length doesn't seem to be that critical but hose size is.Also just a tidbit of information,not that it applies here,they used to run a boost bottle on the Kawi 300sx back in 91-92 era.That engine is basically half of a 650 and needed all the bottom end it could get,there was a noticeable difference in the earlier models which did not have the boost box and the later ones which did.and

 

[the only couch rider]

i have not seen any remote mount boost bottle systems, and of the ones i have seen (rius racing, and riva's) all are mounted right above the carbs

 

[Big Kahuna]

i have not seen any remote mount boost bottle systems, and of the ones i have seen (rius racing, and riva's) all are mounted right above the carbs

you sure that was not a Air Fuel Seperator???

 

[xxx2]

I was thinking more towards putting under the intake manifold, It would be about the same length as the manifold itself and made out of 2/2.5 inch alum pipe.

 

[LBE]

The one pictured is pretty large, but I think it may be worth a try. It is a simple mechanical setup and seems like it would be easy to expariment with it. Give it a go and let us know!

 

[RoyalFlush@PCB]

Hmmmm...

Two things come to mind:

1. Did you ever get your ski running right WITHOUT some silly boost bottle? :biggrin:

2. Why would YOU, of all people, suggest this idea? Didn't you make a comment about not needing any more power than your 650 will already produce? :cool2:

Nelson Marine must be REALLY slow. Lemme' hook up the boat and take it down to the shop so you have something to do...:sneaky:

 

[xxx2]

1. yes I did. Now I am working on the jetting :arms:
2.I thought "maybe" It would be a usefull Idea for others and I think a little more bottom end never hurt anybody:sneaky:
Hook that boat up and bring it over, I'm always happy to help you part with some of your money.

 

[WFO Speedracer]

i have not seen any remote mount boost bottle systems, and of the ones i have seen (rius racing, and riva's) all are mounted right above the carbs

Pretty much all of the boost bottles on the bikes were remote mounted.I am not saying that is good or bad and it will probably work better if it is closer to the manifold.All I am saying is it will still work if it is remote mounted,also the one on the 300sx was remote mounted and hooked on a bracket next to the flame arrestor.

 

[Matt_E]

The manifold I run has ports for it. Never used it though.

 

[xxx2]

I was thinking something allong these lines, I should have room, and I have a spare intake manifold and I have a good friend who is a machinist. I am thinking it should have bungs welded to the manifold and a short piece of probably 1/2 or 3/4 hose, 1 or 2 inch long connecting the bottle to the manifold. It's worth a try I guess?

 

[RoyalFlush@PCB]

I'm always happy to help you part with some of your money.

Damn---and I thought I'd be getting a discount for letting you use my tools and store your ski at my house for, oh, six months or so...:biggrin:

Are you sure your last name isn't Edwards? :sneaky:

 

[xxx2]

I could have kept it @ my shop (more room/tools), But then you wouldn't have been able to experience the joy of working on a X-2:arms: O.k. now I am done...Back on topic
After a little research on sizes I came up w/ Singles = usually the CC of one cylinder or larger. 700cc Twins = 300cc boost bottle. 700cc Triples = 225cc.
Variables: Engine CC's, Carb Size, RPM below pipe, Number of cylinders. Large carbs Typically like larger bottles/tubes. Triples like smaller due to less time between pulses.

 

[the only couch rider]

you sure that was not a Air Fuel Seperator???

i have seen remote mounted fuel/vap separators, but not boost bottles

 

[Waste Land]

Remember the volume of the boost bottle must be equal to the volume of the cylinder.

My expeirence with boost bottles on gopeds and RC cars

Cleaner response when in the turns, not much but just noticable. Goped and RCs have this problem of bogging more then a regular two stroke because of the simple engine.

Slight increase in top end

Can be a beeotch to tune because depending on the volume taken up in the boost bottle you can be lean on WOT run and rich on another


Over all opinion....the tiny bit of throttle response you'll receive isnt worth the head ache, money, or reliability isue

 

[WFO Speedracer]

I can be remote mounted,kinda like the funnel on a beer bong is remote mounted.

 

[xxx2]

Remember the volume of the boost bottle must be equal to the volume of the cylinder.

My expeirence with boost bottles on gopeds and RC cars

Cleaner response when in the turns, not much but just noticable. Goped and RCs have this problem of bogging more then a regular two stroke because of the simple engine.

Slight increase in top end

Can be a beeotch to tune because depending on the volume taken up in the boost bottle you can be lean on WOT run and rich on another


Over all opinion....the tiny bit of throttle response you'll receive isnt worth the head ache, money, or reliability isue

On twins it should be half as big, and on tripples it should be 1/3 as big. I was told this from a good friend (LRD performance, Portland Oregon) This is a general rule but, He uses TSR computer software to calculate the Boost Bottle demensions for specific set up's (Dune Banshee's high hp)
I would imagine the gains on small motors would be minimal. With that said I have only messed with them on banshee's and 250r's, On the last 250r I built I ran It without then with, and the response was Very noticible (see pic of last bike!) I could see tunability being difficult if you were using it as a cross-over port (I.E. 2 carbs/2cyl.) but with 1 carb and 1 or 2 cyl. I couldnt see where it would be any more difficult to tune.
If you look @ how a 2 stroke works the same backrush of air that closes the reeds will cause a small amount of air to backrush through the carb, which causes a host of problems at low rpm. A boost bottle helps to alleviate this.

Air is rushing through the carb, reeds, and into the crankcase. Suddenly, the reeds snap shut. The air coming through the carb still has inertia, so it compresses a little against the reeds, and then decompresses BACK through the carb, causing a double-rich mixture for that small amount of air.
However, now your bottle is slightly pressurized. The other end of the bottle is connected to the other intake, which is just opening up, so the pressure goes there instead of going back through the carb.

So, by eliminating those small pockets of double-rich fuel/air mixture, you improve throttle response.
At high rpms, the reeds are opening and closing so fast, the air doesn't have time to compress against the reeds, so a boost bottle isn't needed.

So, that's the basic theory as I understand it :dunno:
P.s. did you ever find your big cup @ daytona?

 

[GIL]

I was thinkin bout the Banshee.

 

[Waste Land]

Yes...found my cup but lost my girlfriends....

I didnt not know the half and 1/3 rule. interesting