Boost bottle

[freakboy]

I some one around here mentioned on i did research and found out what it was but i am wondering how would one make one? and Also will it work with a twin cylinder with only one bottle? And how do i find out how many ccs one cylinder has on my 20 hp briggs straton?

 

[Kaptain Krunch]

I some one around here mentioned on i did research and found out what it was but i am wondering how would one make one? and Also will it work with a twin cylinder with only one bottle? And how do i find out how many ccs one cylinder has on my 20 hp briggs straton?

I honestly dont think they will do all that much, its pretty much just supposed to take that little bit of gas in the intake manifold that doesnt make it into the cylinder after the valve closes, and push it in during the next firing stroke. So pretty much its giving you a bit of extra gas during each fire, but i have never tried one so i wouldnt know, go for it. As for how many CC's each cyl has, get the total displacement of the engine and divide by 2.

 

[freakboy]

i have no idea about this engine all i know is its a 20 hp thats all i know. and that its a briggs and straton.

 

[Kaptain Krunch]

i have no idea about this engine all i know is its a 20 hp thats all i know. and that its a briggs and straton.

Give me the model/ type/code and ill see what i can do.

 

[freakboy]

460777-1279-01-9512105c
Thank you so much Kaptain

 

[Kaptain Krunch]

Ok heres what i got on it.

46 CI block, made in Dec. 10, 1995. Full pressure lube, plain bearings, electric start with alternator.

 

[freakboy]

thanks alot Kaptain!

 

[lemegacool]

i have one on my pocket bike and it works for me... i got more low end torque...

 

[freakboy]

I want it for my mower and just to i can brag to my freinds that i have something that makes it better then theres ahahah and its cheap power.

 

[lemegacool]

even if it's not working its adding dome cool factor to your ride...

 

[freakboy]

yeah im just making it out of a limited edition mountain dew bottle it has hippies on it and if i can get a small military gas can type thing ill make it out of that but im definitly not sacraficing my ww2 german one for that

 

[Kaptain Krunch]

get a fire extinguisher, im considering doing this to my 12hp briggs or 12.5 kawasaki, the junk...err i mean Redneck recycling store down the road has a few fire extinguishers sitting around, might see if i can get me one then pain it blue. I could even use the electric PTO switch with a solenoid valve and make it on/off, none of my friends would know its not nos

 

[freakboy]

hahaha nice i have a empty one in my garage i was going to use a co2 canister for a paintball gun till i relized it still had co2

 

[Kaptain Krunch]

I just did a search because i was thinking, and i did some reading and guess what, boost bottles aren't supposed to work on 4 strokes.

heres what i read on another forum.

When I had high interest in performance on the little chinese engines, I did some research on boost bottle technology, and here is the Reader's Digest Condensed version.

The total displacement of the boost bottle and it's lines and fittings, to be most efficient, should match EXACTLY the displacement of the engine. Ported into the intake, when the 2-stroke "sneezes" back into the carb, it would (presumably) "charge" the bottle with mixture, and upon intake, the contentents of the bottle would "push" a little, while being sucked back into the crankcase. This was thought to be a little like "supercharging" the crankcase. This system was credited to Yamaha Corp in the dissertations I read.

Ok, now if the reed (in between the engine and carb) would stop the action of the bottle, what do you think might happen with our intake valve? A good running 4-stroke will NEVER sneeze into the carb. We also do not charge our crankcases with mix to run, we port gas mix directly above the piston.

We concern ourselves with combustion chamber size and shape, cam profiles (lift and duration) carboration, cam and ignition timing, belt management, and other such issues.

In reality, there are very few simalarities in 2-strope and 4-stroke tuning and performance.

now that made sense to me, so it probably wont work, but hey it might you never know, dont let it stop you i want you to be the lab rat

but then heres a whole argument countering that one

First off for the question that was asked. "Has any body tried a boost bottle on a whizzer 4 stroke,or do they only work on 2 stroke engines???
Bill b"

I'm not sure if anyone has tried one on a 4 stroke "wizzer" BUT if you get the size right, and your manifold is not already tuned well, then you can increase performance... ON A 4 STROKE. So there are some "if" "ands" and "buts" but yes... it's possible that it will. The second part of my answer is that... most of the gain you will see form the bottle would be bottom range and a 4 stroke usually doesn't lack in that area.

"Hi, well, the boost bottle is strictly to "pulse" back into the cylinder increasing the charge in the head, on a 2-stroke. It will have no logical effect on a 4-stroke engine.

performance concepts are in most cases completely different."

Wrong in a few ways. The boost bottle does more than that. The scavenging of fuel and air was actually meant to make the engine work "normal" at low RPM and not to increase power. If you don't understand the inner workings of a carb then it won't help you to read the next part.

The problem in the intake is this. Air flows threw the intake tract as the engine demands it... ( 2 or 4 stroke ) then when the engine blocks the flow ( a valve or piston ) the momentum of the air causes a positive pressure to build on the engine side of the carb and intake manifold. At low RPM the air "bounces" back over the jet tube ( or whatever in the carb supplies fuel ) and draws out more fuel ... just as it did going in the first time. This causes the mixture at low rpm to be rich.

The bottle is simply a space for the pressure to relieve into so that it doesn't pass over the jet tube and cause the enriching problem. The size is important because the bottle will fill in a given time depending on it's size. For it to work properly it fills and starts to reverse and come back out just as your engine starts to demand another intake charge.

Other than that... performance concepts are the same ... more fuel and air = more power... till something gives or melts

"If you had read this stuff, one thing came out in the first page that the boost bottle PROBABLY (read WON'T) work on a reed-valve engine."

90 % of the boost bottle engines that I've seen, and that's more than a few, are reed valve. Reed valve has very little effect on an engine "needing" a boost bottle.

"Ok, now if the reed (in between the engine and carb) would stop the action of the bottle, what do you think might happen with our intake valve? A good running 4-stroke will NEVER sneeze into the carb. We also do not charge our crankcases with mix to run, we port gas mix directly above the piston."

If you've read any of what I've written then you know why this is wrong... It's correct that a 4 stroke won't "sneeze" back... but neither does a properly tuned 2 stroke AND as I have explained .... sneezing isn't the cause for the boost bottle being needed. More so the momentum of the air.

"In reality, there are very few similarities in 2-stroke and 4-stroke tuning and performance."

They are all the same ... just a different way of getting the same result. To make either engine run, and run well, you need proper fuel, air, compression, timing of intake and exhaust and ignition timing. Everything you need to make a 4 stroke work well you also need to make a 2 stroke work well.... it's just different ways of achieving those things.


"Hi, now for me, that makes sense, even tho that technology does not work on any valved engines,
Thanks,"

Again ... wrong. "valved engines do benefit from a bottle.... Many have.

If any of you don't believe what I'm saying then do some research outside of this forum. Tho I'm not cretin who "invented the idea" Yamaha popularized the bottle and has used it on MANY reed valve engines. It's been used on 4 strokes ( many British cars ) and multiple cyl engines as well as singles. Fuel injection and "proper" tuning of intake lengths and volume has made the bottle less popular these days but it still has it's place when used when it's needed.

Understanding how something works, in detail, is often the best way to maximize the benefit if any. For example... putting a turbo ( I know this is silly but a great example ) that flows 100 CFM on an engine that demands 150 CFM of air is only going to harm performance. If your intake pulse is tuned to work properly then a boost bottle will only harm performance.

I am passionate about problem solving and enjoy wrapping my head around the idea of what happens in an engine. Hope I haven't offended anyone.

theres also some good info on getting the correct size bottle. I may try this with a weed eater.

Basic math: above I stated that your displacement should be equal, correct?

If your 9oz bottle holds 9 LICQUID ounces, how many cc's would that be?

1 Liter = 1000cc's
1 quart=16 us ounces
one US quart=946cc's
one 9oz bottle=473 cc's

473cc's + volume inside the lines and fittings do NOT equzl 69cc's?

So pretty much equal volume of cylinder and boost bottle.

 

[freakboy]

ok that made my head and eyes hurt a bit. but im just going to keep toying with this idea and if it doesnt work im going to put a valve on one side of this bottle so i can hook a air compressor to it and then add some more gass or what not and make a ghetto nos without the nos. if that would work.