Quarkdude's bike with Boost Bottle installed ( PICS )

[dave1490]

i dont see how a boost bottle works well on a fourstroke due to the valves but if u say it works i take ure word for it

this depends on the overlap {the point were both intake and exhast valve,s are open 1 closing the other opening}portion of the cam timing,higher reving eng have more overlap to create a slight raming effect and to help cylinder scavaging.this is much more usefull in a 2 stroke without reed,s.

 

[minibiker]

im trying to put a regular soda bottle on as a boost i will let all of ya know how it works im still having problems with putting gears on the bike first (6 of em i hope it works) after i get everything together i will post again

 

[Kep1a]

Well I thought I would chime in on the boost bottle and four stroke thing.

A 4 stroke suffers from plenum float (atomized fuel in the air cleaner floating above the carburetor). All single cylinder and single venturi engines do. I am sure folks have seen Stacks on the top of those webber or solex carburetors on hot rods of the 50's and 60's. You know the ones they put yellow tennis balls in at the car shows to keep those pesky alligators out of the engine. Those stacks help to contain that plenum float so that the individual cylinder, left or right bank won't lean out at certain engine rpm or during a transition from decel to snapping open the throttle.

You would need to match the intake plenum volume, cam lift and duration/ RPM range and stack height to properly contain and control that plenum (pulse) float. Hopped up VW pancake engines have this problem and are still today run as one carburetor venturi per cylinder for hot rod use. They run taller intakes and stacks on the carburetor when they need to control that plenum float effect. I am sure you have seen those 8,10 or 14 inch tall filter risers on motors. These are all acceptable ways of containing the plenum float.

So yes a boost bottle will help with plenum float. It will also richen the mixture at a given speed or plenum resonance or when snapping open the throttle. The boost bottle is helping to create a constant (smoothed out) flow through the carburetor in all engine rpm conditions and especially the higher rpm ranges.

Mostly at the higher RPM ranges is where a stack will help contain that plenum float effect. If the plenum float is not contained or controlled through... multiple pulses on one properly sized venturi (as in complimentary 2 left and 2 right cylinders on one venturi like a Chevy V8), properly sized stack height and diameter or yes a boost bottle. Then top speed, power and fuel economy all will be adversely affected.

The boost bottle will likely be a bad idea however in a cold climate because of fuel vapors condensing inside the bottle and running into the engine as dribbles and not a vapor. So you may want to experiment with stacks and taller air cleaners to fit over those stacks. Remote air cleaners with a flex tube of adequate diameter will also help contain and reuse that plenum float effect too. If the pulses (floating fuel vapor) above the carburetor is not controlled and contained it will be lost and seriously lean out that engine. The problem area of the rpm range is usually at maximum rpm so if that plenum (pulse) float is controlled or contained you will notice more speed because of more fuel at that given maximum rpm. You will likely even notice that you can achieve a higher rpm than before.

Hope this helps
Kep1a

Kep1a

 

[mickey]

I think I followed that ;-)

Thanks Kep

 

[jpilot]

Hmmmm, the whole boost bottle thing sounds like snake oil to me but I may try it.

I'd avoid that silly little nitrous kit though. It will probably destroy your engine. A properly engineered nitrous installation adds additional fuel with the nitrous at a carefully calibrated ratio. Nitrous oxide is an oxygen-bearing gas and adding nitrous without adding additional fuel will seriously lean the mixture resulting in detonation and burned pistons. Tuning a nitrous setup is tricky and best done with a wideband O2 sensor to keep a close eye on the air/fuel ratio.

 

[Kep1a]

Actually...
Doing a boost bottle and painting it as well as labeling it like a real Nitrous bottle would be cool LOL.

Calling it snake oil would be a little harsh. But not too far from the mark. It is not a huge benefit and almost not worth the expense or trouble unless you want to squeeze every drop from your motor and of course you are always on the proverbial pipe as it were (wide open throttle).

If I was looking to race my bike I would look at loosing weight first and this boost bottle thing would be the last to do in a series of other more worthwhile improvements.

For cool factor though it gets a 5 out of 5

Kep1a

 

[jpilot]

By "losing weight" I assume you mean pushing back from the dinner table a little sooner and maybe doing a little more pedaling? LOL

 

[Kep1a]

Yup

 

[Large Filipino]

BOOST! YAY! BOOST!

Ordering....Yellow for "BLAM!"

 

[quarkdude]

BOOST! YAY! BOOST!

Ordering....Yellow for "BLAM!"

Hello Large Filipino,
Going for the yellow boost bottle. Sounds great. I've got nearly 200 miles on my bike with the boost bottle with no fade in power or reliability. I am anxious to try one on a 4 stroke motor - gotta build another bike though
........................Keep us posted....quarkdude