Boost Bottles?

[CBWELLS]

Any of you guys ever put a set of boost bottles on any of the triples?

Been reading some at: http://wikiscootia.wikidot.com/boost-bottle" onclick="window.open(this.href);return false;
and at: http://www.boostbottleindustries.com/Bo ... _page.html" onclick="window.open(this.href);return false; (scroll down to "How a Boost Bottle Works").

I think the two explanations approach the operation a bit differently, but the 2nd one sounds most plausible to me. Just curious if anyone has had any experience (POS or NEG). I would welcome input from any experienced commentors. I suppose speculation is OK too, but I'm capable of my own!

Thanks

[CBWELLS]

Hmmmm! This has been posted for 5 days & has had 45 views, & NO ONE has anything to say!
Curiouser & curiouser! I would have thought SOMEONE out there would have some experience with Boost Bottles. They were (are?) used as OEM items on some Yamaha small two strokes & probably other OEMs. There's claims of 2 to 8 HP gains at the low end of the RPM range (& for a small single, that's remarkable).

None of you Performance Guru guys (who seem to spend endless hours & countless $$$ to squeeze a couple of extra HP from your reluctant 2-strokers) has anything to offer!?! But then, I guess the low end is not where most folks are interested in HP!

Well, maybe the NO COMMENT says something in itself!

Maybe, when the weather improves so I don't freeze the 'nads off out in the garage, & if I get ambitious I'll rig up a set of 3 for the GT550. Seems cheap enough & easy to do. Apparently that will make me the subject EXPERT! Always wanted to be an EXPERT on something. FINALLY MY CHANCE!

Still would welcome your experience.
Thanks

[tz375]

My limited trials so far gave absolutely nothing. Lots of claims and calculations but no tangible results. I read that they are useful under certain circumstances, but I can't remember what those were.

[ja-moo]

Boost bottles are usually on twin cylinder reed valve 2 strokes, as the pistons are at 180 degrees out. The volume is in front of the reeds so the charge is contained in front of the intake tract. I haven't seen one ever used on a piston port. But I have never researched it either.......

[CBWELLS]

Thanks for your input. Doesn't sound all that encouraging!

To Ja-Moo; I've read several things regarding use on small single cylinder engines, and if the theory of "air mass momentum" in the intake passage is valid, (which makes some degree of sense to me), I can see why reed valves might have an impact, but I don't get why the number of cylinders would make any difference (single - Twin - Triple), nor the crank angle displacement, so long as each cylinder has its own intake path (i.e. separate carbs for each).

I don't believe everything I read, but some of it says the bottles work on 4-strokes for the same air flow reasons. This might be the source of the TWIN cylinder & 180° crank idea, although I would think that would actually work best with a single carb twin & a 360° crank due to the equal time between intake strokes.

Any thoughts?

[tz375]

I have read the theory and it is all logical, and MOTA includes a boost bottle as one input option, but I have not tested it.

Over on http://www.2strokeworld.com/forum/index.php" onclick="window.open(this.href);return false; there was a thread about boost bottles and Chuck Quinzler (sp?) had some comments about the circumstances under which they have some effect on a reed valve twin.

[Alan H]

But if the pressure pulse stopping when the piston covers the port causes the boost bottle to fill, the pressure difference would be so small that only a tiny bit would go into the bottle. It would go to the easiest way of escape which would be the open throat of the carb. 'Great acceleration', '4mph extra' - yeh right, highly noticeable then.
More power at low revs? Shirley (don't call me Shirley!) the suction/pressure pulses would be minimal at low revs - also would happen too fast to do any good at high revs. Try getting pulses up a little pipe as against the throttle body and where will they go first? Even at (say) 1000rpm tickover, this would happen 16 times a second so the petrol mixture wouldn't have time (or inclination) to get into the bottle - and back out to do any good at all.
Save your money and fit a 60cc motor to your mope instead.
Not sure how big the bottles are (I got fed up reading the blurb), but they can't be that big or where would they fit?

Absolute bollocks.

Or why not fit an electric turbo instead LIKE THIS?
Of course if it worked as advertised the car would run weak, and if it didn't it would restrict flow and run rich..............

[Alan H]

Just noticed this bit;

Footnotes

1. Since an engine operates as a cycle and explaining the effects of the boost bottle before the process is explained would be too confusing, this article will assume that the cycle previous to explanation was a perfect cycle which did not involve the boost bottle.

Well, that certainly confused me, and if the cycle previous to the explanation was a perfect cycle, then how do you improve it?

[ja-moo]

OK, I was on a different page, most boost bottles are a 2 into 1. Where the pressure is stored and then released in to the opposite cylinder when the pressure drops for a larger charge into the case. That's why I said it works best on a 180 twin.

A boost bottle on a single is basically changing the "area" of the intake tract. This will change the strength of the reversion wave, and most likely change when the systems sync up. It "probably" would take a lot of experimentation, for little if any gain.

[CBWELLS]

OK guys! That's better. I had hoped for some experienced input but this is fun too!

And Shirley (aka Alan H), Nice to hear from you again. Rest assured, I won't spend much (if any) money on this subject and I tend to agree with most of your comments regarding "minimal" effect etc, but here's an interesting video (YouTube is such an authoratarian source! A genuine service to mankind!..... Pardon the sarcasm.)

http://www.youtube.com/watch?v=_9r7wiXrylQ" onclick="window.open(this.href);return false;

Most of the Yahoos I see on YouTube don't seem to know which end is up, but this vid seems to indicate the bottle does in fact do SOMETHING on that little putter...... and if it does maybe there's something to it. Also, OEM use by Yamaha (a trusted source!) seems to support that claim too. AND if one bottle is good, just imagine what 3 would do!!! (OOPS, more sarcasm leaked out).

Well anyway, Thanks for your thoughts. If I ever do anything with this idea, I'll let ya'll know. Generally, I leave things to the OEMs since they have a few more resource to play with.

[ja-moo]

That video is pretty ridiculous in proving anything. Dyno comparisons, or actual mileage comparisons, would tell a tale. All I saw was a bottle that affected the idle screw adjustment.

[CBWELLS]

Ja-moo,
Yeah, it would be nice to have a "before & after" dyno plot set, but let's be real, who's gonna go to that expense to irrefutably prove a minor performance effect on a lo-cost mod? Hell, I've been riding for 40 years & have never had any of my bikes dyno'ed (from CB350 Honda to Goldwing to Vmax). I just don't have the $$$ for that kind of investigation. The point remains: The bottle had a positive effect on the operation of that bike. Maybe it only allowed the idle circuit to be tweaked down a bit. I certainly don't know what else it might do (or not do) but it seems to do something. That is arguably more than many of the alleged performance mods that are routinely tried & touted by "those who know" (ignition relays, different plugs, Precision timing efforts, 97 Octane fuel, rebuilding carbs every other year, Full synthetic oil changed at 1000 mile intervals, shaving heads, etc. Get Real!).

My 38 yr. old GT550 runs as good as, or better than the brand new '72 I had when I was a kid... & I don't mess with much of anything. I'm a firm believer in the old adage, "Speed costs Money! How much do you want to spend?" I'm CHEAP & the boost bottles might be an affordable mod that can be fabricated & installed by the average cycle-monkey (me... or anyone) with little effort to get a noticeable improvement.

In any case, I'm not trying to sell this to anyone. Just looking for some real world experience. Based on the lack of specific details, I'm still guessing that it has not been tried by any of the readers thus far.

Thanks for your thoughts & keep 'em coming. That's what the forum is all about!

[tz375]

What did that "demonstration" prove and how is his boost bottle making a difference?

It is most likely that what happens is that at idle, when the reversion pulse occurs as the piston heads south, usually some air gets pushed out of the carb picking up extra fuel. With his boost bottle, some of the reversion pulse does not go out the carb but goes into the boost bottle. When the piston rises again, some of that pressure is released into the intake port.

What he has done at idle is to change the mixture and he re-jetted for the new condition. Not surprisingly, when he pinches off that tube, the mixture is not wrong and it dies. He has demonstrated no change in performance at idle or any other speed and no change in fuel consumption.

From my perspective that's a snake oil demonstration. He has proven nothing. There is no evidence. No before and after data.

On the other hand we know that fine wire plugs and relays in the ignition circuit help to make the most of a weak ignition system. We know that raising compression improves performance across the rev range as has been documented for decades.

[CBWELLS]

TZ375,
I don't dispute anything you point out. His demo is certainly not a thorough evaluation of the full effects of the Boost Bottle, nor is it intended to be. He is simply showing that the bottle has an effect. Your statement ("With his boost bottle, some of the reversion pulse does not go out the carb but goes into the boost bottle. When the piston rises again, some of that pressure is released into the intake port.") describes exactly what the theory of the bottle claims. Again, I certainly don't know, but if it has an effect at idle I suspect it may have a similar effect at the lower RPM range), consequently better performance in that range, which is all the theory claims. It seems if your statement is correct (& I think you are), a bit of extra fuel/air mix into the intake is somewhat equivalent to what a turbo-charger does, as well as expansion chamber theory.... puts more fuel/air mix into the combustion chamber with each breath. If done right, the theory seems logical.

If it were all snake-oil, I can't get past the fact that OEMs have used this technology on production machines. That lends some credence to the idea. Are they to be duped too? Apparently no one (here) has done a "before & after" evaluation of the bottles. That would be excellent info to draw from, but I was still hoping for some actual anecdotal "seat of the pants" experience to draw from. I have no dog in this race, so I appreciate all the input. Nice chatting.

Thanks to all.

[ja-moo]

Factories are not "immune" to fads, they use them all the time to sell bikes. Yes Yamaha did use the bottles, but dropped them, that says it all. It is true, we are going on physics and engine understanding and not actual use. By all means give it a shot.