boost n mods

[chan_yote]

Post ur' Custom boost tube/ other mod pics

[chan_yote]

I know there are people out there that just want the damn thing they make to work but not make it with some style? I know this is a pocket bike forum, and i have a gas scooter but i have a 49cc pocket bike engine on my scooter. I do about 45 max right now but soon that will change. Here is a pic of my boost tube (its not that great of a pic but it works. I made it out of a fuel safe vacume line two fittings and some pvc. I hope other people post pics of their mods i love to see other peoples rides, so i can see waht i need to do to mine :)

[mblough]

Guys this isnt really a faq type thread unless you make it a how to. Like you dimensions, materials used etc.

[chan_yote]

I was working on the how to and material list for the hp boost bottle but fell asleep before i got them posted. Sry if that bothered you.
Here are the stats for a hp boost tube.
Build the regular boost tube using same volume as engine displacement. But to modify from standard bottle you need to have a shorter tube with a larger diamiter and the largest bore fittings you can fit into your manifold.
My super tube is built out of 3/4 inch pvc with fittings that have 1/4 inch bore inside so that fuel/air mix flows faster. This mod is sort of like putting a larger intake manifold on a old volkswagon. I also bored out my manifold from 16mm to 18mm for more flow. this boost tube added plenty of low and mid torque and even better throttle response. Also if you know what you are doing you can bore your carb and velocity stack for more flow. Over all the smallest area i have is 17mm around the butterfly valve in my carb. After testing my performance i gained about 2-3mph and about 9'lbs of torque. For you with out a dyno that is about a 11.4% increase from stock setup. With full modded engine yhou can gain up to 20% more torque but still only 2-3mph depending on what your gearing is. my gearing is 10:1. If anyone else has better performance than this from the boost tubes let me know

[shuvit]

How does a boost tube work? In other words, what is it doing that improves hp & top end?

[03Mach 1]

i just made this today from the directions from srwsr, cost me less than 5 dollars.

[chan_yote]

Well sorry for taking so long to post but my sbc internet has been down for a while... Anyways it balances the backflow from when the engine does not need fuel air mix. it also preasurizes a little, then bursts it into the engine to boost fuel air pressure in engine for highere compression.
**Some motors you will not notice much change if any. **
***If your tube and connectors are to little it will not help***

Nice tube ( mine cost about $12 for the sticker, paint and vaccume line from kragen) I gained noticible low torque, enough to get a sproket with 6 less teeth for the rear!

Radar top speed=48.8mph
below power ban speed=36.3mph
Total spend to mods=$395

next mod = 49cc headstrong headkit from pocketbikesunlimited.com
Next homemade modifications= 16mm venturi bored carb from wt-603, custom highflow manifold, high volume v-stack or cold air tube.

Projected top speed=55-60mph

[avangusva]

How did you record that speed? Whats mods do you have to begin with, thats a little (REALLY) hard to belive that you hit 48.8 mph on a pocket bike, let alone a bulky super bike!

[avangusva]

Oh sorry, just read u have a scooter, still verry VERRYYYYY hard to belive...