HandlePole INTAKE enough???

[CarterB]

ahahhaha....search Tila Nguyen....you'll be busy for a while
http://www.tilashotspot.com
http://www.myspace.com/tilatequila

 

[Speedfreak]

Finally got a reply. About the air resistance through the intake pipe.... I know that it is too late but basically. Here is Richards simplified answer...

The formulas for fluid flow follow pretty much the same math as the formulas for electrical current. Remember Ohm's law, V = IR, where V is voltage across a component, I is the current through the component, and R is the resistance of the component? Same for fluid flow, except use flow rate (say, cubic feet per minute) instead of current and pressure instead of voltage. Resistance follows the same rules; a 20-foot pipe has twice the resistance of a 10-foot pipe of the same diameter.

So in your case, you are comparing pressure drop Z, flow rate Y, length X to pressure drop Z, flow rate y, length 10X. We can say Z = (flow rate)(resistance) in both cases, and we want to find the flow rate y. Let's say the resistance in case 1 is R; the resistance of a 10-times longer pipe will be 10R. So we set up for equal pressure drops:

Z = Z
YR = y (10R)

Now we need to solve for y:

y = YR/(10R) = Y/10

So not surprisingly the flow will be 1/10 as much for the same pressure drop.

Richard Barrans
Department of Physics and Astronomy
University of Wyoming

 

[freestyler888]

we sell flow-rites that go in the hood. that works great flows really nice and has a clean look under the hood. if any one has questions email me thanks

R-RATED PERFORMANCE

 

[dieseltwitch]

I also have thought about this. the one thing that i came up with is if you could find a way to pull more air through the same hole Dia! so this is what i came up with. if you could find 4X 120mm Computer fans build a small box say out of CF or just glass. connect the box to the pole holes (would need two tube running up the pole IMO) you could* and i would test it! but it might work. but i know where your coming from. o and some how make the fans Water Proof!

 

[dieseltwitch]

Ok so i found the fan i was talking about. set up right it could equalize the pressure in the engine compartment
WaterPoof 120mm Fan Look about half way down

 

[Speedfreak]

Ok so i found the fan i was talking about. set up right it could equalize the pressure in the engine compartment
WaterPoof 120mm Fan Look about half way down

The only thing wrong with adding a fan is that the carb pop off works off of manifild vacuum so if you added pressure your pop off would be way off everything is make to work together. And where would you mount a 4.75 inch fan.

 

[dieseltwitch]

Yeah i was thinking about the mounting problem but with ducting you could put them around the gas or just use 80mm water proof fans. i dont think that the fans will have enough pressure to really effect the carb much. they move alot of air but i don't thing they pressurize it very much heck if any thing you could come up with some type of reed system to vent extra pressure.

I know the the idea is out there but with a little bit of thinking you could do it. and it would work. now how well is another story. but all good ideas came from retarded ones! i want to replace the gas tank in my SX-R with a shorer custom glass one to lower it and build in baffling systems. and was thinking that this system could work right there. really won't take much and the added weight is next to nothing. also you could point one of the fans right at the carb so that it only draws in cool air and less hot air that has been pushed around the engine. just thoughts

 

[CarterB]

tried a 2" hose thru the pole and sealed hood...ran fine around the lake. Might not be ideal, but works.
I'm still adding some intakes into the hood, but thought it was interesting...math is for nerds

 

[dieseltwitch]

Nerds Make MONEY!

 

[WFO Speedracer]

Also remember this equation 14.7 to 1 ratio that means for every gallon of fuel consumed that you will consume 14.7 gallons of air,now multipy that times the amount of fuel your tank holds and you know how much air you must flow through the tubes in a given amount of time.So lets say you consume 4 gallons of fuel per hour 4x14.7= 58.8 gallons of air consumed per hour of use.Now divide that by 60 and you get .975 gallons per minute flow through the tubes.Divide that by 60 and you get .1625 gallons per second.

 

[Speedfreak]

tried a 2" hose thru the pole and sealed hood...ran fine around the lake. Might not be ideal, but works.
I'm still adding some intakes into the hood, but thought it was interesting...math is for nerds

I bet there was enough vacuum that your scupper was sealed tight... LOL I wish you could get it to work I would like the same setup.. I have 48mm carbs so I would need at least 2 - 2 inch tubes. The carbs are 1.889 inches each.

 

[dieseltwitch]

Also remember this equation 14.7 to 1 ratio that means for every gallon of fuel consumed that you will consume 14.7 gallons of air,now multipy that times the amount of fuel your tank holds and you know how much air you must flow through the tubes in a given amount of time.So lets say you consume 4 gallons of fuel per hour 4x14.7= 58.8 gallons of air consumed per hour of use.Now divide that by 60 and you get .975 gallons per minute flow through the tubes.Divide that by 60 and you get .1625 gallons per second.

I dont think that 1 gal a min would be a problem if you use the fan idea each fan can move 120 CFM. even with out the fan idea each carb is only pulling air one at a time. so really your only looking to feed one carb. i think that two intake tubes would be plenty of air flow

 

[Speedfreak]

each carb is only pulling air one at a time. so really your only looking to feed one carb.

Yes but each carb pulls air down it's throat at roughly 116 times per second at WOT. That is pretty well an constant flow. And that is an incredible amount of air.

Leave a ski on the trailer at the boat ramp take your hood off and your airbox then hold a cigarette near the carb and hammer the throttle you would be amaized how far the smoke can be pulled.

 

[Mark44]

u

Yes but each carb pulls air down it's throat at roughly 116 times per second at WOT. That is pretty well an constant flow. And that is an incredible amount of air.

Leave a ski on the trailer at the boat ramp take your hood off and your airbox then hold a cigarette near the carb and hammer the throttle you would be amaized how far the smoke can be pulled.

116 times what per second there Einstein?

Mark44

 

[dieseltwitch]

for thouse of you that requrie the math.
a 780 cc eng (SX-R 800)
will draw at 10,000 RPM
276 CFM of air for both cylinders
each cylinder is only drawing 138 CFM
Not really alot of air when you think about it
( a 120 mm Computer fan can can draw 100 - 130 cfm of air )


Here is the Excel Sheet i used might be a bit confusing
Red Line 10000 rpm
Given RPM 5,000 rpm
Number Of Cylinders 2
Bore 82 mm
Stroke 74 mm
Displacement (1 Cyl) 391 cc 24 ci
Overall Disp 781 cc 48 ci
0.03 cf

CFM/CFS @ Given RPM 5000 RPM
CF/Min (1 cyl) 69.0 CF/M
CF/Sec (1 Cyl) 1.2 CF/S
CF/Min (2 cyl) 138.0 CF/M
CF/Sec (2 cyl) 2.3 CF/S
CFM/CFS @ MAX RPM 10000 RPM
CF/Min (1 cyl) 138.0 CF/M
CF/Sec (1 Cyl) 2.3 CF/S
CF/Min (2 cyl) 276.0 CF/M
CF/Sec (2 cyl) 4.6 CF/S

 

[Matt_E]

Also remember this equation 14.7 to 1 ratio that means for every gallon of fuel consumed that you will consume 14.7 gallons of air,now multipy that times the amount of fuel your tank holds and you know how much air you must flow through the tubes in a given amount of time.So lets say you consume 4 gallons of fuel per hour 4x14.7= 58.8 gallons of air consumed per hour of use.Now divide that by 60 and you get .975 gallons per minute flow through the tubes.Divide that by 60 and you get .1625 gallons per second.

Absolutely incorrect.

14.7 AFR is correct, but your math is way off. The ratio is for gases, not liquids.
You cannot calculate flow that way. I gallon of gas does not equal the 1 in 1:14.7 :biggrin: .

 

[dieseltwitch]

Even my math is a little off but it give you a good idea of WOT usage.

 

[Speedfreak]

Yes but each carb pulls air down it's throat at roughly 116 times per second at WOT. That is pretty well an constant flow. And that is an incredible amount of air.

116 times what per second there Einstein
Mark44

I was calculating on a freestyle motor WOT is no where near the RPM of a race ski.


This is for Mark.....:biggrin:
7000 RPM (rotations per minute) devided by 60 seconds in a minute = 116.666~ rotations per second. SO each carb pulls air at 116.666 breaths of freash air per second.

 

[CarterB]

i dont have a scupper but i do have twin 48's and it was fine with the single 2 inch tube

I bet there was enough vacuum that your scupper was sealed tight... LOL I wish you could get it to work I would like the same setup.. I have 48mm carbs so I would need at least 2 - 2 inch tubes. The carbs are 1.889 inches each.