some of u snorkel experts, got a question

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C1iffBurton -> some of u snorkel experts, got a question (9/17/2008 1:53:09 PM)

i know a snorkel tries to serve a purpose as letting the bike go deep

and i know there is some sort of mathmatics that go along with making them and the jetting that goes along with them

but my delimna is this but really its not
to me and my thinking this is the same thing between the two of these, anyhow going from a 1.5" flex hose from the airbox to a 1.5"x2" reducer then going with a 2" 90 turning up and a foot or foot and a half of pipe then another 90 or 180 on top
or going with a 2" flex hose out of the airbox then doing the same thing as above stated but the pipe sizes just change locations

to me the bike will get the same amount of air no matter what but i know it has to do with volumes and stuff like that, so lets hear what yall have to say about it

to me if u have a 2" hole at the end of the snorkel getting reduced down to 1.5" then going into the airbox that is easitially the same as having a 1.5" hole at the end of the snorkel and the reducer instead of reducing it just opens up to a 2" pipe to the airbox

now i want to say with the foremans which is what this is for the 1.5" going into the airbox actually fits into the stock piece and can still use the stock clamp to hold it together, whereas with the 2" at the airbox it goes on the outside of the airbox piece and u have to use a bigger hose clamp....now i know inside of the piece that the stock snorkel hooks to at the airbox, it reduces or has a shoulder in it that only lets u push the piece so far into the tube before it wont go anymore, meaning the opening at the end is a little bigger than the shoulder inside so when u stick the stock snorkel piece or whatever in it the inner diameters should be the same size per say

i also know alot of it has to do with how many bends u get in the pipe and such and has to do with the airflow running through it and all
but to me if u ran the snorkel the exact same way as i stated above just the pipe sizes are flip flopped, it will only suck so much air so hard at 2" at the top of the snorkel and im sure if u put a 1.5" at the end it will still suck the same amount of air but it will just seem to be sucking it harder
is my theory on this correct or incorrect, i did go to college and graduated but there are just so many aspects to this that im either overlooking or cant determine or i am just looking to far into this whole thing

sorry for the long post but ive always wondered and would like to know even more now since im about ot snorkel a friends bike for him, i have found 2 different plans to make them both of which the design is the same but the pipe sizes are flip flopped, each plan that i got it from didnt have to rejet but im not fully convinced which one to go off of, one of which the plans is a personal riding buddy of mine and id trust him before id trust someone just randomly off the internet

thanks, lets see what yall can pop out of yalls heads on the issue



C1iffBurton -> RE: some of u snorkel experts, got a question (9/18/2008 8:44:11 AM)

41 views and no one knows or has the least bit of info to put into the thread:(



kingtimb1 -> RE: some of u snorkel experts, got a question (9/18/2008 9:03:01 AM)

you are making this to hard on you r self stick 1" 1/2 pipe on there and be done with it. it will work.



muddyfuzzy -> RE: some of u snorkel experts, got a question (9/21/2008 2:04:23 PM)

you won't gain anything unless you open the box intake up. having the extra volume ahead of the intake could help prevent cavitation in some extreme situation but your air flow will re relatively smooth all thru the powerband. get creative and open the intake up to 2", rejet accordingly and watch it go.



paulatgis -> RE: some of u snorkel experts, got a question (9/23/2008 3:40:49 PM)

Answer: 1.5 inch bell mouth intake, expansion from 1.5 inch to 2.0 inch enroute to air box, 2.0 inch elbow at air box with 2.0 inch dia hole cut into airbox air box.  but you might not need that much flow so could go 1.5 all the way, just keep the bell mouth intake.

air flow through a 2 inch pvc pipe has half the velocity of the same air flow through a 1.5 inch pvc pipe.
q = av where a = pi*d*d/2,  d*d for 2 inch pipe is 4, d*d for 1.5 inch pipe is 2.25, so 4 is almost twice area of 2.25.  since q is constant then v almost half of v required for 1.5 inch pipe.  .56 to be exact, call it .5 for ease of use.  how is v, velocity, used?

Bernoulli states that an energy term is proportional to v squared. So when calculating head loss, friction loss, etc. you multiply K, friction term, with v, velocity, squared.
Hloss = K*v*v,  so plug in the two v's
1.5 inch  Hloss = K*1*1 = K  (let v=1)
2.0 inch Hloss = K*.5*.5 = K*.25  (so far about a quarter the loss when compared to 1.5 inch pipe)  Whats K then?

constriction  2 inch pvc leading to 1.5 inch pvc
K is .42 (from standard formula)
Hloss = .42 * 1 = .42

expansion 1.5 inch leading to 2 inch
K is .56 (from standard formula)
Hloss = .56 * .25 = .12
so, less loss from expansion as intuitively thought.

Pipe elbows.
Let K for 90 = K90 (just a term) then
hloss for 1.5 inch diameter = k90 * 1
hloss for 2.0 inch diameter = k90 * .25,  so only a quarter loss with larger elbow.
Now make that 90 a 45 angle elbow which has .7 loss of the 90 bend
hloss for 1.5 inch diameter = k90 * 1 * .7 = k90 * .7
hloss for 2.0 inch diameter = k90 * .25 * .7 = k90 * .18
so 45 bend of 1.5 inch is better than 1.5 90 degree bend, but still greater than either 90 or 45 degree of 2 inch bend.

exit (into air box)  here k = 1 so hloss follows benefit of pipe size
1.5 inch hloss = k * 1 = 1*1 = 1
2.0 inch hloss = k * .25 = 1*.25 = .25
or one fourth the loss with larger diameter.

entrance has K = .5 for sharp edge but only .04 for bell mouth (my jeep has a bell mouth intake)
sharp edge entrance 1.5 inch hloss = .5 *1 = .5
sharp edge entrance 2.0 inch hloss = .5 *.25 = .125
again better for 2.0 inch hloss
bell entrance 1.5 inch hloss = .04 * 1 * 1 = .04
bell entrance 2.0 inch hloss = .04 * .5 * .5 = .01

I referenced these two pages for notes on constants and formulas
http://webpages.eng.wayne.edu/~ah8818/Webpage1.htm
http://www.engr.iupui.edu/me/courses/hydraulicresistance.pdf



longdude17 -> RE: some of u snorkel experts, got a question (9/23/2008 4:15:08 PM)

dude unless you have  some experience with the above equations or your an engineer like me...no one will understant that.

to the original poster...keep it simple...more pipe equals more drag on the air coming in...go up in size lets more air in with a little more drag...the less bends and less pipe the better.



toyazman76 -> RE: some of u snorkel experts, got a question (9/23/2008 4:16:29 PM)

What kind of engineer ar you?



Parts Pimp -> RE: some of u snorkel experts, got a question (9/23/2008 4:25:42 PM)

Lord......use 1.5 pvc. Pipe....like others said...Keep it simple and it will be great.



jdscm4 -> RE: some of u snorkel experts, got a question (9/25/2008 2:21:26 AM)

Dude....You made my head hurt.....I havn't seen that stuff since fluids class......Cliff, use what ever size pipe you you can make fit with the route you want to take and just put a ball valve somewhere in the line.  This way if you don't want to rejet you can just pinch down the airflow until it runs correctly.  If you decide to rejet later, just open the valve.



Cracker -> RE: some of u snorkel experts, got a question (9/25/2008 8:03:10 AM)

That made my eyes bleed.



Parts Pimp -> RE: some of u snorkel experts, got a question (9/25/2008 8:46:13 PM)

quote:

ORIGINAL: Cracker

That made my eyes bleed.


Funny as Hello^^^^^ I was like um.................I was lost after the first sentence!



Massmudman -> RE: some of u snorkel experts, got a question (9/27/2008 7:10:23 PM)

I did my whole snork with 2" no problems and no box mods. When I took it to my dyno guy he couldn't make it work (FOR MY QUAD). He said too many engine mods and variables. He put the reducer back in like the way I brought it to him and did some tweaks and it works better than ever now.  There is way more to a carb than just air entering it. Lots to do with turbulence and pressures for the slide and carb as a whole to work properly. Maybe Jake450 will find this thread and lend his knowledge here too. [:D] If anyone knows the WHY, it WILL be HIM.



lumberjack -> RE: some of u snorkel experts, got a question (9/28/2008 9:14:25 AM)

quote:

ORIGINAL: jdscm4
...just put a ball valve somewhere in the line.  This way if you don't want to rejet you can just pinch down the airflow until it runs correctly.  If you decide to rejet later, just open the valve.


The snorkel adds restriction, and to band aid the A/F ratio, your fix is to add more restriction?

It's possible if you used small enough pipe you could increase the velocity to the point where it improved volumetric efficiency at a specific RPM to the point it pushed the A/F to the point you would notice it.  Unless it's sized to do that at WOT, it will add alot of restriction everywhere above that point and still add some below it.



curt234 -> RE: some of u snorkel experts, got a question (9/28/2008 10:50:56 AM)

Use 1.5" hose until you're outside the airbox than use 2" hose the rest of the way. I Have tired 1.5" hose the whole way and its way to restrictive. I tried 2 inch the whole way right inside the air box and it did not run right. 1.5" to 2" run's very close to stock  and is least restrictive on a foreman 400.



Waveslider330 -> RE: some of u snorkel experts, got a question (9/28/2008 11:21:06 AM)

We did my buddies 07 foreman 500 with 2in pvc all the way through with only a few bends and the thing runs great. and we did not rejet either. He swears it feels like its got a little more throughout the whole RPM range. He was VERY happy with it, and thats the bottom line really.



lsu_fan91 -> RE: some of u snorkel experts, got a question (9/28/2008 11:27:06 PM)

quote:

ORIGINAL: paulatgis

Answer: 1.5 inch bell mouth intake, expansion from 1.5 inch to 2.0 inch enroute to air box, 2.0 inch elbow at air box with 2.0 inch dia hole cut into airbox air box.  but you might not need that much flow so could go 1.5 all the way, just keep the bell mouth intake.

air flow through a 2 inch pvc pipe has half the velocity of the same air flow through a 1.5 inch pvc pipe.
q = av where a = pi*d*d/2,  d*d for 2 inch pipe is 4, d*d for 1.5 inch pipe is 2.25, so 4 is almost twice area of 2.25.  since q is constant then v almost half of v required for 1.5 inch pipe.  .56 to be exact, call it .5 for ease of use.  how is v, velocity, used?

Bernoulli states that an energy term is proportional to v squared. So when calculating head loss, friction loss, etc. you multiply K, friction term, with v, velocity, squared.
Hloss = K*v*v,  so plug in the two v's
1.5 inch  Hloss = K*1*1 = K  (let v=1)
2.0 inch Hloss = K*.5*.5 = K*.25  (so far about a quarter the loss when compared to 1.5 inch pipe)  Whats K then?

constriction  2 inch pvc leading to 1.5 inch pvc
K is .42 (from standard formula)
Hloss = .42 * 1 = .42

expansion 1.5 inch leading to 2 inch
K is .56 (from standard formula)
Hloss = .56 * .25 = .12
so, less loss from expansion as intuitively thought.

Pipe elbows.
Let K for 90 = K90 (just a term) then
hloss for 1.5 inch diameter = k90 * 1
hloss for 2.0 inch diameter = k90 * .25,  so only a quarter loss with larger elbow.
Now make that 90 a 45 angle elbow which has .7 loss of the 90 bend
hloss for 1.5 inch diameter = k90 * 1 * .7 = k90 * .7
hloss for 2.0 inch diameter = k90 * .25 * .7 = k90 * .18
so 45 bend of 1.5 inch is better than 1.5 90 degree bend, but still greater than either 90 or 45 degree of 2 inch bend.

exit (into air box)  here k = 1 so hloss follows benefit of pipe size
1.5 inch hloss = k * 1 = 1*1 = 1
2.0 inch hloss = k * .25 = 1*.25 = .25
or one fourth the loss with larger diameter.

entrance has K = .5 for sharp edge but only .04 for bell mouth (my jeep has a bell mouth intake)
sharp edge entrance 1.5 inch hloss = .5 *1 = .5
sharp edge entrance 2.0 inch hloss = .5 *.25 = .125
again better for 2.0 inch hloss
bell entrance 1.5 inch hloss = .04 * 1 * 1 = .04
bell entrance 2.0 inch hloss = .04 * .5 * .5 = .01

I referenced these two pages for notes on constants and formulas
http://webpages.eng.wayne.edu/~ah8818/Webpage1.htm
http://www.engr.iupui.edu/me/courses/hydraulicresistance.pdf



[sm=agreed.gif]....not really...in english please? lol



Bunk650 -> RE: some of u snorkel experts, got a question (9/29/2008 10:48:18 AM)

just run all 2" and put a 1.5" reducer at the top of your snorks. that way when you decide to rejet you can open 'er up and let it eat!!



matprice -> RE: some of u snorkel experts, got a question (9/29/2008 3:26:41 PM)

quote:

ORIGINAL: lsu_fan91

quote:

ORIGINAL: paulatgis

Answer: 1.5 inch bell mouth intake, expansion from 1.5 inch to 2.0 inch enroute to air box, 2.0 inch elbow at air box with 2.0 inch dia hole cut into airbox air box.  but you might not need that much flow so could go 1.5 all the way, just keep the bell mouth intake.

air flow through a 2 inch pvc pipe has half the velocity of the same air flow through a 1.5 inch pvc pipe.
q = av where a = pi*d*d/2,  d*d for 2 inch pipe is 4, d*d for 1.5 inch pipe is 2.25, so 4 is almost twice area of 2.25.  since q is constant then v almost half of v required for 1.5 inch pipe.  .56 to be exact, call it .5 for ease of use.  how is v, velocity, used?

Bernoulli states that an energy term is proportional to v squared. So when calculating head loss, friction loss, etc. you multiply K, friction term, with v, velocity, squared.
Hloss = K*v*v,  so plug in the two v's
1.5 inch  Hloss = K*1*1 = K  (let v=1)
2.0 inch Hloss = K*.5*.5 = K*.25  (so far about a quarter the loss when compared to 1.5 inch pipe)  Whats K then?

constriction  2 inch pvc leading to 1.5 inch pvc
K is .42 (from standard formula)
Hloss = .42 * 1 = .42

expansion 1.5 inch leading to 2 inch
K is .56 (from standard formula)
Hloss = .56 * .25 = .12
so, less loss from expansion as intuitively thought.

Pipe elbows.
Let K for 90 = K90 (just a term) then
hloss for 1.5 inch diameter = k90 * 1
hloss for 2.0 inch diameter = k90 * .25,  so only a quarter loss with larger elbow.
Now make that 90 a 45 angle elbow which has .7 loss of the 90 bend
hloss for 1.5 inch diameter = k90 * 1 * .7 = k90 * .7
hloss for 2.0 inch diameter = k90 * .25 * .7 = k90 * .18
so 45 bend of 1.5 inch is better than 1.5 90 degree bend, but still greater than either 90 or 45 degree of 2 inch bend.

exit (into air box)  here k = 1 so hloss follows benefit of pipe size
1.5 inch hloss = k * 1 = 1*1 = 1
2.0 inch hloss = k * .25 = 1*.25 = .25
or one fourth the loss with larger diameter.

entrance has K = .5 for sharp edge but only .04 for bell mouth (my jeep has a bell mouth intake)
sharp edge entrance 1.5 inch hloss = .5 *1 = .5
sharp edge entrance 2.0 inch hloss = .5 *.25 = .125
again better for 2.0 inch hloss
bell entrance 1.5 inch hloss = .04 * 1 * 1 = .04
bell entrance 2.0 inch hloss = .04 * .5 * .5 = .01

I referenced these two pages for notes on constants and formulas
http://webpages.eng.wayne.edu/~ah8818/Webpage1.htm
http://www.engr.iupui.edu/me/courses/hydraulicresistance.pdf



[sm=agreed.gif]....not really...in english please? lol


wow thats the first time i have seen Bernoulli ref. on this forum whos next boyle?!?!?!



paulatgis -> RE: some of u snorkel experts, got a question (10/2/2008 7:16:03 PM)

boyles law would be tough, because then some form of work would be taking place.  that is work to compress the volume as in the cylinder by the piston. pvt diagrams are interesting though. I did research on this during college with computers and it mostly paid off when explaining how air conditioner compressors work.  I think next would be to see how air box size affects performace.  I even see people with no air box, just their filter atop their snorkle.



paulatgis -> RE: some of u snorkel experts, got a question (10/2/2008 7:26:15 PM)

in brief, 2 inch hose is 4 times better than 1.5 inch hose which is why a 2 inch 90 degree bend is better than a 45 degree 1.5 inch bend.  Surprisingly a bell shaped inlet is a great performer, but typically we like to use 90 degree elbows so we can slip in restrictors to avoid rejeting.  dont forget all this does is fill the airbox, snorkles arent connected directly to carburetors.



VT_Grizzly -> RE: some of u snorkel experts, got a question (10/2/2008 7:36:38 PM)

Airbox dimension and the way enters definately affects the way certain carbs work.  When I first bored my Grizz 600 to a 675, with all the mods I could do to the motor, exhaust, filter, porting, etc.... I wanted to let in more air.  I still had the stock Mikuni 40mm carb.  I drilled a bunch of large holes in the top of the airbox and put filter material over the holes.  I couldn't get it tuned right no matter what I used.  Mid - top was great, but there was always a low end bog.  I was also inhailing steam at every water crossing and bogging down.  I put a short snorkel on a new lid that was 3" diameter (more air - even worse), but installed an Edelbrock pumper carb for a 660.  This fixed my problem, and now it loves the extra air.  The fuel delivery needs to be able to match the extra air.

You should be fine with a 2" snorkel the whole way - since it'll have restrictions, then tune your carb accordingly or add a chack ball valve (I'd tune for the extra power).



paulatgis -> RE: some of u snorkel experts, got a question (10/2/2008 7:48:58 PM)

im wondering if when latching a seat down imposes restrictions on stock air box lids and a snorkle is directly exposed to the atmosphere so requires smaller inlets.  my 250 suzuki's have large stock intakes at the lid, but require much less when snorkled.  i haven't run any tests, but will soon.



paulatgis -> RE: some of u snorkel experts, got a question (10/2/2008 8:00:16 PM)

vt_grizzley, was the end of your short snorkly exposed to the atmosphere?  -from outside and not beneath the seat?



VT_Grizzly -> RE: some of u snorkel experts, got a question (10/3/2008 12:13:05 PM)

Yes it is.  I don't have any pics with the seat installed, but it sits right in front of the seat (I had to cut some of the seat away to make it fit).  I added a seat cover and it looks pretty clean.  The piece of pipe was pre-bent at Napa and sitting in the basement, and I used the top off of a 1946 tractor to keep rain and debris out.  It's more air than I need, but it seems to work very well with the new carb. 




[image]local://3040/FBA7A6854A624550A9C67F4B50D8C4FD.JPG[/image]



VT_Grizzly -> RE: some of u snorkel experts, got a question (10/3/2008 12:15:09 PM)

It's also barely behind the gas tank and fairly low.  I need to build up the seat at some point to give my "jewels" some protections, but so far I haven't had any problems. 

[image]local://3040/8F7CFC30AA5D4B519F7B00A8254FFF73.JPG[/image]



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