Author Topic: Anti-Pod mod? (Read 16230 times)

H2Eric · « **Reply #25 on:** November 19, 2011, 05:41:33 AM »

Some measurements of the Keihin CR31's

hope that's what you are looking for

Cheers
Eric

orkid1989 · « **Reply #26 on:** November 19, 2011, 06:11:38 AM »

Quote from: H2Eric on November 19, 2011, 05:41:33 AM

Some measurements of the Keihin CR31's

hope that's what you are looking for

Cheers
Eric

thanks and very nice looking carbs.

orkid1989 · « **Reply #27 on:** November 19, 2011, 10:43:41 AM »

ok i defiantly feel like an idiot now. i was confused about something that just wasn't adding up on the design so i went back and read the dimensions that tintop gave me and realized that he gave me inside diameter dimensions and i put them as outside diameter. ill redo my math and see but i think that the stacks should fit his setup fine. if everything fits right all that would have to be done is the plates would need to be bored out slightly to compensate for the larger stacks. buying a lathe today (found an awesome deal) and should be able to make a good mock-up part by next week depending on how long it takes me to learn how to use it lol

orkid1989 · « **Reply #28 on:** November 20, 2011, 09:26:06 PM »

got everything drawn up and ready to go for both the CR's and RS34's. i picked 2 slightly different designs and i was wondering which one everyone thinks would be better. the first one is the same shape as tintop's but i wasnt sure how it would perform due to the bell being smaller because of the size increase. the second is what i thought up to possibly try and compensate with a curve that is twice as long as the other. both bells are the same diameter. the difference is in the curve

Retro Rocket · « **Reply #29 on:** November 20, 2011, 09:35:59 PM »

Not trying to be a hindrance at all but have you seen tintops stacks in person? It may be a good idea to see if you can get one of his for reference, those drawings appear to be too Straight, no taper on the "tube " part of the stack. I have some velocity stacks here on a set of Yoshimura set up CR31's and they are tapered as well, actually, every set of "proper" velocity stacks i have ever seen are tapered. \It may be worth having a chat with Brian {tintop} to see what he says, he spent a lot of time getting his stacks right and they also have an improved rolled lip which helps with better flow... Sorry to be a bummer Orkid... Your first stack is slightly better than the second one, it would produce less turbulence.....

Retro Rocket · « **Reply #30 on:** November 20, 2011, 09:39:20 PM »

I have sent Brian a PM....

orkid1989 · « **Reply #31 on:** November 20, 2011, 09:50:52 PM »

Quote from: Retro Rocket on November 20, 2011, 09:35:59 PM

Not trying to be a hindrance at all but have you seen tintops stacks in person? It may be a good idea to see if you can get one of his for reference, those drawings appear to be too Straight, no taper on the "tube " part of the stack. I have some velocity stacks here on a set of Yoshimura set up CR31's and they are tapered as well, actually, every set of "proper" velocity stacks i have ever seen are tapered. \It may be worth having a chat with Brian {tintop} to see what he says, he spent a lot of time getting his stacks right and they also have an improved rolled lip which helps with better flow... Sorry to be a bummer Orkid... Your first stack is slightly better than the second one, it would produce less turbulence.....

ok i was just curious and the stack does taper on the inside. it is just hard to tell from the picture. the outside is straight to make it more sturdy. an email with the cad drawing the other day but didnt get a response yet.

Retro Rocket · « **Reply #32 on:** November 20, 2011, 10:01:47 PM »

Brian hasn't been around much lately, hopefully he's just busy with work. I am not trying to make things hard for you with this project bud, just trying to help get it right....

I really think getting hold of one of Brian's stacks will help immensely....

orkid1989 · « **Reply #33 on:** November 20, 2011, 10:04:51 PM »

Quote from: Retro Rocket on November 20, 2011, 10:01:47 PM

Brian hasn't been around much lately, hopefully he's just busy with work. I am not trying to make things hard for you with this project bud, just trying to help get it right.... I really think getting hold of one of Brian's stacks will help immensely....

it absolutely would. i am on the list so should get them whenever he finishes.

Syscrush · « **Reply #34 on:** November 21, 2011, 06:10:22 AM »

Quote from: Retro Rocket on November 20, 2011, 10:01:47 PM

Brian hasn't been around much lately, hopefully he's just busy with work. I am not trying to make things hard for you with this project bud, just trying to help get it right.... I really think getting hold of one of Brian's stacks will help immensely....

I believe he's in the middle of a move. When I saw him a couple of weeks ago he was getting his apartment ready to show to other renters and planning a move to a new city (where he has family) about 200 miles away.

orkid1989 · « **Reply #35 on:** November 21, 2011, 09:21:17 AM »

Quote from: Syscrush on November 21, 2011, 06:10:22 AM

Quote from: Retro Rocket on November 20, 2011, 10:01:47 PM
Brian hasn't been around much lately, hopefully he's just busy with work. I am not trying to make things hard for you with this project bud, just trying to help get it right.... I really think getting hold of one of Brian's stacks will help immensely....
I believe he's in the middle of a move. When I saw him a couple of weeks ago he was getting his apartment ready to show to other renters and planning a move to a new city (where he has family) about 200 miles away.

o ok i just figured he was busy with the next batch of stacks. also i am going to be running some CFD tests on the stack and see what happens

Syscrush · « **Reply #36 on:** November 21, 2011, 10:03:00 AM »

I'm no expert, but to me the 2nd one looks like a non-starter.

Tintop · « **Reply #37 on:** November 21, 2011, 06:35:29 PM »

Syscrush is correct, I am moving in 4 days, so have been consumed with getting bikes / parts moved & stored for the winter. Not to mention all the packing.

orkid1989 there is a chart in my filter thread that shows different shapes (bells & throat) and their effect. I'll try to find it, no time right now (think its about 4 pages back).

Besides the shape you also have to take into consideration the length. One of the reasons mine work is they maintain the original intake tract length, and internal sizing. This is why it will work with the stock idle/slow jet.

Some things to consider -
>the intake tract is the installed distance from the head to the beginning of the bell. Is the RS the same installed 'thickness' as the stock carbs? Are the RS engine side boots the same installed length? The +/- difference will effect stack length requirement.
>where do you want it to have the greatest effect (low mid / upper mid / WOT?), that will determine a length of the stack. If the stack is shorter than stock, do you need to increase the runner length on the engine side to compensate?
>Is it for street or race, what kind of power band is needed (they are very different)?
>While the rolled bell is the modern preferred shape (& most effective), the orignial shape could also be used, that's what Sudco supplies. For the rolled edge to work the best it should be about the radius of a dime.

Oh, in answer to one of your questions my back plates are 2mm thick.

orkid1989 · « **Reply #38 on:** November 21, 2011, 08:09:14 PM »

Quote from: Tintop on November 21, 2011, 06:35:29 PM

Syscrush is correct, I am moving in 4 days, so have been consumed with getting bikes / parts moved & stored for the winter. Not to mention all the packing.

orkid1989 there is a chart in my filter thread that shows different shapes (bells & throat) and their effect. I'll try to find it, no time right now (think its about 4 pages back).

Besides the shape you also have to take into consideration the length. One of the reasons mine work is they maintain the original intake tract length, and internal sizing. This is why it will work with the stock idle/slow jet.

Some things to consider -
>the intake tract is the installed distance from the head to the beginning of the bell. Is the RS the same installed 'thickness' as the stock carbs? Are the RS engine side boots the same installed length? The +/- difference will effect stack length requirement.
>where do you want it to have the greatest effect (low mid / upper mid / WOT?), that will determine a length of the stack. If the stack is shorter than stock, do you need to increase the runner length on the engine side to compensate?
>Is it for street or race, what kind of power band is needed (they are very different)?
>While the rolled bell is the modern preferred shape (& most effective), the orignial shape could also be used, that's what Sudco supplies. For the rolled edge to work the best it should be about the radius of a dime.

Oh, in answer to one of your questions my back plates are 2mm thick.

i did the calculations as far as induction waves and in order for the stacks to produce the same induction waves the 55mm can be 10mm shorter. i havnt taken any classes on fluid dynamics so i might just be misunderstanding the problem. also though if i make them to where the outside is smooth i could make them a bit longer. that way they can be cut to fit as far as length?

Retro Rocket · « **Reply #39 on:** November 21, 2011, 08:36:50 PM »

Quote

also though if i make them to where the outside is smooth i could make them a bit longer. that way they can be cut to fit as far as length?

Interesting

orkid1989 · « **Reply #40 on:** November 21, 2011, 08:45:52 PM »

think it might work? that way everyone can tune it to their needs?

Retro Rocket · « **Reply #41 on:** November 21, 2011, 08:57:14 PM »

I don't know for everyone but if i am going to try and use an airbox, that would surely help....

orkid1989 · « **Reply #42 on:** November 21, 2011, 09:38:00 PM »

Quote from: Retro Rocket on November 21, 2011, 08:57:14 PM

I don't know for everyone but if i am going to try and use an airbox, that would surely help....

possibly. i would still need the measurements of the thickness of the box though so i know how large to make the groove for you. i figure it would make it much more usable. because no 2 bikes are the same. one bike might be basically stock and the other might have a racing cam and high flow exhaust. also one guy might want power in the low to mid range while someone wants his power in the mid to high.

Retro Rocket · « **Reply #43 on:** November 21, 2011, 09:46:45 PM »

Yeah, i know what you are saying, i don't care if i lose a little at the extreme top end in favor of a bit more midrange....

orkid1989 · « **Reply #44 on:** November 23, 2011, 04:27:52 PM »

Quote from: Retro Rocket on November 21, 2011, 09:46:45 PM

Yeah, i know what you are saying, i don't care if i lose a little at the extreme top end in favor of a bit more midrange....

likewise. my bike isnt a racebike. would rather have a low to midrange power. but seeing as people with RS34's have everything from stock bike all the way too a drag bike. i think by making these cut to fit they should allow almost any bike to use tintops intake setup. also i can cut them to whatever size someone wants. like i said though it is just a thought

orkid1989 · « **Reply #45 on:** November 23, 2011, 08:20:55 PM »

finished running the CFD tests and you guys were 100% right about the best shape of the bell. i am talking with one of the machinists on this site about making a mold on a cnc so it will be as exact as possibly. it needs a bit of tweeking to get it just right but so far this is what he has.

Tintop · « **Reply #46 on:** November 24, 2011, 06:27:19 PM »

Hi guys, would like to contribute more, but my move is tomorrow. I should be back online in a day or so, and will try to catch up then.

Looks interesting so far. One question - with the Honda carbs there is a 2mm+/- edge, which is covered/smoothed by a step in my stacks (like stock). Will something like the be needed with both the CR's & RS's?

Retro Rocket · « **Reply #47 on:** November 24, 2011, 06:32:31 PM »

Quote from: Tintop on November 24, 2011, 06:27:19 PM

Hi guys, would like to contribute more, but my move is tomorrow. I should be back online in a day or so, and will try to catch up then.

Looks interesting so far. One question - with the Honda carbs there is a 2mm+/- edge, which is covered/smoothed by a step in my stacks (like stock). Will something like the be needed with both the CR's & RS's?

Thats a good question, i haven't actually seen a velocity stack for the RS so i can't really say.

orkid1989 · « **Reply #48 on:** November 24, 2011, 06:47:01 PM »

that is a good question but from what i can see the in pictures (don't have a set of rs carbs yet) it has almost no lip at all. i could be wrong because i don't have one in person to look at. any chance someone can check and see? if so could you give me the measurement as well? i haven't made anything yet so it will only take a few minutes to modify the drawing to compensate.

Edit: i took a closer look at the pictures and their is an edge but that is where what looks like holes for the pilot circuit. looks like their is a fraction of a millimeter on both the CR's and the RS's. so it might disrupt the pilot cercuit by adding that edge. like i said before though i could be wrong because i dont have one directly infront of me

Tintop · « **Reply #49 on:** November 24, 2011, 07:12:02 PM »

Sudco offers an adapter for the CR's that has a dip in it to clear the air correction holes. The picture(s) I've seen of the Sudco RS stacks are simple alloy clampon's, with a basic flared bell end.

That's it for now, have to pull the plug. Back in 24/48.

tintop

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Author Topic: Anti-Pod mod? (Read 16230 times)