Single Carb. Conversion, VW Plenum & Modding, the OEM Manifolds

[westgl]

well thanks Joe, I think?

Was looking at the VW plenum, that outlet and volume is nice and small.

I hate to be going back and fourth, But I want Rev.#2 to have, as few of possible failure points as i can possibly have, Durability is a very high priority!!!

I want my manifold to last decades, with Zero maintenance, or removal required.

I also want my manifold, to look great and like a factory unit, or at least something that could have been from the factory, if they would have gone this route.

If I can pick up some performance along the way, then great.

In going to 1/8" larger diameter in the ID of the tubes x4ea plus Much smoother transitions between VW plenum outlets all the way to intake ports, and not have any tubes collapse, or kink at all.

I would think, that I should have some kind of a performance increase.

But, if it at least does as good as it did, I will be very happy.

I am really wanting to get this back together, so i can test ride it.

Although I see weather wise, Tuesday, Thursday, & Friday, are the only days that look to be clear of (Clear of Liquid sunshine) rain right now.

 

[dan filipi]

For me anyway Joe, I didn't understand at first your use of the word "choke".
To me that refers to the choke plates themselves as a means to create a suction and lower the pressure just before the fuel delivery jets.
Now I see your "choke" is being used to slow the flow after the throttle plates?
Maybe you could elaborate on this more for us all and how it works.
My extent of a fuel intake experience is mostly multi carb bikes and Chevy, Dodge intakes which don't have this choke after the carbs that I know of so I don't really understand the reasoning behind it.
I can understand reducing the runner size to reduce volume, that would speed up the flow but restricting it to slow the flow I'm still scratching my head some.

I don't mean to put you on the spot or make you feel like you have to proove it does what it does, just trying to understand.

 

[westgl]

When I use the word Choke,

I mean Venturi Choke, or a funnel shaped venturi opening that reduces diameter from carb opening down then after choke opens back up to throttle plate size, after the choke plates, but before the throttle plates.

So the 32DFT is a 32mm carb opening, choked down to 22mm, then opens back up to 32mm at the throttle plates

This is used to speed up the air/fuel charge, through the carb., my 32DFT carb has 2ea 22mm venturi chokes.

Another choke could be added in the tube runner, between the VW plenum and OEM manifold.

But for now, i am going to test it, without that 2nd choke in place

The VW plenum is reduced down to a 1-1/8" to 1-3/16" opening, at the small end of the plenum outlet inside, I am going to use that as my after carb Choke, for now.

 

[joedrum]

west I wish I could draw a picture ...because my words fail to get across and I cpmpletely understand why ...I have trouble to reading my stuff .... but no matter how hard I try ... im not beating this anytime soon or ever .....me drawing pictures like first grade stuff would work better for me and all on the forum ......sheesh LOL ...im sort of hopless here but its and wish I could do better ....im sure if everyone would choke down there manifold just like mine they would all be giving great ride reports and these threads would be all different ....its like ATF everyone thought I was insane for a yr or two before igot someone to try it ....so im used to it ... and wish I could explain myself better ... best to all going for the single

ok dan dan if you hook a vacume cleaner to a 10 inch pipe ... one end blocked off where hose goes in and other end open ... turn on vacume ...and its 2inch pie connected to 10 inch pipe it will not have much vacume at all and pic up nothing ....

if you close off the 10 inch end doen to vacume hose sixe or lower it will pic up now ... the smaller the hole the faster the air .....

if the ten inch pipe is sized right ... the expantion of the ten inch pipe will cause a small tornado effect and will icrease the power of suction to the smaller hole on the other end ......

and more powerful than the vacume hose by itself right at hose ...

expantion chambers are costless power increasers flat out costless

now these cambers cant be to big ... thay have to be sized right for the beginning suction force of the vacume its being put on .... in other words there a point of dimisishing return

on our manifolds all this stuff applys if you wan the fastest possible air for a car carb on a oldwing ypo havto realy set it up right to get the to small motor to atomize the gas right ...big wide popen runners so far to carb is all workin to make this problem bigger the absolute wrong direction .... unless you choke it at the manifold like if done from the start

my bike hes ran two carbs now .... and neither bogged at all ...everyone here but westgl has bogiing issues with this wide open set up here on this forum ....

is it all vacume leaks ... don't know im not there ....but I bet I could get every one of these bike running if I was there ...I dot know what else to say :builder: :mrgreen:

except again excuse all the mis spelled and wrong words sheeesh :smilie_happy:

 

[dan filipi]

Your example helps a lot Joe!

Ok so... Wouldn't smaller runners from the vw manifold all the way to the head have the same effect?

 

[westgl]

No,

You want to reduce down for speed up then open back up for the volume through the larger tube

Engine is a air pump, more in more HP out, to a point

 

[westgl]

If I can get my manifolds welded today, i will provide a ride report soon.

I hope they can get my two manifolds welded today, so i dont have to wait.

 

[joedrum]

tp some degree but without the expantion chanber you will not get the fastest air ....like on 2cycle exhaust when the exhaust goes into the expansion it sust he ehaust out of the motor big time over a small pipe ....then closed off on the other end the ehaust is way up high as it is at the motor or more at the end of exhaust ....the wide open chamber to the manifold dose improve what your trying to do dan and then choked right at carb gets maxium air speed as I see it the rinner is not passed the point of diminishing return on expansion chamber .... other side of this or opposite is even steady atomized fow to head all bennies in my book

 

[joedrum]

your just flat out wrong westgl

 

[westgl]

My bike ran great with the 1-1/4" ID hose the whole run.

In going to the 1-3/8"id diameter, i want to see if anything more can be had.

Like I said the 1-3/8" is a perfect match to the OEM Manifold ID and provides a Extremely smooth transition.

Much better than i had with my 1-1/4"ID.

But you never know, I had the face of the 1-1/4" in the flow of the air/fuel mix that may have slowed down the fuel air charge, But it ran Great!

So if more volume can be had, i want to at least try it.

To see if one way or the other.

I can always go to a alum. tube, that is 1-1/4" ID with a 1-5/8" OD alum. tube, that would make a good seal plus the ID would be back to what worked before.

 

[KYWinger]

joedrum » Mon Sep 30, 2013 6:21 am[/url]":1qekyhoi]
.... other side of this or opposite is even steady atomized fow to head all bennies in my book

what does this mean?
I've been following the bazillion posts on this and west's manifold looks extremely promising.

 

[westgl]

So Joe,

If not reducing just a short portion of the runner down in the ID to say 1-1/4"iD then back open to 1-3/8"ID, for speed up and more volume,

Are you saying to reduce the ID down the whole length of the runner then?

joedrum » Mon Sep 30, 2013 6:22 am[/url]":39p1a3jd]
your just flat out wrong westgl

 

[joedrum]

no maybe I misunderstood ...if runner is big to manifold then reduced there ...that is exactly what I did ...the bigger size runner will put nore power and speed to the air than same size pipe as choke all the way to the head ...

 

[westgl]

Today, after my contractor leaves, he should not be to long.

I will take my 2ea Oem manifold to be seam welded.

I will finish cutting my Alum. tubes.

The two alum. tubes that will be angled, are cut at a angle where the tube meets the Plenum outlet

some pictures of fitment, sealing area, and tube to Oem manifold transitions

Some pictures it is hard to see but the transitions are flush with each other.

P1020156

• westgl
• Sep 30, 2013

Tube to OEM manifold seal is good

P1020155

• westgl
• Sep 30, 2013

1-1/2" ID hose to 1-5/8"OD tube seal, is good

The picture below shows the transition between the tube ID and ID of OEM manifold, it is perfect

P1020153

• westgl
• Sep 30, 2013

Transition from 1-3/8" ID tube and manifold is very Good,
1-1/2" ID hose to 1-5/8"OD tube seal...

P1020151

• westgl
• Sep 30, 2013

Good seal between 1-5/8"OD tube and OEM manifold

P1020150

• westgl
• Sep 30, 2013

Very Smooth Transition between the OEM manifold and 1-3/8"ID tube

 

[joedrum]

looks good

 

[dan filipi]

KYWinger » Mon Sep 30, 2013 7:26 am[/url]":2kyrlgr1]

joedrum » Mon Sep 30, 2013 6:21 am[/url]":2kyrlgr1]
.... other side of this or opposite is even steady atomized fow to head all bennies in my book

what does this mean?
I've been following the bazillion posts on this and west's manifold looks extremely promising.

Lol, I promise we will consolidate all this once all the back and forth commentary is over and we have working manifolds.

Joe, try not to get worked up over this.
We're just trying to understand why and follow an already confusing subject so we can hopefully do this mod ourselves.
Take it slow, preview your posts and edit them before posting.
Your example already help loads in understanding.
Do more of that.

Ok....where I have some trouble is when words are being used to reference different things.
Manifold...to me that means the vw manifold or the part the carb is mounting to. I've read the runners being referenced as manifolds....confusing.
Choke....is being used as a reduction in pipe size, acting as a venturi? Again....confusing.

Yes, drawings would help so we're all on the same page.

 

[westgl]

Lets hope that,

my Ride Report proves just as promising.

KYWinger » Mon Sep 30, 2013 6:26 am[/url]":1qzbaz8x]

joedrum » Mon Sep 30, 2013 6:21 am[/url]":1qzbaz8x]
.... other side of this or opposite is even steady atomized fow to head all bennies in my book

what does this mean?
I've been following the bazillion posts on this and west's manifold looks extremely promising.

 

[joedrum]

I try guys..... I do I just get lost in typing and loose right words and it gets worst from there .. :hihihi: im not work up guys .. except over the fact its a fight every time I try to post something :swoon: ... I can do better...... than I talk about it ... :head bang: :mrgreen:

 

[82a]

joedrum » Mon Sep 30, 2013 9:21 am[/url]":1dt9r50r]
.... other side of this or opposite is even steady atomized fow to head all bennies in my book

i understand 'bennies' here as perks, bonus, benefits, all good,

fow = flow

i've also seen 'iggy' used and i think that is short for ignition (systems)

 

[mcgovern61]

82a » Mon Sep 30, 2013 10:34 am[/url]":5f2h4spu]
i've also seen 'iggy' used and i think that is short for ignition (systems)

Well that blows apart my interpretation.....I thought "iggy" was a new Member here! :smilie_happy: :wave: JK