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Discussion Starter #1 (Edited)
In an attempt to bring out the best in my '92 carb, I purchased a Dial-a-jet. It works and I love it. So, I decided to see what else I could do with Thunder Products stuff.

The first is an air stabilizer called the Quad Flow Torque Wing, installed on the engine side to divide the air flow into quadrants and reduce turbulence. And the second is the Ultimate Flow Optimizer, or UFO. It is inserted into the bottom of the slide to further straighten the air, as well as to move the suction to better pull gas from the needle opening.

Both of those require modifications to fit in a TW carb, and I will post pics as I get them put in. However, now I have a dilemma. My carb is using the stock #40 pilot jet, and is already way too lean, because I have a high flow air filter. That will only get worse when I install my new exhaust later this week.

I wouldn't have a problem picking out a new jet, except for one thing, Lonn over at Thunder Products suggests cutting the size of my pilot jet in HALF. This is the case because much more gas will be pulled up the needle when I give it throttle, which improves response. I called the guys at Procycle, and they suggested I start a thread here.

I hadn't planned on reporting until I knew whether the news would be good or bad, but maybe there is someone else who has already experimented with these. If those who have much more knowledge about carburetors than I wish to weigh in, I would appreciate it. Otherwise, I'll report what I find out so that others might benefit.
 

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You may be in uncharted territory. There have been a few TW Dial-a-Jet users, but I can't recall anyone also using the Torque Wing and UFO.

It is my understanding that with the Dial-a-Jet, your carb should be set at the leanest possible jetting, then adjust the "dial" to get the proper fuel mixture.

Shouldn't the Dial-a-Jet compensate for a lean pilot jet, and the change in air flow?

My guess is that you will need to do a lot of trial and error testing.

From the UFO description: **When installing UFOs, the pilot jet must be reduced substantially (usually about 50%, sometimes even more).
From the Torque Wing description: ...the Torque Wing is easy to install and requires no tuning.

jb
 

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You can do it!!!! I'll be cheering for you and watching intently..........


Tom............ with a fresh bag of popcorn.
 

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Discussion Starter #4
Hi guys, I didn't expect a reply so quickly. Makes me feel better knowing there are others interested. I will surely have to try several sizes to get it right.

Jbfla is absolutely right, but while talking to the inventor, Lonn, I got the feeling it wasn't so clear cut. He led me to believe that it should be 50% of a properly running pilot jet, which mine is certainly not.

If I were to go up in size to, say a #42, it probably still would be on the lean side, but at least runnable without the choke. If I hadn't invested in the UFO, I would be buying jets right now. So, let's say something like a #44, for instance (I don't know if that exists) might be correct. That means 50% in size would be a #22, or I might be over-thinking this entirely.

Oh, and the cool thing about combining the dial-a-jet with the UFO, is that they work on different rpm's and compliment each other. The UFO improves atomization at low rpm's and throttle response, while the dial-a-jet evens the fuel distribution at the mid to high range and also improves response. Include the torque wing in the equation and I should have the response of a carburetor twice the price of mine. (No, I don't work for them. I'm just excited!)
 

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I really want you to be successful with this. So many "upgrades" on here have been done to death, or perfection, depending on your perspective. Truly uncharted territory is exciting!:) I wonder what this would do for gas mileage? Hope it is not just snake oil.



Tom
 

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Discussion Starter #6
Me too, Tom. The installation will probably be Wednesday, (I need to use a buddy's lathe) after which I'll be posting pictures. Then the trial and error will begin.
 

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Me too, Tom. The installation will probably be Wednesday, (I need to use a buddy's lathe) after which I'll be posting pictures. Then the trial and error will begin.
Seriously, I wish you all the luck in the world with this. I would maybe try this even if there were zero performance gains but a decent increase in fuel mileage. I am already averaging 70 mpg too. 90 would be nice though;)


Tom
 

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Discussion Starter #10
Thanks for the encouragement and the link to part numbers. I just ordered a #20 and a #25 to start, which weren't on the list or even on the forum's radar, for obvious reasons. The list will come in super handy for main jets later though, so I'm bookmarking it.
 

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Discussion Starter #11
I do apologise for luring you here under false pretenses, and I should have made it clear that the math was about pilot jet sizes. I just wanted a cool sounding thread title. You are welcome to watch as I screw up a perfectly good carb with a $40 piece of plastic.:D
 

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Yeah – but that was a long time ago – lol

So – what do you reckon ?

Perhaps if they had “vaned” or bladed the device slightly it would be more efficient at mixing the flow, but then that comes at the cost of the flow rate itself.

I’m also thinking that once the engine gets enough revs up, the “back reflection” on the in-put side is going to confuse things to the point where you’re going to be back to square one. This may go some way to explaining the claim of more power “off the mark”, but no further.

Yet despite the difference in power performance across the rev range (high and low) it is still supplied by a lower jet size – half the recommended size. This is where my education fails me. I can visualise the need for less fuel more efficiently delivered at low revs, yet at high revs, once the device has been (more or less) defeated, how does that reduced jet size still continue to supply enough fuel to stop the engine from running lean ?

There’s often a huge difference between being smart, and being smart and educated. I’ve known people with Masters Degrees who couldn’t tie their own shoe laces. Mike – you’re that rare beast who, (perhaps despite their level of education), never allowed that education to get in the way of both enjoying and embracing all that this life has to offer. We’ve both been professional teachers in our lives, and that is what I ask of you now.

How the hell do they do that ?

(I hope you guys appreciate the level of “blowing sunshine up his arse” I’ve gone to here – talk about “taking one for the team”) ………………….. :rolleyes:
 

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I read through the patent application info, and if I understand the concept of the UFO, it basically is an effort to make a round slide carb into a flat slide (at least to behave like one).....to provide a smoother airflow.

The diagram provided shows an old Mikuni round slide carb, with no cutaway. The UFO provides a cutaway on a slide that doesn't have one. This is probably a simplification, but is the basic idea.

I don't have the slide Teikei carb (old version) at hand, but I believe the slide already has a cutaway, negating at least some of the advantage of the UFO.

In addition, by reducing the size of the pilot jet by half is asking for trouble, at least in the real world. The standard pilot jet already has the smallest openings in the carb, and is the first thing to become clogged up by fuel varnish, gum, and dirt.

So the question for you physicists is, "Am I at least close in my understanding of the UFO?" I am willing to be educated... ;)

jb
 

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Discussion Starter #15
Hopefully I understand these things well enough that I can clear up your doubts (or I might be deluding myself, who knows).

To Purple: The reduced pilot is to compensate for more fuel pulled up the needle at a lower rpm. While at higher rpm, the natural amount coming from the needle won't change. In addition, if more air starts flowing through the carb, and therefore more gas is needed, in theory the dial-a-jet should pick up the slack.

To jbfla: My slide looks close enough to the diagram that I should benefit at least a little, I hope. It has a diagonal cutout on the air box side, and a lip similar to the pictured mikuni slide on the engine side.

I've tried to read up on everything I can to get a better idea of what I'm dealing with, but the aid of a physicist among other things would greatly improve my chances of getting this right.
 

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Discussion Starter #16
IMAG1451.jpg

IMAG1452.jpg

IMAG1453.jpg

Here's some pictures with some scale and from different angles so you can get a sense. Although I still won't be able to install them until at least tomorrow.
 

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Thanks for the clarification (appreciated) - although just how much of a twist on the throttle do you expect to get before the main jet kicks in on a TW ?

Sounds like the UFO on its own would have effect for about one and a half seconds before the dial-a-jet has a chance to have an influence on the proceedings.

Interesting stuff - I'll be watching to see how you make out .........
 

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Discussion Starter #18
I think I remember Lonn saying that the dial-a-jet kicks in around 30-40% throttle. So, you're probably spot on by saying 1 1/2 sec, since the nozzle on the dial-a-jet works on the Bernoulli principle and needs a certain air velocity to work. However, at higher rpm's the air flow should be more responsive to changes in the throttle, making 30-70% feel better than 0-30%. (i made those numbers up as an example, since I don't know for sure.)
 

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My slide ...... has a diagonal cutout on the air box side, and a lip similar to the pictured mikuni slide on the engine side.....
That's what I am trying to understand. If the stock TK slide already has the diagonal cutout, how much more will the cutout on the UFO add to the fuel flow at idle?

The fuel mixture of the carb at idle is controlled by the size of the pilot jet, and the size of the cutout on the slide.

Unless the angle of the cutout on the UFO is significantly different (smaller....smaller angle means faster air flow, more fuel, more Bernoulli :) ) than that of the stock slide, I don't see it making much difference.

As you said the Dial-a -Jet doesn't kick in until 30-40% throttle. So from idle to 1/4 throttle, the fuel is all from the pilot jet and slide cutout air flow, and perhaps with some "bleed over" from main needle jet.

If I understand this correctly, the Dial-a Jet people are saying the UFO increases the fuel flow from the main needle jet , at idle, enough to be able to cut the size of the pilot jet in half?

And, as Purple mentioned, I'm concerned that the back pulses from the cylinder will negate the benefits of the Torque Wing.

I'm in no way trying to discourage you. I can see myself doing the same thing. I'm only trying to understand the principles involved.

Please keep us posted.

jb
 

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Discussion Starter #20
Oh, at this point, I'm too excited to be discouraged by logic (maniacally laughing). Anyway, I think the UFO isn't trying to correct the angle on the air side as much as eliminate the flat lip on the engine side, which would block air and cause that circular turbulence in the diagram you saw. Normally, air would flow down and around the slide and either continue below the slide, or hit the lip, turn up into the slide center and then rejoin the lower air column. Does that make sense. I'm sorry if I'm not very good at describing it. Then imagine what it would look like if you put a flat piece diagonally from the highest part of the cutout, to the bottom of the lip. The air would lose its biggest obstruction, and would flow around the slide more freely. That's my understanding, and it may change when I actually get it running.

Also, could you explain what you mean by "back pulses" please? I'm pretty new to working with engines, and am doing well just understanding how jets work. I am reading everything I can to understand better, and opening everything up to do small modifications is helping me learn fast. I'm so glad I picked a TW to learn on, by the way.
 
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