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 Post Posted: Wed Jun 29, 2011 9:42 pm 
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Hey All,

Its been a while since and I wanted to discuss something I found on my carb. It is a holley dominator with the weber plates. Well as I have tune this carb, I have found there is a significant jet stagger in the rear. In the rear, it is approximately 8 jet sizes and in the front it is 5.

So i have a spare set of the plates, so I am looking at them, and I notice that where the plates come together for the passage from the e-tube to the booster, there is an offset, and it is not equal on both sides. I measure the size of the passages to be approximately .213. To get an idea of the differance on the misalignment, I started sticking numbered drill bits through the passage to see what size would go through, Well in the back, one side would take .190 and the other was .172. On both sets of plates, one side is larger. So I am thinking I have the same thing on the set that is on the carb.

I think I know the answer, but with all the things being equal, one passage to the booster is smaller/restricted vs unrestricted. Which side would run richer/need smaller jets?

I am thinking it will all clean up just running the .213 bit through there.

So do you all think I am on track with this?

Thanks

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 Post Posted: Wed Jun 29, 2011 10:04 pm 
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Bill I'm not quite sure I understand what you are talking about? Can you post a picture? :-k

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 Post Posted: Thu Jun 30, 2011 5:47 am 
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I will get you pictures tonight of what I am talking about.

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 Post Posted: Thu Jun 30, 2011 10:09 am 
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hey bill,

subscribing to the thread................... my testing continues, will keep you posted.

jerome

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 Post Posted: Thu Jun 30, 2011 11:58 am 
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This picture is looking down at the passage that delivers the air fuel mixture to the boosters
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another view

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 Post Posted: Thu Jun 30, 2011 12:07 pm 
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There is a misalignment where the two plates comes together, it is not even on both sides, There is a .020 different in the sizes of the # drill bits that I can pass through them.

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 Post Posted: Thu Jun 30, 2011 1:00 pm 
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So what you are referring to is what we call the crosswell or angle channel on a Holley metering block? If that's the case, I'm not sure that making them larger is desired as @.213 that means that you will be flowing from that .213 hole into a .169 ID stake tube/booster pin! There has been some discussion elsewhere that the fuel channels need to INCREASE in size from the MJ on, ie, those channels "should" get progressively larger from the MJ to the booster channel. That's why the mainwells in a Holley block are tapered larger from bottom to top. If you got an opening that is .044 larger than the LAST channel in the circuit then there might be problems.

Some of the others here might be able to put more light on this subject as I'm not what you'd call an "expert" and the guy I use to talk to about this kind of stuff won't talk to me any more. =P~

So what did TP have to say about this? :-k

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 Post Posted: Thu Jun 30, 2011 3:26 pm 
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Yes, that is exactly what I am talking about, I was not planning on making it any bigger overal, just in the area where the misalignment is. That way at least it will be uniform from side to side, which in my mind will give a more overal consistent mixture through out the carb.

Don't get me wrong, I like the plates, the ease of jet changes and such makes dialing in on a tune very easy. But they are not magically as some would like you to believe. I figure the dominator is about a .10 faster then my demon, and I attribute that to the increase in cfm.

You know TP, if something is wrong with the carb, I must have done it, and the reason I am not getting spectacular results is because I am not giving him information he needs. We had a bit of a falling out to put it delicately. He basically sold me a modification that in his words helped prevent fuel starvation in hard launches. Well turns out the only way I could get the hesitation out of it, was too disable the mod. I requested information regarding what application he tested this on, he refused to give any. Then I see him making a post out on speedtalk where he has altered the modification based on what he had learned from me. So I called him on it. He choose to personally attack me and its been down hill since. I also had to chase some other issues with the carb that came as a result of him converting it to use holley jets.

I don't know if you follow speedtalk at all, but recently he told a guy that if his carb didn't pick his car up .2 that he would give him his money back quareeted. Well all this deal happened, the short story is the guy got tired of dealing with Troy and sent the carb back, well Troy decided it was a conspiracy to make him look bad and as of now has not returned the money.

He also kept posting stuff about our experiance, and i kept correcting him and point out the truth and it went down from there. I probably took it too far but just burns me that he makes these crazy claims which gets people who don't know better hooked, then when it fails to produce, its the users fault. You know he tried to convince me I was going to see .5 in my car.

Oh if you know who I am referring to, please don't use his name or company name, because I don't want him to be able to locate this post that identifies issues with those plate.

So that the story, enough of him, Lets get to the plates,

Once I get the plates where I feel I got the most out of them, I really want to go back and try a decent set of metering blocks to see if there is any real performance gains to be had one way or another. Like I said the ease of adjustability on these things is awesome, I can make a jet change in less then two minutes, and I don't have to spill any fuel. After working out several issues, they are meeting my expectations, and I am happy with them.

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 Post Posted: Thu Jun 30, 2011 5:47 pm 
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But if you open up those holes, you create a larger channel that has to flow into a smaller one? Yes/No? If that's a yes then that's where the problem lies. I'm not sure that's the best approach to fuel circuit flow.

Maybe shrinker has had some dealings with those Webber Power Plates and can give you some feedback. One of the complaints with them was that NHRA Pro Stock guys never used them and that if they were as good as TP made out they were, then they would have. That and some of the emulsion holes were actually above the fuel level of the bowl, which would really hork with AFRs down track.

Ennywho, sorry it didn't work out with him but I think I did try to warn you? ;-) Sorry but yeah, I'm one of them "I told ya so" kind of assholes! =; And he wondered why I refused to activate his registration here?? The guy has been a nut case for a long time, has been under psychiatric care in the past and has even posted on some psychiatric forums too.

I'm not sure how those Webber plates work but I will suggest that you try a set of QuikFuel billet 2 circuit blocks as an alternative as they are cheap and I've had dealings with 3 sets on Dominator conversions that have worked fine. Only mods that needs to be done to them is to relocate the IJ at the bottom of that circuit like the old style Holley 2 circuit blocks had and open up the crosswells.

And on another note, you being in here is like mental telepathy or something like that because I was thinking about you two days ago! O:)

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 Post Posted: Thu Jun 30, 2011 6:42 pm 
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You can try a set to see what it changes, it may slow the fuel down but I think it would be better to balance them.

Have you tried to go back to the 2 circuit setup to see if it makes a difference at this point? A lot of things effect how an engine burns fuel, The Weber plate use radial emulsion that can make the fuel exiting the booster slightly better mixed art lower speeds but should not make a significant difference at higher RPM's once velocity through the carb gets high enough. Also, what plug are you running in the engine?


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 Post Posted: Thu Jun 30, 2011 8:03 pm 
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When using Weber plates the fuel bowl is moved further away from the barrel center-line. That is part of the reason for the large jet discrepancies. G force moves the head of pressure in the metering block and when the bowl is further away it moves it more and when the head alters the accuracy of emulsion is destroyed. Another effect is small differences in any part of the system result in mayor tune errors. Also small differences in engine needs show up as large differences in jetting.
That is why Weber NEVER marketed the blocks for drag racing. The design is not suitable for drag racing. Weber marketed the blocks for the purpose of fuel economy on standard road cars.


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 Post Posted: Thu Jun 30, 2011 8:20 pm 
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I'll explain the g-force issue. The surface of the fuel moves due to acceleration. Ok so think about the rear bowl as one example. On Bills car its at the back so during acceleration the surface of the fuel is angled so that the surface level at the main jet entrance is lower than when the car is stationary. so the pressure upon the main jet entrance is very low. We also have to consider the fuel level in the main well and thats low too, now the emulsion bleeds are way above the surface of the fuel so the amount of air introduced is greater. Imagine what the tune would be like if you built your carby so that the e-bleeds are all that far above the surface of the fuel and then put that on a dyno. Self explanatory isnt it.


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 Post Posted: Thu Jun 30, 2011 8:20 pm 
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Well the way it is, its already a larger area dumping into a smaller area. The problem area(restriction) is right on the exit of the e-tube. In my mind, I would expect evening up the areas would increase flow through the channel as right now, as the mixture exits the the e-tube, its hitting a lip caused from the misalignment, I would think it would be a smoother flow once I remove it.

Regarding the e-tubes, there are many differant types, with holes positioned in various locations, with this e-tube, all the holes are below the fuel level.

Ken, I knew exactly what I was getting into with troy, thanks to you, but I wanted to try them and I found something I like, and want to further test. I made the gains I expected to make.

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 Post Posted: Mon Jul 04, 2011 12:00 pm 
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jmarkaudio wrote:
You can try a set to see what it changes, it may slow the fuel down but I think it would be better to balance them.

Have you tried to go back to the 2 circuit setup to see if it makes a difference at this point? A lot of things effect how an engine burns fuel, The Weber plate use radial emulsion that can make the fuel exiting the booster slightly better mixed art lower speeds but should not make a significant difference at higher RPM's once velocity through the carb gets high enough. Also, what plug are you running in the engine?


Sorry Mark I missed your question, I am running the NGK-8s with the projected tips.

I would like to find a decent set of blocks to try, anyone have a known good set that I can borrow to try? I have a set of stock blocks, but I never had any luck getting them to work right.

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 Post Posted: Mon Jul 04, 2011 2:36 pm 
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fourtenposi wrote:
I have a set of stock blocks, but I never had any luck getting them to work right.


Bill please define "work right"? Exactly what did they do or not do that you were looking for? Reason I asked is because I ran a pair of stock 780 primary Holley blocks with the listed tuneup in my old style 8896 and it ran as good with those as it has with the billet QuikFuel blocks that are on that carb now?? :-k

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