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Frank my lord
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186 Posts
Discussion Starter #1
i have a hilborn alky setup, my problem is that its running wayyyy to rich from idle to 1/4 throttle i adjust barrel valve to compensate but then i have a huge stumble and most time lean pop back though blower when trying to excellerate of idle. i have tried to lower my secondary bypass pressures to compensate the rich condition but its just returning more fuel to the tank and causing the same thing, not enough fuel pressure for the full throttle transition from idle and then again lean pops back on blower. when its running way to rich other cylinders light off others byway of the zoomies being next to each other, backwards threw the zoomies:)st. anybody have any suggestions, what should i be tuning. where im i going wrong?
 

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Whats your set-up? Where are the nozzles at and how many? Which Hilborn, 4 hole upright or forward facing? Which barrel is in the valve?
 

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Ain't Right Racin
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Frank my lord
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186 Posts
Discussion Starter #4
set up

Whats your set-up? Where are the nozzles at and how many? Which Hilborn, 4 hole upright or forward facing? Which barrel is in the valve?
upright 4 hole 4" tall 3" butterfly's injector hat,4- #104 nozzles. 80a pump .050 main return pill, .024 secondary bypass spring . high speed cut off circuit with a #70 spring and .050 pill. alcohol barrel valve i believe.
hope thats all the info you may need. thanks
 

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Gone
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upright 4 hole 4" tall 3" butterfly's injector hat,4- #104 nozzles. 80a pump .050 main return pill, .024 secondary bypass spring . high speed cut off circuit with a #70 spring and .050 pill. alcohol barrel valve i believe.
hope thats all the info you may need. thanks
Well that is the right nozzle.
I'd say you probably ought to have a main by pass pill of 70 to start....and forget the high speed....turn the can around backwards till you know where you are at in the fuel curve. The 80a pump is basically your high speed.

What Lb spring is in the main jet can? (Where your 50 pill is now).
That should be real weak...about 2 or 3 lbs.

I'm thinking that part throttle bypass....that deal mainly for gas.....you might want to call Hilborn. They may have you not use that bypass. I wouldn't with alcohol.
 

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Frank my lord
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186 Posts
Discussion Starter #12
Well that is the right nozzle.
I'd say you probably ought to have a main by pass pill of 70 to start....and forget the high speed....turn the can around backwards till you know where you are at in the fuel curve. The 80a pump is basically your high speed.

What Lb spring is in the main jet can? (Where your 50 pill is now).
That should be real weak...about 2 or 3 lbs.

I'm thinking that part throttle bypass....that deal mainly for gas.....you might want to call Hilborn. They may have you not use that bypass. I wouldn't with alcohol.
the lb spring is real weak like you said, only 2-3 lbs and that part throttle bypass seams to be the exact spring, i measured the pill it is .187 thick and the part throttle bypass from hilborn has an .187 thick open shim behind the spring, they seem to share the job at idle bypassing fuel. i called hilborn and they said the the pump could out flow the single cicuit in certain cases so thats why there is the secondary bypass. the barrel valve completely shuts the secondary bypass off when the throttle gets pass quarter throttle.
 

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the lb spring is real weak like you said, only 2-3 lbs and that part throttle bypass seams to be the exact spring, i measured the pill it is .187 thick and the part throttle bypass from hilborn has an .187 thick open shim behind the spring, they seem to share the job at idle bypassing fuel. i called hilborn and they said the the pump could out flow the single cicuit in certain cases so thats why there is the secondary bypass. the barrel valve completely shuts the secondary bypass off when the throttle gets pass quarter throttle.
Ok then first I have to ask if you are SURE you don't have the barrel valve spool in 180 out. Just take the inlet fuel line off and look into the BV and then open the throttle.....in which you should see the cutaway open up. It sounds dumb but it does happen.
When you are idling....the main jet is flowing back to the tank. You adjust the BV for your idle and "transition" to open throttle. With a 50 pill in there you have plenty of fuel.....your high speed should not be flowing due to 70 lb spring....your part throttle by pass is probably flowing some (depending on spool cut).
At part throttle (where the secondary bypass should be closed)...last thing you should have is a hesitation....because all you are flowing return wise is the main jet.
So check that spool. That sounds suspect.
You can also remove the shim stack in the secondary and put a pill in there (same thickness as you noted).....this will make the part throttle transition fatter...where you are getting that "bang" through the blower.
I still say you can do without that secondary if you want to.....at least testing wise to fatten and get above that hesitation. Basically that is what Enderle does per say....flow the "secondary" through the main jet can...which is always going to have a pill in it....and a pill is a restriction of fuel back to the tank so the system is richer.

One other thing to note is the pump....be sure the fuel shutoff opens all the way and is this a "known" good pump......which flows close to 7 gpm.
One more thing is if you question you have a gas or alcohol spool....usually the only difference is the size of the hole (that the secondary bypass flows through) Alcohol spool has a bigger hole than gas. Maybe you can measure that and tell Hilborn.
 

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Frank my lord
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186 Posts
Discussion Starter #14
i checked the spool its correct in its operations and installation, the pump is a known good pump which flowed 6.7gph. i can adjust the bv so it makes the transition well but in a few seconds of idling it starts running waaaay to fat again, and as it runs it just keeps slowly getting richer. even running it up a little bit to blow it out it, or clean its throat it starts running rich all the way up to about quarter throttle.
 

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Frank my lord
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186 Posts
Discussion Starter #16
at this setting no pop back but it slowly starts running so rich that it starts lighting the unburnt fuel in the air and popping backwards through the zoomies. im now starting from scratch and going one item at a time and making sure everything is correct and operating correctly, i called hilborn 'thanks fiat48' and they gave me a base to start with to try this again. its all completed and will fire it back up tomorrow night. ill let you know how it went.
 

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Well here is a list of what I would do in checking the system:
1. Fuel supply line to the pump. Make sure there is no "flapper" that happened when the fittings were installed in the fuel line.
2, Same thing for the main line from pump to the BV block....and all lines for that matter.
3. Main return line is plumbed to come off the pump...and that the main jet can is facing "poppet toward the pressure."
4. Secondary is plumbed from the out port and jet can facing same way.
5. Hilborn may have given you a leak setting for the BV.....if not....I use 35% leak with out port plugged. That is to start.
6. BV spool indexed right....but we covered that earlier.

And I have to throw this one in there because I saw it done......and a blower leave the manifold because of it.
If you have a 4&7 swap cam......you gotta swap the wires. :)
 

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Frank my lord
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186 Posts
Discussion Starter #18
its alive again

well i decided to completely start from scratch, pulled all lines off, made sure bv clocked correctly 'it was' , pulled all bypasses apart and made sure the plungers actually moving correctly, had to clean one of the plungers was sticking a little bit, hilborn gave me a measurement of 2.980 center to center on bv adj. linkage arm, checked all lines 'ok', decided to pull blower and their it was a section of gasket missing, i think i was tuning it with a blownout blower base gasket. reassembled all components, next i checked all the screens in the injectors, and blew compressed air through all nozzles. went from a .030 pill to a .060 pill in primary bypass, left the secondary bypass alone. high speed bypass also put .050 pill, fired boat up and was within a half of a turn a now motor runs bad ass again, thanks fiat48 for all the info it really helped solve these frustraiting issues. i still dont know what fixed it, because so many thing were changed, but it runs bad ass again.:D
 

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I run the same hillborn injection on an 871 454 7.5-1 11%over but I was only running 1 bypass. very simple set up and it ran like crazy last year. this year I droped in a 505 7-1 comp and bumped the boost to 20% and called hillborn and they told me to change the pill from the 65 to a 55 and it ran like crap so i went to a 50 and no change but the I realized my distributor had turned on me so after a few adjustments withouit a light I got it ballparked and now its running great but not perfect I think i need to lean it out to a 55again and give it another try (I ran out of time hadto head home at night since the motorhome was running like crap in the heat) when I got home my work truck and personal truck had been loaded up with my posessions from the house and stolen about 2 hours before I got home. basterds got alot of my stuff but they did overlook some expensive things as well . They took my gun collection (6 handguns and an Uzi) but left an AR 15 and belgum made browning and various other rifles and overlooked a currancy collection worth about 5 grand. it was all locked up in a locker and not a safe. something that I just kept saying I would do never did was get a good safe. now I get to haggle it out with my insurace co. oh they recovered the work truck the next day (less tools) so I had to go shopping the next day and that was 5 grand that my employer covered. hopefully the dick heads will get caught with one of the guns and then maybe I will have a chance on finding out who it was. its my guess someone saw me hooking up the boat to the motor home and knew i was leaving for the lake. it would make my day to catch someone in the act. they would be begging me to call the cops on them!
 
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