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 Post Posted: Fri Mar 30, 2012 10:08 am 
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It would be nice to know the hp of the test engine. I'd think my little 580 hp engine wouldn't have as much going on as the test bowl did.


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 Post Posted: Fri Mar 30, 2012 11:01 am 
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Ron, it's a 1200+ HP big block. Not something you would use on your engine, however no reason not to run a .140 N&S and drop your fuel pressure.


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 Post Posted: Fri Mar 30, 2012 11:31 am 
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So, is that really the crux of it ….. Larger N&S to lower fuel pressure for less turbulence.


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 Post Posted: Fri Mar 30, 2012 11:32 am 
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jmarkaudio wrote:
no reason not to run a .140 N&S and drop your fuel pressure.


So is the premise now that LARGER n&s and lower fuel pressure is an "advantage" even on a standard Holley type n&s? Less foam?? Reason I ask is that at one point I was running .150 methanol n&s in my 8896 on gas? :-k

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 Post Posted: Fri Mar 30, 2012 1:14 pm 
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How do you determine the correct pressure? In my tunnel ram days (2 1050's) we would run 8 psi and cross the line at 4. In the 70's a Holley tech told me the pressure can't be below 3 at the stripe. These days I don't think it drops much at all.


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 Post subject: New Holley N&S Design
 Post Posted: Wed Apr 04, 2012 2:09 pm 
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J_6961 wrote:
So, is that really the crux of it ….. Larger N&S to lower fuel pressure for less turbulence.


Basically - yes. Elimination of the 'foam' is the overall goal. How to do that and what to do afterward is the interesting part.


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 Post Posted: Wed Apr 04, 2012 2:23 pm 
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Ron Gusack wrote:
How do you determine the correct pressure? In my tunnel ram days (2 1050's) we would run 8 psi and cross the line at 4. In the 70's a Holley tech told me the pressure can't be below 3 at the stripe. These days I don't think it drops much at all.


Run the highest pressure that will not produce foam, that the float (& N/S) can control and will keep the jets covered.


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 Post Posted: Wed Apr 04, 2012 6:38 pm 
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My 1150 methanol Dominator with PCI bowls seldom sees more than 6.5 psig down track with dual .150 titanium n&s per bowl. Recovery time on the graph with my BLP bypass belt drive pump shows that I could probably go lower but never have tried to do that. When I get that carb back on the engine, I just might give it a try just to see how it plays out. Ya never know ti'll you try, hey! ;-)

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 Post Posted: Sun Apr 08, 2012 7:27 am 
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I have a question, and without pullin gmy own n&s yet, how do you know what size they are? is it stamped on the seat component or the needle? Just trying to learn.
Good thread too guys, lots of cool info for both gas and alky.

So, from what I read here is, with a larger n&s, you can then lower the fuel psi down a bit and still keep the bowls full of enough fuel not to starve the jets, and keep the airation down as well?

I run an 1150 gas dom. and do you think I could help my carb out a bit by changing my parts to the .150 n&s's? If et gains show on the slip I know I will be going in the right direction for sure, but I run a heavy chassis and run high 8.90's with only 1.28 60ft. times and I my fuel psi is 7psi.
Thanks for any reply's.

John

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 Post Posted: Mon Apr 09, 2012 5:58 am 
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great & very informative post guys, i am impressed

i am chaseing a lean cylinder myself & this has got me thinking

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 Post subject: New Holley N&S Design
 Post Posted: Mon Apr 09, 2012 1:47 pm 
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Elkyman wrote:
I have a question, and without pullin gmy own n&s yet, how do you know what size they are? is it stamped on the seat component or the needle? Just trying to learn.
Good thread too guys, lots of cool info for both gas and alky.

So, from what I read here is, with a larger n&s, you can then lower the fuel psi down a bit and still keep the bowls full of enough fuel not to starve the jets, and keep the airation down as well?

I run an 1150 gas dom. and do you think I could help my carb out a bit by changing my parts to the .150 n&s's? If et gains show on the slip I know I will be going in the right direction for sure, but I run a heavy chassis and run high 8.90's with only 1.28 60ft. times and I my fuel psi is 7psi.
Thanks for any reply's.

John


Our n/s housings have the orifice size stamped on the upper machined flat that protrudes out the top of the fuel bowl. (You will need to remove the adjusting nut.)

I would advise that the ultra-low fuel pressure technology is still very new. The 6-7 psi set-ups have been used for a very long time and despite the foaming issue; still work pretty good. You may or may not see a performance gain. You should definitely notice a consistency improvement though. Keep in mind that as you lower pressure, the float level will need to be reset. And as you decrease foam - jet size will also need to decrease. If you're going to try this; make slow and deliberate changes.

I assume that you're running .120 n/s or close to it. Have you reduced pressure with your current n/s to see what happens? You might try reducing by 1/2 psi - reset float level, make a run and evaluate any change; then repeat. It may be that you can get down below 6 psi with your current set-up. If the carb shows rich at lower pressure; you are reducing/eliminating foam and need to richen jets accordingly. The .150 n/s set-up may be ideal; however I would try adjusting your current set-up first.


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