Holley 950 Ultra HP Carb

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USMC_Spike
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

@Tuner,
I place your suggestions in this 3rd revision. Having to decifer your nomenclature a bit, I think I placed
them in the proper location.

Is that what you mean have a 10 jet size between the primary main jets #82 and secondary main jets @92?
That is a huge difference is it not? Just checking before I go further.

--thx Spike
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

So with the annular venturi, can that have the step cut in it as this carb had it cut into it?
Would that make for a more effective:
A. Stronger signal
B. Better Fuel atomization

Any one know the cost for fitting this carb with annular boosters?

--Thx Spike
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Re: Holley 950 Ultra HP Carb

Post by ClassAct »

USMC_Spike wrote: Fri Mar 10, 2023 2:40 pm So with the annular venturi, can that have the step cut in it as this carb had it cut into it?
Would that make for a more effective:
A. Stronger signal
B. Better Fuel atomization

Any one know the cost for fitting this carb with annular boosters?

--Thx Spike
AFAIK, no one machines annular boosters like the dog leg. You are worried about things that don’t relate.

Call Mark Whitener at Lightning Racing Carbs and let him pick the booster you need.
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

@ClassAct,

I have and left messages, hasn't called back yet.

--thx Spike
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Re: Holley 950 Ultra HP Carb

Post by Tuner »

He's a busy guy. His "day job" is audio engineer for TV broadcasts of pro sports teams, Orlando Magic, Tampa Bay Lightning, Tampa Bay Rays, some other ML baseball spring training games, Yankees, etc, etc.
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Re: Holley 950 Ultra HP Carb

Post by Tuner »

USMC_Spike wrote: Fri Mar 10, 2023 2:35 pm @Tuner,
I place your suggestions in this 3rd revision. Having to decifer your nomenclature a bit, I think I placed
them in the proper location.

Is that what you mean have a 10 jet size between the primary main jets #82 and secondary main jets @92?
That is a huge difference is it not? Just checking before I go further.

--thx Spike
6.5 PV primary no PV secondary (no SPV)

My post was. "I suggest .033" IJ .070 IAB #82 PMJ .070 PPVCR #92 SMJ (no SPV) use the O2 sensor and seat of the pants and adjust as required."
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

@Tuner,

I'm not sure if I followed you correctly, I'm dense sometimes.
I did update the metering block graphic, is that incorrect?

.033 IJ same as Idle Feed Restriction?
.070 IAB - is the Intake Air Bleed and these are .070 as diagram.
#82 PMJ - Primary Metering Jets, change from #093 Jet in front block.
.070 - Primary PVCR to .070 from .073.
#92 jet- Secondary Metering Jets (with exstension) #93.
Block the secondary PVCR.

For the latter, do I just fit brass plugs where the .073 jets were located?
Or, do I fit some king of bolt in there to plug the whole thing up?

Maybe I put the information on the incorrect location in the graphic.
Didn't change the graphic, but it would read 6.5 for the PVCR.

This goes against what Holley and DV have written.
I'm just making sure you know my idle vacuum is from 4.5 to 5 inches at idle,
with automatic transmission.

Here is link to Holley instructions:
https://documents.holley.com/199r10565-1rev.pdf
Two paragraphs from Page 8 are attached.
1.3 Install Instructions.jpg
Please advise.
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Last edited by USMC_Spike on Fri Mar 10, 2023 7:10 pm, edited 2 times in total.
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Re: Holley 950 Ultra HP Carb

Post by steve cowan »

20230308_160431.jpg
20220911_170607.jpg
20220911_170532.jpg
I have removed factory downleg and fitted removable annular boosters on a couple of mainbody.
This is not a difficult modification as I used a drill press and patience. I have ran the 850 annular with no issues.
Jamie (HQM383) supplied me boosters and nut tool which I greatly appreciate
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Re: Holley 950 Ultra HP Carb

Post by HQM383 »

Tuner wrote: Fri Mar 10, 2023 1:25 pm 2: Folks just don't seem to understand that the idle jet reverses at large throttle opening when the lowest pressure in the carb moves up to the venturi so booster and main well have lower pressure than IAB and IJ ... so at WOT air flows back through the idle jet and leans the WOT. A larger IJ richens the idle-off idle transition small throttle and leans the WOT when the flow reverses. This of course depends on the size of the IAB. A small IAB which is smaller than the idle jet, like in the secondary of a vacuum secondary carb, reduces the leaning effect of air flow through the IJ at WOT.
This is an example of why “Folks just don't seem to understand”. I’ve read a lot of what Shrinker (RIP) had put out there over the years and not many come close to him for carb information (and engine in general) on several different forums. The information he gave was usually backed up by data of real world testing of his own. He didn’t so much quote reference material but his results and experiences. Unfortunately most of his great information is lost due to the demise of the Innovate forum and the Motorsports Village forum. Below is from the racingfuelsystems forum c&p directly;
01-18-2008, 05:23 AM
shrinker
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Location: Adelaide South Australia
Posts: 2,420

Hi there all; the idle./transfer circuit will (if over fueling the engine at its normal zone of operation) richen the top end of the engine at FULL THROTTLE. The correct idle/transfer stalling of jets etc eliminates this. The throttle vacuum builds as the engine powers up and the transfer slot responds to that. At full throttle load on some carbys the idle transfer circuit can supply up to 20 or even 25% of the full load fuel requirement of the engine. Thats is the main is the jet but 20% of the fuel comes out the t-slot hole. Never blame the e-bleeds etc unless you understand the idle and transfer.
And
01-19-2008, 02:38 AM
shrinker
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Location: Adelaide South Australia
Posts: 2,420

hello all; Well to answer your question I have run an engine with the transfer slot blocked and it runs lean at WOT. The T-slot supplies lots of fuel to the engine at WOT. EVERYTIME i tune an engine i tune the idle and t-slot first. If you dont get it right forget making full power.
heres some figures. 719hp increased to 735 by adjustment of idle mixture screw.
520 increased to 535 by IFR, IAB relationship.
485 hp increased to 563 by IFR, IAR, t-slot mods. Same main jets in all cases. Its not the volume ot fuel that you give an engine its the quality of it and how it exits the idle jet and transfer outlets and where it goes etc.
57 hp increased to 84 by IFR/IAB and T-slot mods. Same original booster and main jet, just altered the idle and transfer circuit. Different types of engine and carbys there in those examples. Not my carby just Holleys, Solexes Bg;s etc.

I know I keep harping on about this but is the truest thing i can say; You will never work it out unless you use a gas bench. AFR only is a waste of time for tuning performance engines.
That’s the information I’ve been working with influenced a lot due to quoting results. I’m not saying you are wrong but it’s no wonder that some folks don’t get it with two very knowledgeable guys giving conflicting information.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
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Re: Holley 950 Ultra HP Carb

Post by Tuner »

HQM383 wrote: Fri Mar 10, 2023 6:43 pm
Tuner wrote: Fri Mar 10, 2023 1:25 pm 2: Folks just don't seem to understand that the idle jet reverses at large throttle opening when the lowest pressure in the carb moves up to the venturi so booster and main well have lower pressure than IAB and IJ ... so at WOT air flows back through the idle jet and leans the WOT. A larger IJ richens the idle-off idle transition small throttle and leans the WOT when the flow reverses. This of course depends on the size of the IAB. A small IAB which is smaller than the idle jet, like in the secondary of a vacuum secondary carb, reduces the leaning effect of air flow through the IJ at WOT.
This is an example of why “Folks just don't seem to understand”. I’ve read a lot of what Shrinker (RIP) had put out there over the years and not many come close to him for carb information (and engine in general) on several different forums. The information he gave was usually backed up by data of real world testing of his own. He didn’t so much quote reference material but his results and experiences. Unfortunately most of his great information is lost due to the demise of the Innovate forum and the Motorsports Village forum. Below is from the racingfuelsystems forum c&p directly;
01-18-2008, 05:23 AM
shrinker
Registered User Join Date: Dec 2006
Location: Adelaide South Australia
Posts: 2,420

Hi there all; the idle./transfer circuit will (if over fueling the engine at its normal zone of operation) richen the top end of the engine at FULL THROTTLE. The correct idle/transfer stalling of jets etc eliminates this. The throttle vacuum builds as the engine powers up and the transfer slot responds to that. At full throttle load on some carbys the idle transfer circuit can supply up to 20 or even 25% of the full load fuel requirement of the engine. Thats is the main is the jet but 20% of the fuel comes out the t-slot hole. Never blame the e-bleeds etc unless you understand the idle and transfer.
And
01-19-2008, 02:38 AM
shrinker
Registered User Join Date: Dec 2006
Location: Adelaide South Australia
Posts: 2,420

hello all; Well to answer your question I have run an engine with the transfer slot blocked and it runs lean at WOT. The T-slot supplies lots of fuel to the engine at WOT. EVERYTIME i tune an engine i tune the idle and t-slot first. If you dont get it right forget making full power.
heres some figures. 719hp increased to 735 by adjustment of idle mixture screw.
520 increased to 535 by IFR, IAB relationship.
485 hp increased to 563 by IFR, IAR, t-slot mods. Same main jets in all cases. Its not the volume ot fuel that you give an engine its the quality of it and how it exits the idle jet and transfer outlets and where it goes etc.
57 hp increased to 84 by IFR/IAB and T-slot mods. Same original booster and main jet, just altered the idle and transfer circuit. Different types of engine and carbys there in those examples. Not my carby just Holleys, Solexes Bg;s etc.

I know I keep harping on about this but is the truest thing i can say; You will never work it out unless you use a gas bench. AFR only is a waste of time for tuning performance engines.
That’s the information I’ve been working with influenced a lot due to quoting results. I’m not saying you are wrong but it’s no wonder that some folks don’t get it with two very knowledgeable guys giving conflicting information.
Shrinker and I discussed this subject on skype several times. We would BS for hours. You need to remember his carby is a very different design than the Holley type and in some his the idle circuit was divorced, not connected to the main, so a lower pressure in the main did not affect his idle/transition circuit. He finally got the chance to A-B-A changing only the IJ size on a Holley and conceded a larger IJ makes WOT leaner.

You must realize manifold pressure (vacuum) has large pulsations with every intake stroke and reflected wave. The vacuum gauges we use for tuning have a small orifice to damp the pulses so the needle is not a blur.

Oscillating manifold vacuum is why a high idle jet causes such erratic A/F. With a high IJ the air from the much larger IAB is at near atmospheric pressure and can get back upstream of the IJ restriction and passes through the IJ with much greater ease than solid liquid fuel. Because the manifold pressure (vacuum) oscillates the liquid fuel and air mixture sloshes back and forth through the IJ like aerated water through your teeth when you rinse your mouth. This, of course, causes the fuel in the idle well upstream of the high IJ, between the high IJ and main well, to oscillate and disturb flow through the main well by oscillating the pressure on the down stream side of the main jet.

With the idle jet low at the bottom of the idle well, air from the IAB cannot get to it to get upstream of it and solid (non aerated) fuel has much higher viscosity than aerated fuel so the flow through the low IJ is less erratic.
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Re: Holley 950 Ultra HP Carb

Post by HQM383 »

Tuner wrote: Fri Mar 10, 2023 7:35 pm Shrinker and I discussed this subject on skype several times. We would BS for hours. You need to remember his carby is a very different design than the Holley type and in some his the idle circuit was divorced, not connected to the main, so a lower pressure in the main did not affect his idle/transition circuit. He finally got the chance to A-B-A changing only the IJ size on a Holley and conceded a larger IJ makes WOT leaner.
Not to be argumentative but he wasn’t talking about his Smart carb in those quotes:
.....Different types of engine and carbys there in those examples. Not my carby just Holleys, Solexes Bg;s etc.

With the idle jet low at the bottom of the idle well, air from the IAB cannot get to it to get upstream of it and solid (non aerated) fuel has much higher viscosity than aerated fuel so the flow through the low IJ is less erratic.
To compliment Tuners quote here is a visual for the boys and girls out there to show how a poor combo can affect idle/transition allowing combustion reversion to get into the circuit. A carb I purchased second hand for refurb. Had a factory high idle jet so wouldn’t have been fun to tune.

Image
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
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Re: Holley 950 Ultra HP Carb

Post by 1980RS »

USMC_Spike wrote: Thu Mar 09, 2023 10:49 pm
1980RS wrote: Thu Mar 09, 2023 8:09 pm The part number on my 950hp is 80496, here are a couple of pictures of it
20150308_031110.jpg 20150308_031100.jpg
That's a good looking carb, 1980RS seems you sorted it out also.
not being used and sitting in the bin? Did you want me to try it out
on my engine?

When you get the chance, can you measure the following:
Idle Air Bleeds
High Speed Bleeds
The Squirter size.

Do you recall what sizes(s) for your e-holes (3,4, or 5) and PVCR?

Anything else that would help me out?

--thx Spike
Funny thing is I did use it last year, it's just the way it came form Holley many years ago no tuning. I ran 11.10@118mph with it last fall before my 454 expired, but the 950 worked great. You can try it, but you'll have to come to WI. to try it out. :mrgreen:
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Re: Holley 950 Ultra HP Carb

Post by Monza355 »

1980RS wrote: Sat Mar 11, 2023 1:20 am
USMC_Spike wrote: Thu Mar 09, 2023 10:49 pm
1980RS wrote: Thu Mar 09, 2023 8:09 pm The part number on my 950hp is 80496, here are a couple of pictures of it
20150308_031110.jpg 20150308_031100.jpg
That's a good looking carb, 1980RS seems you sorted it out also.
not being used and sitting in the bin? Did you want me to try it out
on my engine?

When you get the chance, can you measure the following:
Idle Air Bleeds
High Speed Bleeds
The Squirter size.

Do you recall what sizes(s) for your e-holes (3,4, or 5) and PVCR?

Anything else that would help me out?

--thx Spike
Funny thing is I did use it last year, it's just the way it came form Holley many years ago no tuning. I ran 11.10@118mph with it last fall before my 454 expired, but the 950 worked great. You can try it, but you'll have to come to WI. to try it out. :mrgreen:
It would be interesting to compare the numbers on the airbleeds and emulsion bleeds to the newer 80496 950hp which looks identical but has a screw in airbleeds in the mainbody.
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Re: Holley 950 Ultra HP Carb

Post by treyrags »

USMC_Spike wrote: Fri Mar 10, 2023 5:55 pm @Tuner,

I'm not sure if I followed you correctly, I'm dense sometimes.
I did update the metering block graphic, is that incorrect?

.033 IJ same as Idle Feed Restriction?
.070 IAB - is the Intake Air Bleed and these are .070 as diagram.
#82 PMJ - Primary Metering Jets, change from #093 Jet in front block.
.070 - Primary PVCR to .070 from .073.
#92 jet- Secondary Metering Jets (with exstension) #93.
Block the secondary PVCR.

For the latter, do I just fit brass plugs where the .073 jets were located?
Or, do I fit some king of bolt in there to plug the whole thing up?

Maybe I put the information on the incorrect location in the graphic.
Didn't change the graphic, but it would read 6.5 for the PVCR.

This goes against what Holley and DV have written.
I'm just making sure you know my idle vacuum is from 4.5 to 5 inches at idle,
with automatic transmission.

Here is link to Holley instructions:
https://documents.holley.com/199r10565-1rev.pdf
Two paragraphs from Page 8 are attached.

1.3 Install Instructions.jpg

Please advise.
Follow Tuner's advise. Holley and DV are wrong about the PV. It has no influence at idle. I have a 10.5 PV on my street engine that has 9 inches vacuum at idle and it idles and transitions clean. The PV needs to be tailored to your cruise vacuum. Also, don't be scared to have a big jet split between primary and secondary. As long as you compensate with the pvcr size it will be fine, Mine has a 13 size split with a .092 pvcr. I confirmed the primary mixture by disconnecting the secondary and checking the afr at wot. This where an O2 sensor comes in handy.
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Re: Holley 950 Ultra HP Carb

Post by USMC_Spike »

@treyrage, Tuner, Everyman,

I've only done this one other time, so forgive my ignorance here.
What I am asking for is that I placed correct sizes in green on the graphic.
If that is correct, then I will make the e-holes and change the jets as recommended.

For example, I want to make sure IJ = IFR.
Things get confusing when different initialisms are use.
To make things simpler I will assume I got it correct,
if anything is incorrect, please let me know, and thanks
for the recommendations etc.
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