Carb holley ultra 500 two barrel review

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jeepinocala1111
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Carb holley ultra 500 two barrel review

Post by jeepinocala1111 »

It is VERY simple the absolute best carb I have run yet I gained power with this carb and believe I can add pitch to my prop again. I have my prop 72" ngq on a 220 gpu with high compression pistons anyway prop is set at 2.5 it would turn 2700 to 2750 range before this new carb Holley 500 ultra I hammered for just a few seconds it went to 2850 and felt like it may have gone a bit further. I am going to leave it as is for now but dam the carb is great. :cheers:

rjonesboy
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Re: Carb holley ultra 500 two barrel review

Post by rjonesboy »

do you have a CHT gauge? If not check your plugs make sure its not too lean. Lean condition will increase rpms. I speak from experience, ive blown up a couple GPUs with dome pistons.

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glades cat
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Re: Carb holley ultra 500 two barrel review

Post by glades cat »

I agree. It is a good carb.
Remove the bowl and check the jet size and power valve number.
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SWAMPHUNTER45
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Re: Carb holley ultra 500 two barrel review

Post by SWAMPHUNTER45 »

Great advice

jeepinocala1111
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Re: Carb holley ultra 500 two barrel review

Post by jeepinocala1111 »

glades cat wrote:I agree. It is a good carb.
Remove the bowl and check the jet size and power valve number.
What jet size should it have? It ran cool. It comes with a #73 jet.
Last edited by jeepinocala1111 on Sun Mar 13, 2016 7:55 pm, edited 1 time in total.

jeepinocala1111
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Re: Carb holley ultra 500 two barrel review

Post by jeepinocala1111 »

rjonesboy wrote:do you have a CHT gauge? If not check your plugs make sure its not too lean. Lean condition will increase rpms. I speak from experience, ive blown up a couple GPUs with dome pistons.
To be honest I think it is much better cause my old one needs rebuilding including throttle shaft bushings. But I am going to check all of this it may save an engine.

dshaw94
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Re: Carb holley ultra 500 two barrel review

Post by dshaw94 »

Most say you should run a #78 jet and a #10 power valve. Stock power valve and 73 jet is definitely to lean.
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rjonesboy
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Re: Carb holley ultra 500 two barrel review

Post by rjonesboy »

And with the high comp pistons in the gpu, you really have to run AV gas

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glades cat
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Re: Carb holley ultra 500 two barrel review

Post by glades cat »

See what you have and go from there. It is an important step to confirm what is inside. Jet size is relevant on Holley carbs. Down-Leg Boosters, which I believe your carb has, produce a stronger signal in the venturi than Annular type, so a 72 jet in a down-leg boosters will draw more fuel than one with annular boosters….so it is relevant. 72 may be just fine….or not. :shock:
I believe the power valve circuit is important during higher throttle operation. It enriches the mixture. The usual way to determine what number to use is to check the vacuum at idle… divide reading in half, and that is your power valve number. 10.5 seems to work well on stock 220's. Tune yours accordingly.
Read the plugs on all cylinders after a hard run and prompt shut-down. They will tell you a lot.
"Leave a legacy...Preserve the irreplaceable"
12' x 7' sled built by Scorpion, Cont. O-470-K, 72" Whisper Tip
Rigged by Gladescat & sons in 2009

jeepinocala1111
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Re: Carb holley ultra 500 two barrel review

Post by jeepinocala1111 »

glades cat wrote:See what you have and go from there. It is an important step to confirm what is inside. Jet size is relevant on Holley carbs. Down-Leg Boosters, which I believe your carb has, produce a stronger signal in the venturi than Annular type, so a 72 jet in a down-leg boosters will draw more fuel than one with annular boosters….so it is relevant. 72 may be just fine….or not. :shock:
I believe the power valve circuit is important during higher throttle operation. It enriches the mixture. The usual way to determine what number to use is to check the vacuum at idle… divide reading in half, and that is your power valve number. 10.5 seems to work well on stock 220's. Tune yours accordingly.
Read the plugs on all cylinders after a hard run and prompt shut-down. They will tell you a lot.
I will put this advice to work this week I do run only avgas cause it is pretty cheap here and CAN GET IT 24/7 I have the gate code. I will find out exactly what was in my old carb tomorrow and what is in my new carb it is a lot easier to deal with even has a drain screw for the bowl. Thank you.

jeepinocala1111
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Re: Carb holley ultra 500 two barrel review

Post by jeepinocala1111 »

glades cat wrote:See what you have and go from there. It is an important step to confirm what is inside. Jet size is relevant on Holley carbs. Down-Leg Boosters, which I believe your carb has, produce a stronger signal in the venturi than Annular type, so a 72 jet in a down-leg boosters will draw more fuel than one with annular boosters….so it is relevant. 72 may be just fine….or not. :shock:
I believe the power valve circuit is important during higher throttle operation. It enriches the mixture. The usual way to determine what number to use is to check the vacuum at idle… divide reading in half, and that is your power valve number. 10.5 seems to work well on stock 220's. Tune yours accordingly.
Read the plugs on all cylinders after a hard run and prompt shut-down. They will tell you a lot.
I just found out the carb comes with a 74 jet and a 3.5 power valve so I am going to pick up a 10.5 power valve today. Ordered two today a 10.5 and a 8.5

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