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SDBA #819
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who is running a 1050 dominator carb? would there be any benefit for me switching from a 4150 flange QFT 1050 to a holley dominator?

motor is just a hair over 12-1cr 496 with rec port heads with 345cc runners. no clue on hp
 

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Some guy
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who is running a 1050 dominator carb? would there be any benefit for me switching from a 4150 flange QFT 1050 to a holley dominator?

motor is just a hair over 12-1cr 496 with rec port heads with 345cc runners. no clue on hp
I think the key question is, what kind of RPM are you turning?
 

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steelcomp was here
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With those heads you might as well. :shock:
 

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I think going from a 4150 flang to a Dominator flang will be the big difference. Both carbs flow the same but the 4150 flange would be more restrictive.
 

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I think going from a 4150 flang to a Dominator flang will be the big difference. Both carbs flow the same but the 4150 flange would be more restrictive.
Carbs are rated by a given pressure drop, regardless of their falnge bolt pattern,
They can both flow 1050 at the same pressure drop, and I would rather have the 4500 dominator than the 4150 at anything over 850. The largest throttle blade on a 4150 is 1 3/4". To get the CFM up, they have to open up the venturi. The shape os the venturi is less than ideal. The diameter to height is compromised. This makes the carb less responsive at anything less than WOT. Whereas the Dominator uses a 2" throttle blade and much better shaped, taller venturi.
The 1050 QF 4150 uses the same main body as the Holley 1000 4150. Both carbs are fine for use when there is a throttle blade diameter rule that restricts the blade to 1 3/4". But anytime you try to gain that much CFM by way of a venturi, you're making compromises.

In almost all cases the dominator will be a better carb than the 1050 4150. It may not be any faster, or make any more HP at WOT, just better throttle response and better part throttle metering.



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steelcomp was here
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Carbs are rated by a given pressure drop, regardless of their falnge bolt pattern,
They can both flow 1050 at the same pressure drop, and I would rather have the 4500 dominator than the 4150 at anything over 850. The largest throttle blade on a 4150 is 1 3/4". To get the CFM up, they have to open up the venturi. The shape os the venturi is less than ideal. The diameter to height is compromised. This makes the carb less responsive at anything less than WOT. Whereas the Dominator uses a 2" throttle blade and much better shaped, taller venturi.
The 1050 QF 4150 uses the same main body as the Holley 1000 4150. Both carbs are fine for use when there is a throttle blade diameter rule that restricts the blade to 1 3/4". But anytime you try to gain that much CFM by way of a venturi, you're making compromises.

In almost all cases the dominator will be a better carb than the 1050 4150. It may not be any faster, or make any more HP at WOT, just better throttle response and better part throttle metering.
I couldn't disagree with this more. When you leave out any mention of the booster you're only telling half the story. There are plenty of examples where a 4150 will get down the track quicker than a 1050 on a given combination.
The 1050 has a venturi of 1.690, the 1000HP has a venturi of 1.560. The smaller venturi will have higher airspeed at the same flow rate...higher perssure drop, better signal and atomization. Always. The 1050 is great for WOT but no where near as clean or responsive as a 1000hp.
 

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I couldn't disagree with this more. When you leave out any mention of the booster you're only telling half the story. There are plenty of examples where a 4150 will get down the track quicker than a 1050 on a given combination.
The 1050 has a venturi of 1.690, the 1000HP has a venturi of 1.560. The smaller venturi will have higher airspeed at the same flow rate...higher perssure drop, better signal and atomization. Always. The 1050 is great for WOT but no where near as clean or responsive as a 1000hp.

So with a T/R this is the same?
 

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I couldn't disagree with this more. When you leave out any mention of the booster you're only telling half the story. There are plenty of examples where a 4150 will get down the track quicker than a 1050 on a given combination.
The 1050 has a venturi of 1.690, the 1000HP has a venturi of 1.560. The smaller venturi will have higher airspeed at the same flow rate...higher perssure drop, better signal and atomization. Always. The 1050 is great for WOT but no where near as clean or responsive as a 1000hp.
In many these cases you make a great point. although the 4150 has a smaller venturi, the shape SUCKS and its sitting on top of throttle blade that is too small for the size of the venturi. As opposed to the 950's 1.376 venturi with THE SAME throttle blade. NOW THAT IS A RESPONSIVE CARB, although it really doesn't flow anywhere near 950. The puny 1 3/4 blade under that 1.560 venturi on the 1000 4150 is like opening a 2.19 intake valve on 385 CC intake port! Sure, the velocity in the venturi COULD POSSIBLY be higher than the dominator, IF IT DIDN'T HAVE A FREEKIN CORK JAMMED UNDER IT!

I will take a 2" blade under a 1.69 venturi, with a annular booster and 3rd circuit anyday.

The 1050/4150 is a crutch carb. Total polar opposite of the 950 which may possibly be the best all around performance carb Holley has ever built.



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steelcomp was here
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In many these cases you make a great point. although the 4150 has a smaller venturi, the shape SUCKS and its sitting on top of throttle blade that is too small for the size of the venturi. As opposed to the 950's 1.376 venturi with THE SAME throttle blade. NOW THAT IS A RESPONSIVE CARB, although it really doesn't flow anywhere near 950. The puny 1 3/4 blade under that 1.560 venturi on the 1000 4150 is like opening a 2.19 intake valve on 385 CC intake port! Sure, the velocity in the venturi COULD POSSIBLY be higher than the dominator, IF IT DIDN'T HAVE A FREEKIN CORK JAMMED UNDER IT!

I will take a 2" blade under a 1.69 venturi, with a annular booster and 3rd circuit anyday.

The 1050/4150 is a crutch carb. Total polar opposite of the 950 which may possibly be the best all around performance carb Holley has ever built.
OK...here's some airspeed numbers to consider:
(and again, without mentioning the booster it's all moot since it's the booster that really delivers the fuel)

The venturi for the HP1000 is 89% of the throttle, and for the 1050 it's 84%. There's a 5% delta.

The effect of that percentage:
For a 496 turning 6500rpm you have 932cfm @ 100% VE /4 = 233cfm per venturi @ WOT for either carb.
@ 28", that's 292fps for the HP1000 and only 249fps for the 1050 in the venturi. The HP1000 actually has 5% more velocity even though it's 5% bigger. :notsure:
It doesn't matter how big the throttle blade is. The min. area restriction will have the highest velocity based on total airflow. On a 6500rpm 496, the HP1000 will be a better, more responsive, cleaner carb IMO. The 950 may show signs of being a restriction, depending on other factors since, like you said, it doesn't flow 950cfm.
If your engine is built as a working combination where, like on the 509 I just did, nothing is any bigger than it needs to be, there would be zero benefit of putting a 1050 on it. That's why there aren't any Vic Jr. intakes with 4500 flanges. If you want to turn the 496 and make peak power at 7000, then it's a different ball game.
:)hand
 

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OK...here's some airspeed numbers to consider:
(and again, without mentioning the booster it's all moot since it's the booster that really delivers the fuel)

The venturi for the HP1000 is 89% of the throttle, and for the 1050 it's 84%. There's a 5% delta.

The effect of that percentage:
For a 496 turning 6500rpm you have 932cfm @ 100% VE /4 = 233cfm per venturi @ WOT for either carb.
@ 28", that's 292fps for the HP1000 and only 249fps for the 1050 in the venturi. The HP1000 actually has 5% more velocity even though it's 5% bigger. :notsure:
It doesn't matter how big the throttle blade is. The min. area restriction will have the highest velocity based on total airflow. On a 6500rpm 496, the HP1000 will be a better, more responsive, cleaner carb IMO. The 950 may show signs of being a restriction, depending on other factors since, like you said, it doesn't flow 950cfm.
If your engine is built as a working combination where, like on the 509 I just did, nothing is any bigger than it needs to be, there would be zero benefit of putting a 1050 on it. That's why there aren't any Vic Jr. intakes with 4500 flanges. If you want to turn the 496 and make peak power at 7000, then it's a different ball game.
:)hand
Like you said in you first post, there are bigger issues here than the venturi to throttle blade ratio.
496 with rec port heads with 345cc runners. no clue on hp
With those heads you might as well. :shock:
Yes, it ALL MOOT with no mention of the booster. SOOOOO, I would perfer to run a 3 circuit 1050 dominator with GOOD winged annular booster over a 1050 with a down leg. If the 1050/4150 has a annular, you just joke it well below 1050. Even the 1050/4500 suffers a little from the annular, but in the 4150 suffers more.



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That's why there aren't any Vic Jr. intakes with 4500 flanges.

I just ordered one yesterday, EDL #2907 to go under the 1050 E-85 carb that I am getting from Mark Sullens for the PS 303 boat and engine that I recently bought, 482 1/4 stroke 13/1 injected alcohol that I am converting to run the new 95 mph class on E-85.
 
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