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Discussion Starter · #1 · (Edited)
Discovered this on another forum, thought it should also be discussed by the panel of experts available here.
"I was surfing and found a link to a site saying that works will produce a 201 cu inch blower after the 140 cu inch blower's are run... do you have any insight to this? Is there such a thing as too big, or would we just get more hp per # of boost? Would you theorize any loss of street ability with too big of blower? I'm thinking a 201 blower on a 4.6L should act about like a 8.6L engine???? That would have too produce big #'s. I'm thinking a 140 is like 70% of a 201, therefore in theory, you could estimate we would see like a 129-143hp increase at the same boost level?
If that's the case have them hold off on building any 140's and lets just go straight to the 201's.......Seriously your comments on the bigger blower will be completely understood as theory, so please let us know your thought's!"
:jawdrop
 

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Snake Charmer
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281UndrPressure said:
I'm thinking a 201 blower on a 4.6L should act about like a 8.6L engine???? That would have too produce big #'s. I'm thinking a 140 is like 70% of a 201, therefore in theory, you could estimate we would see like a 129-143hp increase at the same boost level?
If im not mistaken boost is boost no matter how you slice it. A smaller blower is just going to have to work harder (ie spin faster) to make as much boost as a larger(or more efficient) blower.

12 psi from a small 140 is going to be the same as 12psi from a 201, the difference will be that the 140 has to spin faster to build as much pressure which usually means it develops more heat as well and loses efficiency.
 

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it gets a little more involved than that, I can only type for 2 min sorry, 1 thing the bigger blower will move more air. thus may make more power , , , May ! Sometimes uses more power to tune it !! peace . time is up
 

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the larger blower will flow a greater volume of air at the same boost level..remember true horsepower comes fro mthe volume of air..cause 10 psi on a 1 in hose and 10 psi on a 4 in hose...are way diff amounts of air
 

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but like pete said, it will probably take more hp to power it. You can do all the speculating you want, but the truth is we won't really know if its worth it or not until someone tests it.
 

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yes..but thats all a question of its efficiency...and thats like arguing a 4.6 versus a 5.7 liter...sometimes there is no replacement for displacement
 

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CobraVert99 said:
the larger blower will flow a greater volume of air at the same boost level..remember true horsepower comes fro mthe volume of air..cause 10 psi on a 1 in hose and 10 psi on a 4 in hose...are way diff amounts of air
Thats just it boost is boost, air pressure is air pressure, if we are measuring air pressure in the manifold then how much air the blower moves is irrelevent because 12psi in the manifold is 12 psi in the manfiold. It all symantecs at this point really. Yes a larger blower will move more are in a given revolution but the pressure inside the manifold is still boost and what creates that pressure doesnt matter, PSI is PSI.

Now, a blower with 30% more volume has the "potential" to build more boost in the same number of revolutions but running s 12psi on one is the same as 12psi on the smaller if measuring manifold pressure. It all boils down to efficiency and which is more so. If the larger blower can be more efficient then great, it has merrit But if it creates too much heat from the greater surface area and more power required to spin it then bigger may not be better.
 

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Shadowgray03 said:
Thats just it boost is boost, air pressure is air pressure, if we are measuring air pressure in the manifold then how much air the blower moves is irrelevent because 12psi in the manifold is 12 psi in the manfiold. It all symantecs at this point really. Yes a larger blower will move more are in a given revolution but the pressure inside the manifold is still boost and what creates that pressure doesnt matter, PSI is PSI.
Not exactly. At least on the turbo cars, the larger turbos produce denser air and therefore more power at the same boost levels as smaller turbos. It also has to do with the efficiency and the heat produced.
 

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It doesn't matter what the displacement is, as long as you run the blower at the rpm at which it was designed to run, moving the cfm it was designed to pump.

A bigger blower is not neccesarily better. A larger blower will obviously have bigger heavier rotors, which will have more parasitic loss to turn. It will have bigger bearings, again more loss. It will be heavier, more weight to drag down the track, etc.

Good engineering is optimizing, not just making something larger to be larger.

It looks like the KB is large enough to move the required CFM for normal people (i.e. people other than Pete, Lol). Maybe when we try to get to 800+rwhp, a bigger blower will be required.

BTW, boost level is more or less irrelevant. It is just a by product of trying to force more air into the engine than would normally "fit". What makes the HP is the volume of air and fuel that actually make it into the combustion chamber, not how much restriction is in front of the combustion chamber. think of it like this, take a given blown or turbo'd car, and put in smaller intake valves and intake ports, you will show more boost, but the power will be down.

JT
 

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JT said:
BTW, boost level is more or less irrelevant. It is just a by product of trying to force more air into the engine than would normally "fit". What makes the HP is the volume of air and fuel that actually make it into the combustion chamber, not how much restriction is in front of the combustion chamber. think of it like this, take a given blown or turbo'd car, and put in smaller intake valves and intake ports, you will show more boost, but the power will be down.

JT
Good point JT.
 
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