Colvindesign

all I know is this, it will have 450hp (probably at the wheels) from the factory and with a pulley change, intake and full exhaust, it will make me laugh like a retard, so I am not too concerned about what type of supercharger they put on there.

hayburner

The 03/04 Cobra is a zero screw blower. It is an Eaton roots style blower, it looks similar to the Lysholm (twin screw) but functions 100% differently. The Eaton just pumps air, it does not compress it. Despite rumors to the contrary, I expect that the GT500 will have a Lysholm design simply because the Eaton M112 is not big enough to feed the 5.4L. I suppose Eaton could create a bigger roots blower, call it an M134 ... but I sure hope not .

Dave
[/b][/quote]
:scratch: Hmm...have to beg to differ.The Eaton produces boost,therefore it compresses air. If it did not compress air there would be no increased density and no horsepower gain.All blowers pump air,just some more than others.

S197Cobra

:scratch: Hmm...have to beg to differ.The Eaton produces boost,therefore it compresses air. If it did not compress air there would be no increased density and no horsepower gain.All blowers pump air,just some more than others.

Quoted post

[/b][/quote] <!--QuoteBegin-www.automotive.eaton.com
How does an Eaton supercharger work? A supercharger is a positive displacement pump. Its purpose is to increase air pressure and density in the intake manifold. It does this by pumping more air than the engine would use without a supercharger.[/quote] 'Tis a pump . The compression occurs in the intake manifold, not inside the supercharger. All the Eaton does is pump an excess of air into the manifold, and prevent that air from escaping ... which causes the air to compress...

The twin screw compresses internal to the blower itself. Turbos and centrifugal blowers also compress internally. AFAIK the only type of blower that just pumps air is a postiive displacement roots-style.

Dave

hayburner

<!--QuoteBegin-www.automotive.eaton.com
How does an Eaton supercharger work? A supercharger is a positive displacement pump. Its purpose is to increase air pressure and density in the intake manifold. It does this by pumping more air than the engine would use without a supercharger.[/quote] 'Tis a pump . The compression occurs in the intake manifold, not inside the supercharger. All the Eaton does is pump an excess of air into the manifold, and prevent that air from escaping ... which causes the air to compress...

The twin screw compresses internal to the blower itself. Turbos and centrifugal blowers also compress internally. AFAIK the only type of blower that just pumps air is a postiive displacement roots-style.

Dave
[/b][/quote]
'k...then they are "pumps" if you wish ,Dave.
Procharger,K-B,Paxton...all pumps. Just different kinds of "Pumps".Most folks call them superchargers or turbochargers.
You can call it a pump if it makes you happy.

S197Cobra

Actually, the Kenne Bell, Paxton, Vortech, etc ... are compressors. The Eaton is a pump. And the old Holly/Weiand roots design... also a pump. All of them, however, are superchargers...

I guess this is a difficult concept to understand?

Dave

hayburner

Actually, the Kenne Bell, Paxton, Vortech, etc ... are compressors. The Eaton is a pump. And the old Holly/Weiand roots design... also a pump. All of them, however, are superchargers...

I guess this is a difficult concept to understand?

Dave
[/b][/quote]
Yeah Dave... apparently it is.A Procharger has an impeller making it a "pump" as well. Eaton calls their product a Supercharger.If it compresses air in the intake system and produces boost , who cares what housing it is in.All air pumps compress air somewhere. You have the distinction of semantically naming an Eaton supercharger a pump.Good luck convincing the rest of the world to use your semantics. SVT bought Eaton's supercharger ,not Eaton's air pump.









i

S197Cobra

Yeah Dave... apparently it is.A Procharger has an impeller making it a "pump" as well. Eaton calls their product a Supercharger.If it compresses air in the intake system and produces boost , who cares what housing it is in.All air pumps compress air somewhere. You have the distinction of semantically naming an Eaton supercharger a pump.Good luck convincing the rest of the world to use your semantics. SVT bought Eaton's supercharger ,not Eaton's air pump.
[/b][/quote] You crack me up. I am going to let this whole topic die, because it is obvious that I do not have the skills to explain to you the difference between an air pump and a compressor. The differences are really only important to those of us who modify our cars. If you plan to just leave the hood closed and drive it from A to B ... then who cares how exactly the go pedal makes it move forward ... right?

And since I have failed to explain such a simple concept to you in terms that you understand, I will avoid the topic of boost altogether, m'kay? Suffice it to say that a supercharger does not produce boost, as you seem to think. If you are interested in knowing why, Google it or something, because trying to phrase everything in small words makes my head hurt .

Happy driving,

Dave

hayburner

You crack me up. I am going to let this whole topic die, because it is obvious that I do not have the skills to explain to you the difference between an air pump and a compressor. The differences are really only important to those of us who modify our cars. If you plan to just leave the hood closed and drive it from A to B ... then who cares how exactly the go pedal makes it move forward ... right?

And since I have failed to explain such a simple concept to you in terms that you understand, I will avoid the topic of boost altogether, m'kay? Suffice it to say that a supercharger does not produce boost, as you seem to think. If you are interested in knowing why, Google it or something, because trying to phrase everything in small words makes my head hurt .

Happy driving,

Dave
[/b][/quote]
:scratch: Gee..there is a novel way to walk away from a debate you lost.Condescend on the way out the door."M'kay?"

428_CBRA_JT

know what i dont get??? who would want to F*** around with the engine of an 07 cobra... or better yet let some idiot who used to work at pep boys do it (long story) To me i dont give a woot what it has under there because i know its enough to kick the crap outta that ls2... Anyways not all of us are millionares that can afford 1.111111119 mpg highway..... so as far as putting more in or playing with it... hahaha shoot me first.... id rather brag that my car beat yours with a stock engine then go on and on about how much cash a wasted to beat a GM vehicle that wasnt worth my time in the first place...

just my $0.02

jsaylor

Let me take a crack at the explanation. Both superchargers eventually create pressure, but when and how they create pressure is totally different.

The rootes blower creates pressure and boost by simply pushing as much air into the manifold as it can. However, since the rootes blower does not compress air within the blower itself you are always somewhat limited by atmoshperic pressure, because of this rootes blower always lose efficiency due to backpressure once pressure in the manifold equals pressure in the blower.

A twin screw actually compresses the air inside the blower and this makes the difference. Unlike the rootes blower above the pressure coming out of the twin screw will always be positive assuming the ports are the proper size for the boost you intend to run. This obviously forces more air into the manifold itself than can a rootes type blower.

For a simple demonstration imagine the rootes blowers operation as me pouring water into a glass. Now imagine I am compressing the water first and then pushing it into the glass with more force than is the rootes blower. That is the difference between a twin screw and a rootes design and part of the reason why the twin screw creates more hp with similar boost. Because of this rootes type blowers will always be more inefficient than a twin screw design due to greater parasitic drag, etc. Or, put most simply, compared to a rootes design the twin screw design thinks it's bigger than it really is.

As far as one being a compressor and the other not you could argue semantics. The most accurate way to describe the difference is to call one an internal compression supercharger and the other an external compression supercharger. Between the twin screw and rootes the internal compression of the twin screw makes it the superior design.

jsaylor

I would definately swap the 07 Cobra's rootes to a twin screw design if I had the cash. The potential for more power, less heat, and similar if not better gas mileage. Where do I sign up?

wsmatau

S197Cobra: "I'm smarter than you, but not smart enough to explain myself..." :scratch:

Jsaylor...thanks for your explanation. I like to think of it outside the example of fluid dynamics. Try thinking of packing people into a room with only one door (your intake). Pushing people in one at a time is more like the "Pump" vs pairing (compressing) them up and pushing them through the door (Twinscrew). The second way is more efficient. Both accomplish the same thing but the second way is better and in your engine that equates to more HP.

hayburner

Let me take a crack at the explanation. Both superchargers eventually create pressure, but when and how they create pressure is totally different.

The rootes blower creates pressure and boost by simply pushing as much air into the manifold as it can. However, since the rootes blower does not compress air within the blower itself you are always somewhat limited by atmoshperic pressure, because of this rootes blower always lose efficiency due to backpressure once pressure in the manifold equals pressure in the blower.

A twin screw actually compresses the air inside the blower and this makes the difference. Unlike the rootes blower above the pressure coming out of the twin screw will always be positive assuming the ports are the proper size for the boost you intend to run. This obviously forces more air into the manifold itself than can a rootes type blower.

For a simple demonstration imagine the rootes blowers operation as me pouring water into a glass. Now imagine I am compressing the water first and then pushing it into the glass with more force than is the rootes blower. That is the difference between a twin screw and a rootes design and part of the reason why the twin screw creates more hp with similar boost. Because of this rootes type blowers will always be more inefficient than a twin screw design due to greater parasitic drag, etc. Or, put most simply, compared to a rootes design the twin screw design thinks it's bigger than it really is.

As far as one being a compressor and the other not you could argue semantics. The most accurate way to describe the difference is to call one an internal compression supercharger and the other an external compression supercharger. Between the twin screw and rootes the internal compression of the twin screw makes it the superior design.
[/b][/quote]
:worship: Well done Jsaylor.One minor thing though is that water does not compress,but I "get" what you're saying. The twin screw does what you say,it does compress air within itself,the roots compresses in the manifold and to a lesser extent the chamber. Twin screws I'm told are a little more expensive because of the tolerances,but that is getting easier to do because of technolgy advancement. Thanks for bringing civility back to the thread.

jsaylor

Yeah, I thought about that before I posted as I know water doesn't compress. But, I just couldn't seem to quickly think of anything that actually does compress and provide a simple explanation, and seeing how I have exams today I just went with what I had. Well, truth be told I had thought of the "people compressing" example like wsmatau used but for some reason it just seemed a disturbing comparison so I took a pass on that one.

hayburner

Yeah, I thought about that before I posted as I know water doesn't compress. But, I just couldn't seem to quickly think of anything that actually does compress and provide a simple explanation, and seeing how I have exams today I just went with what I had. Well, truth be told I had thought of the "people compressing" example like wsmatau used but for some reason it just seemed a disturbing comparison so I took a pass on that one.
[/b][/quote]
I think wsmatau was thinking was more along the lines of say compressing people into a subway..not soilent green or boca burgers Though that would give the highest compression ratio...(yuck)

Paleoc

[/quote]

I would definately swap the 07 Cobra's rootes to a twin screw design if I had the cash. The potential for more power, less heat, and similar if not better gas mileage. Where do I sign up?
[/quote]

It is a twin screw design and not a rootes.
See: http://www.whipplesuperchargers.com/...sp?ProdID=1170

"Largest displacement screw compressor available

2.3 Liter axial entry Whipple Twin screw supercharger

Axial supercharger case entry offers nearly 10% higher efficiency than radial entry compressors

3 ¼” (11.5PSI), 3” (13.5PSI), 2 ¾” (15.5PSI), 2 ½” (17.5PSI) with STOCK 7” crank pulley

3 ¾” (12.5PSI), 3 ½” (14.5PSI), 3 ¼” (16.5PSI), 3” (18.5PSI), 2 ¾” (21PSI), 2 ½” (23PSI) with 9” crank pulley

Same supercharger as the new Ford GT, 07’ Cobra, 08' Lightning & Harley Davidson Truck, Mercury Marine 600SCI and 1075HP EFI"

PolkThug

There are two types of supercharger and the first, a centrifugal supercharger, is an air pump driven directly from the crank, injecting air it has ALREADY compressed. It delivers exponentially increasing boost as rpm increases.

Of the two types of supercharger the second, commonly called a Roots blower, is a positive displacement air pump driven directly from the crank, injecting air it has NOT compressed. It delivers linearly increasing boost as rpm increases. The great difference of the roots type blower is that it produces high boost at low end rpm, with no significant lag.

The twin-screw supercharger is a positive displacement air pump driven directly from the crank, injecting air it has ALREADY compressed. It delivers linearly increasing boost as rpm increases. The twin screw delivers full boost at low rpm, like the Roots, but also delivers compressed air, like the centrifugal and the turbo.

Although both its original inventor Lysholm and its foremost American producer Whipple call it a positive displacement compressor, one commentator in Motor Sports Digest has suggested making the twin-screw its own new category of supercharger. http://www.motorsportsdigest.com/forced3.htm Nice thought.

-Colorado Cobras

hayburner

Geez...It's a "pump",it's "positive displacement",itsa, itsa ..supercharger already!!
They cost $5000 give or take, make your car go faster and come from different manufacturers in different designs with different results. If ya tweak them up too high they will fry your engine. This is all good info.The one comment I found really odd was that they don't "produce boost". So, according to that guy,maybe the mere presence of said"pump" hypnotizes your engine to make more power :scratch: I think we have beat this one to death and made Dave leave in self-righteous indignation. He left to go find a peer group he feels is more multi-syllabic...I'm happy here with the gearheads.

S197Cobra

Sorry to offend you, but I did not leave in "self-righteous indignation". It's just that I generally don't spend all that much time surfing the forums, and I'm only willing to spend a limited amount of time educating you. I thought I'd come back over to Brad's to see if any new useful information was posted about the GT500, and I'm surprised to see that this thread is still alive. Hehe...

Anyhow... you want to know why a supercharger doesn't produce boost? Easy -- boost is not produced, it is a measurement. A supercharger forces more air into the motor, easy as that. There are many modifications you can make to a boosted motor, in fact, that will increase horsepower while reducing boost.

And with that, I'm off again to other places, I have no more time tonight to spend on this (as much fun as it is to Argue On The Internet, I feel the call of the track this evening...). But I'll be back sometime in the next few days no doubt, perhaps the thread will still be going strong .

Later,
Dave

hayburner

Sorry to offend you, but I did not leave in "self-righteous indignation". It's just that I generally don't spend all that much time surfing the forums, and I'm only willing to spend a limited amount of time educating you. I thought I'd come back over to Brad's to see if any new useful information was posted about the GT500, and I'm surprised to see that this thread is still alive. Hehe...

Anyhow... you want to know why a supercharger doesn't produce boost? Easy -- boost is not produced, it is a measurement. A supercharger forces more air into the motor, easy as that. There are many modifications you can make to a boosted motor, in fact, that will increase horsepower while reducing boost.

And with that, I'm off again to other places, I have no more time tonight to spend on this (as much fun as it is to Argue On The Internet, I feel the call of the track this evening...). But I'll be back sometime in the next few days no doubt, perhaps the thread will still be going strong .

Later,
Dave
[/b][/quote]
Welcome back Dave.....So boost is not produced, it is measured...sure.
For that matter ,following your logic, floor space is not built ,but measured.
Then horsepower is not produced , just measured.
My paycheck is not produced , just measured.
Boost just serendipitously shows up in an intake manifold and is measured.I see...

IS the track is calling you? What does the asphalt say, Dave?

And thank you ,oh so much, for taking your precious time to "educate"me,
it's really gracious of you. I wait with eager anticipation more of your edifying
physics lessons. Thanks for using small words.
P.S...need some aspirin??