quote Originally posted by darkhorizon: A roots blower DOES NOT compress air in the blower, it stacks air inside the intake manifold to make "boost". A turbo/csc also do not make boost, they just push air in faster than the motor can use it.

That is all incorrect.

A true supercharger and a turbocharger both compress the air. "Pushing air faster than the motor can use it" is wrong, Boost refers to the increase in manifold pressure that is generated by the turbocharger or supercharger in the intake path or specifically intake manifold that exceeds normal atmospheric pressure. Which a supercharger or a turbocharger BOTH do. Just blowing air really fast does not compress it. A turbocharger actually uses compressor vanes to compress the air in the turbo body and a supercharger like a roots or screw type compress air inbetween the rotors/screws. On a roots blower, If the supercharger stops spinning (and there is no safety by-pass) it will cut off all air to the engine and the engine will not run.

A roots blower DOES compress the air within the case (it's compressed between the rotors) and pressurizes the intake manifold. (it is a form of a screw type blower.) It has nothing in common with a fan.

http://en.wikipedia.org/wik...ts_type_supercharger

[This message has been edited by Oreif (edited 09-18-2007).]

quote Originally posted by darkhorizon: A roots blower DOES NOT compress air in the blower, it stacks air inside the intake manifold to make "boost". A turbo/csc also do not make boost, they just push air in faster than the motor can use it. A screw type "compressor" blower, makes boost insdie the case of the blower, and then outputs air at a higher pressure. So technicly, the electric fan blowers are no different than a roots blower, a roots blower just happens to move a stupidly large amount of air per revolution, and easily overcomes the air used by the motor. A plastic fan inside a housing, is never ever going to be capable of moving a decent amount of air, the fan will start cavitatiing on even a lawnmower engine at wide open... I would bet that those fans in the intake are better at making power in the form of eletricity if they are turned off.

Your right. At WOT they are not going to do much at all. Thats not really what they are for. I'll get the testing started soon and have some real data to decide for sure. At least E-ram offers a money back guaranty if it does not produce at least a 4% increase in power. They will pay for half of the Dyno costs also and they accept the G-tech as a test. The e-ram has a metal impeller by the way NOT plastic.

None of them make power even when turned off. They only use power and produce the effect when you want them to and only for short bursts. When not in use gas mileage and everything else stays normal. No nitrious bottles to refill, extra exhaust piping, or drag from a belt and the E-ram does not cause a restriction when not in use. I've been researching this for a while and weighed the pros and cons including cost of all the different types I can find. It will not add the power of a turbo or supercharger but may be able to give an extra 10-25hp when you want it. We'll see for sure soon enough. I'm just going to pick up a G-tech so I can test everything with the same equipment. According to their site is should be within 1% of the actual HP and TQ. This should be close enough to find out if it will work or not plus I can pull multiple tests with everything without breaking the bank on Dyno costs.

[This message has been edited by Fieroseverywhere (edited 09-18-2007).]

Honestly Oreif, roots blowers ARE blowers, they have been called blowers forever, never anything else. As you will see in this animation, the air never changes volume, the chambers inside of the blower never change shape or size, it merely accelerates the air.

http://www.mekanizmalar.com/roots3.shtml

That animation is slightly inaccurate due to the coloring, the actual compression obviously takes place in the outlet... The size and shape of the "container" of air on the outside of the case is constant during the entire cycle.

quote From http://www.superchargersonl...om/content.asp?id=22 The two rotors trap air in the gaps between rotors and push it against the compressor housing as they rotate towards the outlet/discharge port. During each rotation, a specific fixed amount of air is trapped and moved to the outlet port where it is compressed

The important part is "moved to the outlet" and then compressed after the outlet, as there air can not go back up through the blower. The compression takes place inside of the exit port. A twin screw or compression supercharger, is not a blower at all, it creates pressure in between the screws by squeezing it, outputting air at a specific pressure already, and then gives the motor a small package of air directly.

This argument is really a pointless one, but technically a roots blower does not compress anything inside the blower itself, it uses the outlet to "stack" air molecules on top of eachother.

One other way to think about it is like this:

Imagine you blocked off the outlet port of a roots blower, then started cranking it. The air would be getting trapped inside the outlet, and the air inside the blower vanes touching the case would be at atmosphere pressure. The air coming in gets stuck because it cant go back out the way it came, and the center of the blower is air tight.

[This message has been edited by darkhorizon (edited 09-19-2007).]

quote Originally posted by darkhorizon: One other way to think about it is like this: Imagine you blocked off the outlet port of a roots blower, then started cranking it. The air would be getting trapped inside the outlet, and the air inside the blower vanes touching the case would be at atmosphere pressure. The air coming in gets stuck because it cant go back out the way it came, and the center of the blower is air tight.

If you blocked off the out let of the supercharger, (referring to the pic I posted) section "C" would compress the air with each revolution. Yes, Section "B" would still be at atmpspheric pressure, But once it becomes "C" it will compress against the blocked or pressurized output. As the air has no place to go and more air is being pushed into the outlet chamber. (which is technically still in the case of the supercharger) Section "C" which is inside the case would NOT be at atmoshperic pressure. The only difference between a roots and a screw type supercharger is that the roots requires a sealed "tank" or intake manifold in order to actually compress the air inside a chamber, where as the screw-type forces air between the decreasing "pocket" of the screws. A turbocharger spins fast enough so that the air is forced down the decreasing turbine vanes (in the case) and the pressurized output is directed into the intake.

So this statement:
"A roots blower DOES NOT compress air in the blower, it stacks air inside the intake manifold to make "boost". A turbo/csc also do not make boost, they just push air in faster than the motor can use it."
Is inaccurate because a roots blower DOES compress air it just requires a sealed chamber (intake manifold) to compress it against.
and here is your statement to disprove your first one:
"The compression takes place inside of the exit port"
Isn't that "inside the case" of the supercharger??? (see section "C" of the pic above)
If the intake is at say 5 psi, Won't section "C" also be at the same pressure and forcing the air towards the outlet increasing pressure??

And this statement:
"the electric fan blowers are no different than a roots blower"
Is inaccurate and thanks for proving it yourself with:
"The air coming in gets stuck because it cant go back out the way it came, and the center of the blower is air tight."
and
"the fan will start cavitating"
It cavatates because the air CAN go back out the way it came and thus it cannot compress the air. So an electric fan and a roots blower are not "technically" the same.

[This message has been edited by Oreif (edited 09-19-2007).]

yes, the cavitating fan issue does present one very large difference between the roots blower and a fan type blower. A 1 way valve, and a fan is the only true way to make positive pressure.

You cannot have pressure without restriction. If it weren't for some kind of restriction, there would be no pressures. Even in a piston type motor, or air compressor (same thing, different cam profile), without restriction, no pressure. By shutting the valves, the piston creates pressure. Open the valves, and it becomes an air compressor, unless you put the exiting air into the atmosphere, then it becomes a noise maker due to lack of restriction. A roots blower carries air the exit side without letting it go back to the inlet. If it is contained it will increase in pressure, if not, it is a noisemaker. A turbine, fan, open blade configuration has to OVERCOME it's restriction to build pressure by force. The way a turbo is built is that it slings air out to the edges of the blades making the airflow have a much more difficult time flowing in reverse. A fan blade can be designed to move air from the center to the tips also (research static pressure, facinating subject). The leaf blower utilizes somewhat of a squirrel cage blade arrangement, which also throws air outward. With enough power from the engine, it CAN produce pressure with the proper restriction. Pressure=Boost. BTW, Merry X-mas Y'all!!!!

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