Thrasher EP is getting some pretty impressive numbers out of 3800 SC's (using a $$$$$$ billet intercooler) with the Eaton M90 roots type blower. How much more power could be extracted using the more efficient screw type compressor, such as Whipple sells?
The Whipple 1200AX appears to be approximately equivalent (~1.2 litre/rev) to the Eaton M90.

http://www.3800performance.com/

Makes a nice S/c upgrade. They also make a Trans that can hold 500hp.

Whipple's are NOT more efficient than Eatons. FYI.

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[]image dropped temporarilly[]
TRiAD Motorsports ~ Performance Tuning of European, Japanese and Domestic Automobiles
Project MR1 / Let the modding begin! ~ triadtuning@hotmail.com * AIM ~ Michael Blue 72
Only the dead have seen the end of war. ~ Plato

Eatons are conventional roots type, right?That's what it looked like on the website.

If twin screw superchargers are not more efficient than roots, how did the idea that they are get propagated?

No offense, but do you have more info than just your say-so?

Geez , I don't even really want to post this , but since it has been brought up. A whipple charger is quite a bit more efficient. Lingenfelter has a few articles on this and other issues involving Screw type superchargers , optimum performance , atomization of fuel , Intercoolers...ect. If anyone keeps on top of this subject a lot they will know about lingenfelters latest supercharging projects. I know a bit ont he subject , but I tend to believe if a mogul of performance like John lingenfelter has researched and writen articles on it , then it's probably true.

I would be more than happy to send anyone the article if you want the real facts on the matter. I don't have ascanner with me , but I will get it scanned for those interested.

JM

quote Originally posted by Will: Eatons are conventional roots type, right?That's what it looked like on the website....

http://automotive.eaton.com/product/engine_controls/superchargers.html

"designs, manufactures and markets modified Roots-type positive displacement pumps..."

They have LITTLE in common with "conventional" roots-type blowers.

"The roots supercharger has been around for a long time, how is the Eaton supercharger different? The Eaton supercharger is essentially a Roots blower pump, with one substantial design wrinkle; each rotor has been twisted 60 degrees to form a helix. The two counter rotating rotors have three lobes, which intermesh during operation. These twisted rotors, along with specially designed inlet and outlet port geometry, help to reduce pressure variations resulting in a smooth discharge of air and a low level of noise during operation. This arrangement also improves efficiency over traditional Roots superchargers. With helical rotors and an axial inlet the Eaton supercharger can be spun to up to 14,000 rpm, thereby reducing package size."

There you have it...

quote Originally posted by TRiAD: Link?

Im not even going to dignify this with a response.

Grow up... If your trying to start a business this is not the way

I will post the articles on monday, Im headed home and will pick them up.

If you want a good route to supercharging a Fiero I suggest you track down someone who has the article written 5-6 years ago about the gentleman who used a Vortec type blower on a Fiero with a cross shaft , much the same as the New vortec units for Hondas now available.

Good day.

JM

[This message has been edited by Slammed Fiero (edited 03-26-2002).]

quote Originally posted by Slammed Fiero: Im not even going to dignify this with a response. Grow up... If your trying to start a business this is not the way I will post the articles on monday, Im headed home and will pick them up. If you want a good route to supercharging a Fiero I suggest you track down someone who has the article written 5-6 years ago about the gentleman who used a Vortec type blower on a Fiero with a cross shaft , much the same as the New vortec units for Hondas now available. Good day. JM [This message has been edited by Slammed Fiero (edited 03-26-2002).]

Both 'positive displacement' types of superchargers are inefficent comparired to Turbos....

Rogue

quote Originally posted by TRiAD: "The roots supercharger has been around for a long time, how is the Eaton supercharger different? The Eaton supercharger is essentially a Roots blower pump, with one substantial design wrinkle; each rotor has been twisted 60 degrees to form a helix. The two counter rotating rotors have three lobes, which intermesh during operation. These twisted rotors, along with specially designed inlet and outlet port geometry, help to reduce pressure variations resulting in a smooth discharge of air and a low level of noise during operation. This arrangement also improves efficiency over traditional Roots superchargers. With helical rotors and an axial inlet the Eaton supercharger can be spun to up to 14,000 rpm, thereby reducing package size." There you have it...[/B]

Notice that they don't say how much more efficient. They have delta-T graphs on their website (graphs which only go to 12,000 RPM, BTW). I've e-mailed Whipple for similar information, but haven't heard back yet.

Please find more compelling evidence than this. Something with numbers, and maybe a graph or two

There's a reason industrial air compressors are almost all twin screw instead of roots or modified roots.

[This message has been edited by Will (edited 03-27-2002).]

Do you think the power gains (if any) from a Whipplecharger would be worth the extra cost? Considering that the Eaton is essentially free (comes with the engine), you'd be putting out 2 or 3 grand extra for just a few hp. Then you need to machine an adapter to make it fit.

What kind of power gains are they getting with the TEP intercooler and a small pulley?

They have a test car which has dynoed a tick over 300 at the wheels, but it wasn't clear from their website exactly what was on that car. They also sell long tube headers, which may also have been on the car (GM FWD something or other).

One of their customers has gone 12.548@110.52 on slicks and race gas in a Grand Prix GTP. He has quite a few other mods. His website: http://www.c-ya-racing.com/

Their complete intercooler kit is $2000.
A Whipple 1600 whatever (I've decided this would be a better match for the M90) is $1760 by itself.
By itself, it probably won't do as well as their intercooler and a smaller pulley, but in any given situation, it should make more power than the Eaton, if for no other reason than being more efficient makes it easier to spin at any given boost level.

Heck Will, $1760 is a Chrfab N* computer and cam set

OK, I'm done here.

Best!
Ben.

PS: Eatons *look* essentially like a screw compressor to me...

quote Originally posted by Will: They have a test car which has dynoed a tick over 300 at the wheels, but it wasn't clear from their website exactly what was on that car. They also sell long tube headers, which may also have been on the car (GM FWD something or other). One of their customers has gone 12.548@110.52 on slicks and race gas in a Grand Prix GTP. He has quite a few other mods. His website: http://www.c-ya-racing.com/ Their complete intercooler kit is $2000. A Whipple 1600 whatever (I've decided this would be a better match for the M90) is $1760 by itself. By itself, it probably won't do as well as their intercooler and a smaller pulley, but in any given situation, it should make more power than the Eaton, if for no other reason than being more efficient makes it easier to spin at any given boost level.

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Ben Cannon
88 Formula, T-top, Metalic Red. "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

quote Originally posted by artherd: PS: Eatons *look* essentially like a screw compressor to me...

I second that.

Rogue

whipples are more efficient for 1 reason.

They don't produce as much heat.

They use the same amount of energy from the engine. Energy output is directly related to the amount of energy inputed in simple mathmatic equation (eg. addition)

Energy input = enrgy out put (boost in hp) + loss due to friction + loss due to heat + loss due to sound

In both a whipple and a eaton they consume the same amount of energy lets say 100kJ's (unrealistic but hey it's equal for both)

we will assign both superchargers the same loss due to friction of 10kJ's So both are left with 90kJ to split between heat and actual output. It is well known that the whipple style charger will produce much less heat than the eaton. Heat is a measure of the average kinetic energy within a substance (it is energy so we have to include it in our equation). A eaton supercharger produces intake temperatures of around 150 degrees so for simplicity we will assign it with a 15kJ loss due to heat. Also superchargers make noise, and noise is a form of energy, so we will assign the noise a 5kJ loss for the eaton. This gives us a final output on the eaton (again theroretical because the loss to friction might be to hight or to low, but these numbers do represent what would happen in the real world) of 70kJ's

100kJ= 70kJ(output) + 5kJ(sound) + 15kJ (heat) + 10kJ(friction)

Now for the whipple, a whipple produces less heat than an eaton and is quieter (slightly, but it adds up)

So for a whipple if we say it puts out 130 degrees of intake heat we asign this a 13kJ loss, and if the whipple is quiter it would have a lower loss due to sound so we will say 4kJ here. We come up with a total output on the whipple of 73kJ.

100kJ = 73kJ(output) + 4kJ(sound) + 10kj(friction) + 13kJ(heat)

so the whipple when given 100kJ of energy in my lab produces 3kJ more output than the eaton. In the real world the whipple also has less internal friction, and has a much lower intake air temp than the eaton, so the energy difference would be much larger.

NOCONES - I do believe you just scientificaly b!tch-slapped Triad - thats gotta hurt

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( the above was the thoughts, views, and opinions of a disgruntled Fiero mechanic, and do not express or
imply those of West Coast Fiero, Fieros West, or any other organization - just that of this poor
bastard ) :)

Eric Nelson
Technician,
West Coast Fiero
310-305-4111

quote Originally posted by NOCONES: whipples are more efficient for 1 reason. They don't produce as much heat.

I appreciate your effort, but I'm well aware of the physics involved. You answered the wrong question.

quote It is well known that the whipple style charger will produce much less heat than the eaton.

This is the point that's in contention. Is a Whipple actually more efficient than a twisted rotor roots? Triad says no. I say that I would like to see more evidence, preferably a plot of delta T vs. pressure ratio vs. RPM

Eaton has these on their website: http://automotive.eaton.com/product/engine_controls/M90.html

The change in temperature for an M90 averages over 160 degrees at 10 psi across the blower's RPM range.

Whipple does not have this information for their blowers on their website.

I don't like to take someone's word for it without seeing the graphs or knowing the numbers involved.

P.S. A blower will consume a certain number of Joules every second. Most of us call these units Watts (W)

Doing further research i've learned a coupele of things.

There are two sides of the "positive displacement" supercharger camp. The roots (eaton) lovers. I class eaton in the roots class because at 3 points in rotation the eaton is closed, true positive displacement. And the twin screw kenne bell, whipple camp. Interestingly twin screw chargers are never closed during operation(much like a centrifical supercharger).

Both groupls claim lower intake charge temp, and quitest charger on the market. AT moderate <10psi boost levels it seems the charges stack up pretty equally. However at high boost levels it seems that the roots produces much more heat than the twin screw. The efficience number i have seen online is 60% for the eaton, and 72% for the whipple. I really wish i could find a graph for the temp on the twinscrew supercharger, as i've seen people that claim it produces more heat than the eaton, and vice versa. The eaton increases inlet air 160 degrees over ambiant air temp Whipple claims to be within 20% of ambient air.

As for aplication, i never said i didn't think the eaton was a better charger i'm just saying the twin screw is more efficient. The twin screw seems beter suited for towing and low rpm installs, as the twin screw has a very very flat boost curve (supercharged 4.9L caddy anyone). The eaton seems to be a better all around supercharger. It produces strong low RPM boost, as well as a upward sloping boost curve for high rpms. Dissadvantages of both are for most eaton installs at high boost levels the inability to intercool, and with the whipple internal lubricant (this is a big deal, has to be changed to maintain reliability)

I do whole heartidly agree that for a street/race aplication the eaton style charger would be a better charger, but it is slightly less efficient than the whipple.

will.. thanks i couldn't remember that about watts, so i just used kJ's

And west coast, that wasn't the point, i'm not trying to start errrr.. continue a flame war. I like will would like to see a graph, but i am saying if the lower charge temp is correct with the whipple there is no way the eaton is more efficient. The physics of it are imposible.

[This message has been edited by NOCONES (edited 03-31-2002).]

quote Originally posted by NOCONES: It produces strong low RPM boost, as well as a upward sloping boost curve for high rpms. I do whole heartidly agree that for a street/race aplication the eaton style charger would be a better charger, but it is slightly less efficient than the whipple.

???? Look at the CFM vs RPM "curve" I posted previously. It's straight line. The only way boost would rise is if the engine's VE decreases as RPM increases, which is entirely possible, but is not a characteristic of the supercharger.

Are you talking straight rotor roots or twisted rotor roots? I don't think there's any doubt about twin screws being more efficient than straight rotor roots. The question is are they more efficient than twisted rotor roots. The twisted rotor roots bears some similarites to the twin screw in that it compresses the air before it opens the charge up to the intake manifold. The twisted rotor will also make less noise than the straight rotor for the same reasons that helical gears make less noise than straight cut gears.

Why do you think the eaton style is better for the street? More efficiency equals, well, more efficiency.

When people research this, and group Eaton with "roots" and therefore rate brand X vs a regular "roots" and say the results also apply to an Eaton, they are simply wrong.

Try researching the Eaton blower as it's own unit, and not just researching "roots" information, because it is not applicable to Eatons.

Positive displacement = low end torque.

Slammed saying to "look up the centrifugal kit, if you want to see a "good" kit" is just humorous.

I'd never choose to use a centrifugal blower of ANY kind over positive displacement.

The eaton seems better for the street because it produces a broader range of boost. Everything i've seen on the twin screw says that it well suited to towing and hardcore racing applications. The eaton just seems to be a more proven reliable aplication. The internal oiling with the whipple wories me.

I have no doubt that the whipple can be used reliably and well on the street, but if i where to install a supercharger i'd use a eaton.

I'm refering to the straight roots, but the 60 degree twist that is in the eaton still behaves like a straight roots. It is just more efficient and quieter than a straight roots, but is still less efficient than the twin screw because all the benefits of the twin screw aren't present.

and with the boost graph i got mistaken and transposed the hp graph.. my bad

[This message has been edited by NOCONES (edited 03-31-2002).]