Do some vendors/companies not know the difference between Twin Screw and Roots?

[47AJV8]

Or am I just misinformed? (Hopefully not).

So I'm dealing with a large tuning company, extremely well known and respected and send them an email enquiring about their 600 and 700 BHP kits and this is how the conversation goes down (they just started emailing me back on Saturday I sent my inquiry Monday):

(They only have kits based around Maggies, and Edelbrock blowers)

Me: "Thank you, and I was also wondering if you would be offering kits built around a twin screw or centrifugal supercharger? I've run roots before but have never really been a fan. Thanks, I look forward to hearing back from you."

Vendor: "Hello Noah,

Both the Magnuson and Edelbrock supercharger are twin screw Eaton rotating assembly’s.

Thank you,"
---------------

So I said, I know those a twin vortices but they are still roots blowers, I'm looking for a twin screw such as a Whipple or KB (or a centri setup), and now they haven't gotten back to me even though before we were emailing back and forth every 10 minutes or so...

So my question is... Am I misinformed or are they? Because I'm very certain I know the vast differences between twin screw and roots and I'm even more certain that the new maggie and edelbrock e-force kits are roots... Tell me if I'm wrong but I just think it's very concerning that individuals working for a large tuning company don't know the difference

If anyone else has encountered this I want to hear! I don't want to think I'm going crazy!

[jessrayo]

I think because the roots type superchargers have two lobes they generally get lumped together with the lysholm design true twin screw. For automotive applications I really don't think the true twin screw design is a significant engineering advantage. Having said that, whipple does make a good blower. If you really want twin screw I suggest you ask about whipple.

[old motorhead]

Comparing a t'screw and a modern roots blower at "street" type boost levels, there really isn't that much difference. A pretty good argument can be made for either one. I wouldn't pound too hard on the guy that didn't know the difference....although, I agree that a pro should know the difference.

[47AJV8]

Originally Posted by jessrayo

I think because the roots type superchargers have two lobes they generally get lumped together with the lysholm design true twin screw. For automotive applications I really don't think the true twin screw design is a significant engineering advantage. Having said that, whipple does make a good blower. If you really want twin screw I suggest you ask about whipple.

Ya I was actually most interested in a whipple setup, the reason I am so keen as I like to have the headroom for if I build the engine a bit, the 2.8L whipple can support a ridiculous amount of HP considering it's size.

Originally Posted by old motorhead

Comparing a t'screw and a modern roots blower at "street" type boost levels, there really isn't that much difference. A pretty good argument can be made for either one. I wouldn't pound too hard on the guy that didn't know the difference....although, I agree that a pro should know the difference.

Ya I would agree to some extent, the reason why I didn't name names is because I figure it could be an honest mistake, but when dealing with someone who I could possibly be handing over 15XXX dollars I really want everyone involved to know exactly what they're talking about :P

[RankSS]

I don't think they do twin screw but Davenport in Calgary is who I would talk to if I were you.
They have been doing the FI game a long time and have great customer service.

[47AJV8]

Originally Posted by RankSS

I don't think they do twin screw but Davenport in Calgary is who I would talk to if I were you.
They have been doing the FI game a long time and have great customer service.

Ya I have been talking to them they are super knowledgeable and great to deal with.

[jessrayo]

Well since this post is kind of turning into a supercharger comparison I'll toss out my opinion. I'm sure if others disagree they will comment.

Roots superchargers - make boost at very low rpm and the motors make more torque than any other supercharger. The power tends to die off at the very top of the powerband because the "boost" is generally the increased air pressure associated with more heat rather than more oxygen molecules. Basicially if you want more hit below 5200 rpm, this is the best blower.

Centrifical superchargers - generate boost in a linear fashion and make much more power on top than they do at the bottom. As the rpms climb...so does the power. Pretty tame at idle but once you get it going, hang on. If your transmission gearing can keep you high in rev range, great performance potential. Also the top dyno performer for hp. They just keep climbing.

The twin screws - Blend the two above, better torque than the centri's but not as good as the roots. Beter top end performance than the roots but not as good as the centri's. There just are not that many manufacturers. Of the ones out there Whipple has the most units produced and the best customer satisfaction history.

[47AJV8]

Originally Posted by jessrayo

Well since this post is kind of turning into a supercharger comparison I'll toss out my opinion. I'm sure if others disagree they will comment.

Roots superchargers - make boost at very low rpm and the motors make more torque than any other supercharger. The power tends to die off at the very top of the powerband because the "boost" is generally the increased air pressure associated with more heat rather than more oxygen molecules. Basicially if you want more hit below 5200 rpm, this is the best blower.

Centrifical superchargers - generate boost in a linear fashion and make much more power on top than they do at the bottom. As the rpms climb...so does the power. Pretty tame at idle but once you get it going, hang on. If your transmission gearing can keep you high in rev range, great performance potential. Also the top dyno performer for hp. They just keep climbing.

The twin screws - Blend the two above, better torque than the centri's but not as good as the roots. Beter top end performance than the roots but not as good as the centri's. There just are not that many manufacturers. Of the ones out there Whipple has the most units produced and the best customer satisfaction history.

So the thing is, everyone always says that roots make more torque, but I've never really seen any dyno's to back this up, and I don't understand why they would because don't they make boost based on throttle position just like a roots? (And as far as I've seen they make more peak torque further up the RPM band)

[jessrayo]

Originally Posted by nbrigdan

So the thing is, everyone always says that roots make more torque, but I've never really seen any dyno's to back this up, and I don't understand why they would because don't they make boost based on throttle position just like a roots? (And as far as I've seen they make more peak torque further up the RPM band)

I can't believe how long I looked for dyno sheets or videos.

Here is the ZL1 dyno thread, with the exception of the Barron, all standard roots, torque very high, very early. Torque about the same as hp.

http://www.camaro5.com/forums/showthread.php?t=314663

Here is a typical centri dyno, both torque and hp climb and the hp is much higher.



Here is a whipple dyno, pretty good torque at the onset but the hp spikes at the top of the powerband, more hp than torque.

http://www.camaro5.com/forums/showth...ght=dyno+sheet

If you look at all the supercharger dyno sheets you can pretty much tell the type by the way the torque compares to hp.

And just in case you are wondering, these are the first I found of each type. Didn't search at all for better looking graphs.

[realcanuk]

Its a fine line. A twin screw by definition, is a roots type supercharger, although a more efficient design. From the horses mouth..

Eaton’s new Twin Vortices Series (TVS) is a Roots-type supercharger for a variety of engine applications that delivers more power and better fuel economy in a smaller package, for uncompromising, high-performance driving.

http://www.eaton.com/Eaton/ProductsS...Superchargers/

[OneSickS10]

Edelbrock E-Force Superchargers are twin screw, as are the Whipples as the others stated above.

It is my understanding that the root style superchargers create more heat and do not compress the air before delivering it to the motor. The air is delivered through the vanes that you can see on the outside of the casing of the blower.

The twin screw superchargers compress the air before delivering it into the motor. They run cooler than root style superchargers, create more (low end) torque than centrifugal superchargers but plateau in the higher RPMs.

Depending on what you plan on doing, the centrifugal's will create more power and more boost at higher RPM's but take longer to get going, like turbos, since they are remote mounted and lack the low end torque you would find on the root or root style chargers..

Hope this helps.

[47AJV8]

First off thanks to everyone for their replies!

Originally Posted by realcanuk

Its a fine line. A twin screw by definition, is a roots type supercharger, although a more efficient design.

I was under the impression that their only similarity was that they were both positive displacement, and that whether they were roots or T'screw was based on the style/design of the rotors. No?

Originally Posted by OneSickS10

Edelbrock E-Force Superchargers are twin screw, as are the Whipples as the others stated above.

Really? I don't think so, they use the rotors from Eaton, and those I'm very sure are a 2.3L roots, at least I think so.

[oachalon]

Edelbrock E-force uses the Eaton TVS 2300 rotors just like magnuson and SLP

[10aSSee D]

I agree, both are PD blowers but a different rotor design and how it is compressed. To me the only thing they have in common is they are PD.