Roots vs Twin Screw.... - TCCoA Forums
 
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post #1 of 11 (permalink) Old 11-08-2005, 02:08 PM Thread Starter
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Roots vs Twin Screw....

Does anyone have any data in regards to discharge temperatures between the two? I realize that the Twin Screws run cooler at higher blower speeds than Roots blowers do, and Roots blowers run cooler at slower blower speeds but I can't seem to find much in the line of comparable data between the two. Bits and pieces here and there, but not enough for a direct comparison between the two. Does anyone have any hard numbers between the two for comparison?

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post #2 of 11 (permalink) Old 11-08-2005, 03:06 PM
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You're going to need info on specific blowers for hard numbers. There are too many other variables otherwise.
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post #3 of 11 (permalink) Old 11-08-2005, 03:32 PM Thread Starter
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Yeah, I realize that, I'm just trying to put an end to the Twin Screws being a more efficient blower myth that's been circulating amongst a lot of short sited Mustang owners. I of course know that when you're really spinning the two, the Eaton falls short from the over all volume of air produced/ACT respect, but I've been trying to enlighten several non believers over at another board that refuse to acknowledge the fact that the Twin Screw efficiency rate isn't the clear cut victory a lot of them think it is. Under lower level and modest boost conditions because of it's internal compression design, in comparison to the Eaton Lobe design the Twin actually makes more heat by comparison and most of KB faithfuls just can’t fathom that?

I'm not anti-Twin Screw, by any means, but I'm sick of reading threads about people looking for opinions about different superchargers, and it's always the Kenne Bell owners that have to pipe up with something stupid like "Kenne Bell......nuff said" or "more horsepower per pound of boost", blah, blah, blah and nothing to back their claims. They refuse to acknowledge the screw compressors weak points and another blowers (whether it be Roots, or Centrifugal) strong points.

I've never disputed the claims of the Kenne Bells making great power, but they haven't exactly monopolized the market on superchargers. And I've just gotten sick of their owners treating anyone who hasn't got one like they haven't got a clue how to make power.

So yeah….basically, I’m looking for hard numbers to solve a pissing match.

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post #4 of 11 (permalink) Old 11-08-2005, 04:09 PM
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Without having any hard numbers in front of me and currently running both Eaton helix roots and A/R twin screw blowers I can give you my honest experience with them both.

The Eaton helix roots type blower size for size when compared to a twin screw will generally give you better low end to mid end power (not much though). You may also notice slightly less ACT with the roots helix at lower blower rpm's (lower boost). Both plusses yes.

This extra low to midrange power I believe is due to the the eaton blower using less power to spin at LOWER blower Rpm's. At those lower blower RPMS the ACT will also be lower on the eaton because it isnt working as hard.

Now at higher blower RPMS and higher boost the eaton helix beats up the air so much that it raises the ACT drastically as well as using mega HP to turn it killing top end power whereas the twin screw shines here due to its inherant desighn.

In short you can take your m90 off and throw a 1.7 liter A/R and make substantial gains in power. I have personally seen 100rwhp. 100 that the eaton could never achieve regardless of the amout of OD. And that basically says it all without going into heavy theory on the two designs.

Interestingly enough the new Shelby Mustang will come with an Eaton helix roots blower instead of the Twin screw because of availability...cost...and the loss of low end and midrange power the twin screw would offer. And Ford tested the crud out of these.


There are pros and cons to both units. But performance wise you will never prove the twin screw inferior to the roots helix.

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post #5 of 11 (permalink) Old 11-08-2005, 04:12 PM
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Also the heat produced by the twin screw when compared to the helix at those lower boost levels are almost a non issue.

Pros of a helix eaton when compared to a twin screw

Cost
availability
durability

Performance is not one of them

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post #6 of 11 (permalink) Old 11-09-2005, 01:59 AM
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At low boost levels (less than 9psi) the Eaton is better, but above that, the twin screw is better.




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post #7 of 11 (permalink) Old 11-09-2005, 06:20 AM
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This has been beat to death on SCCoA. Do a search, you'll find it. Thread is like.. 8 or 9 pages +
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post #8 of 11 (permalink) Old 11-09-2005, 10:28 AM
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Beaten to death on the SCCOA isnt always a good thing. BTW even at 9psi I was making more power with my 2.2 A/R on my 3.8 then with my modified m90. I will however be modifying my current M90 on my AED kit to see where that will take me. I'll post pics whenever that is completed. Made a noticable difference on my 3.8 ACT wise and boost wise. Was very simmiliar in design to the new Magnum Powers MPIII M90 however it was created using a S type blower with a lil grinding and welding.

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post #9 of 11 (permalink) Old 11-09-2005, 03:41 PM
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I would like to see act discharge temps off boost and on boost?
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post #10 of 11 (permalink) Old 11-09-2005, 09:36 PM
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B96B- Your "life sucks" post and your avatar disturb me.

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post #11 of 11 (permalink) Old 11-09-2005, 10:35 PM
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Quote:
I would like to see act discharge temps off boost and on boost?
You may be able to get these off a supercoupe guy that has an AR on his car. My setup is a liquid to air and replaces everything so I cant really make any meaningful comparisons. Dave Dalke may know over at teh SCCOA

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