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Don’t need to. Compressor charts tell a good story.


http://www.musclecarmodfather.com/forum/showthread.php?80-Twin-Screw-vs-TVS-Blower-efficiency


Not a whipple but good data nonetheless.


A good authoritative post:

“While logically based on a pure displacement scenario and Whipple's website - this would seem to be that case, but unfortunately it is not entirely true.

The Whipple is a screw charger requiring a male and female rotor to achieve the claimed internal compression. Due to this design the rotors must have a different number of lobes on each rotor - Whipple's design uses 5 lobes (on the female) and 3 lobes (on the male) Since the female rotor is the driven rotor, the male rotor must spin 5/3 times faster. The max RPM for the 2.9L is rated at 18000 RPM which means the male rotor is turning 30000RPM which is a pretty high bearing speeds for this unit.

The Eaton TVS 2300 is a high-helix roots supercharger meaning it utilizes a set of matched rotors (same # of lobes on each) and due to it’s design, it is not capable of internal compression (which minimizes pumping losses during cruise). It’s Eaton OEM rated speed is at the highest speed allowed for infinite bearing life (yes that means the bearing is expected to last forever) and a max temperature rise across the SC of ~130 degrees C (max outlet temp of 150C) which occurs at 18000 and 2.4 pressure ratio (21psi boost).
Not surprisingly the Whipple 2.9 uses the same bearings, so as you might guess there is quite a bit more flow in the Eaton TVS if we were to set its max speed to the same level as the 2.9L screw. Since both rotors spin the exact same speed in the TVS let’s increase that allowed bearing speed limit to 24000RPM. Now our 150C (302F) outlet temp still applies so we probably can’t run 21 PSI of boost continuously, but 18psi will probably be just fine for a V8 application.

At 18000 RPM a Whipple 2.9L blower is capable of moving 1720 CFM as per the Whipple website.
At 18000 RPM a TVS 2300 blower is capable of moving 1461 CFM.
At 22000 RPM a TVS 2300 blower is capable of moving 1770 CFM.
At 24000 RPM a TVS 2300 blower is capable of moving 1900 CFM.
So to match the 18000 RPM max output of a Whipple 2.9 you need to spin the TVS to about 21,500 – beyond that speed it will outflow the Whipple 2.9L.

A 90mm throttle body is enough flow to support about 750-800 RWHP on a TVS 2300 (the vacuum created by the inlet restriction will cause the bypass to start opening causing high inlet air temps, limit the boost and prevent higher power). To go beyond this you will need a larger 102mm or 108mm throttle body. At about 23000 RPM the inlet port in the TVS 2300 housing will become the restriction and prevent efficient operation at any higher speed so I don’t recommend operation beyond this point with a TVS2300.”



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Kevin, time to show off what you have been doing as of lately. Let's see it :)
 

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jan. 2020 just gat here to this forum, came across this thread, nice build, hope your health is good, that sound iz amazing. thanxx for all the pics, that lil collie is epic
 
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