Sprintex vs Eaton ??

[Calum]

I'm trying to compare the Eaton R900 to the Sprintex S5-335. Clearly the 335 has a much larger displacement/revolution, but the R900 can spin significantly faster. Unfortunately Sprintex doesn't seem to publish compressor maps. I did find that Sprintex lists a max volumetric flow rate of 740 cfm, but at what pressure ratio and efficient I have no idea. The R900 seems capable of ~618 cfm at a pressure ratio of ~1.8 and 60% efficiency.

Does anyone know anything about the Sprintex specs and how they were measured? I'm guessing that even if Spritex's has conducted their tests under extremely favorable conditions that the 335 will still be capable of more flow and thus more power than the R900. I'm wondering how far behind the R900 will be, and what kind of inlet temperatures could be expected for similar power levels?

Thanks

Sources: http://www.sprintex.com.au/superchargers/ (click S5-335) and http://www.eaton.com/ecm/groups/publ.../ct_127897.gif

[bfrank1972]

Originally Posted by Calum

I'm trying to compare the Eaton R900 to the Sprintex S5-335. Clearly the 335 has a much larger displacement/revolution, but the R900 can spin significantly faster. Unfortunately Sprintex doesn't seem to publish compressor maps. I did find that Sprintex lists a max volumetric flow rate of 740 cfm, but at what pressure ratio and efficient I have no idea. The R900 seems capable of ~618 cfm at a pressure ratio of ~1.8 and 60% efficiency.

Does anyone know anything about the Sprintex specs and how they were measured? I'm guessing that even if Spritex's has conducted their tests under extremely favorable conditions that the 335 will still be capable of more flow and thus more power than the R900. I'm wondering how far behind the R900 will be, and what kind of inlet temperatures could be expected for similar power levels?

Thanks

Sources: http://www.sprintex.com.au/superchargers/ (click S5-335) and http://www.eaton.com/ecm/groups/publ.../ct_127897.gif

Interesting topic - just poking around ran across this comparison:

http://www.modularfords.com/threads/...omparison-maps

Bigger models, not sprintex, but it is a TVS vs twinscrew comparison, so maybe we can extrapolate from this writeup.

[CSG Mike]

Originally Posted by Calum

I'm trying to compare the Eaton R900 to the Sprintex S5-335. Clearly the 335 has a much larger displacement/revolution, but the R900 can spin significantly faster. Unfortunately Sprintex doesn't seem to publish compressor maps. I did find that Sprintex lists a max volumetric flow rate of 740 cfm, but at what pressure ratio and efficient I have no idea. The R900 seems capable of ~618 cfm at a pressure ratio of ~1.8 and 60% efficiency.

Does anyone know anything about the Sprintex specs and how they were measured? I'm guessing that even if Spritex's has conducted their tests under extremely favorable conditions that the 335 will still be capable of more flow and thus more power than the R900. I'm wondering how far behind the R900 will be, and what kind of inlet temperatures could be expected for similar power levels?

Thanks

Sources: http://www.sprintex.com.au/superchargers/ (click S5-335) and http://www.eaton.com/ecm/groups/publ.../ct_127897.gif

Both blowers offer enough flow that you cannot take advantage of their maximum flow rates without a built engine.

[Calum]

Originally Posted by CSG Mike

Both blowers offer enough flow that you cannot take advantage of their maximum flow rates without a built engine.

Exactly what I was expecting. Any idea which is more efficient though?

[CSG Mike]

Originally Posted by Calum

Exactly what I was expecting. Any idea which is more efficient though?

That depends on your power target. The TVS is more efficient, but the Sprintex has more potential.

If the potential isn't needed, then there's no reason to go that way.

[Calum]

/thread

Thanks Mike.

[D K]

60% efficiency?

Isnt Rotrex in the high 70's?

[CSG Mike]

Originally Posted by D K

60% efficiency?

Isnt Rotrex in the high 70's?

Yes

The TVS hits 70% at its peak/sweet spot (albeit small one), while the Rotrex C38-91/92 hits 75%.

[D K]

Is there even ANY advantage of a positive displacement compressor?

[bfrank1972]

Originally Posted by D K

Is there even ANY advantage of a positive displacement compressor?

Yes, huge advantage. Centrifugal compressors build boost exponentially as a function of compressor speed, that's why you see rotrex, vortech, etc. belt driven superchargers make big torque only at higher engine speeds. A PD unit will make a much broader torque curve - just compare the area under the hp/torque curve for one of the rotrex kits vs. this new 335 unit Moto East is playing with (another thread). Both could be tuned to hit 320 whp on E70, but just look at the torque curve of the 335.

[Calum]

Originally Posted by D K

Is there even ANY advantage of a positive displacement compressor?

Possibly area under the curve and/or more power in the daily driver parts of the rpm band. Either way the decision will be subjective when we finally get some decent PD offerings. (Puts on flame suit)

[Calum]

Originally Posted by D K

60% efficiency?

Isnt Rotrex in the high 70's?

Aren't the rotrex kits already running past their efficiency island?

Edit: looking at the compressor map for the c30-94 and assuming ~90k rpm and 1.8 pressure ratio it looks like they're running at about 55%. Please, if I'm not reading that right, show me why instead of flaming.

[CSG Mike]

Originally Posted by Calum

Aren't the rotrex kits already running past their efficiency island?

Edit: looking at the compressor map for the c30-94 and assuming ~90k rpm and 1.8 pressure ratio it looks like they're running at about 55%. Please, if I'm not reading that right, show me why instead of flaming.

You want to be looking closer to the 1.45-1.65 and between 60-85k. The reasoning behind this, is that the nominal used RPM range for redline pulls, is about 5k-7.4k, which yields boost in the 0.45-0.65 bar range, and impeller speeds between 60k (5k rpm) and 89k (7.4k rpm). You only see 89k rpm at redline, momentarily.

If you draw a line following the pressure and rpm used by the Jackson Racing kit, you'll note that the unit is sized as close to ideal as possible from the superchargers in the Rotrex range for the powerband used during pulls; it crosses directly across that "sweet spot".

The compressor map reads identical to a turbo. Let me know if you need specific explanations or have questions!

[Calum]

Originally Posted by CSG Mike

Let me know if you need specific explanations or have questions!

Nope, that covers it.