Sprintex vs Eaton ??

[xwd]

The 335 doesn't need to spin as fast as the 900 because it is so much larger in displacement. It's a significant difference. The 335 is going to make more power everywhere than the R900 with the right kind of gas.

It also comes down to the engine displacement and VE and whether it can really take advantage of what the blower is doing. I've seen 335 dynos where it drops like a rock from a huge mid-range point, if you had say FBM's stage 2 heads on there I'm not sure that would happen.

This is a dyno from KSR's FR-S with the TRD S/C which is a TVS1320, comparable in displacement to the 335. This is on a 9.5:1 built engine, 98 octane gas, running ~13 PSI.



They went with the 1320 because they could make more power and not have to spin it to the extreme they would have to spin the 900. They also didn't care about retaining things like A/C, which needed to be ditched to make the 1320 fit.

[vgi]

Originally Posted by Calum

Unfortunately Sprintex doesn't seem to publish compressor maps.
Sources: http://www.sprintex.com.au/superchargers/ (click S5-335)

You should have downloaded the technical PDF

Originally Posted by CSG Mike

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.

doesn't look like TVS is more efficient (for some reason TVS marks only every other area??):
http://www.eaton.eu/ecm/groups/publi.../ct_127897.gif
http://www.sprintex.com.au/wp-conten...File-Rev-2.pdf

PS not sure how much marketing in this article - it's from kenne bell after all, a twin screw manufacturer, but still:
http://kennebell.net/KBWebsite/Commo...romcatalog.pdf

[CSG Mike]

Originally Posted by dwx

The 335 doesn't need to spin as fast as the 900 because it is so much larger in displacement. It's a significant difference. The 335 is going to make more power everywhere than the R900 with the right kind of gas.

It also comes down to the engine displacement and VE and whether it can really take advantage of what the blower is doing. I've seen 335 dynos where it drops like a rock from a huge mid-range point, if you had say FBM's stage 2 heads on there I'm not sure that would happen.

This is a dyno from KSR's FR-S with the TRD S/C which is a TVS1320, comparable in displacement to the 335. This is on a 9.5:1 built engine, 98 octane gas, running ~13 PSI.



They went with the 1320 because they could make more power and not have to spin it to the extreme they would have to spin the 900. They also didn't care about retaining things like A/C, which needed to be ditched to make the 1320 fit.

Don't forget that the 335 also saps more power from the engine because it's larger.

Larger superchargers require more power to be used to be spun. It's not "free" like with a turbo.

[Calum]

Originally Posted by CSG Mike

Don't forget that the 335 also saps more power from the engine because it's larger.

Larger superchargers require more power to be used to be spun. It's not "free" like with a turbo.

Spinning it slower though, may offset the difference, no?

[boredom.is.me]

Originally Posted by Calum

Spinning it slower though, may offset the difference, no?

I'm not the person who knows (and experienced) much about how a SC operates, but the basic law of 'give and return' shouldn't change (much). If you put two apples in a pie, there will be two apples in that pie. A bigger unit that is capable of putting out more at any given rpm requires that same 'proportion of more' at whatever rpm. If you don't need much out, then you won't put much in. So slow x a lot can equal fast x little.

[Xero-Limit]

Originally Posted by Calum

Spinning it slower though, may offset the difference, no?

May be some merit here in the grand scheme of things.

The drag through the bearings should be about the same. The drag difference through the longer, heavier rotors themselves should be inconsequential I think --it would be very small since the rotors don't actually touch. What you do have is a bit more parasitic drag from accelerating the assembly, much like a heavy flywheel or crank pulley. Then the rest should be proportional to the HP being produced. Overall fuel economy is a bigger hit IMO than the power loss at high loads.

I'd think the bigger issue with too big a blower is ending up in an inefficient range. So gearing down the 335 or larger TVS to make only 7 psi probably doesn't make much sense.

[Calum]

Originally Posted by boredom.is.me

I'm not the person who knows (and experienced) much about how a SC operates, but the basic law of 'give and return' shouldn't change (much). If you put two apples in a pie, there will be two apples in that pie. A bigger unit that is capable of putting out more at any given rpm requires that same 'proportion of more' at whatever rpm. If you don't need much out, then you won't put much in. So slow x a lot can equal fast x little.

Yes and no. Drag generally increases with the square of speed. Which means it can take a lot more power to move something faster even if the output is the same. That said I'm a long way from those classes, I left that field almost five years ago. So I could easily be wrong.

[boredom.is.me]

It applies if the frictional force changes, but do the frictional forces change in this case? Hmmm...

[diodelphi]

if twinscrew is better why cosworth use eaton?

[xwd]

Cosworth has had a deal with Eaton for a couple years now.

[350matt]

the sprintex unit ( twinscrew) is marginally more efficent by about 1%

however the TVS unit can spin a good deal faster, 20K rpm compared to 15K rpm
and that 20Krpm speed is a continous speed , these TVS units will allow sporadic use of 24K rpm as well

the TVS unit also doesn't use oil, whereas the Sprintex gearbox needs topping up due to oil consumption

Eaton SC's are used by Toyota, Jaguar and Mercedes as original equipment

and OEMS tend to select a robust product to avoid warrenty claims but they've also got to meet power figures , noise requirements and cost

So I'd say cosworth have made the right choice and yes they have a history of using Eaton products

[JDM4E]

- Do all PD blower types have the same whining sound, or can it be said that one is more quiet then another?

[350matt]

I think yes all PD will whine but its very dependent on the intake design , stiffness of the pipes and how much detail design has gone into the supercharger outlet

I've heard the same unit ( Eaton R1300) installed in a Jaguar V8 and also heard it in a mercedes V8 and the merc install was much quieter ,as it has much more stiffening and ribs on the inlet manifold and intake pipe

[Xero-Limit]

Originally Posted by JDM4E

- Do all PD blower types have the same whining sound, or can it be said that one is more quiet then another?

Twin screws are definitely more loud and "whiney" than a roots blower. The roots has more of a howl than a whine given the same speed and intake design, and less volume overall. Lots has to do with the intake design, but for the same airflow the twin screw is definitely more noise. Both can be rendered dead silent with OEM style plastic intakes with resonating chambers.

Google some sprintex and whipple videos--you'll find many less having that kind of noise with a roots blower.