[mines13]

Originally Posted by gmookher

Ok, I'll bite:

there is a little more to it, when you compare other salient features, with out turning this into a roots vs centri debate thread:

First off, greetings all.

1-fuel injection needs to properly fuel either solutions differ, the two present different requirements at both stg1 and especially stg 2 implementations as far as fuel demands, blow off and surge management and subsequent limits build specs and costs that you might set for each. Stage2 at one solution is not equal to stage2 at another, it should be noted.

Yes, the non intercooled kit does not require any upgraded fuel system components. The intercooled kit will include upgraded fuel injectors. For those that wish to make their own decisions regarding fuel/tuning they may purchase a tuner kit, which will not include these ancillaries. the bypass valve configuration is identical between the two versions.

2-the way each systems reacts to throttle modulation,differs greatly between both systems, one is not better than the other, but each has a different 'character; if you will. I kno why I chose what i did and you should know why youre choosing what you want too. what will you drive like in snow? rain? when sideways?

Agreed, this surely would come down to the end users personal desires. If you define better as near instant throttle response, near no ramp in boost to peak pressure, more torque per lb of boost, (essentially feeling like a larger displacement NA engine) a twin screw would be superior to a centrifugal. But this may not apply to everybody.

3-the weight of each system and location of that weight differs, tho not that significant to most buyers, it does impact things like upgradeability significantly.

Very true and well said. More on that later...

4-there is a noteworthy difference in both when you look adiabatic efficiency, output charge temps, loaded boost latency, and parasitic drag when comparing centrifugal solution from Vortech vs this twin screw setup from innovate on a smaller motor like ours, especially as the given application's scaling increases.

Under light load conditions this has a pretty negligible effect. The advantages of the power delivery however offset most of this in real world use.

5-Twin screws are typically used in low RPM applications because they give the full charge right off the line. Centrifugal Blowers will produce more top end power and tend to be very easy if not better on fuel consumption during normal driving conditions.

I would argue that the advantages of a twin screw system are most obviously at lower engine speeds. Not having to downshift, cursing in a higher gear, etc. All of this has a pretty dramatic effect on fuel efficiency and drive-ability. The peak RPM advantages of a centrigual make a lot of sense in larger displacement engines where the power tends to fall off up top. Those Paxton Viper kits were pretty mean.

6-There are a few major issues why OEM installs are shying away from Roots type blowers. To the best of my knowledge there has never been a twin-screw unit used in an OEM application, it is not even considered as one of the competitive designs when you look at the oem marketplace for sports and super cars, money no object.

There have been plenty of twin screw OEM supercharger applications. Mercedes Benz (AMG 55 series cars), Ford (Ford GT super car), Mercury Marine, etc. There are also several current gen Roots supercharged engines. Jaguar, Ford, Cadillac, Chevrolet, Holden, Lotus...

8-twin screws are all real loud and typically trade off lower end for top end to some extent, many who have them share that they don't make good top end power as stated.But as far as getting that pinned to your seat feeling at lower rpms, its prolly the way to go. if you wan that power at redline, it may not be.

I would agree with the power delivery of a twin screw. As for the sound, personal preference prevails. I think most performance oriented drivers will find it quite addicting.

9- Factually speaking:The centrifugal unit is also an OEM unit just like the Eatons were for TRD back in the day. Toyota (TRD) have kicked Eaton to the sideline in 2004 favor of Vortech as their supplier for other systems/current applications. This is not solely cost driven. This means these centri's will be EPA approved. Vortech have cast TRDs name onto their units and designed kits for them in the past. This is public knowledge on the interweb, since 2005 btw.

I do not know enough of TRD's internal decision making process to determine what their reasoning is for selecting one design over another. Cost/packaging is always a factor though... If I had to wager a guess.

10-Centrifugal units can run 20 psi with approx 20hp draw. Eaton units become very inefficient when attempting over 10psi and draw upwards of over 40hp at that point on a like for like application.This info is direct from their respective manufacturers.

There are trade offs without question, a roots or screw will make vastly superior low end boost/torque/throttle response vs a centrifugal; but will produce a lower peak number at said peak boost pressure.

while it is low on my list lastly...
11-roots units, cause higher emissions than centrifugal units, because of load being more constant on them given their design.

Tuning, cam phasing (valve over lap), etc. play a major role in out right emissions. The Innovate Motorsports positive displacement twin screw system will be CARB approved.