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Uncle Buck
10-16-2015, 07:58 AM
I found this on the Steeda site. I'm more in the PD camp myself but thought I'd post and let the debate spool up.

At Steeda Autosports, our DNA mandates that we are constantly testing and pushing the levels of vehicle performance above and beyond the norm – all in the quest of ensuring that our customers have the option of purchasing the best performance products available anywhere. When it comes to superchargers, we have done a tremendous amount of testing on the dyno, on the street, at the drag strip and at the race track – and we can unequivocally state that there is only one type of supercharger that we have found that offers the sustained power and efficiency in an integrated package.
There are essentially two types of superchargers in the market today, a Roots type and a Centrifugal type – and there are major reasons why you should only consider one over all others. These reasons all are based on our real world performance evaluations, not marketing hype or driven by profits – rather these are our own observations after thousands upon thousands of miles of rigorous testing.

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Let us explain…

Roots Type Superchargers
Many auto manufacturers opt for the Roots type supercharger for a variety of reasons, the most prevalent reason being lower Tier 1 cost. It should be noted that this type of supercharger is not actually a compressor – rather it is just an air mover. Specifically, air moves on the housing sides within the rotors voids. By virtue of moving air into the cylinder heads at a higher rate than the engine consumes it, pressure is built. But sustained efficiency and power are lacking for a variety of reasons, namely:
Heat Soak Effect – This is a major issue with the Roots design that is sold today and it simply cannot be avoided with this type of design. Whenever you operate a Roots type supercharger, it is probable that almost half of the input power is consumed to make heat rather than power – essentially creating a parasitic power drain on the engine. We have equipped our own race cars with the best Roots system money can buy, only to discover that after just a few laps the engine becomes heat soaked and power levels dramatically decrease. Even with extensive intercoolers, you simply cannot overcome this devastating issue – we have tried to no avail. Advocates of the Roots systems will usually showcase dyno runs on cool engines, preferring not to show a real world effect that driving on the street or racing would have as the engine warms up and loses its performance gains.
Weight – We all know that weight is the enemy of performance, a typical Roots supercharger easily outweighs a Centrifugal type and in addition, it requires a more substantial cooling system – adding yet even more weight to the supercharger package – and this weight is at the worst possible location, by being principally on top of the engine raising your vehicle’s center of gravity.
Efficiency – Adiabatic efficiency (the real measure of a supercharger’s efficiency) is where the Roots type fails miserably with efficiency ratios typically in the low 50% or below range. This causes excessive heat build-up and parasitic drag on your engine. Centrifugal type superchargers operate typically in the mid to upper 70% range. The major cause of this inefficiency is based on the inherent design of the Roots system where you have reversion occurring as the rotors open up and pressure is normalized in the manifold.
Boost curve – Advocates of Roots systems point out that they make their power at low RPMs. While this is true, this feature is actually much less helpful than it appears. Realizing that excessive boost cannot be utilized at these low speeds due to traction limitations and also on most engines the ignition timing must be significantly retarded to avoid destructive detonation. Additionally, low engine speed is not where power is made… rather it is the higher RPM band where you want your boost and subsequent power and this is where the centrifugal supercharger really shines.
Removal of Tuned Intake Runners – Installation of a Roots type supercharger requires removal of the tuned intake runners – resulting in a loss of those free benefits – whereas a Centrifugal Supercharger leverages the tuned intake runner benefit to the max.

Centrifugal Superchargers
Serious performance aficionados and racers know the real benefits that centrifugal superchargers provide. When you want serious supercharger power, power that is available before your engine gets heat soaked, and power that is available when you need it – then the only alternative is a centrifugal supercharger. As part of our real world testing, we have tried all of the most popular superchargers under essentially all conditions. At the extreme level, when we equipped our #20 race car with a Vortech supercharger and ran some of the most grueling laps possible at Sebring, Daytona, and Palm Beach Raceway, we obtained absolutely superb results… far better and much more consistent results than when we had a Roots type installed on it. On our street cars we have put untold thousands of miles testing under virtually all conditions – hot, cold, wet, dry, stop light to stop light, and on the drag strip and autocross track… all with the same truly exceptional results. Vortech supercharger systems are a great value. Dollar for dollar, Vortech systems deliver more horsepower than virtually any other method of upgrade. Also, driven normally, gas mileage often increases rather than decreases.
With power that does not fade, superior efficiency, and full 50 state emission compliance, the Vortech Centrifugal Supercharger earns the Steeda Seal of Approval as being our preferred supercharger of choice.

Stephen06GT
10-16-2015, 08:49 AM
If centrifugal chargers are so great for racing apps. why doesn't John Force use one. :D

Tailites
10-16-2015, 09:09 AM
notice how they avoided turbos altogether?

& yet almost every major manufacturer has had a turbo equipped vehicle at one time or another

92redragtop
10-16-2015, 10:14 AM
If centrifugal chargers are so great for racing apps. why doesn't John Force use one. :D

He doesn't have far to go????? :stickpoke:

Ray721
10-16-2015, 12:28 PM
Turbo for me please [emoji1]

allicedout
10-16-2015, 01:20 PM
Its debatable......

RedSN
10-16-2015, 01:26 PM
Interesting article about Roots type vs. Centrifugal type superchargers
....right up until the point where they starting singing the praises of Vortech.
Why not just keep the comparison generic? Kind of lost some credibility at the end.

NickD
10-16-2015, 02:09 PM
It's sponsored by vortech I'm sure, I like that they kept referring to roots blowers when 90% of the stuff on the market is twin screw which does actually compress air and does so with far less heat. So yeah in their comparison of a weiand 8-70 vs a new vortech the centrifugal is better...

Sent from my HTC One_M8 using Tapatalk

ZR
10-16-2015, 02:59 PM
Being a fan of big low end grunt, will need to pull the PD blower outta my cold dead hands. For others, mid to top end charge of a Centri better suits their wants n needs, cool part, we have choices, lotza choices. Unfortunately, far too many base the purchase solely on price and are disappointed in the end.

Ray721
10-17-2015, 04:03 PM
Don't most people sell their cars or yank the Centri out for a PD months later? Just sayin...[emoji12]

Mrods
10-17-2015, 09:14 PM
I researched this for 2 years and bounced back and forth between PD and Centri. I am very happy I went PD, as i have massive torque from 2000 rpm up. For keeping IATs down, I'm running an afco, with a 2013 GT500 HE pump. Zero regrets about my set up. Think I would have been disappointed with a centri for the type of driving I do.

G-ForceJunkie
10-18-2015, 03:08 PM
I've always thought of Centrifugal's as just less efficient turbo's. Twin-Screw = Instant Power, at the expense of extra heat and reduced efficiency. If you're willing to wait for power, you might as well make it efficient and go turbo.

Tailites
10-18-2015, 05:52 PM
Turbo for me please [emoji1]

atta boy!!!

ZR
10-18-2015, 06:42 PM
Don't most people sell their cars or yank the Centri out for a PD months later? Just sayin...[emoji12]

Back in the 2v haydays, yes it happened a good number of times.
On the flip side, virtually never happens when a PD is installed from the get go.

ZR
10-18-2015, 09:53 PM
Stock style with larger reservoir and heat exchanger.

FordFTW
11-07-2015, 03:54 PM
Centris FTW!

ZR
11-07-2015, 04:41 PM
If it suits your wants n needs, for sure. ^^

86gtvert
11-07-2015, 10:16 PM
I have a centri only pushing 7# pounds boost and love the top end power.Not very practical for street as full boost isnt attained till high rpm but getting on highway and at track is a blast .

92redragtop
11-08-2015, 02:25 AM
I'm in my 5th year with my Vortech V2 and still lovin' it. I believe boost was set to around 7-8 lbs and boost comes on around 2300 rpm which it hits very quickly with 373's out back. The car has great low end torque on its own without boost. Still puts a smile on my face.

Visited ZR's shop today for some e-fan wiring work and had a few people put down their window next to me in traffic today to listen to the car/blower whine.

Hutch
11-08-2015, 01:00 PM
I had a KB blower on my fox and the car would roast the tires in first and second all the time. It was actually anoying. Doing road course stuff it was way too much on tight corners but up in the rpm in third the car was unreal. The heat was something else too. I kept it on for a summer and then sold it and haven't looked back with how the car is now. My needs for the car where better suited without it just running N/A. I also have to agree with Don's first statement about that article. I had a 2.3 turbo mustang coupe that I ran 19 lbs of boost through a front mounted intercooler. That car was a blast. If I was building a car for max power I would go turbo after feeling what that little car could do. Turbo's have come a long way and are designed to not have as much lag like older ones.

ZR
11-08-2015, 03:53 PM
I'm gonna trade in my tire smoking, monster torque Whipple........................................... .................................................. .................never!!!

ZR
11-08-2015, 03:53 PM
Do have to admit, more power does make the car a whole bunch harder to drive on the race track.

HyperGT
11-08-2015, 04:36 PM
pushrod...centri
mod motors Pd.

both better with turbo

Tailites
11-08-2015, 04:56 PM
pushrod...centri
mod motors Pd.

both better with turbo

LIKE

MEANMCHN
11-08-2015, 05:12 PM
Guess that makes sense why I murder so many "600 HP" Cobras at the track.

2:20 to watch a 590RWHP Cobra fall to a 450RWHP GT

https://youtu.be/OXTBUqx_gCM

ZR
11-08-2015, 05:30 PM
In the same statement, would be fairer to add you log hundreds of laps a season compared to many that are lucky to see a lapping day or two a year. Even with that in mind, doesn't take away the fact you lay down some real times.

92redragtop
11-08-2015, 08:34 PM
LIKE

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