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Discussion Starter · #1 · (Edited)
Let's have a smack-down. Using some charts.

In the left corner, a Magnuson TVS blower featuring Eaton's TVS2300 roots type blower, 4 lobes, 160 degree twist. Yes, ladies and gentlemen, these are the same screws used in the Roush TVS R2300, the Edelbrock E-Force, and the new Corvette ZR1.



In the right corner, a Lysholm twin-screw. 2.3 liters of displacement

(Oh noes, you can't possibly do an apples to apples comparison using blowers of the same displacement! OH noes!!! Kenne Bell, can you hear me?)



You don't have to be an engineer to see what these charts mean...the bottom line is the left axis is boost. It is expressed in pressure ratio. We know that sea-level standard pressure on a standard day is 14.7 PSI (If you really care, that is also at 59 degrees F / 15C at 1013.2 millibars of pressure and 29.92 inches of mercury).

The formula for converting boost in PSI to P/R is (14.7 + PSI)/14.7 - P/R

So at 18 PSI your pressure ratio should be (14.7 + 18) / 14.7 = 2.22

Zero boost would be a pressure ratio of 1.0 or atmospheric pressure (14.7).

No need to understand that since I am about to add a boost chart on the right axis for you...

The bottom axis is the amount of airflow through the supercharger.

See the "rings" and the "islands"? These are supercharger efficiency maps. The little "islands" are showing how efficient the supercharger is at a given pressure ratio and flow rate. The smallest little island is the supercharger's "sweet spot" where it is most efficient.

You can compare two different superchargers by comparing these efficiency maps.

I have accomplished an overlay of the two charts, and I added boost to the right column for your reference based again on sea level pressure at 14.7:

The result is educational.



What does it mean to me? It means the TVS is more efficient design until we exceed about 16 PSI. Why? Let's continue...

Let's take the very best the 2.3 Lysholm twin screw can do...and that is its "efficiency island" which is at a BLOWER RPM of 8,000 and 10-13 PSI of boost - it is at 65%.

The TVS, at the EXACT same location has an efficiency of 67-68%, and the TVS is spinning at 12,000 blower RPM. Advantage TVS by 2-3%.

What if we go the the TVS sweet spot? That is at 9,500 TVS blower RPM and 9 PSI of boost, and is 72%. How is the twin-screw doing at that point? It is spinning at 6,600 RPM, making the exact same boost, but its efficiency is only 64% - so an 8% difference favoring the TVS.

Where does the twin-screw have an advantage? Look at 16 PSI at 2200 M3/MIN...the TVS efficiency is at 61%, and the twin-screw is at 62%...so above 16PSI the advantage shifts to the twin-screw. At 18 PSI @ 2400 M3/MIN the TVS is 58% efficient - and the twin-screw is at 62% (actually off the twin-screw chart, but we can interpolate).

I have read that interpreting this is kind of like looking at peak horsepower and torque. What is more important is not so much peak values but looking at "the area under the curve" on a dyno chart - and the TVS appears to have superior efficiency throughout more of the chart until we get above that 16 PSI level. Guess what a stock pullied Roush P-51 makes? You guessed it, 15-16 PSI - right at the top of the TVS designed sweet spot.

I, like many others, initially read this article...

Mustang GT500 Supercharger Tests - 5.0 Mustang & Super Fords Magazine

...and determined that the twin screws were superior to the TVS. I think my determination was wrong, and that is why I am posting this.

That article is not a fair comparison for one major reason: You are comparing a 2.3 liter TVS to a 2.8 liter twin-screw. Now if I owned a GT500, what would I install? Probably a KB 2.8 it simply makes more power and does so more efficiently because it is BIGGER.

But if we level the playing field (as I have done here in my comparison) or, if Eaton were to build a 2.8 liter TVS to go against KB's 2.8 liter twin-screw I personally think the TVS will prove to be more efficient design until you get into boost exceeding 16 PSI (as I have shown above)...but even respecting the twin-screws advantage at higher boost levels above 16 PSI, taken as a whole I think the TVS will still have more "area under the curve" if you will and be overall superior to the twin-screw design.

For a street car, I think the TVS design is the cat's jammies.

Flame away.
 

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good to know man:D good info,surprised someone did this,jim bell is gonna freak...........ive got a friend debating what blower to put on his 06gt:p he wants me to pick for him haha
 

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Discussion Starter · #3 ·
good to know man:D good info,surprised someone did this,jim bell is gonna freak...........ive got a friend debating what blower to put on his 06gt:p he wants me to pick for him haha
LOL,

As that article I posted that KB was involved in clearly shows, the KB 2.8 whips the TVS2300. No doubt about that. But I believe, as stated above, that is because it is bigger.

Just so my point is not misconstrued, I am not saying that KB or Whipple are not excellent products...in fact any of their blowers with MORE displacement than the TVS are going to punish the TVS...and I would gladly run a KB or Whipple on my car. On a GT500 the KB upgrade is a no-brainer.

...but I have wanted to compare the technologies on a level playing field since the Eaton TVS rotors came out and that is what I have attempted to do here.
 

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ya i totally agree,on paper on a stock block GT it seems the TVS will do better,as witha built shortblock and or any car,the twin screw design is superior...if your running above 16psi that is,which almost everyone is
 

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As I posted on the other Forum...This is a Compressor map for a standard TVS2300 from Eaton. Ford and Eaton have an agreement to withhold the actual FRPP TVS Compressor Maps and I have heard they were better than the standard one.
 

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It would be interesting to see how the 2.3L Eaton TVS compares to the "Gen 2" Whipples and the new "Big Bore" KB's.
 

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Dimora, you can't compare a Lysholm compressor to a Gen2 Whipple or even a Gen1 Whipple for that matter. There's no comparison, Whipple's in house compressors are superior to Lysholm....it's 2009, not 2005 anymore. Like I said on this matter on another forum...get some sleep, your blower is a good one. You don't have to justify it.
 

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This is good info, thanks. This is only one piece of the overall puzzle though. Look also at intake track, runner design, intercooler placement size and efficiency. By pass valve location as well.
 

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The Lysholm chart is in M^3 /hr, and the TVS chart is in M^3/min. So the overlay is not correct.
The twin screw is turning at 6600 rpm, and the TVS is spinning at 12000 rpm and making the same boost? I am assuming the TVS charts are adiabatic efficiency. What about volumetric efficeincy?, What about hp required to turn the blower. The TVS charts have no info on this.
The sweet spot for the TVS is at a flow rate of 578 CFM? HP is related to flow rate times the pressure ratio. So at a pressure ratio of 1.8 (i.e) 18 psi, the volumetric flow is 578 CFM. That's a pretty small engine and HP level. So Adiabatic efficeincy corresponds to lower IAT's? Everyone knows that the roots blowers make lower IAT's.

At 18 psi, a KB 2.6 stage 2 is putting out about 1100 CFM, a KB 2.8 is putting out about 1800 CFM. I would imangine the whipple 3.4 is similar to the 2.8. You can't spin the TVS fast enough to get those flow rates, or horse power levels.

At 10 psi, the TVS is pretty comparable to the KB 2.6, or the Whipple 2.3, if not slightly more adiabatically efficient, i.e. (sligthly lower IAT's). which is great for the street.

So lets say I want to take my car to the track for a day, throw some 100 octane in it, and change the pulley to a 15 psi, or 19 psi pulley, and make 700+ hp. That's why I'm glad I have a twin screw.

The TVS is actually good blower, but thanks for misleading us with the charts.
 

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Discussion Starter · #10 · (Edited)
Dimora, you can't compare a Lysholm compressor to a Gen2 Whipple or even a Gen1 Whipple for that matter. There's no comparison, Whipple's in house compressors are superior to Lysholm....it's 2009, not 2005 anymore. Like I said on this matter on another forum...get some sleep, your blower is a good one. You don't have to justify it.
I just did.

And I think they are the same compressors. Even the model numbers are virtually the same.

And show me Whipple's new maps. Prove it. I'm still waiting.

I e-mailed Whipple and asked them for maps, but they have not responded.

I'm not losing sleep nor justifying my blower. Just gaining a better understanding of the two technologies.

Not dissing...don't be defensive since you have a Whipple. When I outgrow my TVS I will have to go to a Whipple or a KB - they move more air...nobody is disputing that.

Now put up some facts...I've seen enough threads with opinions. Show me some charts.
 

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Discussion Starter · #11 · (Edited)
The Lysholm chart is in M^3 /hr, and the TVS chart is in M^3/min. So the overlay is not correct.
The twin screw is turning at 6600 rpm, and the TVS is spinning at 12000 rpm and making the same boost? I am assuming the TVS charts are adiabatic efficiency. What about volumetric efficeincy?, What about hp required to turn the blower. The TVS charts have no info on this.
The sweet spot for the TVS is at a flow rate of 578 CFM? HP is related to flow rate times the pressure ratio. So at a pressure ratio of 1.8 (i.e) 18 psi, the volumetric flow is 578 CFM. That's a pretty small engine and HP level. So Adiabatic efficeincy corresponds to lower IAT's? Everyone knows that the roots blowers make lower IAT's.

At 18 psi, a KB 2.6 stage 2 is putting out about 1100 CFM, a KB 2.8 is putting out about 1800 CFM. I would imangine the whipple 3.4 is similar to the 2.8. You can't spin the TVS fast enough to get those flow rates, or horse power levels.

At 10 psi, the TVS is pretty comparable to the KB 2.6, or the Whipple 2.3, if not slightly more adiabatically efficient, i.e. (sligthly lower IAT's). which is great for the street.

So lets say I want to take my car to the track for a day, throw some 100 octane in it, and change the pulley to a 15 psi, or 19 psi pulley, and make 700+ hp. That's why I'm glad I have a twin screw.

The TVS is actually good blower, but thanks for misleading us with the charts.
The M^3 per minute is obviously a typo on the Lysholm chart. Kind of like ' vs " for feet vs. inches. Obvious mistake by whomever made the chart, but it doesn't invalidate the map.

By the way, M^3/min referes to cubic meters per minute, and M^3/hour refers to cubic meters per hour...both are fluid flow rates.

Let's do some more math:

The conversion factor for M^3/hour to M^3/min is to multiply M^3/hour by .0167

So the TVS at 1200 M^3/"hour" on the chart is actually flowing 20.04 M^3/minute (which would be 707.8 cubic feet per minute) compared to the Lysholm's 1200 M^3/minute or 42,384 cubic feet per minute)?

On a 4.6 liter engine...4.6 liters of displacement is equal to .162 cubic feet.

Every RPM equals .162 cubic feet of air moved, right?

4000 RPM times .162 = 648 cubic feet of air required per minute.

So the Eaton chart is obviously correct and the Lysholm chart is mislabeled in error, you see?

And while we are at it, a 2.3 liter blower displaces 2.3 liters of air per revolution.

That 2.3 liters converts to .081 cubic feet.

So...if we have a TVS blower, for example...and we spin it with a 7" crank pulley driving a 3" supercharger snout pulley, we get a drive ratio of 2.333:1

So at 4,000 RPM so I can stay consistent, we get a TVS RPM of 9,332.

Since we are moving .081 cubic feet of air per revolution, we multiply that times 9,332 and voila!...we see the TVS is moving 755.89 cubic feet of air per minute. But if the engine only needs 648 cubic feet of air per minute per my above calculation, and we are giving it 755.89 cubic feet, what is gong one? Well, the air is compressed, and that is where we get boost.

Here...do your own calculations::stars:

http://www.engineeringtoolbox.com/flow-units-converter-d_405.html

Stonehenge! (Spinal Tap inch vs. feet humor for the un-cultured).



The Lysholm chart has both adiabatic (black lines) and volumetric efficiency (purple lines), the Eaton TVS chart does not.

We are looking at Adiabatic efficiency in this comparison, as should be obvious by the islands.

Additionally, you are partly correct about IAT's - usually twin-screws make lower IAT's at boost...but at idle roots are better since they are not actively compressing when in bypass.

And where have I mislead? I posted charts with an accurate overlay - something KB doesn't do when they skew the axis on the right and left columns to make it appear their superchargers make more torque down low. Like this. Now this is misleading. See how they skewed the torque scale up a hundred or so vs. the HP on the right? Any professor would deliver an F on this report to any first semester college student for that little stunt.



Now post up some charts with some factual information if you have some data that contradicts what I am showing here.
 

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Discussion Starter · #12 ·
You folks with screws need to not be so defensive. I love screws. If I outgrow my TVS, a Whipple or KB is an obvious choice.

I would be quite pleased to run a Whipple or KB on my car. But that is not my point here.

Did you even read the article I linked to? On a GT500, a T/S is a no-brainer....it punishes the TVS. My contention is because the T/S moves more air...not because its design is superior.

All I am doing here is showing an "apples to apples" comparison - something the magazines and all the propaganda out there is NOT doing. So stop referencing imaginary Whipple charts and anecdotal evidence that so-and-sos screws are "superior with their super-secret design" and give me some data!
 

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Great read! Thanks for the info.
 

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Discussion Starter · #14 · (Edited)
Also, Belinda, a TVS R2300 CAN support up to 20.58 PSI at 18,000 RPM with a pulley change.

Horsepower on a GT500 with a TVS will exceed 700...on a 4.6 GT it will be in the high 600 range. To go beyond that a new throttle body is required.

As I stated in my comparison, a T/S IS SUPERIOR to the TVS at higher boost...so yes, if you want to run over 16 PSI regularly, a T/S is the clear choice. AT that boost, the T/S is more efficient and delivers lower IAT's from what I have seen.

As far as RPM's of the screws, don't let that throw you off. It is a function of the design differences between the two technologies. A T/S has a 5 lobed screw and a 3 lobes screw (male and female screws)...and one is spinning MUCH faster than the other...and timing gears keep them synchronized, whereas on a TVS both rotors spin at the same speed, thus the RPM differences for a given amount of boost.

Look at the left image:

 

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Let's do some more math:

The conversion factor for M^3/hour to M^3/min is to multiply M^3/hour by .0167
Unit conversions are pretty elementary,
Cross multiplying we get: (m^3/min)*(60min/hr)=m^3/hr, clean it up and it is simply (m^3/min)*60=m^3/hr.

why not just state the obvious and say divide or multiply by 60?
 

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I'm definitely not going to continue with this pissing match other than to say that the Whipple Gen1 and Gen2 have much closer tolerances than any screw design that came from Lysholm. I mean the proof is in the psi compared to pulley diameter. For example, the Gen2 runs about 1 lb more boost with the same pulley as a Gen1. That's not even debatable.

Dimora, I have seen mostly positive write ups on the TVS design and nothing but strong reviews. That article you are referring to if I remember correctly was actually written before a whole lot of testing was done and the TVS was actually proven in a wide variety of venues. Most magazine articles are at least 2 months behind release.
 

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LOL I can hear TVS owners at car meets now...

"IT DOESN'T MATTER THAT I LOST THE RACE, MY BLOWER IS MORE EFFICIENT SO I WIN!!!"
 

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Discussion Starter · #20 · (Edited)
I'm definitely not going to continue with this pissing match other than to say that the Whipple Gen1 and Gen2 have much closer tolerances than any screw design that came from Lysholm. I mean the proof is in the psi compared to pulley diameter. For example, the Gen2 runs about 1 lb more boost with the same pulley as a Gen1. That's not even debatable.

Dimora, I have seen mostly positive write ups on the TVS design and nothing but strong reviews. That article you are referring to if I remember correctly was actually written before a whole lot of testing was done and the TVS was actually proven in a wide variety of venues. Most magazine articles are at least 2 months behind release.
Anthony, please don't think that I am in a pissing contest, nor think that I am dissing your blower.

Let's try again. Forget what blower you or I have. It is irrelevant.

Here is my point: Go to KB or Whipple's websites. Read all the information. You will leave thinking roots blowers are inferior to screws. That they are "Heatons" as I have seen them called. You know what? I think that was true until the TVS came out. The M90 and M122 were definitely inferior to screws of the same displacement.

All I'm doing here is comparing a TVS to a screw design of the same displacement. You can see they both have their merits. Gonna run over 16 PSI? Twin Screw FTW! It's a no brainer! The TVS loses efficiency over that level compared to the screws.

I also said that a KB 2.8H will punish a 2.3 liter TVS. That is proven. Read the article I posted...is there any doubt?

You are missing the point. I am discussing BLOWER DESIGN...not suggesting that a TVS can compete with a KB 2.8H or a large displacement Whipple...

What I AM saying is that I believe that on a level playing field (equal displacement) the TVS will ramp up torque and boost quicker than the T/S and do so more efficiently up to 16 PSI in the case of the 2.3 liter displacement unit.

Let me ask again. Are the screws in this blower - the Whipple W140X:

http://www.steeda.com/products/whipple_supercharger_s197.php

and the Whipple W140AX:

http://www.whipplesuperchargers.com/product.asp?ProdID=1162

different than the ones in the Lysholm LYS 2300AX:

http://www.opcon.se/index.asp?sPage=1&langID=1&cID=14

Does anyone know? I am NOT a Whipple expert. I don't know what a "Gen 2" is...I don't see it in any of the model numbers for a 2.3 liter blower offering.

Which one is a "Whipple HO"?

And where are the efficiency maps for these things besides the Lysholm?

Bueller?

I think the manufacturers don't want these charts out because the competition can see what they have done and the consumer can make an informed decision. It's better to market with smoke and mirrors I guess.

One thing we can all agree on - they are all awesome units, and I personally would be happy to run any of them on my car. Don't think I have a pro-TVS bias. There is a TVS on my car for one reason only - I got a killer deal, and I already had an M90, so the install took half a day (I'm a do-it yourself guy). I had decided on a KB 2.8H before I stumbled across my TVS deal.
 
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