[DiMora]

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.

PLEASE NOTE: I MADE A MISTAKE ON THIS OVERLAY, IF YOU GO TO POST #21 YOU WILL HAVE AN ACCURATE OVERLAY. MY SINCERE APOLOGIES. I HAVE EDITED THIS PARTICUALR POST ON 12/14/2009 TO ADMIT MY ERROR AND GIVE AN ACCURATE CHART AND ANALYSIS STARTING WITH POST #21. - SHANE

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 :yes 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 is the cat's jammies.

Flame away.

 

[vastang757]

Yeah I didn't understand much of that until you got to the explination under the graphs. Reps for you for digging into the so much. Good info and food for that

Edit: Dammit, I can't rep you yet

 

[05mustang_TT_charged]

Good write up....I really wish Kenne Bell would release there maps since I would love to know how efficient my 2.6H is at 21 psi. The charts explain alot about the design of the actual supercharger as the TVS 4 lobe is better for a car that will run under 16 psi. most of the time. The article is typical magazine hoopla as that 500 cfm advantage of the 2.8 Kenne Bell shouldn't be in the test. If they want to da a test like that then get the 3.4L Whipple vs. the 2.8L Kenne Bell but it will still be lop sided due to the Whipple have the displacement advantage.

Again good write up..

 

[03_StangGuy]

REPS!!! Fantastic write up! Thats the way on the consumer market. Rarely do you see a straight up comparision.

 

[05mustang_TT_charged]

DiMora for the record that is a compressor map for the standard TVS2300 Series Supercharger from Eaton. The Ford Racing TVS is actually a little better than that but isn't released to the public due to Eaton and Ford Confidentially Agreement.

 

[fullboogie]

Best explanation I've ever seen on this topic - thanks!

 

[onederful100]

reps for that comparison and explaination, very well done!


IIRC, Lysholm SC makes the ford GT SC and the vortech TS SC, (vortech has bought out Opcon in the Lysholm company). whipple and KB design are similar but not Lysholm SC, although whipple does have its history with Opcon Autorotor, SRM, and Lysholm Technologies in Sweden. in 2005 whipple started making its own SC, more effecient than the Lysholm design.

 

[06VistaGT]

very nice right up.

 

[Anthony05GT]

Right, the Lysholm 2.3 is less efficient than the Gen1 Whipples of a few years ago. The newer 2.3 Gen2 Whipples are extremely efficient. I like the top end feel of the twin screws compared to the TVS set ups, but overall I have to say they are all pretty much the same in overall performance. There's really no need to try to justify your blower...it's a good one so get some sleep.

 

[DiMora]

Right, the Lysholm 2.3 is less efficient than the Gen1 Whipples of a few years ago. The newer 2.3 Gen2 Whipples are extremely efficient. I like the top end feel of the twin screws compared to the TVS set ups, but overall I have to say they are all pretty much the same in overall performance. There's really no need to try to justify your blower...it's a good one so get some sleep.

I'm not justifying a thing...just trying to separate facts from advertising BS and biased magazine drivel and gain a better understanding of options for our cars and learn about the true (provable) differences between TVS roots rotors and twin-screws.

Interestingly, I e-mailed Whipple and asked for their efficiency maps but I haven't received anything yet.

I personally believe the Lysholm I posted and the 2.3 Whipple are identical - the model numbers are almost the same too - I believe that Lysholm map I used is the map for the Whipple W140AX. Is that the same as the "Gen 2"?

Got a 2.3 Gen 2 map you can post up? How else would you know the Gen 2 is more efficient? I'll do a fresh overlay if you provide me with one. It MUST be a blower with 2.3 liters, though, or we are back to apples and oranges.

Oh, haven't lost any sleep yet over this either.

 

[Nasty]

Well, the Whipple Gen2 is more efficient but how much? Probably not leaps and bounds. I mean those compressor maps are for the 'old' TVS, too!

 

[UrbanRedneck]

Where did you get those? I'd be interested to see a compressor map comparison of a tvs or twin screw versus a centrifugal supercharger.

Oh, and btw, Nasty, how much did that tvs cost you?

 

[navyman8903]

Vote for stickey anyone? MODS?

 

[Nasty]

Oh, and btw, Nasty, how much did that tvs cost you?

Here you go.

VMP Tuning - Buy Ford SCT & GM Custom Handheld Flash Tuners Performance Economy Towing: Roush P51 SC Kits

 

[DiMora]

Where did you get those? I'd be interested to see a compressor map comparison of a tvs or twin screw versus a centrifugal supercharger.

Oh, and btw, Nasty, how much did that tvs cost you?

The Lysholm twin-screw map was obtained from the Lysholm website.

The R2300 map was obtained from a gentleman on a Corvette forum who received it from Magnuson. As I may have stated above, the Corvette ZR1 is using an Eaton-rotored R2300 supercharger. That particular map is VERY hard to find as Eaton does not publish it on their website, but they DO publish all the smaller TVS chargers.

As Nasty stated, perhaps the TVS has been upgraded and it is not published to compete with Whipple and Kenne Bell...they are all doing the "my design is so good it is secret and I can't show you my maps" thing.

I have heard from others that the FRPP TVS is also upgraded (Beyond the Roush, Edelbrock, and Magnuson rotors) with even more efficiency than the map I used in this thread...but I cannot confirm that.

 

[Nasty]

I have heard from others that the FRPP TVS is also upgraded (Beyond the Roush, Edelbrock, and Magnuson rotors) with even more efficiency than the map I used in this thread...but I cannot confirm that.

That's not true. It's the same exact thing with a slightly different exterior case just to make it a little different.

 

[Anthony05GT]

The Whipple gen 2's for example produce at least one more pound of boost with the same pulley as a gen 1. There has been plenty of tuning going on in the past 5 years where the results from the newer rotor designs speak for themselves. I don't have any proof on paper nor do I need any. For example, there's a group of '03-'04 cobra guys I know that pretty much tune their cars to the max. It's well known among these guys the results that they have seen pushing their 4-valve engines between the Lysholm design from 5-6 years ago to the gen 1 and gen 2 designs of later years. The same pulley size has netted as much as 2-1/2 to 3 lbs of boost variation between the 3 screw set ups. According to them, this variation is quite common and repeated throughout their expanded east coast group.

Dimora, my car was on the cover of MM&FF and I counted 9 lies or mis-truths in the article. My buddy's 55 Chevy was on the cover of Hot Rod and they put all kinds of bullshit in that article. When I did the very first S-197 automatic to manual transmission swap in my car, 5.0 and MM&FF were not interested in helping me share the information. Instead, 2 years later they did a big spread in 5.0 rag about how AMP Performance had just achieved this amazing feat. I guess buying a full 2 page ad every month gets them the credit. Don't take this one article too personal.

 

[DiMora]

The Whipple gen 2's for example produce at least one more pound of boost with the same pulley as a gen 1. There has been plenty of tuning going on in the past 5 years where the results from the newer rotor designs speak for themselves. I don't have any proof on paper nor do I need any. For example, there's a group of '03-'04 cobra guys I know that pretty much tune their cars to the max. It's well known among these guys the results that they have seen pushing their 4-valve engines between the Lysholm design from 5-6 years ago to the gen 1 and gen 2 designs of later years. The same pulley size has netted as much as 2-1/2 to 3 lbs of boost variation between the 3 screw set ups. According to them, this variation is quite common and repeated throughout their expanded east coast group.

Dimora, my car was on the cover of MM&FF and I counted 9 lies or mis-truths in the article. My buddy's 55 Chevy was on the cover of Hot Rod and they put all kinds of bullshit in that article. When I did the very first S-197 automatic to manual transmission swap in my car, 5.0 and MM&FF were not interested in helping me share the information. Instead, 2 years later they did a big spread in 5.0 rag about how AMP Performance had just achieved this amazing feat. I guess buying a full 2 page ad every month gets them the credit. Don't take this one article too personal.

It's all good Anthony...I'm just a tech-nerd and seeking the truth. Not because it matters, just because I find this stuff kind of fun. :drink

 

[Anthony05GT]

I see that. Any of the big named positive displacement blowers will make a 4.6 feel like a big block. I'd be happy with any of them.

 

[Last Call Racing]

In reading different compressor maps you have to make sure that they are scaled the same in which case these were not. So the overlay and interpretation and write up is wrong. The problem is the X-axis. On the TVS compressor map it is shown to be in cubic meters/ hour (m^3/hr), so therefore all the values would need to be divided by 60 to be in cubic meters/ min (m^3/min). As example, 1400 m^3/hr = 23.333 m^3/min.

This changes everything written.

The TVS is WAY more efficient by these compressor maps, and also has a higher max pressure ratio of 2.4 (20.5psi) compared to the Lysholms 2.2PR (18psi). Now I know you can spin the 2.3 Whipple harder than 18 psi, and we have done 24 psi, but it's totally out of it's range and just making hot air.

At 10psi (1.68 PR) the TVS is capable of ~23 m^3/min airflow at a 70% efficiency.
At the same parameters, the Lysholm is in a 60% island.
Both a little over 10K rpms.

At 15psi (~2PR) the TVS is capable of ~26 m^3/min at a 66% efficiency.
At the same parameters, the Lysholm is in a 60-62% efficiency.
Both spinning about 12K rpms.

So, just for the sake of making sure correct information is out there when people search, I wanted to set it straight.