I was asking for your proof about the roots building boost faster than a twin screw. I thought that's what you meant by saying "proof"? after you said the roots builds faster.
Honestly I don't want this to turn into a pissing match, but I cannot leave you guys misinformed

Let me find the rule where NHRA outlawed twin screw compressor usage in top fuel because they built boost too quickly. That is the only reason there is not a twin screw compressor on top of that top fuel engine. (that and beside the fact that more power=less chance of traction for them anyway)

Here is a link to some real info about a twin screw compressor.
http://www.lysholm.se/PDF/diagram_lys2300ax.pdf
In this case, it references the Lysholm 2300ax. Maybe if Magnuson would come out with a detailed readout of their M-112 blower we could at least compare some real data.
Food for thought...why have roots blowers become "modified" by twisting the impeller lobes? They leak air.

Really? This is what came off of one of your sources. "The primary reason that blowers aren't optimized by their manufacturers is that the tooling necessary would push the cost into an area which would make the units prohibitive to the OE marketplace, which is "the" big consumer". I know this was taken a bit out of context as they were mainly describing why the housings and such of blowers are not hand finished. But the tooling needed to make a twin screw lobe is several more times the cost of a roots lobe.

BTW: If that were the case, then why is Eaton getting liscense to sell twin screw compressors instead of roots blowers? Why does the new Pherd GT use a twin screw compressor?

 

Liter for liter, twin screws beat a modified roots. It's a much more efficient design. If Whipples for the General's cars were intercooled, there would be lots more of them here on the board....I would be one of them.

It's so stupid of them not to do it, they would own the market.

 

First, you don't have to worry about getting into a pissing contest with me, I'm just here for the constructive exchange of facts/ideas/opinions.
I respect you and your opinions, just like evryone else.
to be continued............gotta go to work

 

no doubt, twin-screw is more efficient.

Modified Roots = 60%
Twin Screw = up to 75%

It's not like the old days though when straight rotor roots where only 40-50% though.

 

Here is one comparing a Whipple 2300AX and Eaton m90. They are using a Grand Prix as the test vehicle but you will get a good picture.

http://members.***.net/animul67/whippletechinfo.htm

 

Also, just because the twin-screw is more efficient, that does not = faster off idle boost.

A turbo can be the MOST efficient, however, they are not known for their off idle performance characteristics.

 

Something else to think about. Doesnt the supercharger weigh an extra 100- 150 pounds ? The turbo probably weighs less. Probably doesnt make that much difference though.

 

Too bad he didn't compare the Whipple 2.3L to the M112.

I believe the off-idle difference between the twin screw and the modified roots is negligible, if there is any at all.

 

Overall, I think the weight is about the same. The Radix is heavy (70lbs, or so), and the turbo is a lot lighter, but add in all the piping, in the case of the STS, differences are probably minor.

 

explain please, not sure if I'm following you correctly.