Why twin screw

[Skunkworks]

I have been reading alot about the effeciency of the twin screw blowers, although I still have some questions. If I only want to go about 13-15 psi boost, I could just use a 2.76 pulley on my 03 Cobra.

(Besides the money), is there an advantage to going with KB or Whipple at same boost level? I hear they run cooler...HOW MUCH COOLER? More power at same boost level becuase charge is cooler? Longer life?

 

[GodStang]

Yes there is longer life and runs cooler not sure on temps off the top of my head. Also the eaton tends to fall off at higher Rpms where the Twinscrews do not. Also you will have alot more growing room and there is a good bit of difference in HP at any given PSI.

 

[03_stanger]

Tt

 

[Skunkworks]

Tt

sorry, what's "tt" and "ttt" mean that I see all the time...?

 

[GodStang]

TTT means To The Top. It is for when it gets far down on the list it bumps it back to the top.

 

[CDR Stang]

Twin screws are very different in the way they build manifold pressure. The Eaton (roots) pulls air into the compressor house and build pressure by loading up the air at the end of the lobes. At that point there is turbulance where the high and low pressure zones are very different. Twin screws compress the air as the air is being drawn through the screws. By the time the air reaches the end of the screws it's already compressed. There is no great high and low pressure zone so turbulance is at a minimum and efficiency is up.

 

[SlowSnake]

If I'm makin 476 rwhp now with a 2.75 on a eaton what would that be around on a KB or whipple at the same boost level? Any ideas?

 

[jlauth]

If I'm makin 476 rwhp now with a 2.75 on a eaton what would that be around on a KB or whipple at the same boost level? Any ideas?

I would say your likely running about 15 psi. With a KB or whipple that would be about 540-550.

These twin screws are much more efficient, which means at the same psi there is less heat and more air flow.

 

[19COBRA93]

Don't the rotors touch on the Eaton, and on the twin screws they do not? That would create a good amount of heat.

 

[CDR Stang]

Don't the rotors touch on the Eaton, and on the twin screws they do not? That would create a good amount of heat.

No. The rotors or screws should never touch. Never ever. They have very close tolerences. What causes heat is air friction as a result of turbulance and cavitation. The only time things will touch is when you hear about people icing the blower housings at the track and the cold housing constricts around the hot lobes that are expanded. This can cause the blower to sieze which scores the lobes and machining on the inside of the housing.

 

[ReVviNg HiGh]

less heat, less HP to drive.

 

[sambandit]

If you are only truly planning 13-15 lbs of boost, I WOULD NOT buy a twinscrew.

 

[Skunkworks]

If you are only truly planning 13-15 lbs of boost, I WOULD NOT buy a twinscrew.

I RESPECT YOUR OPINION, BUT COULD YOU ELABORATE WHY NOT? SOUNDS LIKE THE EFFICIENCY ALONE WILL GET YOU 75/75 RWHP/TQ

 

[udlose03]

I RESPECT YOUR OPINION, BUT COULD YOU ELABORATE WHY NOT? SOUNDS LIKE THE EFFICIENCY ALONE WILL GET YOU 75/75 RWHP/TQ

I think he's saying its not worth the money, ~$2,500 for 75/75. When you can pick up like i did, a dynotunes dry kit 75 shot for ~$450. And that is with a bottle opener, and other upgrades.

Also with the KB, you'll probably need a new TB, injectors (same for the N20), BAP, etc.

if you are only looking for 75hp spray.

 

[Skunkworks]

I think he's saying its not worth the money, ~$2,500 for 75/75. When you can pick up like i did, a dynotunes dry kit 75 shot for ~$450. And that is with a bottle opener, and other upgrades.

Also with the KB, you'll probably need a new TB, injectors (same for the N20), BAP, etc.

if you are only looking for 75hp spray.

I agree.
Not a big nitrous fan.
Yes, twin screw at 15 psi is an expensive endeavor no doubt, my (limited) understanding is the higher the HP the more the cost...sort of an exponential curve. BAP, injectors, TB, twin screw, tune, you might drop $5k total. Just thinking it's the safest most effecient way to 550/550?

 

[Sonic605hp]

If you like Linear power spend the money on a positive disp. blower.....I've had both and prefer the way the power is always there with the twin.....just a preference i guess...but when you whack the throttle on a twin screwed car you damn well know it.

 

[F8LBYTE 1]

I thought running a 2.76 on a twin screw was about 21lbs, i ran a 2.8 when i had mine and it was hitting 19lbs. think u need about a 3.1 reichard racing pulley