do you launch at 1,000 rpms? no. are you ever driving at 1,000 or even 1,500 rpms??? probably not if so your not going to be flooring it to get somewhere fast. when a turbo is building boost at 2,000 rpms that's insane... you have to realize that each rpm is going to be building more and more boost till he reaches his max boost by 4,200. which is insane at that horsepower level i've ridden in cars with that kinda of boost situation... trust me it's not lag. i couldn't even tell you when mine builds boost or even makes full boost. i drive it hard every single day as of lately and all i know it it's powerband is perfect. completely usable for stop light to stop light, passing traffic in 5th gear, to destroying the mustang that rolls up next to me with an attitude all this junk about superchargers make instant boost is rediculous. ride in a car that came with a turbo stock. it feels linear, because it has a properly sized turbo. if you put a s/c on our rotaries that's made for a damn 408 big block.. it will not make instant boost.

my vote obviously goes for turbo since that's what i've been enjoying on my own ride now. the great part is.. i just get to increase hp from here on out. i am not limited as i would start to be if i had a s/c. woot

 

What torque numbers for each PSI dyno'd?

 

All displacement type SC make instant boost no matter what size they are. Even if the SC is way too big or way too small for the engine. A mismatched blower will have other problems but lag will not be one of them.

At any RPM you can press the pedal to the floor and you will have full boost when your foot hits the floor.

With a turbo there will always be some lag from when your foot hits the floor. A well designed turbo can get that delay acceptably short but there is still a delay.

ed

 

i see lots of mustangs and other v8 filled cars with blowers on them every week. my friends dad owns a large performance shop here. Carolina Performance Racing. there is definately lag. not much, but it's not as instant as you say. but in any case, i guess it really depends on if you plan to get groceries with the car and have some fun on the way there or if you plan on hittin the highway and getting some nice pulls and walking the competition down. low end (which rotaries dont need because you get to rev so high) or the never ending power band. 3,000 and up or in DF's case... 2,000 and up

 

My sanctioning body does not allow SC on my Rx7 but I have an Mr2 supercharged bumped up from stock 8psi to 12psi. The boost gauge shows no lag. Most mustangs use centrifugal superchargers because they don't have room under the hood for a huge roots blower. Technically they don't have lag but they don't get full boost until the last 1000 RPM.

ed

 

why is it that centrifugal superchargers don't perform as well as the roots type?

 

Centrifugal superchargers perform quite well in their own range. I feel that range does not fit well with a street car or an autocross car.

Most drag cars and road racing cars are able to setup so that they perform in a predictable narrow RPM range and that can work well with centrifugal superchargers.

A roots SC is less efficient but it has a much wider RPM range. My preference is roots or Lysholm if I could afford it.

Most turbos with quick spool and good low end boost tend to run out of breath at the top end, if you favor the top end you usually have to give up some of the other two. The roots SC is a lot less efficient than a turbo but usually has a wider range and faster response. The choice is not so clear cut but I prefer the Roots on the street.

ed