I have owned many cars and trucks. Some had small displacement high RPM engines, and some had large displacement low RPM engines.

It is my opinion that having high amounts of torque at low RPMs is preferable to earning or waiting to have it at high RPMs. Having low-end torque provides you a kick in your pants that is definately addictive.

Because of this, I am leaning towards upgrading the Z with a turbo. They appear to achieve more torque at lower RPMs than superchargers.

Comments?

 

Having raced Turbo Buicks and Supercharged Buicks,I believe you have this reversed,particularly if the blower is a roots type-bottom and mid range.

 

If you want a lot of low end torque, get a truck :P

 

It's pretty much mostly personal preference.

From a purely performance standpoint, HP combined with proper gearing is fastest. However, for many types of driving, you aren't always in the higher RPM ranges and so having more power down low (more low end torque) can make a car feel faster since you get more punch by simply mashing the gas.

As for Turbo VS S/C, you can search for peoples opinion in that, but it is typically personal preference as well.

A roots/screw S/C has a more immediate low end than any turbo IMO, but a turbo has a better low end than a cetri S/C. Turbo's and Centri S/C's are typically more efficient than a Roots S/C, and a turbo doesn't sap any engine power to drive the compressor so they can usually make the most power of all for a given boost level.

There many reasons to choose any one of the options over another, so the best bet is to figure out what is most important to you and go with that.

-D'oh!

 

Obviously is matters tremendously whether the supercharger is a positive displacement type (like a roots or lysolm) or a dynamic compression type (all the centrifugal SC's including Vortech, ATI, Powerdyne, etc). Postive make boost off idle and reach peak very early. Centrifugals are RPM dependant and therefore have a relatively high boost threshold and make peak boost at peak RPM.

For a turbo engine the sizing of the turbo, type of turbo (true ball bearing/very low drag, conventional bearing, turbine and compression design) and the execution of the system all effect response (low RPM boost profile). On a well designed street system it is very reasonable to see boost by 2000rpm (or lower) and can often make full boost by 3000rpm. A centrifugal is lucky to make boost by 3000rpm and doesn't reach peak boost until redline. Under these assumptions... Fuzzy is correct. A comparable turbo will (almost always) deliver more low RPM torque/power than a centrifugal and always make peak boost before a centrifugal.

Regarding torque, D'oh is correct because you can gear multiply torque but cannot do the same with power. Peak power represents maximum QUANTITY of torque. Peak torque is the maximum instantaneous value. Would you rather be hit once with a 5 pound hammer or 20 times with a 4 pound hammer? The 5 pounder has a higher instantaneous value but the 20x4 pounder has MUCH more total QUANTITY of force and therefore does more work.

That said, tuning an engine to maximize its low to mid RPM torque/power values pays big dividends for streetability and fun.

 

JBrady u da man!