What Is A Supercharger Kit? Roots, Twin Screw & Centrifugal

Turbo Throttle Lag

A turbo, relies on exhaust gasses to propel or turn the turbo or turbine impeller, to draw in and increase air into the engine. Exhaust gasses must be increased first, to spin the turbo impeller faster, to increase the volume of air into the engine. The way to increase exhaust gasses is to increase engine speed first.

The engine has to make slightly more power on it’s own without the aid of the turbo first. Then when the turbo impeller speed increases, the volume of air from the turbo into the engine, increases as well. The time delay between the throttle opening, expending more gasses from the engine, to spool the turbo, is commonly known as turbo lag. The pitch and size of the turbo impeller, will determine how quickly the turbo spools up to make boost.

How Does A Supercharger Make Boost?

The supercharger is mechanically driven. This is via a belt that is fitted to the crankshaft pulley of the engine and the supercharger pulley. By changing pulley ratios between the two points where the belt is fitted, air flow can be increased into the engine. Along with more fuel of course. This is commonly known as boost.

The amount of performance and horsepower that the engine can be increased by depends on a few more factors as well. If you’re fitting a supercharger kit onto a stock engine, then you are limited to how much boost you can safely make. As factory engine compression ratios are near optimum for pump gas on most modern engines. Typically, 5 to 6 pounds of boost is ‘safe’ to use with a stock engine. As long as there is enough fuel supply and the ignition timing is adjusted or tuned for boost.

Water to air intercoolers can be used to cool the intake charge or air/fuel before entering the engine. By cooling the intake charge, air density is increased along with volumetric efficiency. This is another way air flow can be increased into the engine to make more power.. For more info about how this works see the link here https://www.vestas-aircoil.com/vestas-aircoil/charge-air-cooler/explained

Roots Type Supercharger Kit

The roots type supercharger is the most recognisable supercharger of them all. This supercharger was commonly found on heavy diesel engines. From locomotives to larger earth moving equipment. It was quite common to see two roots superchargers, used inline, on one engine.

You’d have two v8 diesel engine blocks bolted together back to back. Sharing one long crankshaft. So effectively a v16 engine. One supercharger faced forward and the other facing backwards. They were mechanically driven with steel gears, not belts like you see used on drag cars and hotrods today.

There are a lot of different types of roots superchargers found on cars dating back to 1921. They were found on Mercedes vehicles. Known as the Kompressor model. They were the first production series produced roots blowers. They fitted under the hood as well. The diesel engine roots blowers just described, are more commonly used on hotrods, muscle cars and drag cars. This is the supercharger kit that I’m referring to. They are commonly known as a 6/71 or 8/71 supercharger.

Here’s a website I’ve found that best describes the history of the diesel engine roots supercharger. http://www.mini-blowers.com/roots-blower-history.php

A typical roots supercharger kit comes with the following parts and accessories:

• 1 6/71 roots supercharger. The 6/71 is the most commonly used size on a street or drag racing engine.
• 1 blower case snout, usually fitted to the blower case. You can buy different lengths to work with your engine application.
• A single or double carburettor adaptor plate.
• Two pulleys, one to be fitted onto the crank pulley, the other is fitted to the blower snout.
• One idler or belt tensioner.
• One idler bracket.
• One intake manifold, the stock engine intake manifold needs to be replaced with a roots blower intake manifold.
• One blower belt.
• One gasket set
• All necessary hardware to fit the kit to your engine.
• Throttle linkages will be required and not usually sold with the kit.
• Not suitable for emissions controlled vehicles.
• Limited 90 day warranty is typical.
• Each part is serviceable and can be replaced or bought separately.
• Heat exchanger not required although heat can be an issue. A heat exchanger can be used. This will add to the overall height of the fitted kit.

Twin Screw Supercharger Kit

The twin screw supercharger kit is a more compact and versatile kit. Most kits will fit under the stock hood of most modern vehicles. There are many different brands including, Whipple, Keene Bell and Lysholm to name a few. Depending on the brand chosen, the accessories as such as alternator, power steering pump and air conditioning pump will stay in the stock or factory location.

The twin screw supercharger design is far more efficient when comparing to a roots supercharger. They do work in a similar way, as far as being mechanically driven, as a roots supercharger. For more information about the twin screw supercharger design visit the link here https://www.carthrottle.com/post/a7bzmy3/

Depending on the kit or brand chosen a typical twin screw supercharger kit includes:

• One liquid cooled twin screw supercharger. This is a Keene Bell feature. No intercooler or heat exchanger required. Other brands will require a heat exchanger. Whipple screw superchargers have an in-built heat exchanger. Additional intercoolers may be required.
• 3 to 10 rib supercharger pulleys. Cogged style belts aren’t typically used.
• Built in intake manifold, usually part of the supercharger.
• Fuel injectors.
• Fuel rails.
• Air filter intake tube.
• Fuel pump booster.
• Map sensor.
• Plug and play connectors.
• V-belts.
• Some kits may not meet California emissions.
• Some manufacturers offer up to one year warranty.

Note: depending on brand/kit chosen some additional parts may be necessary.

Centrifugal Supercharger Systems

A centrifugal supercharger is basically a mechanically driven turbocharger. They infact look like a turbo but are mounted on the front of the engine with brackets. There is a large pulley fitted the the back of the centrifugal supercharger. This is driven off the crank pulley off the engine, in the same way the roots and twin screw systems work. As mentioned they are mounted differently. For more info on how they work see the link here https://www.procharger.com/centrifugal-supercharger

In many applications a heat exchanger is not required. The air outlet of the centrifugal supercharger is directly connected to the air intake or carburettor on the engine. For carburetted vehicles a blo-thru style carburettor is required. Depending on the kit and brand chosen, some kits come with everything you need to install and run on a late model vehicle. Some brands like Vortech for example meet all 50 state emissions requirements. This makes installing a supercharger kit on a daily driver more appealing to just about everyone.

A typical centrifugal supercharger kit includes the following:

1. One centrifugal supercharger
2. One engine mounting bracket
3. Two ribbed pulleys. Depending on kit used either 3 to 10 ribbed or grooved pulleys
4. 1 v-belt
5. All necessary silicone air duct tubes with the appropriate bends
6. Intercooler where necessary
7. Carburettor hat where necessary
8. Upgraded fuel pump usually optional extra
9. For late model PCM’s the supercharger manufacturer re-calibrates and tunes (some not all).
10. All necessary hardware
11. Complete instructions
12. Usually an unlimited mileage or 3 year warranty

That concludes my review on what a supercharger kit is. We offer a wide range of supercharger kits of various types, for all kinds of vehicles and applications. From daily street use, drag racing, off road and heavy towing. For more information on where to find a supercharger kit to suit your needs, visit the link here https://quartermileaddiction.com/supercharger-kit-for-dodge-ford-chev-bolt-on-more-power/

If you have any questions or want to leave a comment you can do so by entering your question in the comment box below. Alternatively, you might be interested in our drag racing apparel found here at this link.