Superchargers

[GT-Driver]

Hi,

I was wondering, we only see turbo charged F1 cars and other circuit race cars but no superchargered race cars (aside from the production cars).

Even in some applications like diesel engines with heavy machinary and marine engines most engines come with turbos not superchargers.

The only racing application where superchargers are common is drag racing. But I dont normaly hear about circuit race cars or even a track day prepared car being equipped with a supercharger. Why?!! is it not durable enough?

[GORDON STREETER]

Basically a turbo produces more boost for a given speed of the engine and as it is using "free power" the engine is more fuel efficient.
There are "pro's & cons" for both that you could argue about all day but in simple terms that how I see it.

[bdwoody]

ashley hargeaves uses one on his pug 306 to great effect in the qmn championship as does an alfa i believe from ah motorsport.

[Notso Swift]

The boost provided by a Supercharger is directly proportional to its drive speed, it is basically a secondary pump
This is great because:
1, the relationship is perfectly linier (no lag)
2, the charger can be tuned to the specific revs, especially for boosting torque in normal drive ranges
3, while compressing air always adds heat, there is less than running through a hot turbo

But, this is not so good:
1. You need power to drive it, power that could be driving the car.
2. If you gear it to get the instant torque that road cars have then it chokes up top
3. The seals get hot and have a usable RPM limit which you need to work with (ie the supercharger itself has a red line) so you slow them down and put a bigger unit on... increasing power of 1, above
4. That positive displacement is a positive block once the air volume and rev limit are reached
5. economy suffers driving the supercharger when you do not need it, although the last generation of Eaton (as per Mini and Mercedes) did employ a smart clutch, there is still drag, tellingly both have moved away from supercharging...


The next BIG new thing will be electric driven super chargers combined with turbo's on small capacity motors. These electric units are not powerful enough to run the super charger all the time, but with the new capacitor batteries they will be able to provide a few seconds of boost (which will also help spool the turbo faster) and be swicthed off once the turbo is spooled (ie "X" psi) there will be no issues with wasted drive at part throttle. Plenum chambers are about to become even more complex with switching between boosted and un-boosted tracts.
Use google to check out the recent Ricardo article on this, they achieved less an 90g CO2 with 2 litre performance

PS those big drag supercharges draw HUGE amounts of power, 15+% type of huge literally in the many multiple '00's, but not so much of an issue when you have 6000 to spare!