Daily Archives: May 19, 2008

Turbocharger vs. Supercharger – what’s the difference?

Posted by David Hurst on May 19, 2008 12 comments

I got asked this the other day, and after fumbling through my answer, I thought I’d better do some research. Having completed said research, I am ready to impart my new-found wisdom to the masses…

Basically, both turbochargers and superchargers do the same job – delivering compressed air to the engine. Why? Because if the air is compressed, you can get more in, and if you get more in, the fuel burns better, and if the fuel burns better, the engine goes faster. Make sense? Good. Here’s the key difference then:

A turbocharger has a turbine that is fed by the exhaust gases of the engine. These gases cause the turbine to spin, which powers the compressor.

A supercharger is belt driven by the engine.

Because of these differences, a turbocharger becomes more effective as the engine load increases. This is why you get a sudden burst of acceleration in turbocharged cars at about 3,000 RPM. This also has the added benefit of being more fuel efficient. The downside is the turbo lag issue.

Looking at my car as an example, which is a Fiat Coupe 20V Turbo, it generates 220BHP. The normally aspirated (or none turbo charged) version generates 154BHP. That’s some difference that the turbo makes! If you are driving at low RPMs and the turbo isn’t fully effective, then you can see that the performance gap is pretty huge. Simple solution: if you want to drive fast, keep the revs up.

The supercharger is connected to engine speed not engine load. The faster your engine is running, the faster your supercharger will run. The benefit is that you don’t have to build up exhaust gas pressure to get the supercharger going – it’s always on. So the upside is no turbo lag. The downside is the increased fuel bills, but then if you can afford the average modern car fitted with a supercharger then fuel bills probably aren’t much of a concern.

The two chargers sound different too. A turbo whistles as the engine revs pick up, whereas a supercharger makes a distinctive whine that is ever present.

I’m no mechanic, so if I have anything wrong, please submit your corrections below.

Who is David Hurst?

Posted by David Hurst on May 19, 2008 4 comments

I’ve found myself asking this question quite a bit this week as I’ve been watching my Google rank for “David Hurst” slip a little. Clearly, with only 1 Google top spot up for grabs, and a whole bunch of us David Hursts competing for it, it’s inevitable that my site wouldn’t stay number 1 forever. Unlike these other chaps, I don’t have the time or inclination to actively market my personal blog in Google. I was interested though to see who exactly I share a name with. So, for those with time to spare, here’s my rundown of five David Hursts, starting with myself:

David Hurst – PHP / MySQL, REALbasic & Javascript Developer
Yep, that’s me. I build websites and software for my company Higher Sites Limited. I also give of my time to the Connecting Somerset Technology for Business programme, where I run workshops and seminars on practical search engine optimisation. I’ve been doing this stuff for 11 years, and that’s pretty much millenia in Internet terms.

David Hurst – Actor
I never saw any of his films, and he doesn’t seem to have done much since the 1980s. Is he still alive? Was he any good? I don’t know. Interesting that he was born in Berlin to Austrian parents. I had always thought Hurst was an English name.

David Hurst – Wedding Photographer
Fairly new to the Google top ten for my name is this chap, who by the looks of his portfolio, knows his photography. Very nice.

David Hurst – Owner of Onrec.com & Public Speaker
This David Hurst set up an online recruitment website that appears to be a directory of other recruitment websites. Pretty useful if you’re looking for a job I guess. He doesn’t look anything like me, by the way.

David Hurst – Author
His book is called “Crisis & Renewal: Meeting the Challenge of Organizational Change”. I’m guessing from the mis-spelling of organisational that this David Hurst lives stateside. I must confess I haven’t read his book…

All in all, we’re not a particularly thrilling breed are we? So, if you’re still reading and haven’t drifted into a coma, let’s just have a quick look at what the names mean:

David
David is a name of Hebrew origin, rather famously owned by King David of Israel, an ancestor of Jesus. It is generally thought that the name means “beloved”.

Hurst
Hurst is an old English word meaning a wood or small thicket of trees.

So, David Hurst = Beloved Wood.