Thread: Stoopid Turbo Question

There are no stupid questions, only stupid people.... heh heh LOL

The short answer is yes and no.

Any form of forced induction (turbo or super charging) is used to artificially increase the volumetric efficiency of an engine. That is, to get more air (and fuel) into the engine to give a higher power output for a given size.

If you run any engine "on boost" it will use more fuel than "off boost". Generally speaking you can't just hang a turbo or supercharger off a stock engine andexpect it to hang together, there is a bit more to it than that.

As far as which is better, there is no easy answer to that question. Turbochargers use waste exhaust gas to generate the boost, so it is in effect 'free' power. A supercharger is belt driven off the engine, therefore uses some power to create the boost. There is a net gain because you create more power than you use.

Have a look at this, Wikipedia article, or this from Exploroz.

Cheers
Simon

Oh!

So a turbo is more efficient than a supercharger. So how come they still supercharge cars, especially Rangeys and Mercs?

I think a supercharger works all through the rev range. Sorry tdi turbo only kicks in at about 2000 revs. If you want turbos that work across rev range you have to get into variable vanes or two turbos, or other complicated stuff.

Cheers
Simon

Just saying that a turbo is more efficient than a supercharger isn't really accurate.

New vehicle manufacturers and aftermarket suppliers have many problems to work around with either installation.

These include marketing, heat issues (turbo chargers get VERY hot), packaging (what will fit in the space), required outputs (as mentioned, superchargers work off idle, turbo chargers need to spool up), etc.

So what about this, I saw a performance guy the other day who sells Blow Off valves. He reckons that they work well because the back pressure on decelleration doesn't slow the turbo down. So each time you change gears your turbo is on max boost.

Yep, what is the question?

Superchargers were popular in the 1920s & 1930s with the more expensine machinery. Mercedes & I think Bentleys had them on a clutch - floor the pedal & the clutch would engage - bit like a modern kickdown.

But manufacturers like GM figured thay could get the same fuel/air volume, same horsepower by simply fitting bigger & bigger engines. No excess parts, no warranty issues, lesser thermal loads, longer engine life.

I'm intrigued why they're back too. Why on earth did GMH fit a supercharger to the commondoor 3.8? Beats me.

Can't speak for Mercedes, but I know that Aston Martin fitted the twin Eaton superchargers to their V8 purely for throttle response reasons. No lag. The greater fuel economy that could be had with a turbo setup won't worry the average new Aston buyer!

Regards
Max P