Fitting multiple turbos? (As in more than two)

[Luigi Fettini]

Can someone please tell me what the problems with fitting several turbos to an engine are?
Apparantly there's the problem of driving them all i.e. the exhaust doesn't have enough power to drive them all. For example with a straight six, couldn't you just fit six small turbos each one driven by one of the exhaust outlets of each cyllinder?

[chassis 33]

At a guess it's due to ineffienices. An IC engine breaks down the energy gained from burning the fuel into approx a third mechanical power, a third is dumped as heat into the cooling system and a third dumped into the exhaust.

A turbo works by gaining back some of this wasted energy, if the turbo is too big or theres too many of them then there wont be enough energy in the exhaust to spin the turbos to give and boost, remembering that turbos arent anywhere near 100% efficent.

Regards
Iain

[stevieturbo]

And apart from the above, plumbing them up would be a nightmare.

In general, 2 turbos are more than enough for any engine. For most, 1 is quite capable. It mostly boils down to packaging, and which is easiest.

[eliot]

stevieturbo said:

And apart from the above, plumbing them up would be a nightmare. In general, 2 turbos are more than enough for any engine. For most, 1 is quite capable. It mostly boils down to packaging, and which is easiest.

Having done twin turbo's the only other direction I would consider is less turbo's NOT more. All that plumbing and fabrication gets expensive.

Of course you could ignore all that advice and stick 8 turbo's on your V8 like this one:

www.ls1tech.com/forums/showthread.php?t=218783

[lawrence1]

What is generally done is you put the turbos into a supercharger if you want more power. Check out those guys who do tractor pulling. They have enourmous horsepower and use turbos into superchargers.

And just to note, the gasses leaving the turbos head into an "intercooler" then into the supercharger. This is because it is the 'INTERmediate' cooling stage.

If the turbos vented straight into the engine instead of the supercharger the correct terminology for the 'cooler' is "aftercooler".

I guess it just sounds better for boy racers to say 'intercooler', and not aftercooler.

[JonRB]

The Bugatti EB110 had a quad-turbo V12 if I recall correctly, but that is pretty unusual. Generally twin-turbo is the most people do.

[r988]

lawrence1 said:

What is generally done is you put the turbos into a supercharger if you want more power. Check out those guys who do tractor pulling. They have enourmous horsepower and use turbos into superchargers. And just to note, the gasses leaving the turbos head into an "intercooler" then into the supercharger. This is because it is the 'INTERmediate' cooling stage. If the turbos vented straight into the engine instead of the supercharger the correct terminology for the 'cooler' is "aftercooler". I guess it just sounds better for boy racers to say 'intercooler', and not aftercooler.

Also intercooling was developed for turbo supercharged aero engines in WW2, by the allies

[Pigeon]

lawrence1 said:

What is generally done is you put the turbos into a supercharger if you want more power. Check out those guys who do tractor pulling. They have enourmous horsepower and use turbos into superchargers.

A lot of the time they do that because they're using Detroit Diesel two-strokes that were built like that. A two-stroke diesel doesn't use crankcase pumping and needs a blower to provide scavenging air - it doesn't necessarily provide boost; that depends on the valve timing. The later Detroits were fitted with a turbo which took over once it had spooled up and unloaded the supercharger, so the power to pump the scavenge air comes from the exhaust rather than the crank.

[steve_d]

Steve