typer522

hi ppl
i am doing a final year project about turbo engine.
can some on explain to me what is 'turbo lag'?
why ppl say turbo engine is more fuel efficient than NA?
also has anyone done a report or essay about turbocharged engine which they can send to me?

typer52@talk21.com

many many thanks

ALi-B

iTrader: (1)

short answer for turbo lag is the time it takes from you putting your foot to the floor and you actually getting a response. Where you have to wait for the turbo to "spin up" to speed.

It varies depending on the turbo system (anti-lag etc) size of engine, size of turbo and engine speed. A large turbo at low engine rpm will take alot longer to spin up than a small one.

When you say turbo engines are more effcient than n/a it is not a correct assumption, you do not say if it is for petrol or diesel engines. Assuming a petrol engine, the turbo allows for more air to be pushed into the combustion chambers. To stop it running lean, it must have more fuel injected.

So the more air, the more fuel. Then we move on to detonation and high combustion chamber pressures and temperatures, where a turbo engine has to use a lower compression ratio and a much more retarded ignition timing. Both of these make the engine less efficient. Also a third measure of injected extra fuel making the engine run rich as an aim to help aid combustion chamber cooling and reduce detonation - once again increasing fuel consumption. A turbo petrol engine is only efficient through a very narrow load/rpm range when compared to a n/a engine

However it is different with diesel engines as they rely on high compression and combustion pressure to actually run.

hope it helps

chrisp

This webpage explains the basics

http://auto.howstuffworks.com/turbo.htm

greasemonkey

Lag, is, in as simple terms as possible, the time difference between you depressing the throttle and the turbo being able to flow/compress enough air to enable the ECU to hit its boost target. There's plenty of good stuff about lag here and in the technical forums, search button's your friend.

That's a bit of a falsehood. Turbos are very good for getting very high specific outputs from an engine of a given size, but to say they're more fuel efficient doesn't really wash.

So you can copy it???

typer522

many thanks ppl

Si of Sheff

What may be being overlooked here is the potential for efficiency with a turbo. Follow this one, it doesn't intuitively make sense.

I drive a car with around 230 BHP capable of 0-60 in under 5.5 seconds (MY00 with decat if anyone cares). I can also cruise at 80mph and get 35 mpg. I don't know of any NA cars that can deliver this performance AND economy by just changing driving style/ situation. It would require 2 different engines! Would this provide a basis that supports you argument?

Si

hugo

Go to www.howstuffworks.com