Hiya guys,

Next friday I have to do a Presentation on turbo's at college (it isnt assessed or anything, just a little class project) and I have chosen to present Turbo lag, and how to overcome it.

Does anyone have a power readout graph (from a Dyno Run or similar) that could show the effects of a large turbo, i.e: really low power till about 3K RPM then a large increase in power. Thats what i understand a very laggy car would look on a power graph.

Cheers guys, I'll keep y'all updated with me progress!

james

 

try...

dyno.scoobynet.co.uk

 

Just stand up up and say you get rid of lag by running an anti-lag system

 

nah, tried asking the tutor that and he said "
if you can say that and make it last 10 minutes, then provide a quiz at the end, go for it"

so no luck im afraid


cheers for the link!

James

 

to remove lag from a large turbo system, add nitrous oxide.

simple

Rich

 

Yeh, i heard that nitrous injection could be used, cheers!

 

got a dyno graph of a really quick spool-up from a small turbo if that's any good for comparative purposes..?

Also Andy F's latest 'Project WRX' installation in scoobymag shows the benefits of a small turbo v's larger turbo in real world terms, due to the quicker response. Could provide some material for you. May be on his web page if you haven't got the mag..!

 

ah cheers jasonius, i'll have a look for that article between small and large turbo's.

Just written about the BMW 535D 3.0 Twin Turbo, thats a really excellent system, using two turbo's of different sizes to counteract and eliminate turbo lag, with a valve that acts both as a turbo bypasser and a wastegate.

Clever stuff, but you don't expect nitrous or anti lag from a beamer do ya

James

 

Someone stop me if I'm wrong but a power vs. rpm graph from a large turbo'd engine is not going to illustrate turbo lag, strictly speaking. The characteristic of late, strong spool up is what large turbos do, with in general small turbos doing the opposite - relatively early spool up but run out of puff higher up the rev range.

STRICTLY speaking, turbo lag is the delay between opening the throttle and the turbo spinning up fast enough to start making good boost. This happens at any revs, even with a small turbo and gives the 'elastic band' power delivery of a turbo compared to a normally aspirated or supercharged motor.

What you were talking about is really just turbo response, not lag. To truly overcome lag, you need a way to accelerate the turbine and thus the compressor almost instantaneously instead of having to wait. This is what rallying anti-lag systems do - effectively keeping the fuel and burn going even when you're off the throttle, which then keeps the turbine spinning.