Not sure if a discussion on turbos has occurred but

[Wanda]

I was thinking about the old diesel engine and how noisy and lack of power, e.t.c, it was.

Now turbo diesels (and petrols) are almost automatically the norm. I was thinking what would be the best way to get rid of the initial delay before the turbo boost kicks in. Twin turbo is a good idea, i.e a mix of small and large turbos. Small one to take you to the big one.

Now BMW 550d with 3 turbos has perplexed me a bit.

http://www.youtube.com/watch?v=cqERH9fky2Q

http://www.youtube.com/watch?v=isSjS...layer_embedded

In theory they have a small turbo to boost from idle then the small one takes over then finally the big one takes over.

Assuming we reach the point where the big turbo kicks in, the other turbos can not spin or "create" the air flow that the big one can so can we assume it would automatically switch off?

I was thinking of experimenting on a 1.5 dci engine with a twin turbo system. (When money is saved).

Kingston University took the 1.5 k9k engine and reported some power gains but thought it would be more than reported.

http://www.ricardo.com/Documents/Do...ons/Kingston_WAVE_Twin-entry_Turbocharger.pdf

 

[Foxspeed]

no lag = supercharger!

bmw tri-turbo - isnt it small large small turbo working?

 

[M19TNR]

Compound charging... Or anti-lag.

Both expensive, complicated, and only worth it if the turbos bigger than your head really...

 

[Foxspeed]

compound charging usually refers to a turbo driving directly off/into the crankshaft

 

[ben_r1]

There are also twin chargers, supercharger for low range lag free boost and turbos for top end delivery.

 

[M19TNR]

compound charging usually refers to a turbo driving directly off/into the crankshaft

There are also twin chargers, supercharger for low range lag free boost and turbos for top end delivery.

http://www.atsdiesel.com/ats2/templates/template_06.asp?p=2029422272&c=36

Compound charging...

 

[shakey_hand_man]

one of the small garrett gtx turbos, would wipe the floor with most setups and reduce complexity.

The effiency islands on the gtx items are massive making them very flexible: quick spool and good pressure ratios.

-Andy

 

[lukeeddy]

The VAG tsi engines seem like a good answer to the lag problem, and am sure you can now get supercharges that can be "switched off" (for want of a better word) when not being used all though am not sure how

 

[Foxspeed]

http://www.atsdiesel.com/ats2/templates/template_06.asp?p=2029422272&c=36

Compound charging...

compound charging was used on aircraft way before vehicles and the turbine is drives onto/into the crank...using two turbos is just high jacking the original wording

 

[Gareth_197]

Thats my lecturer who wrote that, he is the biggest cock out. (I do motorsport engineering there) I think BMW are bringing many new three snail diesels, take a lookat the new x5 coming out, the mpg/emissions and speedis crazy.