With all the talk of turbos lately...

[Toast]

http://www.motorcycledaily.com/16april06_direct.htm

Direct injection turbos.

If it's good enough for BMW, I, like this dude, would say that it's good enough for production bikes.

That would spice things up a bit from the usual yearly rounds of refined and updated 600cc supersport and 1000cc superbike shoot-outs.

[bugjuice]

so what's the different (aside from higher compression) between conventional and direct turbo's then? I don't understand what the 'change' is..?

[Ixion]

It's the injection that is different. Conventional FI squirts the fuel into the intake tract where it mixes with the air being sucked through the intakes. then the fuel/air mix is drawn into the cylinder , through the intake valve and compressed, in the same way as a carburetted engine.

Direct injection works like a diesel. Only air is drawn through the inlet valve, and compressed. Slightly before TDC the fuel is injected directly into the cylinder. Petrol direct injection still uses a spark to fire the mixture though, whereas diesel relies on the very hot compressed air to set the fuel burning.

Because the engine is only compressing air, not air/petrol mix, which can prematurely explode (detonate) whilst being compressed, the engine can use much higher compression ratios (though maybe not as high as diesel ?) . The higher compression ratios suit turbocharging.

I think I got all that right, but it may be I'm talking bollocks, in which case I'm sure someone like Mr Motu will set me right.

[Bangbug]

Ixion you pretty much have it right
No, i don't think you can use compression as high as diesels.
But you're right about the detonation etc and the direct injection.
All good news really.
Good fuel econ, less lagg.

Due to the popularity of the triumph rocket etc it looks like a new horsepower war may be on! 200bhp bikes on the way..... New Kawasaki beats 200hp i think. Some of the older bikers ain't so keen on the corners anymore but still want some power to weight thrills. Nice lazy riding with a big punch in your right fist. Who wants to work the gears right? lol. :P

Not sure if i'd want to straddle myself over rocket with a turbine feeding it........ well....... maybe later :P

So bring back the years of the turbo 600's and 750's..... hehehe. I heard someone in japan turbo'd an Cbr250....... gave him 2 stroke power.......hmmmm :P
Toodles my lemon poodles

[Bangbug]

oh yeah, thats why conventional turbos have low comp..... the forced induction pumps it up. and yes, detonation. (detonation == hot air and fuel! )
Toodles again, clean up your own poopies

[.produKt]

Hmm the phrase 'Direct Injection Turbos' makes me think that the fuel is sucked in with the air from the charge side of the turbo? if that makes any sence..

Just gimme 1600$ and ill mount a turb on my zxr

[Toast]

So bring back the years of the turbo 600's and 750's..... hehehe. I heard someone in japan turbo'd an Cbr250....... gave him 2 stroke power.......hmmmm :P
Toodles my lemon poodles

I heard that it gave him 250GP 2-stroke power...just shy of 100 at the rear wheel I think.

A turbo 600 or 750 is what I'm thinking would be some good stuff.

[Motu]

I hope BMW make a better attempt at direct injection than Mitsubishi did with their GDI engines.They were only game enough to to put them into their own domestic market though.....oops,and then they end up here.They apparently run EGR almost continuously to keep combustion temps down....that detonation mentioned earlier.This then fills the engine with so much crap the only way to clean pistons valves and combustion chambers is by using oven cleaner.The Japanese domestic market is used by the manufacturers for preproduction testing - why the fuck do we end up with the failed experiments?....sorry,rant mode off.

Direct injection is the ideal....pretty soon the petrol engine might be half as efficient as the diesel.

[Ixion]

But we are interested in bikes. And if the big advantage of DI is that it permits higher compression ratios, and higher power at (presumably) lower revs; will we not have the same problem as diesels in bikes. That the engine compenents, castings, scantlings etc have to be so strong and heavy that they are impractical on a bike. (I'm assuming that the turbo lag can be eliminated - not a good thing on a bike , that, I would think).

Dunno, m'self, just wondering.

[Toast]

. (I'm assuming that the turbo lag can be eliminated - not a good thing on a bike , that, I would think).

Dunno, m'self, just wondering.

That seems to be pretty much the whole point in the article. BMW is now using the turbo tech that they have shunned for ages (apart from the old 2002) due to its average throttle response because they reckon that the direct injection helps to get over this.

I think Audi and a couple of others have a range of direct injection petrols on the market now, so I'm guessing that it can be done better than the Mitsi GDIs.

[Crasherfromwayback]

But we are interested in bikes. And if the big advantage of DI is that it permits higher compression ratios, and higher power at (presumably) lower revs; will we not have the same problem as diesels in bikes. That the engine compenents, castings, scantlings etc have to be so strong and heavy that they are impractical on a bike. (I'm assuming that the turbo lag can be eliminated - not a good thing on a bike , that, I would think).

Dunno, m'self, just wondering.

A really interesting item on www.motorcycledaily.com that refers to BMW's fiddling with such engines from memory.
I think it should happen NOW.

[Toast]

A really interesting item on www.motorcycledaily.com that refers to BMW's fiddling with such engines from memory.
I think it should happen NOW.

I think you mean the article referenced at the top that started the whole thread...?

[Motu]

Turbos run on waste heat,not gas velocity,heat is energy,and it converts that energy back into work.The direct injection gives higher compression ratios without detonation,which gives higher combustion temps,which give higher exhaust gas temps,which spool up the turbo quicker and give more waste heat to convert into work.

[Crasherfromwayback]

I think you mean the article referenced at the top that started the whole thread...?

The exact same one.
Pass me another Steinie!

[Toast]

The exact same one.
Pass me another Steinie!

Steinie? That's like, early '90's at best dude...Stella is the beer of choice here in Shit City...actually I think it's Heineken now...things move so fast.