Safe "Antilag", well sort of..

[sergei]

I just thought of something:
Introduce an extra throttle before the turbo and make BOV venting after that extra throttle and before turbo.
This way the energy will not be wasted on "pssht" sound but actually used to spool up the turbo (or atleast keep it spooled).
The extra throttle will make sure the direction of BOV's recycled air.
Now I need to get my hands on 3" butterfly valve...
The throttle will be vacuum controlled.
I've seen something like that on diesels....
PICK-A-PART time!!!

[GorGasm]

While the idea seems good, i do not believe it will work in practice.

The compressor is not designed to catch airflow and spool up.
The closed throttle will quickly create a vacuum and stall the compressor
And, the BOV is there in the first instance to stop compressor stall, the sound is just a 'bonus'.

Traditional antilag is a different thing...

[sergei]

I know how it works traditionally...
For me it means stressing my near new turbo, modifying my exhaust manifold etc..

[fangsport]

why not build an expansion chamber into the exhaust, directly after the turbo??
they work on 2-stroke motorcycle and on glowplug R/C motors, so why not on a turbo engine??

the expansion should create a venturi effect and draw air/ gases into it, keeping the turbo spooled.

[GorGasm]

indeed, it is a particularly brutal way of doing things :]

I like porsches approach which gains the TT carrera full torque from about 1650rpm. Variable geometry turbos!
$$$$$$

[Mr Revhead]

ill sell you a hilux one!

but the ecu needed to run it would prob be a little $$$

[fivebob]

Better idea is one that was banned in the WRC, they used 40-100litre tanks to store excess boost pressure, and feed it back into the system via a big regulator. They even went to the extent of pre charging the system to 60psi.

If you could figure it out you could run the biggest turbo possible and still not have lag problems

[Mr Revhead]

just keep a politician in the boot.....

[fivebob]

just keep a politician in the boot.....

Yeah, but hot air is not good

[Caveman]

ill sell you a hilux one!

but the ecu needed to run it would prob be a little $$$

I dont think the desiel ones can handel the heat and pressure from a petrol engine.

As far as im aware the porsche ones are the only petrol variable geometry turbines on factory cars

[sergei]

What makes you think that diesel run cooler?
I think they run hotter, due to higher enrgy density of fuel and higher pressures involved. There is a reason why diesels use steel pistons (as far as I know)...

[matt dunn]

I also believe that the system will not work.

For you to get any pressure or flow out of the compressor,
yiou must have a reasonable amout of flow through the exhaust
manifold and ehxaust wheel.

As you have the throttle closed still you will not have enough flow to keep the turbo spinning fast enough to make any decent amount of difference.

The way I understand proper anti lag is,

The throttle plate is held open about 30% all the time.
This allows enough airflow through the engine to keep the turbo spinning
at a decent speed.
This now means that the car idle's at 3500rpm or so though,
so to control the idle speed, the ign timing is retarded far enough that the engine speed is brought back down.
How far down is adjustable by Retard, as if you lower the engine speed too much even with the throttle open there is not enough flow to keep the turbo going.
The engine is usually retarded far enough to the point where the engine is firing around the time the exhaust valve is opening.
This means that the usually big increase in combustion chamber pressure is not acted on the piston to increase speed as much as it acts on the turbo vanes to keep them spinning.
Now as the combustion now can occour in the exhaust manifold instead of the head, there high temperatures are really hard on the manifold and turbo, so the air/fuel mixture is increased dramatically to try and keep the temps down as lean mixtures burn hotter, richer mixtures burn cooler.

Now all this is happening at 30% throttle, and the instant the throttle angle reaches say 31%, the timing and mixture returns to normal instantly giving you the instant throttle response.

Right, wrong, otherwise?

If you want cheap version of antilag, wind up the throttle stop so the engine idles at 3500rpm, and adjust the tps so the idle contacts are closed
and it wil hunt around 1500 to 2000 rpm, until you touch the accelerator.

You will get most of the effects of anti-lag,
really terrible fuel consumption,
no vacuum for the brakes,
car that doesn't slow down much when you take your foot off as no engine braking,
and if your lucky you may get a bit of better response.

Matt

[vvega]

just keep a politician in the boot.....

Yeah, but hot air is not good

lol you forget this is toyspeed its all hot air

[method]

Yup matt thats how aintilag works.

And segri hope your idea works out, the BOV would have to be pretty free flowing and the throttle body would have to seal quite well otherwise it would be just like a normal plumb back BOV

You could always keep your foot to the floor when you shit gears that way youve always got air flowing through your turbo