rec.autos.simulators

> Sounds a lot like a turbo pressure release valve operating
> to keep the turbo rpm up.  They are present in some road
> going turbos and you can buy them for about AUS$150.

> I have one in my 86 300zx but since the turbo runs at a low
> boost (relatively), it is quieter and less high pitched than a
> rally or turbo race car.  Might sound sexier when i fit the
> boost controller but I'm not after noise ;)

> The idea is - if you come off the throttle when under high
> boost, you can create a shockwave or at least sudden
> overpressure in the manifold as the engine is no longer
> pumping the same amount of air.  The effect without an
> overpressure valve can stop the turbo in it's tracks or even
> reverse the spin.  120,000+rpm to 0 in a short time is hell
> for bearings, mounts etc.  It also means you need to wait
> for the turbo to spool back up to operating RPM.  With a
> one way valve attached to the intake (usually on the engine
> side of the intercooler) any backpressure can escape and the
> turbo can keep high rpms - reducing turbo lag and increasing
> longevity.  The pressure release is not the same as the
> wastegate - the wastegate re-routes exhaust gases past
> the turbine to limit total boost pressure.

> iksteh

> > Did anyone catch this week's FIA Rally recap from San Remo?  Is there
> > anything better than seeing Tommy Makkinen's Mitsubishi going thru a
toll
> > booth travelling between stages?  That was classic, hehe.

> > Anyway, I've always wondered what the chirping sound is when they are
> > decelerating?

> Just wanted to add to this excelent explaination that "these things" are
> also know as "Anti-lag systems"
> --
> ed_
> The GPLEA
> --------------------------------------
> - My name is Elliott Forbes Robinson.
> Spell it, please.
> - E-F-R.
> No, no, spell your name.
> - E-F-R!!

> > Sounds a lot like a turbo pressure release valve operating
> > to keep the turbo rpm up.  They are present in some road
> > going turbos and you can buy them for about AUS$150.

> > I have one in my 86 300zx but since the turbo runs at a low
> > boost (relatively), it is quieter and less high pitched than a
> > rally or turbo race car.  Might sound sexier when i fit the
> > boost controller but I'm not after noise ;)

> > The idea is - if you come off the throttle when under high
> > boost, you can create a shockwave or at least sudden
> > overpressure in the manifold as the engine is no longer
> > pumping the same amount of air.  The effect without an
> > overpressure valve can stop the turbo in it's tracks or even
> > reverse the spin.  120,000+rpm to 0 in a short time is hell
> > for bearings, mounts etc.  It also means you need to wait
> > for the turbo to spool back up to operating RPM.  With a
> > one way valve attached to the intake (usually on the engine
> > side of the intercooler) any backpressure can escape and the
> > turbo can keep high rpms - reducing turbo lag and increasing
> > longevity.  The pressure release is not the same as the
> > wastegate - the wastegate re-routes exhaust gases past
> > the turbine to limit total boost pressure.

> > iksteh

> > > Did anyone catch this week's FIA Rally recap from San Remo?  Is there
> > > anything better than seeing Tommy Makkinen's Mitsubishi going thru a
> toll
> > > booth travelling between stages?  That was classic, hehe.

> > > Anyway, I've always wondered what the chirping sound is when they are
> > > decelerating?

> They're not anti-lag systems you are hearing. They have them, but they're
> the things that pop and shoot fire and stuff. The chirping is from when
all
> that turbo pressure is released during deceleration I believe, then the
> anti-lag system picks it back up. The reason why I'm saying this is
because
> my dad had a turbocharged car w/o anti-lag that ran 16psi and it made very
> loud chirping noises like that when it decelerated. There was no anti-lag.
> At lots of rallies I've heard anti-lag systems, and they pop and shoot
fire,
> anti lag just keeps shooting fuel to the turbo so it stays spooled, and
then
> all that fuel burns up close to the exaust. You don't get a nice chirp
from
> that :)

> Thanks,
> Alex


> > Just wanted to add to this excelent explaination that "these things" are
> > also know as "Anti-lag systems"
> > --
> > ed_
> > The GPLEA
> > --------------------------------------
> > - My name is Elliott Forbes Robinson.
> > Spell it, please.
> > - E-F-R.
> > No, no, spell your name.
> > - E-F-R!!

> > > Sounds a lot like a turbo pressure release valve operating
> > > to keep the turbo rpm up.  They are present in some road
> > > going turbos and you can buy them for about AUS$150.

> > > I have one in my 86 300zx but since the turbo runs at a low
> > > boost (relatively), it is quieter and less high pitched than a
> > > rally or turbo race car.  Might sound sexier when i fit the
> > > boost controller but I'm not after noise ;)

> > > The idea is - if you come off the throttle when under high
> > > boost, you can create a shockwave or at least sudden
> > > overpressure in the manifold as the engine is no longer
> > > pumping the same amount of air.  The effect without an
> > > overpressure valve can stop the turbo in it's tracks or even
> > > reverse the spin.  120,000+rpm to 0 in a short time is hell
> > > for bearings, mounts etc.  It also means you need to wait
> > > for the turbo to spool back up to operating RPM.  With a
> > > one way valve attached to the intake (usually on the engine
> > > side of the intercooler) any backpressure can escape and the
> > > turbo can keep high rpms - reducing turbo lag and increasing
> > > longevity.  The pressure release is not the same as the
> > > wastegate - the wastegate re-routes exhaust gases past
> > > the turbine to limit total boost pressure.

> > > iksteh

> > > > Did anyone catch this week's FIA Rally recap from San Remo?  Is
there
> > > > anything better than seeing Tommy Makkinen's Mitsubishi going thru a
> > toll
> > > > booth travelling between stages?  That was classic, hehe.

> > > > Anyway, I've always wondered what the chirping sound is when they
are
> > > > decelerating?

>Did anyone catch this week's FIA Rally recap from San Remo?  Is there
>anything better than seeing Tommy Makkinen's Mitsubishi going thru a toll
>booth travelling between stages?  That was classic, hehe.