Techsalvager

Ok normally from what I read the wastegate line goes pre tb post turbo compressor outlet.

Now say you setup your car with the TB infront of the turbo. Where would you look at tapping in for the wastegate line at?

18psi

iTrader: (76)

how in the world did you manage to setup the tb before turbo?
and more importantly, why?
I don't think anyone here has done that before.

Braineack

iTrader: (62)

techsalvager likes to do thinks the hard way

Techsalvager

hmm maybe just into the piping but using a one way check valve to keep vacuum out but only allow pressure to get in.

Techsalvager

after talking to someone else I think there is problem with that, being the pressure will get stuck in there possibily and hold the wastegate open.

So thinking about a check vavle that locks pressure in but when it sees vacuum can shut close and opens the other side to atmo to release the pressure

18psi

iTrader: (76)

so you're overcomplicating things quite a bit.

may I ask why?
what benefits are you looking to gain from doing things weird like that?

Full_Tilt_Boogie

iTrader: (1)

Just let it pull vacuum on the WG, itll help keep it closed. Just beware that you could overspin the turbo if you throttle it in boost.

Also, Pre-turbo TB is epic.

Full_Tilt_Boogie

iTrader: (1)

Turbo doesnt slow down when you close the throttle because its spinning in a vacuum.
No need for a BOV.

Thats how they did it in Formula 1, and they wouldnt do anything like that for no reason.

18psi

iTrader: (76)

hmm, sounds pretty cool.
so how come no one I know has this? a PITA to set up and make work properly or what?

Faeflora

iTrader: (2)

Subscribing for supreme interest.

Full_Tilt_Boogie

iTrader: (1)

Its a pretty unknown thing, and like you said its added complexity that most people wouldnt bother with.
Also, Im not sure if its true with all setups like this, but most of the ones Ive seen in F1 also had normal ITBs with a plenum in addition to the pre-turbo TB.

Whats funny is as many badass turbo setups we see today if you go and look at the setups in use 20+ years ago on rally cars, formula 1, and Lemans youll see that even with new technology were still way behind them.

Techsalvager

overcomplicating what, I don't see any more complication than post turbine tb.

antilag

Techsalvager

I thought from other posts that vacuum to the wastegate would eventually destory it, maybe I was wrong.

I think I'll look around on how the old carb setups did it.

Full_Tilt_Boogie

iTrader: (1)

fooger03

iTrader: (2)

wow...thats...kinda smart.

You shouldn't need to change your wastegate source. Source it anywhere between the turbocharger and the intake ports. It will still open when you reach target boost, and as soon as you go throttle off, it will immediately force the wastegate closed which should continue to help the compressor spin quickly under the vacuum condition. You might have issues tuning your idle (similar to single TB supercharger setups), but beyond that, I don't see any major complications.

astroboy

iTrader: (18)

I would source it from the manifold (unless you are going to have a second tb) because it seems like you are shooting for little to no lag and this is where you would have the least amount. I think anywhere you put it you are going to continue to build pressure (as much as the opening of the throttle will allow) in the system at part throttle. I agree a check valve seems like a suitable solution for putting a vacume on the wg.

04SILVERSI

Info from another web

"This was first used at the Monaco GP in 1982, and developments of the same system are still used in Formula One. But because Boudy defected to Peugeot with his ideas, the 205T16 was the first turbocharged rally car to use his system (The T16 being out before the final evolution R5 Turbo – The Maxi 5 Turbo). Which Renault calls DPV, or Dispositif Pre*rotation Variable (Variable Pre-rotation Device).

"At the very beginning we had made the decision to use it on the Group B R5 Turbo. It's not really necessary for road cars and a little expensive for them, but it's not so complicated". It may not be "so complicated" but the DPV system is an 'extremely effective way of ensuring near-instantaneous throttle response from a competition turbocharged engine’. The system provides for variable air areas and direction angles at the intake to the compressor wheel in advance of the rotation period during which the compressor turbine will require those conditions.

It's not a by-pass system, it's essentially a multi-variable nozzle arrangement which is mechanically linked to the throttle and which changes the direction and area of air which hits the compressor wheel according to throttle position. The rate of change of air flow area and direction is not exactly linear, but it's progressive and always increasing toward full flow at maximum compressor wheel speed.

This irregular mid-compressor-speed flow, which constantly changes the way the air hits the compressor vanes in the mid-range, improves the compressor's efficiency under part-load, because it is arranged so that the turbine will idle at a higher speed than it would given a fixed intake air direction and area. And of course, the higher the compressor idle speed, the shorter the time it will take to reach its important operating RPM. Result: less lag.

The DPV is inoperative at each end of the turbine's speed range. Under pedal-to-the metal full boost conditions it has no effect because there's regular full flow to the compressor, and with the throttle closed the DPV is shut down as well. But it is not just retained inertia and completely eradicated turbocharger lag which form the real benefit of the DPV system, because there's another major advantage in that as a result of there being no by-pass or blow-off to atmosphere, and because it's an internal function to the turbocharging system, there is no pressure wastage in the all*important part-load condition (ie. The blades don't stall during gear changes, or on/off throttle movements). "

Patent for the design
http://www.freepatentsonline.com/4471616.pdf

Faeflora

iTrader: (2)

Wow, that's great, sounds like a piece of cake to design and implement. Yah.

Techsalvagar, do you have any details or pics of your setup? Parts etc?

04SILVERSI

doesnt look like its a throttle body from the patent its more of of what i would relate to a fan inlet vane damper from hvac.

example:
http://www.ruskin.com/catalog/servefile.aspx?id=558

fooger03

iTrader: (2)

Just implement a TPS based EBC instead.