No.

 

@ driftomagnifico:

thanks for the explanations. I think in most of the points we agree. My statement that inetria of the rotating assy does not matter for spool up (in terms of producing boost at a certain rpm) is of coures only true for steady state running and therefore, if tested properly under those conditions the spool up is only a matter of having enough exhaust energy to allow the compressor to produce 1bar of boost for this case. Under transient conditions boost will be retarded to higer rpm (for acceleration) because the turbo. The turbo need to contiuousely chatch up with the new incerased engine speed.

The restrictive intake for running higher boost at low rpm was written incorrectly by myself. It was a shortcut just to express that high boost does not necessary mean high power. On turbocharged race engine more cam overlap is used and some parts of the intake charge are wasted through the exhaust by intention. This tends to drop the bosst pressure seen but the fresh intake mix cool the combustion chamber and other internals which reduces knock. Also the percantage of fresh air to remaining burned exhaust gas in the cylinder during the compression stroke can be increased due to that which increasees power. Depending on how this is all balanced you might make more power by running less boost on one engine compared to another one. This should only express that boost does not equal power or torque.

 

I've uploaded a very good video showing Driftomagnifico's point here:
(please right-click 'save as')
http://www.revline.se/diverse/bromsningS38.wmv

I think it takes somewhere around 15 seconds to build 14 psi at 3500 rpm. Try getting that in real life (on the road)...

 

If it takes that long time to build boost on a load dyno the tires would melt/explode from the heat on the rollers.

In the video it looks like if they let the rpm's get up to 3600 rpm's and letting the rpm's settle at 3500 rpm's before applying throttle. This is typical procedure on a load dyno. Once they apply throttle the boost goes from ~4 psi to 13,7 quickly. They also seem to have either rpm varying boost level since the psi increases in increments and not simply build over the rpm range.

 

I think the bosst build up in common understanding would be starting engine and turbo from low rpm and applying full throttle till redline. If the resulting acceleration is slow and rmp increase slowly you get boost earlier than if the engine rpms climb quickly.
You can also have imidiate boost on downshift or similar to give another extrem example. There are always way you can "cheat" if you want to.

Still it would be nice to get some specs of the "magic" turbo. Certainly I would like to get one of those.
Just still don´t think it is correct to do a post like: I found a solution for a problem and I have the prove that it works but I don´t tell anyone.... What´s the sense in publishing this ????

 

If a product works and it is proven with dyno runs, log files, videos and results from timed events that is all I need to know as a user.

As soon as a manufacturer gives out specs to a well working product it will "inspire" other manufacturers as well. This would in real life be the same as sponsoring your competitor with the time and effort (read = money) from your own research and development.

 

Is this a clue https://rennlist.com/forums/showthre...35#post3013735 post 213 and 214?
Tony

 

The thing is that i am still waiting to see a video

 

a few others are also waiting too for log files and videos... Wasn´t there once of prommis of easily reaching 600WHP till the end of last year?

@sweanders: So you would agree that a post like this could be just for comercial interest?
Shure it is enough for the user to have the prove that things work and there no need to worry about anything else. But I would be interested solely from the engineering and development point of view. I always like to learn more about things I am interested in and apprecheate all arriving input !

 

I don't see a problem that it is a commercial post since Vitesse is a forum sponsor. I can imagine that ST is happy to try out the new turbo and I don't care if or how much he has to pay for it.

I am sure that you can get all the info you want about the turbo, just ask John if you can buy into his R/D..

 

It is a suprisingly long thread considering it is all whats, ifs and maybes
Tony

 

Well I wrote once to ST and John and asked about compressor map on Stage 3 turbo but quess what, no replies, so after that choosed different turbo. I could spend money on Vitesse unit but went with widely known garrett GT30R, so far I am happy...

 

A well engineered in series dual turbo set up, would not suffer from lag, the whole point of having two turbos in series is to have the small spool up quickly and provide instant low RPM torque.

The challenge comes in engineering all the plumbing and controls to allow for a seemless transition from the small turbo to the large one without "dead spots" in the torque curve, managing boost spikes, etc.. This type of set up is not for your average home mechanic, "please do not try this at home" lol...

But really, it would require relocation of turbo(s), re-design and manufacturing of brackets, a much more complex exhaust and intake system, on second thought, it might be too much to ask from the aftermarket crowd, and perhaps only something left to the factory engineers...

 

Should the focus be more on the head/valves/headers and overall flow of the motor itself they are using?

If the flow of the motor from intake to exhaust is extreamly good, then a turbo that can have 1 bar at 3Krpm could be capable of 600whp. Actually that would go hand in hand. Much better low end flow would produce more exhaust energy at much lowerer rpms', thus spool even a bigger/higher flowing turbo at much lower rpm's then without that low end flow.

Is this all still on the 2.5 or 2.8???

 

Once I read about someone here in the forum doing a sequecial turbo set-up for the 951. Don´t know what happened to the project but certainly it was interesting.
Sequential or even parallel turbos are quite complex and from most of the cars I know the target seems to be to get rid of them (Mazda Fd, Sylines, Supras....). Alternatively to the sequencial Ts you could combine supercharger and compressor. Makes the exhaust path easier but adds work in the drive belt installation. This was done on the Lancia S4 about 20 years ago and seems to have its revival in one of the new VWs. I have seen such a set up on a hillclimbe Fiat X1/9 too. It is a very tempting solution. I checked it on one of my 951s and after relocating the alternator, the engine just seems to be made for it. It looked mechanicaly easy (just from the installation point of view). I also have got all the components together. As my time is very limited and other projects run in parallet to this I don´t know if and when I will finaly start working on it.