Trippin...me? Not in this lifetime strad, as a matter of fact last time I tripped was on another forum altogether.strad wrote:you be trippin again.
Trippin...me? Not in this lifetime strad, as a matter of fact last time I tripped was on another forum altogether.strad wrote:you be trippin again.
autogyro,autogyro wrote:Yes but it is the compressor that causes the lag.
Agreed, the comp does not cause the lag, this come from the hotside. If you take a comp heavy hybrid turbo, you won’t get any more lag than the original oem, only a boost spike that will be hard to control. If for some reason you went in the other direction with a hotside heavy hybrid, it would have more lag than the original.riff_raff wrote:autogyro,autogyro wrote:Yes but it is the compressor that causes the lag.
Not really. It's the inertia of the rotating masses, of which the compressor is only part of. The compressor is a dynamic device, and only operates efficiently within a certain range of rotational speeds and pressure ratios. If the compressor could somehow spin up to that speed range instantly, there would be no lag effect. In practice, the compressor will only spin up as fast as the turbine drives it.
If you look at a modern automotive turbocharger, you'll note that most of them use variable geometry (nozzles or vanes) at the turbine inlet. The exhaust gas flow velocity and vector at the turbine inlet are critical for optimum turbine performance, and I believe the optimum exhaust gas flow velocity and vector changes with turbine speed. That's why variable turbine inlet geometry is most effective.
riff_raff
The engine is a 1.8T Audi engine, with a complete rebuild and fitted with a Garrett GT3071R, good for 400bhp. Due to the tight fitting, ie the transfer box, its easier to go with a simple cast iron mani, than a more expensive equal length welded mani, that would only crack.Blackout wrote:Shaddock wrote:Blackout wrote:Something like this ?
http://i69.servimg.com/u/f69/14/79/55/26/tm_2_b10.jpg
Waw very tight packaging... What VW/Audi engine is that? Is it possible to see such tight exhaust manifolds in 2013 ?
Generally, an exhaust manifold having a small internal volume will benefit a turbocharged engine. A small volume will give a rapid rise of the pressure in the exhaust manifold when the exhaust valve opens, which is then followed by a quite rapid fall in pressure after blowdown phase is over. This gives a high pressure pulse during blowdown which help increase boost pressure at low engine speeds, but also a low pressure in the exhaust manifold during the exhaust stroke and during the valve overlap period which provide a good gas exchange and small pumping losses. So having equal length pipes and thus a larger exhaust manifold volume can actually be a disadvantage. Particulary when you have a situation where getting enough air into the engine at high speed isn't the problem, and with the fuel flow restriction I don't think getting enough air into the engine should be a problem.riff_raff wrote:ringo,
At the TIT's and limited fatigue cycles an F1 turbo turbine would see, cooling should not be necessary.
Even with a turbo engine, a tuned exhaust header length would be beneficial. Of course, I4 engine turbos normally use divided turbine housings for some reason.
With regards to the optimum velocity and vector of exhaust flows at the turbine inlet, the reason for this becomes apparent if you consider that the exhaust flow must smoothly pass over the leading edge of the turbine's airfoils which have a very high peripheral velocity. If the velocity and flow directions don't match there will be turbulence, stalling, and loss of momentum.
Regards,
riff_raff
I don't think electric boosting or turbo compounding will be legal in 2013. They agreed to delay all fancy stuff with turbos to 2014. Logically the 2013 solution could be a spec turbocharger. It was discussed by the expert group in September or October. ATM we don't know if they will use a basic specification and allow the competitors to design their own or have a common control design for 2013.autogyro wrote:Turbo turbine driving a MGU coupled to the compressor, that allows the MGU to over drive the compressor when the turbo lags, controls overspeed and captures excess energy.
Using of variable nozzles in gasoline engines is limited by the exhaust gases temperature (higher than in case of diesels). However, as LMPs diesel turbos are working in the temperature similar to what you can find in the road gasoline ones, it just a matter of time before they'll find their way into mass production.Edis wrote:The variable nozzle turbine work by adjusting the nozzle area, the effect is similar to changing the size of the turbine housing. It do cost some peak efficiency though. It's mostly used for diesel engines where it is also used to increase the exhaust pressure for the EGR system.
I think they just delay it to control the development cost. 2013 the core engine, 2014 the turbo issues.autogyro wrote:So F1 is a spec series then?
Shame realy, what a wasted opertunity.