What does a recent car really cost

[louphil]

Well for sure, like the PC manufacturers who do not make drivers for the old windows versions, like that everyone fucks vista who eats 1000 MB of ram to play solitaire ...

For the weight, you speak of an excuse ... If the cars are heavier and heavier, it is because of the safety reinforcements and the 50 or 100 kg of electric cable !! How much does a steel cable 2 m long and 2 mm in diameter weigh? Jokers These Laughing Builders

I am very open to new technologies when they are reliable and justified. Also, I want a steering column and cables and rods for my pedals ... and I don't want to be strolled with europhage diagnostic USB suitcases

I think we almost all agree ... Whether it is the manufacturers of PCs or cars, everything is done to encourage the consumption of goods. For that, the products must be more and more "volatile" with ever shorter lifespans ... It is an economic necessity to grow the GDPs so dear to Christophe's heart.
However, if there are alternatives in the IT field (both in hardware and software), this is absolutely not the case in the automobile. What to do to get around this damn obligation to consume these heaps of junk and oil !? And if I speak of obligation, it is not for nothing !!!
When we think that the services of the Mines were sold a few years ago already to the company Dekra, even if an association proposed a viable alternative by offering vehicles following a different philosophy than that followed by our dear current builders, they would be condemned to barely lying on paper ... So it's a double, triple, even quadruple legal rack of which we are powerless victims ... Help Super Sarko !!!!

remundo wrote:

louphil wrote:
AHHH, of course it interests me !!! I hope he doesn't charge Auvergnat prices ... Cheesy Grin


What are these a priori on the rates Question Exclamation auvergnats Evil or Very Mad Laughing

It is said that the Auvergne are eager to gain, right !? Hihi! But don't worry, I too have a blood cocktail that contains a good part of it ... Have you, by any chance, been hurt in your self-esteem ??? If so, a thousand excuses for this touch of humor, certainly low-end ...

[Flytox]

Hello Remundo

Acoustic impedances are never adapted at the end of the pipe anyway since the outside air is like a pipe of infinite section. There is therefore a return sound wave whose overpressure tends to hinder the evacuation of gases. We can nevertheless look for acoustic resonances according to the number of cylinders to limit the phenomenon, as you point out.

The best solution is the free exhaust manifold, precisely what the kids do with their mob to break our ears. (22 kW).

I think the bulk of the loss comes from fluid rolling much more than return sound wave issues. Now "I could be wrong" .

For the announced powers, this is not very significant without announcing the regime at which they are reached. When we touch the length of the exhaust pipe we touch the speed to which the engine will respond. If the regime to which the exhaust responds is the same as that or the intake responds, it is the big potato. As soon as one leaves this scheme (competition) it is to smooth the torque curve (with compromises).

In any case, the free exhaust (free exhaust from the cylinder head or the cylinder (2 stroke) does not give the best power or consumption efficiency etc ... A simple tube of length which goes well to match the regime where you want the torque at a much better efficiency, power, consumption etc ... The return wave at the right time of the cycle or it helps to fill the engine is much more important than the pressure drop.

The extreme case is the 2 stroke time, I saw on a kart with 250 cc Rotax engine, the preparer missed out and shortened his trigger pot 4 mm too much in the diffuser part. Result it was missing 28% of power at 9000 rpm compared to the previous assembly! It's not 4 mm that makes the difference in pure pressure drop, it's the acoustic tuning lost.

After a pot that throttles the passage of gas by rolling it corresponds to a precise adjustment of all the rest of the engine to obtain pollution and consumption performance well determined, but not to a quest for the cavalry that's for sure. ..
A+

[nofy]

When we think that the Mining services were sold a few years ago to the company Dekra,

The mining service still exists ... it is the heavyweight technical control part which was taken over by the private sector, and not only Dekra ... It was just to add a little precision.

Nofy (the dream)

[Other]

Hello

Your orders of magnitudes in power are very interesting, and I am even surprised by their precision. Are these measurements or calculations

?
This is an example copied from a technical book
for tuned pipes two-stroke snowmobiles if you do not install the approved exhaust manifold on these engines you have a significant loss of performance these engines develop for certain 125HP it makes power for a snowmobile, the youngsters make springboards and make loops with their machine ..

For pipes normally tuned for a 4 cylinder we join cylinder 1 with cylinder 4 and cylinder 2 with cylinder 3 and all in common with many bends to have the same length on the pipes
the principle when the cylinder 1 is in exhaust it pushes the gases quickly in the conduit and the sudden closing of the flow causes a depression in the conduit of the cylinder 4 when it opens the exhaust gases are sucked

On the Lycoming aircraft engines, it sells piping tuned for 2400 to 2500rpm speeds (it is far from being easy to accommodate in this small hood in addition to the heat given off by this collection of pipes, many deflectors must be installed there. ) all this to win almost 10hp on 180 hp ..

This principle is used in pulsos without valves.

Andre

[denis]

that's mechanics !! and for a V12 what order ??
are there sites or prog to calculate all this?

[Remundo]

Thank you André !!

I know by scientific varnish that there are systems "of tuning" of the acoustic waves according to the RPM and the number of cylinders. But I see I'm dealing with a connoisseur

See you soon.

[Remundo]

It is said that the Auvergne are eager to gain, right !? Hihi! But don't worry, I too have a blood cocktail that contains a good part of it ... Have you, by any chance, been hurt in your self-esteem ??? If so, a thousand excuses for this touch of humor, certainly low-end ...

But no, the Auvergne are very keen to reduce spending. This is not the same !!

The joke was good-natured, nothing to shake an Auvergnat

Otherwise, +1 for your comments on forced consumption.

[denis]

Thank you André !!

I know by scientific varnish that there are systems "of tuning" of the acoustic waves according to the RPM and the number of cylinders. But I see I'm dealing with a connoisseur

See you soon.

yes, and for info, the 405 mi 16 of pijo, had the variable tubing, but it was perhaps those of admission just as important, I never understood well how it worked, a variable length according to the regime, a derivation with valve ??
on 2-stroke cross motorcycles (Japanese) there was this system on the exhaust call ypvs, atac for honda cr

[Flytox]

Hello Denis

Yes it was the intake ducts which had a variable length. In the long position to have torque at a lower speed and in the short position to make the speed and the horses speak





On the Honda F1 cars of Senna's time, they had already laid a very sophisticated system which continuously shortened the carbon intake trumpets according to the west wind regime and the age of the captain. (I called the photo ... )


The Yamaha YPVS system is not the length that moves, it is the exhaust diagram (time) that is variable. (increases with diet)





The ATAC system from Honda or SAEC from Suzuki is a system that puts a small chamber in communication with the start of the exhaust, which will change the resonance of the exhaust pipe a little so as to delay the return of the wave. , it's equivalent to having 2 different pot lengths.





A+

[Chatham]

[
yes, and for info, the 405 mi 16 of pijo, had variable tubing, but it was perhaps those of admission just as important, I never understood well how it worked

Sorry it's not on the 405mi 16 (whose performance was very average
see even downright shabby in the "depolluted" version ...) but on the 205 turbo 16 (the one derived from the rally) there were 2 pipes: a short one for high revs and a long one for low and medium revs, a valve passed from one to the other around 4500tr if I remember correctly ...