Crossflow Cylinder Heads

[nomorecatering]

Why do crossflow type cylinder heads work better than whee the intake and exhaust ports ae on the same side.

Often it is mentioned that the new Continental engines with the tuned induction and crossflow heads are superior to the traditional type. is it the heads or the tuned induction?

If tuned induction, crossflow heads and tuned exhaust systems work so much better, why arent they made standard. Especially exhaust systems.

[onetrack]

Why do crossflow type cylinder heads work better than when the intake and exhaust ports are on the same side
Because the intake/exhaust air flow across the combustion chamber is basically in a steady one-way direction, apart from the interruptions created by the valves closing.
The air flow in a head with the intake and exhaust ports on the same side means that the intake/exhaust airflow has to reverse direction to exit the combustion chamber.
Thus we have efficiency losses in the latter, as the airflow loses momentum at higher engine speeds.
In addition, with both intake and exhaust manifolds on the same side, we have heat transfer from the exhaust manifold into the intake manifold, thus creating more inefficiency, as the intake air is heated, and thus loses density.

Often it is mentioned that the new Continental engines with the tuned induction and crossflow heads are superior to the traditional type. is it the heads or the tuned induction?
The crossflow head produces a far greater gain than the tuned induction. However, every little bit helps, and tuned induction can often add around 10% to KW or HP output.

If tuned induction, crossflow heads and tuned exhaust systems work so much better, why arent they made standard. Especially exhaust systems.
Because they cost more, and in the 21st Century, engine manufacturers are run by bean counters. Every 5c they save on the production of 100,000 engines a year translates to a direct increase of $50,000 a year in bottom-line profit. :eek:
In fact, once items are in production, manufacturers continuously look for ways to manufacture every part in that product, cheaper... thus your new engine has been brought to you via great cost-shaving efforts, and from the lowest tenderers in the parts supply chain...... :suspect: :{

[The Green Goblin]

Imagine if the intake of a jet engine was at the back and the jet exhaust exited at the front and was redirected via piping to blow out the rear. How inefficient would this be????? Oh wait a minute, it sounds like a PT6 :}

[Wally Mk2]

"nom" there's oodles of material written about such things but basically x flow design heads simply breath better & are less restrictive in there design. If you can get the gasses in & out faster (by way of x flow heads) then there's more power to be had from the same cubes.Tuned pipe work in & out of an engine is done to also improve the flow as pressure flows can be all over the place if not at least some design effort has gone into gas flows.
Don't forget most of 2days aero engines where designed a zillion years ago where technology was basic & design/building costs where also considered along with reliability. (Automobile engines where far superior in design but they revved a lot harder with smaller capacity) They are large in capacity the plane donks, very low revving so even though tuned pipes & better flow heads are now available in an attempt to squeeze what's left out of the old design/s they would not have been much of an advantage back then. All of which had to be easily serviceable too out in the field where basic tools & basic skills where all that was needed to fix 'em. Just my slant on things:-)

Wmk2

[KRUSTY 34]

Crack-up GG. :D:D:D

[remoak]

Imagine an engine where the intake air turned 30 degrees as it entered the intake, then 90 degrees the other way, then 180 degrees to that, then 180 degrees and then 180 degrees again, then finally 30 degrees to exit through the exhaust...

Yes, the mighty RR Dart. What a ripper...

http://www.pwnz.com/files/images/content/scan0001-%20DART%20comprsd.jpg

[nomorecatering]

There ae several tuned exhaust makers, Powerflow and Leading edge. The 206 tuned exhaust by leading edge seems very effective, seems like a no brainer.

Apparently diamond get their exhaust systems from powerflow. If sessna for instance ored a thousand units they would get them very cheap. Small coin for a big gain.