anong ibig sabhin ng v8 at v12

[AG4]

horizontally opposed yata tawag dyan... kinopya ni Ferdinand porsche sa design nya ng makina ng original, world war ii vintage volkswagen.

The first Porsche car(356) was developed by Ferdinand's son Ferry.
The first production Porsche, the 356 used tuned VW "Beetle" engine.
Horizontally opposed engines have low center of gravity and are usually balanced(opposed pistons cancel out each others vibration).

[Flagg]

...baket di na lang nilakihan yung input and outlet valve openings?...

Bosing, parang cylinders yan. Mas ok ang takbo ng 5.0 V8 kesa 5.0 4cyl. Why? Simply cuz mas maraming 'hands' (mga pistons) to turn the crankshaft... thus higher engine speeds (rpm) and better (steeper) power curve. So sa valves: kung multiple valves, less push ng cam (which is run also by the crankshaft), more fuel & exhaust flow. Di katulad kung 2 giant valves, mas nagwo-work din yung engine.

Malakas din ang 5.0 4cyl pero... ang bagal ng rpm nyan. Kesa kotse e sa genset nalang yan gagamitin. Yung tipong more consistent speed ang required na takbo. Hindi up & down.

Just imagine the acceleration of a 5.0 4... :bwahaha:

HTH

[badkuk]

...and the Subaru Forester

[ian_rex]

medyo na OT na yung thread. but anyways, lets continue the discussion, it gets pretty interesting...

to digress a bit... ano ba advantage pag mas marami valves? mas madami fuel intake? mas mataas compression ratio? or mas mabilis burnt fuel exhaust? baket di na lang nilakihan yung input and outlet valve openings? at pwede bang mag by-pass operation pag nagbara yung isang valve?

more valves means more power by way of more fuel coming in and going out of the combustion chamber. sa mga american V8's mas malaki ang valves hence di sila gumagamit nang multi-valve engine. 1 intake 1 exhaust only. as for the compression ratio, i think this depends on the setting of BTDC or Before Top Dead Center. (i'll get back to you concerning this) as for the by pass thing, there is no such thing- unless you got a very fouled-up engine.

Horizontally opposed engines have low center of gravity and are usually balanced(opposed pistons cancel out each others vibration).

and lower center of gravity means more maneuverability/stability. i do wonder, why is that the VW Beetles were a bit rough if the horizontanly oppossed engines should be 'balanced' is it because they are air-cooled thus no water jacket that acts as a engine vibration dampener?

[rsnald]

medyo na OT na yung thread. but anyways, lets continue the discussion, it gets pretty interesting...

....as for the by pass thing, there is no such thing- unless you got a very fouled-up engine.

pre, masyado ka naman na carried-away..hehehe that was meant as a joke... i'm comparing engine valves with the valves of the human heart.. pag nagbara yung valve ng puso,...pwede by-pass operation but anyways.. salamat sa informative answer mo. keep it up!

[ian_rex]

pre, masyado ka naman na carried-away..hehehe that was meant as a joke... i'm comparing engine valves with the valves of the human heart.. pag nagbara yung valve ng puso,...pwede by-pass operation but anyways.. salamat sa informative answer mo. keep it up!

hehehe. honestly, i've had such encounter on a friend's scooter...

[Flagg]

... sa mga american V8's mas malaki ang valves hence di sila gumagamit nang multi-valve engine. 1 intake 1 exhaust only...

Yung mga Kano, mga V8 nila hindi multivalve not cuz they're big. It's because low-tech sila & these engines are cheap, easy to produce and serve their purpose.

Sa ibang automakers, may mga multivalve V8s & V12s. MB, Audi, BMW, Lexus, etc. Puro multivalve yan. 3 - 5 valves per cyl.

Medyo malayo nga naman price diff & performance ng Tahoe/Yukon sa X5 4.8is... or Crown Vic vs S500...

[Karding]

ian_rex, maybe the Beetle needed an AWD?

[saabulba]

Also, what is "ps" and how is it different from horsepower (hp)? For example, Mazda6 2.3-liter is rated 166 ps and 164 hp * 6500 rpm.

[Karding]

iba iba kseng metric rating ang gamit ng kada-bansa.

166ps is 163.73hp

http://locost7.info/converter.php

PS

This unit (German: Pferdestärke = horse strength) is no longer a lawful unit, but is still commonly used in Europe, South America and Japan, especially by the automotive and motorcycle industry. It was adopted throughout continental Europe with designations equivalent to the English "horse power", but mathematically different from the British unit. It is defined by the Physikalisch-Technische Bundesanstalt (PTB)[1] in Braunschweig as exactly:

1 PS = 75 kp·m/s = 0.73549875 kW = 0.9863201652997627 hp (SAE)

regards,
yer certified intarweb research technologist

[ARB]

bigger valves is better for high rpm, but at low rpm smaller is better, hence the vtec technology of honda.

the multi valve tech is the result of the research on how to enlarge valve openings. but why more valves than bigger valves? reason is you have to fit them to the size of the bore only. putting in two big valves in a small bore wont make them fit, so they made four small valves with bigger openings as opposed to two big valves that will fit the bore. the size of the bore depends on the piston size. there are others that have 5 valves if im not mistaken the ferrari F1 engine before. also others experimented with oval valves. but you have to take into consideration the bigger the thinner the metal that seperates them which makes the heads weaker. dami pa hirap i explain.

[alwayz_yummy]

naku, masyado nang profound, maki ask na din....concern ito sa mulitvalves and valve-timings and lift...

why is it na engines like MIVEC and VTEC have higher RPM safe limit (redline), say 7500-8000, at nasa top end ang power nito, unlike sa normal gas engines na 6000..and anung purpose why yung power nila and max torque nasa halos peak na din ng rpm?may VVT-4age 20V, diba? e ang 4ag-ze, hangang 16-valve lang, mostly pa ata no vvt...

ang alam ko lang japanese V8 is ung sa landcruiser 80-105 or lexus LX450/470..others are american and euro engines na...

may production car gasoline engine that revs up to 10,000rpm redline?, not the ones used in F1 cars,ha..anu manufacturer and engine if ever?

[ian_rex]

always_yummy, the reason behind the higher rpm limit of such variable-timed engines is because of the behavior of the valves while they open and close. i read somewhere that the VTEC technology, especially for the ones like in the SiR, is that, its got 3 settings: low-rpm, mid-rpm, high-rpm.

for low rpm, only one of the two intake valves were utilized. for mid rpm, a solenoid locks the camshaft for the second intake valve, thus producing more power, at finally at high rpm, these two valves were pushed further down to allow more fuel to enter the chamber. therefore, more horsepower...

as for your last statement, well, we could all see that the japanese loves to be practical. you see, they always want to produce pocket rockets! see the Nissan Skyline? 6 cylinder, but the maximum output of the engine could easily surpass the Bugatti Veyron by tweaking the ECU, and retaining the same displacement...

i've heard that the engines over 4 cylinder has this 'smoothness'.

[Helios]

Australia used to build V8 engines for their Holden vehicles which are now supplied by GM. Witness V8 in pure action in Aussies' V8 Supercars and US NASCAR. More valves or cylinders mean more mulah. You can get equivalent and cheaper results with a forced induction engine just by adding a supercharger unit. Although NA engines for me all the way baby.

[Flagg]

Australia used to build V8 engines for their Holden vehicles which are now supplied by GM. Witness V8 in pure action in Aussies' V8 Supercars and US NASCAR. More valves or cylinders mean more mulah. You can get equivalent and cheaper results with a forced induction engine just by adding a supercharger unit. Although NA engines for me all the way baby.

Yung mahirap sa boost is more pressure + more burn = need for stronger cylinders & pistons.

That's why hindi lang basta-basta salpak turbo sa 4g63, naging Evo na.

Yung 4g63 ng evo, among other things, reinforced cylinders & pistons nun... kaya mahal.

[alwayz_yummy]

so anu purpose/advantage na having power on the mid to top end kaysa sa having power from low-mid end...

[ian_rex]

well having power on the mid-range is thought to be most efficient for fuel consumption. you see, more speed means more fuel spent. having power at mid-range has considerable effect- balance between fuel efficiency and power.

[alwayz_yummy]

hmm..pero sa power, anu naman ang effect? civics are know diba parang "mahina humatak sa trafic" because of mid-end max torque, unlike ung others na 2000-400 ang max torque....

[mazdamazda]

hmm..pero sa power, anu naman ang effect? civics are know diba parang "mahina humatak sa trafic" because of mid-end max torque, unlike ung others na 2000-400 ang max torque....

VTEC engines are like that wherein the wild camshaft only kicks in after 5000rpm. you get lower fuel consumption but you'll be taking a hit at low-end grunt. though because of stricter emmission regulations - we wouldn't be seeing again the likes of the 160hp 1.6L B16A.

although the newer i-VTEC (4-cylinder) engines has already addressed this by introducing a variable cam timing (regardless of engine speed) on top of the existing VTEC system. the i-VTEC V6 can shut off 3 cylinders when cruising below 80kph.

[ian_rex]

hmm..pero sa power, anu naman ang effect? civics are know diba parang "mahina humatak sa trafic" because of mid-end max torque, unlike ung others na 2000-400 ang max torque....

no sir. i don't think so. its just that the 1st gear of the civics were tuned in somewhat higher gear ratio- and max torque of civic is at 3800 rpm(*least for the D15Y7). take my case, kaya ko mapag-wheel spin yung lxi ko at 2500-4000 rpm range. then the max horsepower could be had at 6400 rpm.