anong ibig sabhin ng v8 at v12

[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?

[empy]

ayan na namn tayo...seryosong nagtatanong di masagot ng maayos...
ano nga ba uli yon brod?

bakit mo naman nasabi yan...post #2 pa lang nasagot na yung katanungan...

[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

[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?

[yuichi]

bakit mo naman nasabi yan...post #2 pa lang nasagot na yung katanungan...

pangatlo hanggang pang-walo yata eh kulitan na. anyway serious n uli. interesting topic naman siya.

[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'.