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標題: Difference in 4/6 cylinder [打印本頁]

作者: 紅豆冰 時間: 2008-5-30 18:35 標題: Difference in 4/6 cylinder

4 cylinder & 6 cylinder, what is the difference when driving?

作者: LOK 時間: 2008-5-30 18:51

two more cylinder? j/k

I think you need to tell more detail, like what kind of engine (inline 6, V6...), displacement, N/A or turbo...

作者: pkphilip 時間: 2008-5-30 19:18

6 cylinders means more power, torque than 4 cylinders. It depends on the needs again, most fast cars has 6 cylinders or more.

Obviously more power = more gas.

Philip

作者: LOK 時間: 2008-5-30 21:49

原帖由 pkphilip 於 2008-5-30 19:18 發表
6 cylinders means more power, torque than 4 cylinders. It depends on the needs again, most fast cars has 6 cylinders or more.

Obviously more power = more gas.

Philip

6 cylinders doesn't mean more power, more torque.
What about STI and EVO? more torque and power than accord V6, camry V6, BMW 330/328, MB C300/C350...

作者: 紅豆冰 時間: 2008-5-30 22:40

I saw the auto magazine, it said 2.0-liter turbocharged four-cylinder with some 200 horsepower; a 3.2-liter V-6 with around 260; and 3.0-liter turbocharged diesel V6 making 233 horsepower. So which one is better and more power?

作者: kencyliu 時間: 2008-5-30 23:02

一個汽缸的容量最理想是大約五百c.c.左右，所以三千c.c.以下的通常是四缸，容量愈大，汽缸愈多。
你不會買到二千c.c.的六缸或三千c.c.的四缸汽車，便是這個原因。
另外STI是turbo-charged，不能和自然吸氣的AccordV6比較的。
相同c.c.的turbo-charged的引擎輸出的馬力可以是自然吸氣的一倍半或以上。

作者: Vincehk 時間: 2008-5-30 23:02

It is like Superman VS Ironman.

Do you want natural power or boosted power ?

作者: blowfish 時間: 2008-5-30 23:24

Quite often a 6 cyl use almost same amount of gas as a 4cyl.
When u have more torque u no need to step on gas as much as a 4.
f u enjoy fast driving is better to have 6 too, otherwise a 4 u need to put pedal to metal most of the time.
Diesels may show less HP, but the torque output are as much as/or greater than a gas engine with same displacement.

Nowadays everybody is so sensitive that they thnk small engine = use less gas.

A fnd who has an old Toyo Landcruiser, it has a chebby 6. When the engine died he put a 327 V8 in it. The new V8 actually uses less gas, more power on hs truck.

作者: 紅豆冰 時間: 2008-5-30 23:58

If it is diesel, is it hard to find the gas station?

作者: 字典仔 時間: 2008-5-31 00:37

原帖由 紅豆冰 於 2008-5-30 23:58 發表
If it is diesel, is it hard to find the gas station?

disel ain't cheap nowadays, like $145 when 87 is at about $132? u can fill 94 for the same price

one might says gas will consume more gas, but i say diesel will consume more in maintenance lolz...

when one is shopping for a new car, lots of things are just #s

i would say with the technology nowadays a 2.0L turbo can easily compare with a 3.0L to 3.2L V6, a 2.5L turbo is almost in the 3.5L or 4.0L territory...

diesel is a totaly diff type of car, just like hybrid; diesel has very very strong torque but less horsepower that's why it's usually turbocharged nowadays (partially is to gain some power back)...

作者: WaruiOne 時間: 2008-5-31 02:54

so if turbo-charged is so much better, why dont they turbo-charge more of the V6s? or would it be too expensive?

作者: LOK 時間: 2008-5-31 08:57

You cannot say what's better.
S2000 is inline 4 N/A, 240hp
many inline 6 and V6 are also around 240hp

and you can't just compare hp, also need to compare the torque... and also what rpm is the max hp, max torque

作者: LOK 時間: 2008-5-31 09:23

原帖由 紅豆冰 於 2008-5-30 22:40 發表
I saw the auto magazine, it said 2.0-liter turbocharged four-cylinder with some 200 horsepower; a 3.2-liter V-6 with around 260; and 3.0-liter turbocharged diesel V6 making 233 horsepower. So which o ...

it seems you were looking at Audi's engine?! it really depends on the design of the engines, it's hard to say 4 cylinder or 6 cylinder better. Even both engine has same amount of cylinders, there are OHV, SOHC and DOHC... how many valves per cylinder... N/A, turbo or supercharge... compression ratio and some of the newer design have direct fuel injection system (FSI for Audi).
If you are really talking about Audi's 2.0T and 3.2, and you just want to know about power. Just chip the 2.0L for less than $1000, it will have similar hp and torque as the 3.2.

原帖由 kencyliu 於 2008-5-30 23:02 發表
一個汽缸的容量最理想是大約五百c.c.左右，所以三千c.c.以下的通常是四缸，容量愈大，汽缸愈多。
你不會買到二千c.c.的六缸或三千c.c.的四缸汽車，便是這個原因。
另外STI是turbo-charged，不能和自然吸氣的AccordV6比較的。
...

both BMW and Mercedes have 6 cylinder engines which less than 3.0L
Even turbo engine, different turbo size and boost will have different output. Can't just say turbo is better. Some N/A engines have higher output than turbo engines even they have same displacement.

作者: kencyliu 時間: 2008-5-31 11:05

我覺得turbo-charged engine 就像一個有蠻勁的年青人，V6就似一個成熟有內涵的成年人，不知對否？

作者: LOK 時間: 2008-5-31 12:16

原帖由 kencyliu 於 2008-5-31 11:05 發表
我覺得turbo-charged engine 就像一個有蠻勁的年青人，V6就似一個成熟有內涵的成年人，不知對否？

You could say that...
"usually" V6 is more quiet, smooth, more low end torque.
turbo "used" to be not smooth as N/A engine, power feels like "suddenly" come when the turbo kicks in. but now, many cars just added a small turbo with low boost, very smooth too.
there are advantage and disadvantage for different design of engines, Straight(inline), V, W, Flat(boxer)... for the V engines, there are different angle due to different design, usually 60º, 90º, but the VW VR6 is only 15º (if i remember correctly).
The advantage of V engine are shorter/smaller engine block and less vibration. But BMW has very good inline 6, Skyline GTR and Supra used to have inline 6 turbo too.

作者: shutterbug 時間: 2008-5-31 13:21

The general rule is:

1) More cylinders->power strokes are closer->smoother
2) V engines->more compact than inline->fit in a fwd car better
3) Higher displacement->needs more cylinders->heat dissipation problem

Actually, I disagree that diesel engines are higher maint and prone to problems. I think it's just that we only have VW diesels here for cars. Well, you know how VW's reliability is...don't need to say more. Diesels have less parts and their block is built using much stronger materials. Diesel price is higher than gas for the same liter, but diesel engines are way more efficient than gas. I'd say roughly 30-40% more mileage for the same size tank.

作者: 紅豆冰 時間: 2008-5-31 22:44

如果買車, 買邊款車好diesel or gas？

作者: siumaibb 時間: 2008-6-1 01:02

P-O-W-E-R!!!
(and gas....)

作者: siumaibb 時間: 2008-6-1 01:05

原帖由 紅豆冰 於 2008-5-31 22:44 發表
如果買車, 買邊款車好diesel or gas？

Bluetec from Mercedes
Q7 TDI is coming 2009

作者: MyOMy 時間: 2008-6-1 10:56

I agree with Shutterbug. The maintenance cost of should be less for diesel, you can read it from a lot of report or tech write ups. I used to own a diesel, the maintenance cost is less.

The decision criteria you need to choose is what you are comfortable to drive with and what your driving style is.

Diesel has better fuel economy, lower maintenance cost and longer enginer life span. But it has slower accerlation and startup, not cold winter friendly. Also it is more expensive.

So if you like to race between traffic lights and traffics, you will not find driving enjoyable with diesel.

作者: pkphilip 時間: 2008-6-1 12:33

Whether it is NA, Force Induction, there are reasons for putting different types of engines in different cars. Performance or ride comfort and applications are biggest reason I guess.

Generally, you want to pick a car depend on driving habit (majority on city or highway, stop & go, etc) and needs.

Especially with the high gas price these days, there's absolutely no reason to buy a SUV when you are driving alone or carry only 1 pessenger most of the time.

To combat high gas price and keep the maintanance low, I have an Odyssey, Mazda3 and Versa in our family (we need some stuff to write off for my parents' business); for city driving, going to work, I use the Versa because it is light and very flexible, thus saving a lot of gas even in stop and go traffic. Mazda3 is my toy, that doesn't count.

I only use the Odyssey when I have visitors and need to haul a lot of stuff. Out of the 3 cars, the Odyssey uses the most gas 15L/100KM. However, once on the highway, the Odyssey save a lot more gas caz the engine is powerful enough that it only requires little work to keep it at 100kph (higher RPM = more gas used). It deactivate 3 cylinders automatically at crusing speed and that keeps the consumption low. On the other hand, I have to push the pedel harder on the Versa to keep it up to 100kph. 3 different cars for various purposes. In no way I will drive my Odyssey in busy streets during peak hour.

Maybe my answer is irrevelent to the topic, I think cylinders are not so important when buying a car today.

Philip

[ 本帖最後由 pkphilip 於 2008-6-1 12:37 編輯 ]

作者: blowfish 時間: 2008-6-2 10:05

It deactivate 3 cylinders automatically at crusing speed and that keeps the consumption low.

When its running 1500 cc probably is adequate.

I guess Honda is successful to do that, I heard Merc in Europe does that on V8 they run on 4 when cruisng on hwy. Yrs ago GM had 4-6-8 V8 they failed miserably. So as anythng they touched.
If Honda can overcome the parasitic loss from the non running cylinders then s a good thing. Probably de-activates the intake and exhaust valve.
Old diesel boat engine was like that too, there's lever to turn off valves, when you crank the engne to start it has no compresson, so the fly wheel able to spn at a much hgher speed, then you flip the lever and the flywheel has enough energy stored to compress the engine to start.

A turbo engine saves most fuel s when u not usng the turbo, means just cruising along and not stepping on the gas hard.

作者: dtmeurosport 時間: 2008-6-2 22:09

There is no replacement for displacement. FI just don't give the same throttle response as NA.

作者: pkphilip 時間: 2008-6-2 22:14

According to Wiki:

In 2004, Honda introduced an i-VTEC V6 (an update of the J-series), but in this case, i-VTEC had nothing to do with cam phasing. Instead, i-VTEC referred to Honda's cylinder deactivation technology which closes the valves on one bank of (3) cylinders during light load and low speed (below 80 mph) operation. The technology was originally introduced to the US on the Honda Odyssey minivan, and can now be found on the Honda Accord Hybrid and the 2006 Honda Pilot.

Philip

作者: blowfish 時間: 2008-6-3 10:07

There is no replacement for displacement.

It was proven during the 60s' when Ford won the Le Mans , " Nothing beats the inches"
Now with high fuel price, unless you're the nephew of Sultan of Brunei, we all want something easy on fuel.

FI just don't give the same throttle response as NA.

Please elaborate ths phrase. FI= Fuel injection?
NA= Natural Aspirated?

closes the valves on one bank of (3) cylinders during light load and low speed

They may use solenoid opens the intake valves, dsabled the injectors. So there is no load in those cylinders. Closed the exhaust valves.
Maybe the GM failed because those engines were using carb, and cannot stop the gas going into those cylnders, mind as well be running it.

作者: xelloss 時間: 2008-6-3 10:19

原帖由 kencyliu 於 2008-5-30 23:02 發表
一個汽缸的容量最理想是大約五百c.c.左右，所以三千c.c.以下的通常是四缸，容量愈大，汽缸愈多。
你不會買到二千c.c.的六缸或三千c.c.的四缸汽車，便是這個原因。
另外STI是turbo-charged，不能和自然吸氣的AccordV6比較的。
...

Yep...I agree with this.

作者: LOK 時間: 2008-6-3 11:30

原帖由 blowfish 於 2008-6-3 10:07 發表
Please elaborate ths phrase. FI= Fuel injection?
NA= Natural Aspirated?

When he's talking about NA (Natural Aspirated), I believe FI = Force Induction.

作者: shutterbug 時間: 2008-6-3 11:35

BMW made small inline 6 before in their 320 I think. It was only 2L!

I guess...
FI = force induction

作者: MyOMy 時間: 2008-6-3 12:45

Back to the subject. 紅豆冰, have you decided what to buy 4 or 6 ? gas or diesel ?

作者: cyberstudio 時間: 2008-6-4 01:09

This is a complex question with no simple answer. But in my humble opinion, the biggest difference is in "smoothness". The more cylinders you have, generally the smoother will be your torque curve, meaning that you get more or less the same torque regardless of rpm.

For a typical 4 cylinder engine, torque is weak at low rpm. A 5 cylinder engine is significantly smoother than 4. A 6 cylinder shows additional improvement, but not as much an increase as you go from 4 to 5.

There are several configurations for 6 cyclinder, for example, inline or "straight". A straight 6 is a very long engine, and it can no longer be placed in the traverse orientation in the engine compartment. You will find such cars with a relatively long engine compartment, with the front wheels very close to the front bumper, and with some room between the front wheels and the firewall (e.g. Lexus IS250, BMW, Mercedes). This configuration is not good for front wheel drive - you will find almost all straight 6 to be rear wheel drive cars (or all wheel drive).

Volvo is one of the mainstream manufacturers with 5 cyclinder engines. The engine is now just short enough to be placed in the traverse orientation and therefore you find Volvos to be front-wheel drive cars (or all wheel drive). Having an odd number of cylinders, the engine is not naturally balanced and requires certain designs in the crankshaft, flywheel, engine mounts, etc. to compensate.

There are a lot of other configurations, such as H4, V6, H6, etc. Technology has been improving and if you drive for example a 4 cyclinder late model Camry you may notice that while it still drives like a 4-cylinder its smoothness has improved significantly.

V6, being shorter than straight 6, can be placed in the traverse orientation and suitable for front wheel drive. V6 is a lot more popular than straight 6 because front wheel drive is more popular than rear wheel drive.

Horsepower = torque x rpm. It is very common to find high horsepower 4-cylinder cars which revs up to 8,000rpm. Such cars are usually not smooth to drive. Depending on your style you may prefer a car with more cylinders than 4.

[ 本帖最後由 cyberstudio 於 2008-6-4 01:15 編輯 ]

作者: blowfish 時間: 2008-6-4 10:53

We need to ask the owner what cars he/she likes, budget/how deep s the pocket.
No point to go all over the map and dont know his preference.
Some only want cars from Fatherland, and some appy with Rice rockets.
If u know what to buy even a used car can be good, let the frst owner to pay for the initial depreciation.

Some even say u can need to own the car for several yrs longer inorder to justfy a hybrid.

The truth is buying any new car will cause a lot of environmental damages, u need mining, raw materials, energy to make steel. But if everybody stop buying new things our economy will be at a stand still. US account of 30-50% of world market, will see how bad will t affect us if they really catch a bad cold.

Some co design efficient bigger engines, IE Honda's variable 6.
Also depends yoru application, if u need to carry lots of people all the time then a bigger engine is advisable. I learn one organisation use Nissan Altima 2.5 and Camry 4 cyl to shuttle full pass load, the drivers find Camry lacks power as compare the Altima.
So u'll be screwed if u had made the wong choice of engne.

作者: Hyde 時間: 2008-6-7 09:05

just get a car with v8

作者: Godiva 時間: 2008-6-7 15:29

原帖由 cyberstudio 於 2008-6-4 01:09 發表
This is a complex question with no simple answer. But in my humble opinion, the biggest difference is in "smoothness". The more cylinders you have, generally the smoother will be your torque curve, me ...

For a typical 4 cylinder engine, torque is weak at low rpm. A 5 cylinder engine is significantly smoother than 4. A 6 cylinder shows additional improvement, but not as much an increase as you go from 4 to 5.

Mr. CyberStudio,

You are mostly correct in your post here, but the bolded line I quoted here is wrong. 5-cylinder engines are inherently rough-running because of the odd number of cylinders thumping up and down the engine block. In fact, 5-cylinder engines are often considered to be an inferior design because they lack the smoothness and power of a 6-cylinder engine, and the fuel economy of a 4-banger. This is why they are not that common in production cars. Generally speaking, inline 6 engines are the smoothest. V6 and I4 can be made to run quite smoothly as well.

Also, the old Mazda MX-3 Precedia had the the smallest production V6 rated at 1.8L. It was certainly a rare gem.

[ 本帖最後由 Godiva 於 2008-6-7 15:31 編輯 ]

作者: blowfish 時間: 2008-6-7 22:15

just get a car with v8

If your Uncle is Sultan of Brunei then a Bugatti Veyron's engne is still kind of small.

Low teens in MPG is not fun especially when u need to pay for it.
Now put $30 in is like putting in $20 last yr. Doesnt that suck bg time already.

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