4 cylinder traits

Bulkybear

Bulkybear

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Just have a general question about 4 cylinders and vibrations. All of the 4 cylinders I've driven including my si seem to vibrate more, especially idling, than the v6s and v8s I've driven. Why is this? Google search didn't really turn up an answer to this question.
 
You mean while sitting in it? You think 4's vibrate more than 6's? Like you're being shook in the seat?
 
I've driven some powerful 8's that definitely give you a shake at idle
 
Well it seems stock for stock idle vibrations have been worse in the 4 cylinders compared to 6 or 8.
 
If I remember right it has something to do with the firing order. When you have more pistons they fire closer to each other than an inline four which feels smoother. Thats why on something like a Harley Davidson V-twin engine you get more vibration than an inline 4 style bike.
 
Bulky Bear said:
Well it seems stock for stock idle vibrations have been worse in the 4 cylinders compared to 6 or 8.
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There are some different reasons for that , configuration is one, and I'm guessing you're talking about inline 4's . since that's what we have(back to this later)...... you take a boxer 4 and you can balance a 50 cent piece on it's edge(boxer is the same amount of cylinders pointing to the side 180º of each other). Or you can have a V-4 90º engine and that would be smooth also, not as smooth as a harizional boxer.

Now back to the inline engines, the more cylinders the more points of contact by way of crankshaft there will be , and each(how many) cylinder rods that push the CS the smoother the CS turns along with everything else, ie; a 12 cylinder inline would be smoother than a six, etc. (provided it tuned correctly, but that's for another day)..................
 
Monk said:
There are some different reasons for that , configuration is one, and I'm guessing you're talking about inline 4's . since that's what we have(back to this later)...... you take a boxer 4 and you can balance a 50 cent piece on it's edge(boxer is the same amount of cylinders pointing to the side 180º of each other). Or you can have a V-4 90º engine and that would be smooth also, not as smooth as a harizional boxer.

Now back to the inline engines, the more cylinders the more points of contact by way of crankshaft there will be , and each(how many) cylinder rods that push the CS the smoother the CS turns along with everything else, ie; a 12 cylinder inline would be smoother than a six, etc. (provided it tuned correctly, but that's for another day)..................
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Good explanation. This is what I was looking for. My civic has some idle vibrations, had a 92 camry inline 4 that vibrated like crazy. Moms 03 tacoma i4 vibrated a little. My v6 charger was a lot smoother, my 86 camaro iroc z28 idled pretty smooth.
 
Most big luxury cars are 8's cause they are a lot smoother. Power aside they do run a bit more refined. Huge street rod engines are a different story.
 
Bulkybear said:
Good explanation. This is what I was looking for. My civic has some idle vibrations, had a 92 camry inline 4 that vibrated like crazy. Moms 03 tacoma i4 vibrated a little. My v6 charger was a lot smoother, my 86 camaro iroc z28 idled pretty smooth.
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Did you have one of those bumper stickers "iroc do you" :giggle:
 
Want to talk about vibrating? Drive a flat four. They do this weird vibration back and forth thing sometimes that makes you feel like the car is powered by a 1950s washing machine. Although, once I got the pro-tune and had the idle raised to 900 RPM it went away.
 
All Subaru 4's shake a bit? Thought they'd be pretty balanced by design.
 
They do but occasionally they do this weird shudder thing on start up. If you shut it off and restart it goes away. The darn things seem to idle way too low from the factory. Since my tune idles at 900RPM, I don't have this anymore. Jeff probably still gets it.
 
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