Does a V6 Engine Use More Gas Than A V4 ?

geno

Lifer
Dec 26, 1999
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Wow, they're still making V4's? :D Jeez, I don't know how much gas a V4 uses, although Inline 4's (I4's) are pretty efficient on gas :D

Fundamentally, yes, a V6 will use more gas up than a 4cyl. I'm sure there's some older inline4's that will guzzle gas more than a more modern V6....
 

UnatcoAgent

Diamond Member
Oct 25, 1999
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Maybe there is some confusion between V and cylinder. To clear up yes I meant cylinder engine, there are quite a few new cars with 4 cylinder engines. Anyway my question still stands, thanks geno though.
 

thedarkwolf

Diamond Member
Oct 13, 1999
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It depends. There are v8 cars that get around 30mpg highway and there are 4 bangers that get around 25mpg highway. It has a lot to do with weight, wind resistance, and gearing.
 

LAUST

Diamond Member
Sep 13, 2000
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it's not a question of 4 vs 6 cyl it's a case in all engine sizes.. does it have the torque to power the weight/size of vehicle you are driving. If that engine is underpowered and working too hard it will then get less milage. If the I4 had adequate power it will get the better milage in generic cases.

Edit:

See theDarkWolf's post ;)
 

brxndxn

Diamond Member
Apr 3, 2001
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What if it was a huge 4-cyl and a tiny 6-cyl? I mean.. I always wondered why they didn't just make a small 16cyl block
 

LAUST

Diamond Member
Sep 13, 2000
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Originally posted by: brxndxn
What if it was a huge 4-cyl and a tiny 6-cyl? I mean.. I always wondered why they didn't just make a small 16cyl block
Cause larger cylinders/pistons make more energy/torque due to their mass.

 

Howard

Lifer
Oct 14, 1999
47,982
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Originally posted by: LAUST
Originally posted by: brxndxn
What if it was a huge 4-cyl and a tiny 6-cyl? I mean.. I always wondered why they didn't just make a small 16cyl block
Cause larger cylinders/pistons make more energy/torque due to their mass.
I've never heard this before. I'm pretty sure you don't get MORE torque from heavier pistons.

As to the original question, cost, efficiency, and size. You have to replicate the valve actuation system, pistons, rings, conrods, bolts, etc. The second thing - the smaller the displacement per cylinder, the higher the relative friction (per unit of displacement). You want to keep friction as low as possible.
 

vi edit

Elite Member
Super Moderator
Oct 28, 1999
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Peeps are leaving out something very important - GEARING.

 

Thegonagle

Diamond Member
Jun 8, 2000
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Originally posted by: brxndxn
What if it was a huge 4-cyl and a tiny 6-cyl? I mean.. I always wondered why they didn't just make a small 16cyl block

Many more moving parts increase frictional losses. That would decrease mileage, and potential torque/horsepower. The added complexity would offer no advantage.
 

Babbles

Diamond Member
Jan 4, 2001
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I think as others have said by and large a I4 will get MPG over a V6, however I know that my current 3.8 liter V6 gets better gas milage than an old 1982 4 banger Accord I had.
 
Aug 16, 2001
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More cylinders means more valves ---> more intake/exhaust area.
An engine is basically a pump so a bigger area for the engine to breathe through means more power.
 

Howard

Lifer
Oct 14, 1999
47,982
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Originally posted by: vi_edit
Peeps are leaving out something very important - GEARING.
What does that have to do with anything? Torque is torque, RPM is RPM.

Unless you mean they might have different gearing, but why not just assume that they do? I think he wants to know which uses more gas only because of the engine structure.
 

vi edit

Elite Member
Super Moderator
Oct 28, 1999
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What does that have to do with anything? Torque is torque, RPM is RPM.

Unless you mean they might have different gearing, but why not just assume that they do? I think he wants to know which uses more gas only because of the engine structure.

Eh. I guess I looked at it from a practicality standpoint. Who cares how much gas a stand alone engine consumes. An engine sitting on a stand running is useless in figuring out milage numbers.

Just my opinion anyway.

When I said gearing, I was talking about in actual application IE IN A CAR. It's because of gearing that the 5.7L V8's in the Camaro's and the Vette's can pull 28MPG rivalring many V6's and even some I4's in highway gas milage. If they didn't have that 6th touring gear they'd never be able to pull those numbers.
 

Zenmervolt

Elite member
Oct 22, 2000
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Given the two engines in isolation (eg, not installed in a car or any other machine), and given that both engines are identical displacement and given that both engines produce identical amounts of power, then the 4-cylinder engine will use slightly less gasoline than the 6-cylinder engine because of increased frictional losses in the 6-cylinder. If you put the engines in a car, then all bets are off because of variables such as drag, vehicle weight, and gearing. If a 4-cylinder engine has to spin at 3,500 RPM at 70 mph, and a V8 only has to spin at 1,500 RPM at 70 mph, then the V8 can (but does not have to) get better mileage.

ZV