5 Cylinder Engines

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59
Location
Texas
My wife just purchased a Volvo with an inline 5 cylinder engine. I know the Chevy Colorado uses on also. A 5 cylinder engine seems odd to me. Are there advantages to an inline 5 versus an inline 4 or 6? The only things I can think of is maybe it is smoother than a 4 and less expensive than a 6. Jon
 
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43,667
Location
'Stralia
Jon, it's just an engineering compromise, shorter than a straight 6, bigger capacity than a 4. Personally, I don't like the idea of a 5, but they are out there, and work.
 
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4,872
Location
MN
Most engine designs made today are not naturally balanced. The only common naturally balanced engines are an I6, V8, V12 or any boxer engine. To make up for it they use a balance shaft. Most four cylinders use a balance shaft so it's not really that much different in an I5. -T
 

GSV

Messages
696
Location
Utah
I can't see anything inherently bad with an inline 5. A connecting rod on the crank every 72 degrees shouldn't be worse than every 90 degrees in a 4. Since Mitsubishi's patent ran out on counter-rotating balance shafts you can probably smooth out anything besides a single cylinder. I would only worry if the engines design was a poorly executed chopping off of the 6th cylinder from an inline 6. Advantages: More power than a 4 in a non VVT'd / fairly basic design. Lighter and fewer moving parts and friction than a 6. AFAIK they've been around since the 70s in the Audi 5000. [Cheers!] [Patriot]
 
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9,448
Location
USA
It is better then the old V4's that were circulateing for a while! Ford had a V4 that they used in Europe for a while and it was something else! It surely was not one of their better ideas.
 
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23,591
I wish my Audi had the old 5 cyliner inline motor instead of the newer V6! The I-5 was a very rugged, very tune-able Audi motor.
 
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716
Location
San Gabriel Valley
quote:
Originally posted by GSV: I would only worry if the engines design was a poorly executed chopping off of the 6th cylinder from an inline 6. Advantages: More power than a 4 in a non VVT'd / fairly basic design. Lighter and fewer moving parts and friction than a 6. AFAIK they've been around since the 70s in the Audi 5000. [Cheers!] [Patriot]
The newly released Jetta V also has the R("Reihe" - inline)5/I-5 2.5...derived or shall we say "chopped off" from the 493hp 5.0 V10 Lamborghini Gallardo engine. The R5 will also show up later this year in the refreshed '06 New Beetle. A lot of folks commented on such a low hp(150hp) output coming from a 2.5ltr engine...one has to bear in mind that this is detuned for the North American market. Surely future stock versions or a modded one can yield way better. [ May 22, 2005, 07:20 PM: Message edited by: vwoom ]
 
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489
Location
Quebec, Canada
That new VW inline 5 is far from impressive. First of all, before saying that it is half a Lambho V10, look at the bore and stroke? 82.5mm X 92.8mm. Does that ring a bell? Same as the antediluvian 2.0 inline 4... Looks more like a cylinder grafted to that old workhorse than an exoticar engine cut in 2! OK, it has a new head but a heavy iron block for only 150 hp from 2.5l. Compare that with Honda's versions of the 2.4l at 160 and 200 hp and much better mileage numbers. I bet that Honda/Acura motorists won't lose any sleep.
 
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694
Location
Saskatchewan, Canada
An engine is naturally balanced if the angle between firing sequences is a full multiple of the angle between the cylinder banks. So on a 6 cylinder engine for example, you have a firing sequence every 120 degrees. So the only 2 naturally balanced configurations are: 60 degree V6 or I6(360 degree bank seperation). Other naturally balanced engines are: 90 degree V8, 60 degree V12, I4, I5, I6, I8, flat 4.
 
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43,667
Location
'Stralia
olympic, a 90 degree V-twin can have perfet primary balane (with only slight rocking couple if the rods share a crank pin)...unequal torque intervals however.
 
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1,904
Location
Canada
Actually to get no negative-sequence torque harmonics, you need 18 equally angle-spaced cylinders. Otherwise, you will have counterrotating torques which are manifested as negative sequence and zero-sequence harmonics. Everything under 18 cylinders is just a compromise between power, vibrations, and maintenance concerns. Most large diesels are built as 18 cylinder engines for the perfect balance such a configuration provides.
 
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11,247
Location
PA
Every I-5 I have owned was bullet-proof. I feel like it's totally adequate for small car apps where 6 cyl is overkill and 4 cyl is inadequate.
 
Messages
716
Location
San Gabriel Valley
quote:
Originally posted by Minou: That new VW inline 5 is far from impressive. First of all, before saying that it is half a Lambho V10, look at the bore and stroke? 82.5mm X 92.8mm. Does that ring a bell? Same as the antediluvian 2.0 inline 4... Looks more like a cylinder grafted to that old workhorse than an exoticar engine cut in 2! OK, it has a new head but a heavy iron block for only 150 hp from 2.5l. Compare that with Honda's versions of the 2.4l at 160 and 200 hp and much better mileage numbers. I bet that Honda/Acura motorists won't lose any sleep.
[Roll Eyes] Excerpts from the Jetta 5 article at VWVortex(same can be read about just about every article in auto rags about the J5/R-5 engine): "...The new 150-hp inline-5 cylinder has been developed specifically for the U.S. market and replaces the old tried-but-true 2.0 4-cylinder. The 2.5 has been designed to be cost effective, not require premium fuel like a lot of other newer engines, have high torque characteristics and potential for more power over the lifecycle of the engine. Peak horsepower of 150 is reached at 5,000 rpm and peak torque is reached at 3,800 rpm, with 90 percent available from 1,750 to 5,125 rpm. Being based loosely on half of the V-10 Lamborghini Gallardo engine you might hope to see half the Lambo's 500 horsepower, but that isn't the case. VW tells us that the 2.5 is detuned for use as the entry-level engine. This means that expensive variable valve trains, dual plenum intakes and such all got left on the shelf in the name of cost savings. VW's engineers are quick to point out that the 2.5 could make more than 200-hp with some basic modifications. Given that the 2.0T FSI engine is also capable of more than 250-hp from the factory, both engines signal good growth potential and positive signs for the aftermarket which is chomping at the bit to get their hands on something new these days..." http://www.vwvortex.com/artman/publish/article_1283.shtml [ May 23, 2005, 01:16 AM: Message edited by: vwoom ]
 
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2,187
Location
Arizona
I guess I'm a dissenter. I don't see the reason for an inline 5 in something like the GMC Canyon/Chevy Colorado. Harmonic balance is awful in an inline 5, but balance shafts can pretty well eliminate that problem. However, an inline 5 is longer than a compact V6, so you lose packaging efficiency. I can understand it in a transverse layout if you have the engine bay width, because you can have a lower hood than is possible when trying to clear the front bank of a V6 if you rock it backwards, but I don't think VW does that. I suppose it has fewer moving parts, but the total number of moving parts doesn't seem to be of particular concern in a road-going automobile engine. I just don't get it apart from a novelty marketing effort: "This thing has half a Formula-1 engine in it! That is... until next year when they go to V8s..."
 
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47,786
Location
Everson WA - Pacific NW USA
The NA 2.5L I-5 in our Volvo 850 (that's what the 5 in 850 stands for) has been pretty solid. My only problem is the peakiness of the powerband. 168HP at about 70000 rpm or something....but it does wind up pretty good for a heavy car (low gears!)
 
Messages
4,872
Location
MN
quote:
Originally posted by olympic: An engine is naturally balanced if the angle between firing sequences is a full multiple of the angle between the cylinder banks. So on a 6 cylinder engine for example, you have a firing sequence every 120 degrees. So the only 2 naturally balanced configurations are: 60 degree V6 or I6(360 degree bank seperation). Other naturally balanced engines are: 90 degree V8, 60 degree V12, I4, I5, I6, I8, flat 4.
That simply means the firing sequences are balanced. Even 90 degree V6s can have that with a split-pin crank. 60 degree V6 do have an inherit unbalance that is small but still there. Check out this link about engine configurations: http://www.thrashercharged.com/tech_htm/tech_info.shtm I5 engines are done for one reason, to save money. But that doesn't mean they are bad engines, there are thousands of comprimizes made in any automobile for cost. The Atlas series engines are available in I4, I5, and I6 configurations. They can share most engine design and lots of parts. Plus it gives you a nicely spaced outputs so consumers get more choices. -T
 

JonC

Thread starter
Messages
59
Location
Texas
quote:
Originally posted by Pablo: The NA 2.5L I-5 in our Volvo 850 (that's what the 5 in 850 stands for) has been pretty solid. My only problem is the peakiness of the powerband. 168HP at about 70000 rpm or something....but it does wind up pretty good for a heavy car (low gears!)
Pablo, is the NA 2.5L engine in your 850 pretty much the same engine as the NA 2.4L engine in our '05 V70? I agree they are heavy cars - the sticker on our V70 says it is something like 4600 lb. It feels pretty solid. Jon
 
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