# Why 5 cyl?



## wylemans (May 28, 2006)

Can anyone please tell me why VW used a 5 cyl in the Rabbit? I've been driving VW's for 10 years. I love my '08 Rabbit. I'm just curious why they used a 5 cyl.


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## shipo (Jan 3, 2006)

*Re: Why 5 cyl? (wylemans)*

Five cylinder engines are naturally far more in balance when compared to four cylinder engines of the same displacement, and as such are actually cheaper to build to an acceptable level of smoothness. That said, given that both versions of the 2.0T available in the GLI and GTI are equipped with balance shafts designed to cancel out engine vibrations, the I4 is actually smoother than the unbalanced I5. Look at it this way:
I4 (unbalanced) 2.0 liters = kind of a rough engine
I4 (unbalanced) 2.5 liters = a very rough engine (as I4 engines pass 2.0 liters, their vibrations magnify significantly)
I5 (unbalanced) 2.5 liters = a reasonably smooth engine
I4 (balanced) 2.0 liters = a very smooth engine
I4 (balanced) 2.5 liters = a very smooth engine
There is another category of smoothness that all 5 cylinder engines (and "even-firing" engines of six cylinders or more have to an even greater extent) exhibit, and that is in power delivery. Even-firing four cylinders have two periods per rotation where the flywheel is driving the engine, and two periods per rotation where the engine is driving the flywheel. Said another way, there are four "torque reversals" per rotation, and these transients need to be dampened out by a flywheel that is typically much heavier than say one found on a six cylinder engine of similar displacement.
Clear as mud?


_Modified by shipo at 9:57 PM 7-30-2008_


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## sagerabbit (Aug 14, 2007)

So would lightening the flywheel make this 5cyl beast unmanageable?


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## Audi4u (Jun 29, 2002)

*Re: Why 5 cyl? (shipo)*


_Quote, originally posted by *shipo* »_ Even-firing four cylinders have two periods per rotation where the flywheel is driving the engine, and two periods per rotation where the engine is driving the flywheel. 
_Modified by shipo at 9:57 PM 7-30-2008_

How many does the I5 have?


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## vw93to85 (May 10, 2007)

*Re: Why 5 cyl? (wylemans)*


_Quote, originally posted by *wylemans* »_Can anyone please tell me why VW used a 5 cyl in the Rabbit? I've been driving VW's for 10 years. I love my '08 Rabbit. I'm just curious why they used a 5 cyl.

Why not?


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## shipo (Jan 3, 2006)

*Re: (sagerabbit)*


_Quote, originally posted by *sagerabbit* »_So would lightening the flywheel make this 5cyl beast unmanageable?

No probably not. Inline 5-cylinder engines have some overlap on their power stokes and as such there aren't the torque reversals that are exhibited by all 4-cylinder (and fewer) engines.


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## shipo (Jan 3, 2006)

*Re: Why 5 cyl? (Audi4u)*


_Quote, originally posted by *Audi4u* »_
How many does the I5 have?

None.


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## anydub (Oct 3, 2003)

*Re: Why 5 cyl? (wylemans)*

take a lambo 5.2 liter v10(vw owned) cut it in half fill in the giant hole left bye the cuting down to 2.6 liter 5cyl. then change the head and shoten stoke bye .1 now at 2.5 liter mess with the contole systems and poof. i was told bye the toure giver at vw wolfsburg their is no reasoning behind some of the stuff they do other than resurch and developmen all it takes is an idea and they will play with it.


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## shipo (Jan 3, 2006)

*Re: Why 5 cyl? (anydub)*

Keep in mind that VW/Audi has a long history of I5 engines. My 1982 Audi GT Coupe had a 2.144 liter I5 engine that put out a whopping 100 hp @ 5100 rpms and 112.4 lb-ft of torque at 3,000 rpms. Believe it or not, in spite of the weight of ~2,500 pounds, that car was actually considered a "high performance car", errr, at least that's what one officer told me after pulling me over for "excessive acceleration".


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## bweed83 (Feb 25, 2007)

*Re: Why 5 cyl? (shipo)*

i almost got a ticket for the same thing and my tires didnt even break loose


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## MKVJET08 (Feb 12, 2008)

vw is famous for its unnecessary oddness and confusion...
and we all love it


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## BuddyWh (Nov 11, 2006)

*Re: Why 5 cyl? (shipo)*


_Quote, originally posted by *shipo* »_Five cylinder engines are naturally far more in balance when compared to four cylinder engines of the same displacement, and as such are actually cheaper to build to an acceptable level of smoothness. That said, given that both versions of the 2.0T available in the GLI and GTI are equipped with balance shafts designed to cancel out engine vibrations, the I4 is actually smoother than the unbalanced I5. Look at it this way:
_Modified by shipo at 9:57 PM 7-30-2008_

Excellent points, but in truth that's not the reason they put a 5 cyl. in the Rabbit, but it certainly ALLOWS the selection of a 5 cylinder.
http://www.autozine.org/techni...2.htm
Check out the above site for excellent explanation of the relative merits of 5 cylinder vs 4 cyl., etc. smoothness with diagrams.
I think there is no one reason, just a bunch of little ones: 
1) VW wanted more HP in a cheap entry-level car
2) Didn't want the complication/cost/reliability prob's. of a turbocharger for a cheap car.
2) US/Canada we aren't taxed for displacement as is EU so a 2.5L engine is feasible
3) A 2.5 4 cyl. needs a balance shaft (see above) for reasonable smoothness, with it's reliability/complications/cost hurting the business case for a $15K entry level price point.
4) 5 Cylinder in-line production cost is nearly the same for a 4 cylinder in-line _so long as you have the tooling for it_. 
5) VW has 5 cylinder tooling, experience and as well as that engineering/design quirkiness that VW fans seem to love.



_Modified by BuddyWh at 11:45 AM 8-11-2008_


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## T62 (Jun 15, 2006)

*Re: Why 5 cyl? (BuddyWh)*

"and we all love it '
Oh I didn't know that I loved assinine designs.


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## MKVJET08 (Feb 12, 2008)

*Re: Why 5 cyl? (T62)*


_Quote, originally posted by *T62* »_"and we all love it '
Oh I didn't know that I loved assinine designs.

do you own a 5 cyl engine?
if yes, do you like it?


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## BuddyWh (Nov 11, 2006)

*Re: Why 5 cyl? (MKVJET08)*


_Quote, originally posted by *MKVJET08* »_
do you own a 5 cyl engine?
if yes, do you like it?

Actually, I think the original post was about VW's tendencies to odd and quirky design in general...which seem to have been present throughout it's existence. All the way back to the quirky little beetle (I cursed their screwy heaters all the way through high school) the first Rabbit (who'd a thunk fWD would ACTUALLY take over like that?) small diesels and weird engine designs like VR6's and W8's.
The 5 cylinder design is actually kinda mainstream for them...not very quirky at all when taken in the context of THAT design history. And I am positive I have not covered even a fraction of the design quirks they've put into production.


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## CosmicSki (Jul 16, 2007)

*Re: Why 5 cyl? (BuddyWh)*

I don't see how this 5 cyl canbe so appealing , Ive driven my 08 Jetta now for 7 months, and this engine is just noisy, does not like to be reved, does not have a good exhaust note, useless beyond 5k rpm. I have owned a VR6 GTI and the new beetle, miss my VR6 everyday, it was just wicked in 3rd gear. I don't know where the 170 hp are, my vr6 only had 4 more Hp and pulled like it was on steroids. And all my cars where 5 speed.


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## dumbassmozart (Apr 19, 2007)

*Re: Why 5 cyl? (CosmicSki)*


_Quote, originally posted by *CosmicSki* »_I don't see how this 5 cyl canbe so appealing , Ive driven my 08 Jetta now for 7 months, and this engine is just noisy, does not like to be reved, does not have a good exhaust note, useless beyond 5k rpm. I have owned a VR6 GTI and the new beetle, miss my VR6 everyday, it was just wicked in 3rd gear. I don't know where the 170 hp are, my vr6 only had 4 more Hp and pulled like it was on steroids. And all my cars where 5 speed.

The stock engine is very dumbed down. I gave it an intake and software and it transformed a good bit. I think the new manifolds would help quite a bit too.


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## CosmicSki (Jul 16, 2007)

*Re: Why 5 cyl? (dumbassmozart)*

I think we are forgetting that the 5 CYL is the mass production workforce of the VW line up, its not meant to be the performer hence the GTI, GLI etc etc. It just seem the majority are under the impression that there is something of kill switch on the 5 cyl W installed and we have to uncover it to unleash the the ferocious 2.5 5cyl it is, but its not. Reminds me of all the kids trying to squeeze some imaginary gains out of their 1.7l Honda's.
Yes I've seen the "turbo" threads, you can boost anything these days but that's not the point is it?


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## dumbassmozart (Apr 19, 2007)

*Re: Why 5 cyl? (CosmicSki)*


_Quote, originally posted by *CosmicSki* »_ It just seem the majority are under the impression that there is something of kill switch on the 5 cyl W installed and we have to uncover it to unleash the the ferocious 2.5 5cyl it is, but its not. 

There's a guy on here that has matched GTI whp numbers with a non-boosted rabbit. 

_Quote, originally posted by *whatsyourbeef* »_...numbers as follows
178 HP, 204 ft-lbs torque!!! I think the intake Vic is working on will bump that considerably! I'm amazed at the pull in 3rd, 4th and even 5th gear at highway speeds! I love this car!


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## BuddyWh (Nov 11, 2006)

*Re: Why 5 cyl? (CosmicSki)*


_Quote, originally posted by *CosmicSki* »_...It just seem the majority are under the impression that there is something of kill switch on the 5 cyl W installed and we have to uncover it to unleash the the ferocious 2.5 5cyl it is, but its not. ....
Yes I've seen the "turbo" threads, you can boost anything these days but that's not the point is it?

With the way the motor dies as it approaches red line it's really not hard to understand why they'd believe it. Especially since VW has been known to do it before when they feel their entry level car could cannibalize upper tier products. I seem to recall a restricter plate in the exhaust of 1.8L Fox engines. Pull that out, get a free 10 or 20 HP at top end and go hunting GLI's.
I'm really interested in reading of gains to be got as cams come available. Probably no easier or cheaper than a turbo install but I think an NA solution is so much more elegant.


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## undercoverdubber (Aug 24, 2008)

*Re: Why 5 cyl? (BuddyWh)*


_Quote, originally posted by *BuddyWh* »_
... but I think an NA solution is so much more elegant.

Me to, tho I wouldnt say no to a low boost sc.


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## pezzy84 (Apr 12, 2003)

*Re: Why 5 cyl? (CosmicSki)*


_Quote, originally posted by *CosmicSki* »_I don't see how this 5 cyl canbe so appealing , Ive driven my 08 Jetta now for 7 months, and this engine is just noisy, does not like to be reved, does not have a good exhaust note, useless beyond 5k rpm.

If you think your 170HP is noisy and not willing to rev you would shoot yourself in the face if you had to drive the earlier 150 HP version. 
The 170 HP unit is what VW should have released in the first place instead of releasing the half baked 150. Granted I don't hate my '06 Jetta its just the engine seems to be a big compromise of everything. 
I will say though my 2.5 Jetta is smoother running than my carpool buddies '04 2.4L Camry, that thing is a buzzy little beast.


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## mexglx (Apr 22, 2003)

*Re: Why 5 cyl? (pezzy84)*

I searched posts for 150 to 170 hp upgrades. Anyone know of a good one? Is it cost effective to make your '05.5 like an '08 or just as easy to get a chip and intake and get the same results? 
I have seen posts that the intakes trip CELs. Is it easier to go find an intake manifold & ecm off a wrecked '08 car and slap it on the '05.5? 
Sorry to be OT.


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## BuddyWh (Nov 11, 2006)

*Re: Why 5 cyl? (mexglx)*


_Quote, originally posted by *mexglx* »_I searched posts for 150 to 170 hp upgrades. Anyone know of a good one? Is it cost effective to make your '05.5 like an '08 or just as easy to get a chip and intake and get the same results? 
I have seen posts that the intakes trip CELs. Is it easier to go find an intake manifold & ecm off a wrecked '08 car and slap it on the '05.5? 
Sorry to be OT.

Reason intakes throw CEL's is mixture runs lean at high rpm/throttle settings. Best fix is higher capacity injectors. 
A restricter plate in the intake path also fixes it (I think one of the intake mfr's features one standard with their intake) but it sounds pretty sub-optimal to me. I mean, you just put the intake on to let it breathe freely, and then choke it off again to keep CEL's at bay??
That's my take on what I've been able to gather reading the posts, at least.
A GIAC chip gets you to 170 HP territory...check their site and dyno results. There's been lots of talk about p/no differences between 08 and pre-08 but nothing has been definitive about whether anything actually results in higher horsepower. The effectiveness of the GIAC chip really supports the notion it was tuning that provides bulk of the gain and not the parts anyway.
For my money, putting an '08+ ECU means you crap your warranty just as much as burning the GIAC program, but getting the GIAC programming is a lot easier. And you KNOW it will work while the ECU swap is a shot in the dark.
But that's just my thinking...


_Modified by BuddyWh at 12:04 PM 10-21-2008_


_Modified by BuddyWh at 12:08 PM 10-21-2008_


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## CosmicSki (Jul 16, 2007)

*Re: Why 5 cyl? (pezzy84)*


_Quote, originally posted by *pezzy84* »_
If you think your 170HP is noisy and not willing to rev you would shoot yourself in the face if you had to drive the earlier 150 HP version. 
The 170 HP unit is what VW should have released in the first place instead of releasing the half baked 150. Granted I don't hate my '06 Jetta its just the engine seems to be a big compromise of everything. 
I will say though my 2.5 Jetta is smoother running than my carpool buddies '04 2.4L Camry, that thing is a buzzy little beast. 

Am glad I waited for the 170hp version, preferred not to shoot my self in the face.


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## the_humeister (Sep 25, 2008)

I wish they'd offer more fuel-efficient engines as they do in Europe.


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## anydub (Oct 3, 2003)

*Re: (the_humeister)*

if you took your car to europe it would get about 8 more mpg do to better quality fuels, that is the soul reason we did not get the 1.4 twin charged engine(our fuel wll not run it corectly) but you pay a lot more for it so it works out.


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## CosmicSki (Jul 16, 2007)

*Re: (anydub)*

Wish they sold the Polo with the 1.4 superchg/turbo here.


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## shipo (Jan 3, 2006)

*Re: (anydub)*


_Quote, originally posted by *anydub* »_if you took your car to europe it would get about 8 more mpg do to better quality fuels, that is the soul reason we did not get the 1.4 twin charged engine(our fuel wll not run it corectly) but you pay a lot more for it so it works out.

I'm not at all sure what you're talking about regarding the quality of the fuel between Europe and North America. Believe it or not, they're virtually identical; in fact, a huge percentage of the gasoline that we get here in North America comes from Europe. Why? Because they are so diesel-centric over there that they actually produce way too much gasoline for their own consumption once they've distilled what they need in diesel.


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## anydub (Oct 3, 2003)

*Re: (shipo)*

our fuel has mush more additives such as ethinal and such it makes a big differance it is very noticeable in a car, i lived there and brought my 72 beetle with me and carbs dont lie


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## shipo (Jan 3, 2006)

*Re: (anydub)*


_Quote, originally posted by *anydub* »_our fuel has mush more additives such as ethinal and such it makes a big differance it is very noticeable in a car, i lived there and brought my 72 beetle with me and carbs dont lie









I've lived, worked and bought cars over there (including my 530i), and believe it or not, they have identical fuel, even to the point of having ethanol laced brews in many localaties. The fact of the matter is that the automobile manufacturers and the oil companies have come up with global fuel standards, and while some places (India for instance) don't adhere to said standards, Europe and North America certainly do.


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## BuddyWh (Nov 11, 2006)

*Re: (shipo)*


_Quote, originally posted by *shipo* »_
I'm not at all sure what you're talking about regarding the quality of the fuel between Europe and North America. Believe it or not, they're virtually identical; in fact, a huge percentage of the gasoline that we get here in North America comes from Europe. Why? Because they are so diesel-centric over there that they actually produce way too much gasoline for their own consumption once they've distilled what they need in diesel.

In the NE you're certainly right, but not because of diesel. The US barely has refinery capacity to handle our own gasoline demand in so we have to buy overseas and store it for peak season use. Companies can't make a case for a 20 year investment commitment to add to capacity when government regulatory climate so severely discourages it.
If you consider that in the EU they are taxed based on engine displacement and so 2.5L engines are generally found in luxury marks over there, not entry level beaters like the Rabbit. The proletariat get 1.4L toys that need heroic measures to get decent HP for safe hiway use, if they make the effort at all. Result is higher fleet economy numbers.
I've been reading that VW's 1.4L twincharger is a bit of a maintenance nightmare with a lot of very unhappy owners in UK. But then, some people are endeared to mechanical curiosities and make allowances so I guess that won't matter much. The thing that attracted me to this little 5 banger in the first place was it's relative simplicity of design. Nice basic NA motor. 

_Modified by BuddyWh at 7:56 AM 10-22-2008_


_Modified by BuddyWh at 9:01 AM 10-22-2008_


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## shipo (Jan 3, 2006)

*Re: (BuddyWh)*


_Quote, originally posted by *BuddyWh* »_In the NE you're certainly right, but not because of diesel. The real reason is the US barely lacks refinery capacity to handle our own gasoline demand in and we have to buy overseas and store it for peak season use. Companies can't make a case for a 20 year investment commitment to add to capacity when government regulatory climate so severely discourages it.

I'm not sure what you're trying to say here. The fact is that out of every barrel of crude oil, the distillation process yields roughly 50% gasoline, 25% diesel, and 25% other fuel oils, lubricants and asphalt. Given that over half of the motor vehicle fuel sold in Europe is diesel, it is a fact that they're producing LOTS of gasoline that they cannot use. Regardless of whether we were able to increase our refining capacities here in North America, we would most likely still benefit from that surplus of gasoline that the European refineries produce.


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## BuddyWh (Nov 11, 2006)

*Re: (shipo)*

I am sure that EU refiners could find domestic or pipeline- terminus markets for any so-called surplus gasoline without the expense of tankering it to the US. 
Point is: the US needs to import it far more than the EU needs to export it. That's one reason gasoline is so high: it's not due to a shortage of crude stocks, but shortage of refined stocks. If it were as you said, gasoline price should be lower in the US (or at the least more stable) as the EU eagerly dumps an otherwise valueless product over here. 



_Modified by BuddyWh at 3:17 PM 10-22-2008_


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## anydub (Oct 3, 2003)

*Re: (BuddyWh)*

we have gone way off topic but you seem to know a lot about this subject and all i know is off my own exp living both here and there. and as for the 5cyl question why not insted of why?


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