# So what did VW do to add 20hp to the 08 rabbit?



## crosshare (Mar 4, 2008)

I was in Stamford, CT earlier today and talked to a very knowledgeable GTi owner who told me it's just programming. Is this true and could VW offer an ECU software upgrade in the near future? 
I guess I'm jealous even though it's just 20 more horsepower. 
Maybe I could throw a vtec sticker on there and get 30 more Horsepower.








Seriously, though, I bought this car with a 7 year/75,000 mile warranty and I want to keep her as stock as possible without voiding the warranty. I.E. throwing a K&N panel instead of a CAI.


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## qezel (Mar 29, 2006)

*Re: So what did VW do to add 20hp to the 08 rabbit? (Nathan and his Rabbit)*

they just raised the redline... same peak torque, but more hp.. hm? sounds like they just let it spin higher, but they could have given it a different tune


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## crosshare (Mar 4, 2008)

*Re: So what did VW do to add 20hp to the 08 rabbit? (qezel)*


_Quote, originally posted by *qezel* »_they just raised the redline... same peak torque, but more hp.. hm? sounds like they just let it spin higher, but they could have given it a different tune

That's one thing I noticed when I bought my 07 and I have to remind myself that I'm no longer driving a mazda 3 with its 6800 rpm redline.








Nothing mechanically has changed, however I googled it up and found that VW added variable valve timing to the 08s which doesn't sound right for VW.


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## spitpilot (Feb 14, 2000)

*Re: So what did VW do to add 20hp to the 08 rabbit? (Nathan and his Rabbit)*

VW got out its eraser..took out the 5 and wrote in a 7!


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## Jefnes3 (Aug 17, 2001)

*Re: So what did VW do to add 20hp to the 08 rabbit? (spitpilot)*

REAL ANSWER:
The marketing dept. want to see different numbers, and poof the car makes 20hp more.
Some stuff is different form '07 to '08, but nothing to make a real honest 20hp.
-Jeffrey Atwood


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## digitaltim (Apr 17, 2007)

*Re: So what did VW do to add 20hp to the 08 rabbit? (Jefnes3)*

08 = +6hp.
The End. (we wish)


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## 1_BADHARE (Mar 8, 2008)

*Re: So what did VW do to add 20hp to the 08 rabbit? (digitaltim)*


_Quote, originally posted by *digitaltim* »_08 = +6hp.


true story


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## Toiletcar (Aug 3, 2007)

*Re: So what did VW do to add 20hp to the 08 rabbit? (Nathan and his Rabbit)*

there has been much debate over this. i believe it is a cam shaft difference. not ecu or anything else. there aren't that many dynos for 08'. if it does have 170 hp then it should be putting down 145-150 whp which i have seen. pre-08's seem to be putting down 130-138. there isn't a real difference in torque. it makes sense i guess. if you read all the road test in Car and Driver, and Road and track, there is a difference in 0-60, which makes me thing that there is a bigger difference in hp. i plan on getting one soon for a baseline.


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## DC1.8T (Aug 23, 2003)

*Re: So what did VW do to add 20hp to the 08 rabbit? (Nathan and his Rabbit)*

I also noticed VW's specification sheets list the hp figures for the '07 rated on 87 octane and the '08 rated on 93.


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## Toiletcar (Aug 3, 2007)

*Re: So what did VW do to add 20hp to the 08 rabbit? (DC1.8T)*


_Quote, originally posted by *DC1.8T* »_I also noticed VW's specification sheets list the hp figures for the '07 rated on 87 octane and the '08 rated on 93.









could that really make a difference?


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## theskippur (Jun 26, 2000)

*Re: So what did VW do to add 20hp to the 08 rabbit? (Toiletcar)*


_Quote, originally posted by *Toiletcar* »_there has been much debate over this. i believe it is a cam shaft difference. not ecu or anything else. there aren't that many dynos for 08'. if it does have 170 hp then it should be putting down 145-150 whp which i have seen. pre-08's seem to be putting down 130-138. there isn't a real difference in torque. it makes sense i guess. if you read all the road test in Car and Driver, and Road and track, there is a difference in 0-60, which makes me thing that there is a bigger difference in hp. i plan on getting one soon for a baseline. 


Also, in C&D, when comparing the datasheets of the two comparison tests that included a 150 hp Rabbit and a 170 hp Rabbit, the in-gear acceleration times drops by an average of 1 second or more. This, IMO, is significant for passing times and shows an increase on power across most of the powerband of the engine.


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## shipo (Jan 3, 2006)

*Re: So what did VW do to add 20hp to the 08 rabbit? (DC1.8T)*

Per the VW web site, the 2008 2.5 liter Rabbit engine makes 170/177 HP/Torque on "Regular unleaded".
http://www.vw.com/rabbit/compl...w_all


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## digitaltim (Apr 17, 2007)

*Re: So what did VW do to add 20hp to the 08 rabbit? (shipo)*


_Quote, originally posted by *shipo* »_Per the VW web site, the 2008 2.5 liter Rabbit engine makes 170/177 HP/Torque on "Regular unleaded".
http://www.vw.com/rabbit/compl...w_all

lol.
that's not what that states


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## shipo (Jan 3, 2006)

*Re: So what did VW do to add 20hp to the 08 rabbit? (digitaltim)*

What?


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## digitaltim (Apr 17, 2007)

*Re: So what did VW do to add 20hp to the 08 rabbit? (shipo)*

it just says 87 is the fuel requirement.


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## crosshare (Mar 4, 2008)

*Re: So what did VW do to add 20hp to the 08 rabbit? (Toiletcar)*


_Quote, originally posted by *Toiletcar* »_there has been much debate over this. i believe it is a cam shaft difference. not ecu or anything else. there aren't that many dynos for 08'. if it does have 170 hp then it should be putting down 145-150 whp which i have seen. pre-08's seem to be putting down 130-138. there isn't a real difference in torque. it makes sense i guess. if you read all the road test in Car and Driver, and Road and track, there is a difference in 0-60, which makes me thing that there is a bigger difference in hp. i plan on getting one soon for a baseline. 


Welp, if that's true, there goes my letter to VW corporate to offer an ECU reflash for 06/07 Rabbits.


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## shipo (Jan 3, 2006)

*Re: So what did VW do to add 20hp to the 08 rabbit? (digitaltim)*


_Quote, originally posted by *digitaltim* »_it just says 87 is the fuel requirement.


The key word being "_*requirement*_". That means that you should _never_ use midgrade or premium fuel, period, full stop, the end. That in turn means that the 170/177 HP/Torque numbers are achieved on 87 AKI fuel.


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## selfatvi (Aug 13, 2003)

i asked that same question to the sales rep and was told it was a "software" upgrade. However i find this hard to believe.
for $300 i can get a after market software upgrade which will hopefully net me 10hp gains and i must run on 91. So how the heck did VW do 20hp gain with no higher octane requirements?


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## digitaltim (Apr 17, 2007)

*Re: So what did VW do to add 20hp to the 08 rabbit? (shipo)*


_Quote, originally posted by *shipo* »_
The key word being "_*requirement*_". That means that you should _never_ use midgrade or premium fuel, period, full stop, the end. That in turn means that the 170/177 HP/Torque numbers are achieved on 87 AKI fuel.

I'm fairly sure the use of 'requirement" there means that the minimum octane rating needs to be 87 or higher.
As in 85 would not be ok, but 87, 89, 91, or 93 would. you;re not going to void your warranty using higher than 87, but using 85 would.










_Modified by digitaltim at 1:17 PM 5-19-2008_


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## shipo (Jan 3, 2006)

*Re: So what did VW do to add 20hp to the 08 rabbit? (digitaltim)*


_Quote, originally posted by *digitaltim* »_
I'm fairly sure the use of 'requirement" there means that the minimum octane rating needs to be 87 or higher.
As in 85 would not be ok, but 87, 89, 91, or 93 would. you;re not going to void your warranty using higher than 87, but using 85 would.









_Modified by digitaltim at 1:17 PM 5-19-2008_

And I'm absolutely positive that "requirement" means just that, the _required_ fuel for all normal driving, period, full stop, the end. The other language car manufacturers use it which fuels are "recommended", as in BMW saying that Premium fuel is recommended.
When a given grade of fuel is "recommended" that means that other fuels can be safely used, albeit with somewhat reduced performance and mileage, however, when there is a "requirement" for a given grade of fuel, that one grade IS the fuel that should be used.
Another note, all manufacturers publish power and torque numbers relative to their recommended or required fuel, no exceptions.
Regarding your warranty, no grade of fuel will cause VW to void it. In fact, if you drive at high altitudes you'll find that "Regular" fuel is more like 84 or 85 AKI, and not only will that fuel run perfectly well in the 2.5 liter mill when above 5,000 feet MSL, it is still the "required" fuel.


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## digitaltim (Apr 17, 2007)

*Re: So what did VW do to add 20hp to the 08 rabbit? (shipo)*

ok.. I'll go with that


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## MKVJET08 (Feb 12, 2008)

*Re: (selfatvi)*


_Quote, originally posted by *selfatvi* »_i asked that same question to the sales rep and was told it was a "software" upgrade. However i find this hard to believe.
for $300 i can get a after market software upgrade which will hopefully net me 10hp gains and i must run on 91. So how the heck did VW do 20hp gain with no higher octane requirements?

aftermarket software yielding 10 hp and 12tq puts that hp and tq to the wheels... vw didnt get 20 extra hp to the wheels, they got it to the crank


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## selfatvi (Aug 13, 2003)

*Re: (MKVJET08)*


_Quote, originally posted by *MKVJET08* »_
aftermarket software yielding 10 hp and 12tq puts that hp and tq to the wheels... vw didnt get 20 extra hp to the wheels, they got it to the crank

that makes no sense....
those 20 to the crank will carry down additional HP to the wheels, so there is still a net gain of 20hp. Its not like the additional HP disappears because it goes to the wheels.
You take the older 150gp car, maybe to the wheels 130 (guess).
Now you take the new 170hp, maybe get 150 to the wheels (also guess)
Now add 10 to each, 140 wheels for older model, 160 for newer model.
That is still a 20hp difference.


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## Toiletcar (Aug 3, 2007)

*Re: (selfatvi)*


_Quote, originally posted by *selfatvi* »_
that makes no sense....
those 20 to the crank will carry down additional HP to the wheels, so there is still a net gain of 20hp. Its not like the additional HP disappears because it goes to the wheels.
You take the older 150gp car, maybe to the wheels 130 (guess).
Now you take the new 170hp, maybe get 150 to the wheels (also guess)
Now add 10 to each, 140 wheels for older model, 160 for newer model.
That is still a 20hp difference.









the power is more noticeble through out the power band and not at peak. not every engine will put down the same #s. things like what kind of dyno, air temp, humidity etc...make a difference too. i've seen 172 crank VR6 put down anywhere from 135-170 whp. in theory they all should be putting down 150 whp.


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## selfatvi (Aug 13, 2003)

*Re: (Toiletcar)*


_Quote, originally posted by *Toiletcar* »_
the power is more noticeble through out the power band and not at peak. not every engine will put down the same #s. things like what kind of dyno, air temp, humidity etc...make a difference too. i've seen 172 crank VR6 put down anywhere from 135-170 whp. in theory they all should be putting down 150 whp. 

Little confused, you saying that both cars have the same power but numbers were manipulated by testing conditions?
I know they do that for AS SEEN ON TV type BS auto performance parts but would never expect it from such a large company as VWOA


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## shipo (Jan 3, 2006)

*Re: (selfatvi)*

I don't think anybody said that the 2006-2007 2.5 puts out the same power as the 2008. That said, my bet is that under say 4,000 RPMs the additional power of the later engine would be hard to notice.
FWIW, at various times and at various places around the internet I've read that the following items were changed for the 170 HP version of the 2.5:
1) Engine software
2) Intake plumbing
3) Cam profiles
The first one is all but an absolute lock, the second seems highly likely, and the third I'd only give even money on.


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## pmacutay (Aug 1, 2007)

The funny thing is, though, on the GTI's specs page, VW quotes "Regular unleaded" as 91 octane gas. 
If so, then the jump to 170 probably came from a remapped ecu to take advantage of 91 octane gas.








http://www.vw.com/gti/complete...w_all


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## selfatvi (Aug 13, 2003)

*Re: (pmacutay)*


_Quote, originally posted by *pmacutay* »_The funny thing is, though, on the GTI's specs page, VW quotes "Regular unleaded" as 91 octane gas. 
If so, then the jump to 170 probably came from a remapped ecu to take advantage of 91 octane gas.








http://www.vw.com/gti/complete...w_all



dont know if this has anything to do with it
"Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON)."
http://en.wikipedia.org/wiki/Octane_rating


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## shipo (Jan 3, 2006)

*Re: (pmacutay)*

As *selfatvi* wrote, you're confusing European Octane ratings with the wacky AKI thing we have going on over here. Said another way, 91 Octane fuel in Europe is the same as 87 AKI over here.


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## [email protected] (Dec 5, 2005)

*Re: So what did VW do to add 20hp to the 08 rabbit? (shipo)*


_Quote, originally posted by *shipo* »_
The key word being "_*requirement*_". That means that you should _never_ use midgrade or premium fuel, period, full stop, the end. That in turn means that the 170/177 HP/Torque numbers are achieved on 87 AKI fuel.

I'd take a guess and say they meant recommended, instead of requirement. I find it hard to believe that VW requires you to _never_ use a higher grade fuel.


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## shipo (Jan 3, 2006)

*Re: So what did VW do to add 20hp to the 08 rabbit? ([email protected])*

While I agree the language is, ummm, unusual for an engine designed to run on Regular Unleaded, it isn't without precedent either. Why? Well, given the low(er) compression ratio these engines typically have, they don't generate the necessary heat/pressure during the compression stroke to fully utilize higher AKI fuels, and that in turn means that the flame front will be a bit slower crossing the combustion chamber, this of course causes nominally less heat to be generated by the combustion process. The lower the heat from any given amount of fuel, the worst the fuel economy, the lower the power, and more importantly, the _higher_ the combustion chamber deposits.
So, if I was to design an engine that was optimized for Regular, and for whatever reason was unable to have the OBC dynamically tweak the valve and ignition timing enough to take advantage of higher octane fuels, then I too would "Require" 87 AKI fuel.


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## pmacutay (Aug 1, 2007)

from Wiki:
"It should be noted that octane rating *does not relate to the energy content of the fuel (see heating value), nor the speed at which the flame initiated by the spark plug propagates across the cylinder.* It is only a measure of the fuel's resistance to autoignition."
http://****************.com/smile/emthup.gif


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## shipo (Jan 3, 2006)

*Re: (pmacutay)*


_Quote, originally posted by *pmacutay* »_from Wiki:
"It should be noted that octane rating *does not relate to the energy content of the fuel (see heating value), nor the speed at which the flame initiated by the spark plug propagates across the cylinder.* It is only a measure of the fuel's resistance to autoignition."
http://****************.com/smile/emthup.gif

That isn't exactly correct. The speed of the flame front for regular gasoline being burned in an engine designed for regular gasoline should be roughly the same as the speed of the flame front for premium gasoline being burned in an engine designed for premium. Granted it's quite a bit more complicated than that, however, it is safe to say that higher octane gasolines _need_ more pressure/heat in the combustion chamber the get them to burn as designed.
Said another way, if you burn Premium in an engine designed for Regular, the peak pressure and temperature will be lower than optimum, while if you burn Regular in an engine designed for Premium, the peak pressure and temperature will be high enough to cause detonation. Once detonation occurs, one of two things are going to happen, A) the sensors will retard the ignition timing (and valve timing if so equipped) to protect the engine, thus reducing power and economy, or B) the engine might/will suffer dammage (depending upon the severity and duration of the detonation).
Regarding Wikipedia, while a very good source for information, it is NOT a definitive source. If one wants more concrete information on this subject, I suggest a trip through the SAE archives.
http://www.sae.org


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## crosshare (Mar 4, 2008)

I think this might've gone a bit off-topic. 
Is the change in HP based on mechnical upgrades or software?


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## shipo (Jan 3, 2006)

*Re: (Nathan and his Rabbit)*

The consensus is both (i.e. ECU, Intake Manifold, and Cam grind).


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## foolclear (Jun 27, 2008)

*Re: (shipo)*

I think we will never know what they really did to the engine but people here saying they notice the differene from the 150 hp to the 170 hp a broader powerband i have not driven the 150hp model but all i know is i need more power!


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## crosshare (Mar 4, 2008)

*Re: (foolclear)*


_Quote, originally posted by *foolclear* »_I think we will never know what they really did to the engine but people here saying they notice the differene from the 150 hp to the 170 hp a broader powerband i have not driven the 150hp model but all i know is i need more power!









werd. From my experience it's almost pointless to drive past the 4500rpm mark unless you want to dump gas. Unless I spend $4k on a turbo, I guess it's just staying stock. 
I still love my rabbit tho. I wouldn't want anything else.
Well, maybe an R32.












_Modified by Nathan and his Rabbit at 12:20 PM 8-13-2008_


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## bunnyhopin (Dec 19, 2007)

*Re: (Nathan and his Rabbit)*

wait ive been usein regular gas since i got my 08 ??? should i be useing premium???? WTF


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## shipo (Jan 3, 2006)

*Re: (bunnyhopin)*


_Quote, originally posted by *bunnyhopin* »_wait ive been usein regular gas since i got my 08 ??? should i be useing premium???? WTF









Nope, you should be using exactly what you're using. Putting 91 or 93 AKI in your tank is a waste of money unless your engine is "chipped".


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## turbomonkeyexpress (Nov 26, 2004)

Im not quite sure where, but i've seen a dyno graph of an 08 vs 07, and the power/torque curve is much smoother in the 08, vs the 07's choppy curve. Furthermore, I Drove an 07 rabbit / stock, then an 08 Rabbit / stock. The 08 felt smoother and pulled a tad harder, a more refined feel to the motor.


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## bunnyhopin (Dec 19, 2007)

*Re: (shipo)*

thanx for the info i was freakin out for a lil http://****************.com/smile/emthup.gif


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## crosshare (Mar 4, 2008)

*Re: (shipo)*


_Quote, originally posted by *shipo* »_
Nope, you should be using exactly what you're using. Putting 91 or 93 AKI in your tank is a waste of money unless your engine is "chipped".

:werdgah! you guys don't have that smiley here!)
In fact, the first fill up in my rabbit was with 93 and it ran crappy. Stick with 87 and enjoy saving $4-5 per fillup. http://****************.com/smile/emthup.gif


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## joeoregon (Apr 10, 2006)

Here is some info that I sourced from an internal VW website. The site is a forumn for Dealership Employees to ask questions fielded from themselves and customers. 
BTW: the part numbers for the camshafts listed in ETKA from 2006-2008 2.5 engines are all the same thus ruling out anydifference in the cams. 
"The increase is primarily due to some computer "engine mapping" in addition to a few other minor, but effective hardware changes (FSI has not been added.) Please do not expect to add these changes on your own...it's more involved than just this list.
Here's a list of some changes made to the 2.5L engine to increase the HP....I hope it makes sense....ENJOY!!
The following on the engine changes were sent to me in German so I had to get someone to translate it for me...it's pretty close.
- • valve-seat insert and valve guide
- • oilcooler
- • knock sensor and cam sensor
- • In-/outlet valve
- • no sec. air pump pipe for ULEV2
- • no two mass flywheel
- • torsional dumper crankshaft PKO
- • bearing pin transformation chain drive
- • chain drive 1 (Crankshaft,dubblechainwheel, oilpump)
- • change from roller chain to tooth-type chain
- • crankshaft change to tooth-type chain
- • manifold, because 125kw
- • no t-sensor intake air
"
I hope you all find that interesting and helpful.


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## digitaltim (Apr 17, 2007)

*Re: (joeoregon)*

manifold


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## 2ohgti (Nov 8, 2004)

*Re: (joeoregon)*


_Quote, originally posted by *joeoregon* »_Here is some info that I sourced from an internal VW website. The site is a forumn for Dealership Employees to ask questions fielded from themselves and customers. 
BTW: the part numbers for the camshafts listed in ETKA from 2006-2008 2.5 engines are all the same thus ruling out anydifference in the cams. 
"The increase is primarily due to some computer "engine mapping" in addition to a few other minor, but effective hardware changes (FSI has not been added.) Please do not expect to add these changes on your own...it's more involved than just this list.
Here's a list of some changes made to the 2.5L engine to increase the HP....I hope it makes sense....ENJOY!!
The following on the engine changes were sent to me in German so I had to get someone to translate it for me...it's pretty close.
- • valve-seat insert and valve guide
- • oilcooler
- • knock sensor and cam sensor
- • In-/outlet valve
- • no sec. air pump pipe for ULEV2
- • no two mass flywheel
- • torsional dumper crankshaft PKO
- • bearing pin transformation chain drive
- • chain drive 1 (Crankshaft,dubblechainwheel, oilpump)
- • change from roller chain to tooth-type chain
- • crankshaft change to tooth-type chain
- • manifold, because 125kw
- • no t-sensor intake air
"
I hope you all find that interesting and helpful.


truth ^
06' and 07' owners are pissed and don't want to believe









the torque is the same though.


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## digitaltim (Apr 17, 2007)

*Re: (2ohgti)*


_Quote, originally posted by *2ohgti* »_
truth ^
06' and 07' owners are pissed and don't want to believe








the torque is the same though.

did you really just stir the pot? Do you even own a rabbit or do you just like to fart in the presense of others?


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## crosshare (Mar 4, 2008)

*Re: (2ohgti)*


_Quote, originally posted by *2ohgti* »_
truth ^
06' and 07' owners are pissed and don't want to believe








the torque is the same though.

Throw in an exhaust, GIAC software and carbino intake and we're close to 170. Oh well. Not like I'm ricing...I mean racing it.


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## 2ohgti (Nov 8, 2004)

*Re: (digitaltim)*


_Quote, originally posted by *digitaltim* »_
did you really just stir the pot? Do you even own a rabbit or do you just like to fart in the presense of others?

I have an 08' 4 door Rabbit. I found the same info. 
shut up noob http://****************.com/smile/emthdown.gif


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