Hi I have searched and have not found real dyno results between these two models after being tuned with a pulley. I'm looking to purchase a 2009 but not sure if it will have the performce I would like. The differance between the 09/10 could be my deciding factor. Thx for any help

 

Get the 2010. Much higher hp/tq both in stock form and modified unless you spend big $$ on 4.2 mods.

 

Well to be honest the 09 is in my budget the 10 not so much but I guess I should say that the other car I'm comparing is an 08 s6 Audi with the v10 I just don't want to spend the cash on the xf if the 10 is that much better then the 09. That's why I have asked for a real world comparison from the 09 to 10

 

Well after some thought and more reading I will not be buying an xf maybe a posible xfr but not at this point still too expensive I feel. Thx

 

with the v12 in the audi i think you'd want the 5 litre engine to compete from a performance perspective.

when you factor in the depreciation on an '06 vs a '10 -- I kind of figured the audi would win out...

good luck

 

You never have mentioned what your budget is?

 

A 6 year old V10 Audi out of warranty would make me extremely nervous no matter what the price point. Just saying!

 

Well here an 08 Audi or an 09 xf are the same price around 25k but the 11 xfr is priced the same as an m6 or c63 or ctsv so many options at 43k and don't want to spend that.

 

4.2L SC = 420hp, 413tq
5.0: SC = 470hp, 424tq
Difference: = 50hp, 11tq

50hp (at the crank) is not hard to get out of the 4.2 SC. A $250 pulley nets ~35hp (at the crank). The 4.2L SC has some decent aftermarket support since it has been around so long.

Various sites with 4.2L SC pulleys and various other mods:
Jaguar Supercharger Upgrade | Jaguar Supercharger
Jaguar XF Upper Supercharger Pulley Upgrade 4.2L (2.5lb), Eurotoys,Ltd.
Jaguar XF Performance Supercharger Pulley for Jaguar NEW XKR (lists hp at the wheels which will be lower than crank hp)

 

Only point I was making is if you start with a 5.0 then do a tune and pulley for under $2K you can get to about 570 bhp/510 crank torque. It would cost a ton of money to get there with the 4.2.

 

And regardless of what you do the 4.2L will not make that kind of power.

We have been waiting for years for the twin screw blower for the 4.2L and it's only out for the XK guys and it's at least $5K+. We don't really have much if anything for a tune either!

Get the 5.0L it's way ahead of the 4.2L and I have a STR.
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So how do you tell if the supercharged car you are looking at has the good rear diff? Is it all 2009's are more prone to problems and they were fixed in 2010? Or does it have to do with the 5.0 vs 4.2 or something else?

 

It sounds like the OP doesn't want to pay for the 5L SC so it doesn't matter what can be done to the 5L SC. I was trying to show that you can get the 2009 4.2L SC, swap on a pulley, and be just has fast as the 5L SC. You'd save ~$10k which is a decent chunk of change.

 

+1 to your post. If the original poster is not going to modify the 5.0SC (non-R) then I agree 100% with your recommendation. On the STR we have seen 16rwhp (20bhp) and 12rwhp (14bhp) increases from the 1.5 pulley and intake respectively. That's very close to what the 5.0SC makes stock, and probably the 4.2 modded will have more low end torque because of the pulley.

 

Either way make sure it's a SC ...you'll be able to do the mods at your pace...tbird6 is twisted...I have the 4.2 and I'm pushing 490 BHP....having a custome exhaust fabricated and it will put me way into the 500 range. Also have an Audi A6 ...just not as exciting as the Jag !

 

Just a friendly question but where did you find the extra 50 or so HP with your 4.2 SC? In the STR subforum a member got his 4.2R tuned and I believe he yielded 7rwhp peak gain, so taking into account the power increase with the pulley (16rwhp), I am just curous how you got so much more power than anyone else. Would you be able to provide a dyno for reference? I would expect your car to be in the 365 -380rwhp range, but not the 420-430rwhp range where a 500bhp car should be.

 

Rasputin...No Dyno yet ...waiting further custom exhaust work....HP figures based on ECU tune and pulley at bout 65 HP increase...from stock 420 HP...added Mina Exhaust and K&N filters......will provide Dyno once completed.