There are quite a few things you can do to the N/A motor without adding a supercharger to get similar power. The difference between Jaguar’s versions is more than just a super charger and tune, there are numerous mechanical differences including the cooling system, fuel system, engine, suspension and many more. I don’t have to t handy but jaguar did publish a document that listed ALL of the differences frankly I have always found the MSRP price difference bereeen the 2 cars to be negligible considering how much you get for the extra money.

 

Also the transmission is slightly different. I understand. From what I understand, when the supercharger mod is made there is a bit of care that needs to be taken when implementing the power. I am now realizing that I am going to have to look into lowering the 11:1 compression ratio.

Kelly

 

Back in the day people wanted to slap on turbos to NA 944s, and that was silly because you could buy a proper 951 for less than any build. Suspension and Braking was significantly beefed up,plus there are many other little things that you have to replicate or improve on. id buy an XKR and mod it instead. I think the big misunderstanding these cars have, is that most folks assume that they’re just a rebadged Ford or something.

 

The reason I have for taking this route is the 07 xk I have is in super condition and don't want to get rid of it. I have done all black suede interior, some of the parts for which were very hard to find and with only 81000 miles and all lights upgraded and near perfect interior and all available options that I couldn't find on any xkr for $5k more and twice the miles. It's fast but I'm used to GSXR750 fast.

 

Gotcha. This is a bit of a dilemma for ya. Im on the same boat, except I miss having a clutch and the ability to blip the throttle before take off. Im addicted to the interaction. I have an 07 in great condition too, and I find the car to be pretty fast. The only people that I can recommend is SuperchargersOnline in Simi Valley or Nelson Racing in Chatsworth. These parts if the San Fernando and now Simi, are known for having lots of blown cars. I do wish ya luck!

 

I too REALLY miss the total control of complete manual. I do however like that it reaches just short of redline in manual mode before the shift. Though I would trade that for the complete control and the actual clutch. Thanks for the info, I will definitely investigate it further.

Kelly

 

How about adding a rear mounted turbo kit if looking for a decent hike in power, no need to decomp as 5psi would be sufficient.

I've looked at all options on the n/a and realistically the best route is attacking the top end.

 

I doubt I could get close to a hundred hp for under $3k. I'm looking at about $2700. Except that I have still to figure in that I need to find how to lose 2:1 in compression.

 

Hp comes at a cost !

The proper way off decomping would be rebuild with new piston, that being the case your budget would be completely shot .

The other alternative is decompression gaskets unsure how handy you are on the wrench but pulling the heads off isn't going to be a simple 2hr job.

Trust me I've been looking at increasing hp on the n/a without blowing the bank account

The other option is ecu tune, cooler plugs, enlarged crossover mid pipe, 100cell cats + 81mm throttle body (13.5 e.t)

 

How about Nitrous Oxide?

 

+1 nice option and low cost.

 

Moot point as all that stuff is cosmetic and simply unbolts to swap onto the new chassis.

Pointless once the bottle runs out and after a certain level you'll need a wet kit or need to trick the puter into over fueling while the gas is flowing.

Looking at it objectively you could physically bolt a Eaton onto a N/A engine and under drive to compressor to limit the boost but you'll need to modify the tune so the monitored results are within the limited 'safe' conditions to avoid a restricted performance dink. I wonder if Nitrous would flag an R/P limit?

 

Ranch yes he could run less boost on the eaton perhaps 5-7 safely but by the time you factor in parasitic loss due to the supercharger I wonder what the overall gain would actually be

 

That's what they did on the 5.0 Mustang. High factory compression and low boost gives big block torque. I ran a 10-1 setup on my 302 with a 5 psi Paxton and it made a lot of torque. 390 HP / LBFT to the rear wheels at 5200 rpm.

 

With a centrifugal charger yes obviously due to higher efficiency of the s/c -but just unsure how much can be gained at 5psi with the Eaton ???

I've looked at all angles of a build and it keeps going back to top end on these particular engines

 

Interesting, but think very carefully before you commit to starting this project as it will/could quickly become a bottomless pit to pour $$$$ into and kill the existing value of your XK, and for many of us those $$$ are hard to come by.
I can enjoy our 07 XK droptop for what it is, our summer cruiser that is fast enough to rarely be embarrassed for lack of power, the lady loves driving it with friends and needs the auto box.
My trackable / good handling toy is a Mazda RX8 R3, not high HP but don't try and stay with me thro' the curves, oh and it sounds wonderful shifting around 9000 rpm with the 6 speed manual. (and "heel & toeing" while braking for them)
Your GSX is more like my long gone CBR900RR, in its place there is now an 84 GS1150EF, still faster than the cars will ever be.
I will never mod the XK, a lost cause, BUT I am thinking about an old XJS that has already received a modded Corvette LS1 swap and then collecting the parts to convert to a 6spd and lower rear end gears etc... which could replace the RX8... I suspect it won't be long until GM drivetrains are finding their way into our XKs.
Luckily we still have a getting old AWD Toyo van for daily driving.
While anything may be possible, some are just not worthwhile, think VERY carefully before starting, your 81000 mile high compression, high reving aluminium V8 and its transmission may already be getting fragile.
Just wanted to share my thoughts / experience..
Good luck

 

The TVS series of superchargers approach 75% thermal efficiency, which is on par with modern centrifugal compressors.

 

5 PSI setups are not uncommon with the C5 Z06.

The thing about super charging vs more aggressive cam is a much flatter torque curve is achieved.

 

Totally Agree

But the OP is referring to bolting up the 4.2 set up being the Eaton

 

I missed that part. My apologies.