curious if anyone has ever supercharged a normally aspirated xk w/ a 4.2L?


wondering if there is a whipple application that would be fun to add? is it possible with the space? would the whipple be capable of producing more power?


I know there is the option of just buying an xkr version but I just wanted to be provocative...has this been done?

 

ferraripete
There are a couple of posts on the X100 forum where owners with both 4.0 and 4.2L engines have either done it or asked the same question. You might want to look there for some answers. Even though it's the previous generation XK, the 4.2 engine was a carryover til 2010.

Also, I read one of your other posts in which you stated that you owned a Bora, beautiful car which shares many of its parts with my '72 Pantera. The sports cars that came out of Italian design in the early '70's are just incomparable!

 

To make it effective, durable and worthwhile the engine compression ratio needs to be reduced from 11:1 to about 9:1.

Adding substantial boost on top of 11:1 is not a good idea in other words.

 

yes my bora was one a few of the cars I have owned that should have been a keeper. it was an all original 18k mile, zero rust (at least that was detectable) example...never should have sold. I also have always been a pantera fan. I have always thought not many cars scream 70's Italian exotica like a de tomaso and let's face it...the campy's alone are examples of artwork. the pantera's will soon really have their day!!! sorry to get off topic but I had to comment on your pantera as they trump nearly any car I care to discuss

 

Well, I see a familiar name over here.

I feel like its the same as asking about turbocharging a 944, the cost vs just getting a 944 Turbo is going to work out in favor of the factory setup car to start with.

If you kept the stock compression ratio, you'd never really be able to add adequate boost. You'd want a system that only provided forced induction to cover a range where the intake is limited in flow. Lacking the equipment to test flow the head to find out, I can't really know what is worthwhile or not. I would imagine it would be the upper rev range, which would favor a centrifugal setup.

I just did my first fill up on the XK this morning. Got it less than two weeks ago, when did you get yours? Mine was precipitated from having a 2015 Porsche 911 for a day, and I came to realize even if a little more boring, modern cars have their advantages.

 

Andrew,


very good to see you here!! and congrats on your xk...very pretty car!
I bought a 4k mile xk convert about 4 months ago. it was sitting in the scott jaguar showroom. I saw it as I was driving to foreign cars italia to go buy a maser gran turismo coupe. I quickly stopped in to have a quick look at the xk in the showroom and use the facilities. 5 mins later I had bought an as new xk for half the price of the maser. deal done and I was happy as can be!!


please head up my way sometime soon. let's hang out and talk racing and cars


cheers my friend!!


peter

 

Cheapest way: sell car, buy SC car.

 

Hello Pete

With the guidenace of Cambo (moderator of forum) we together have been on a massive journey and have looked at many options for the n/a 4.2 .

The main road block being the standard pistons and obviously funds to conduct the work.

The supercharger route would be a massive task and forget resale on the vehicle the best option Cambo and myself came up with was bolting up the aston martin vantage v8 heads to the jag block the only problem with this method would be the valves would hit the standard pistons and you would be required to get new fly-cut pistons. Due to the sheer expense of that option I decided not to go ahead

The second option we looked at was to get the cams re-grounded and the heads ported depending at what price you can get this option done for this could be a good idea I would suggest getting a few quotes on this unfortunately in Australia I couldn't find a performance shop to carry out the work for less than 15-20k aud so that was canned .

Third option - The option i have gone for
As the Cats are a huge restriction on these motors the best option is replace them with 100 racing cell cats. As far as our exhaust are concerned the 4-2-1 headers are good for up to 400hp and at 2.25" standard exhaust is more than satisfactory . The standard intake is restrictive so a custom job will be required, after all that has been completed the vehicle would need a dyno tune to adjust the timing / fuel.

My vehicle had the cats done last week and is extremely more free revving now , I've got the car booked in for Monday & Tuesday next week to be tuned on the dyno once that is done I will post up before and after charts.

 

great intel steve. I think the cats and headers would be a nice mod...look forward to hearing more about your thoughts and results!!


best,

 

Yes believe me all the hard research has been done when it comes to performance upgrades on the n/a

Yes Pete it should be interesting to see how it goes next week on the dyno

 

steve,


any dyno results to report for the hi-po cats?


look forward to hearing.


Best,


Peter

 

While it's absolutely true that the most economical solution is to buy a supercharged car up front, if money is no object then anything is possible.

Here's some supercharged V8 Vantage's...

RSC Tuning V8 Vantage 4.3L Supercharger Project Completed - 6SpeedOnline - Porsche Forum and Luxury Car Resource

And

GMR 600 Aston Martin V8 Vantage first drive

Did you notice the price for the GMR kit? Twenty Thousand Pounds!

 

I literally just off the phone to Autotech results

Oetuning + 100 cell cats -226 rwhp
Custom tune + 100cell cats -250rwhp

I'll be sure to post up charts once I get them unfortunately I never dynoed the vehicle as a dead stocker but we have come to the conclusion that the 100 cell cats + custom dyno tune is the way to go

 

Hey that's pretty good! What about the torque numbers?

 

I'm actually quite impressed with the figures although would have great to see the dead stock output as I'm sure the cats would have free'd up a few horse power .
Unsure of torque figures I will find out once I get the charts but he did say torque was increase throughout the entire rev range

 

I'd rather see a twin turbo setup if you are spending the money!!

 

Totally agree Phil if your going to spend tt is the way to go !

 

Picked up the xk a few hours ago and I can tell you I'm totally shocked I did not expect so much of a noticeable difference
Along with the overall hp increase torque is also up by 8% throughout the entire rev range
Pete I would highly recommend the 100cell cats and a custom tune it's a proven combination you'll be impressed

 

thanks for keeping us updated!


help me understand how the rwhp works out considering a fairly standard 18-20% driveline loss? I thought stock hp at the crank was on the order of 300?


I am just unclear how the stock rwhp number would seem to be so low? sorry if this is a dumb question.

 

If you take 20% loss then 300hp x 0.8 = 240hp

Assuming that the engine was actually making 300hp in the car when it was new (doubtful).

And that after so many years/miles the engine was still making 300hp (doubtful).

And you can't take dyno numbers as gospel either, my car was on 3 different dyno's and there was 40rwhp difference between them.

The important thing to see with Steve's XK is the gains, not the outright number. If you try to analyse the factory rated power with the dyno number and drivetrain losses you'll just end up confused or frustrated, or both!

But we have seen another 4.2L N/A with cats/exhaust/ECU tweak on the dyno and it made 240rwhp so it's all in the ballpark.

The gain is more important than the outright number.