Hi Stephen, unfortunately this tube will not fit your car it is specifically for the 4.2 supercharged engine.

Best regards,

John

Hey Caldoofy, any updates on the carbon intake?

Hi, stage 2 master part is away to get moulds made hopefully have some progress on this soon.

Do you have a price in mind? I just purchased an 07 STR and will be putting either your stage 1 or stage 2 on!

Not as yet but just over cost price as the stage 1 is.

I am very interested in the stage 1 tube for my 06 XJR. Please let me know how to order 1. Thanks. 2006 XJR

still enjoying the combination? Do you have pix of the intake tube and cold air kit?

Hi caldoofy,

Your revised intake looks beautiful!

I will be very interested to learn about your design theory and to see graphs of the horsepower and torque gains and at what engine speed(s) the increases occur. Are the gains only at the highest revs or are they at more useful low to mid revs? Is the increased noise focused in a particular frequency range or is it an overall increase in sound?

From the little research I've done, the resonators designed into the stock XJR intake plumbing (and those for other cars with resonators) are not for noise reduction alone, though noise reduction and tuning may have been part of the design objective. The primary purpose of the resonance chambers is to better synchronize the actual air supply (mass transfer) with the movement of the pistons at one or more engine speeds. In scientifically-controlled tests, properly-designed intakes with resonance chambers have outperformed straight pipes of larger diameter. See the articles at the links below for just two examples that support the benefits of resonance chambers. Here's just one sentence from the fluid dynamics analysis in the second article:

"The goal [of resonant chamber tuning is] to improve the filling (i.e. the torque) at a certain rpm (for example, to contrast some negative pressure-wave effects) or in an interval of engine speeds (to improve the whole power delivery curve)."

Soarer - The Intake Resonator
FLUID DYNAMIC STUDY OF INTAKE MANIFOLDS OF INTERNAL COMBUSTION ENGINES IN PRESENCE OF ACOUSTIC RESONATORS

Please convince me that your intake really does provide superior performance and not just more noise, because I sure love the way it looks!

Cheers,

Don

There have been back-to-back dyno tests on this type of intake elbow done here on the forum and all of them have shown at least a 10hp gain at the wheels

Here's one

https://www.jaguarforums.com/forum/s...-thread-79842/ showed 10hp at the wheels "Russ' intake tube"

Cambo351,

Thanks for the info and the link. The first comparison between the stock plumbing with drop-in K&N filter and Russ' intake tube certainly looks promising, but it is difficult to interpret the results as accurately as I would like due to the two graphs having different horizontal scales.

And of course, the fact that the early tests were done at 90 degrees F and the final test was done at 60 degrees F no doubt gave the Mina 1.5 pulley some additional advantage in the overall comparisons.

Cheers,

Don

@Don B

The main problem with the standard intake tube is the extra turbulence introduced by the resonance chambers and the corrugated section just after the MAF sensor the articles you have posted relate to naturally aspirated engines and not forced induction, the two types behave very differently.

Quote from the article :

''The article points out the difference between filling a cylinder with air and just straight out flow. The resonator actually helps fill the engine with more air since it is a cyclic event - not a continuous flow as such. The resonator acts as an extra reserve of air to fill the cylinder with more air. Only applies to naturally aspirated engines - so if you turbo or supercharge the engine then you may as well get rid of it''

This turbulence effectively offers resistance to the air being sucked in by the supercharger creating more vacuum. By smoothing this flow, in the same way that you might flow a cylinder head, you are reducing the resistance to flow and therefore increasing the efficiency of the intake system the by product of this is the increased 'whine' from the supercharger and of course a few HP!

The main reason for the resonance chambers on a jaguar is actually to cancel the sound adding to the air of refinement, the mass transfer that you reference could be measured in milliseconds (once the chambers are drained going from closed to WOT) and after that as previously described they become a restriction.

As Cambo has pointed out these mods are well documented on this forum with proven gains and from traces the gains are across the board.

The stage 1 uses 80mm tubing as this is the diameter of the MAF sensor and therefore the point of restriction, with a larger MAF and throttle body alied to larger intake tube more gains would be possible.

Hope that helps and thanks to Cambo for the link.

Hi caldoofy,

Thanks for the reply. Sorry to be so skeptical, but the stock inlet on our XJR has no fewer than six resonance chambers of varying cross-sections and lengths. That's a tremendous amount of engineering and significantly increased manufacturing cost just to quiet induction noise. Based on what I've read, including the articles at the links I provided earlier, I have to believe the Jaguar engineers were tuning engine performance as well, probably to smooth power delivery and broaden the power curve.

I'll anxiously await your dyno graphs! I'd really love to mount one of your beautiful intakes on our car, and hopefully your documentation will convince fact-seekers like me who are jaded by all the snake oil being offered in the tuner market.

Cheers,

Don

Don,

The article you referenced stated itself and i quote

Quote from the article :

''The article points out the difference between filling a cylinder with air and just straight out flow. The resonator actually helps fill the engine with more air since it is a cyclic event - not a continuous flow as such. The resonator acts as an extra reserve of air to fill the cylinder with more air. Only applies to naturally aspirated engines - so if you turbo or supercharge the engine then you may as well get rid of it''

The dyno graph already given shows the gains of these tubes (the scales are like for like and the only change was the intake tube, i think you initially were looking at the wrong two?) And there are others giving the same conclusion - search is your friend here.

And regards to the engineering companies like Jaguar, Bentley, Rolls Royce do indeed invest a great deal of time and money to make their cars as quiet as possible and this is the only reason i can see on a supercharged car to have them. Of course everyone is entitled to their opinion but of all the tubes i have sold on here i have yet to have a disappointed customer which in itself speaks volumes i feel.


Best regards,

John

Hi John,

Thanks for your patient replies. The line you quote is from the non-scientific article of the two I posted, so I tend to discount the author's conclusions compared to the second article. But if the resonant chambers can, or simply SHOULD be removed from a supercharged engine's intake, why did Jaguar include them on the XJR? Which raises another question: Is the XJR intake tube the same design as the N-A XJ8 tube?

Regarding the dyno graphs, I was comparing the first two, since, if I understand the captions, the top graph is for the stock intake plumbing with a drop-in K&N filter as the only mod, and the second graph is for Russ' tube with no other mods reported. In the top graph, the horizontal graduations are spaced at 300 rpm intervals, while in the second graph they are spaced at 350 rpm intervals, so comparing the red line from the second graph with the red line from the first graph is not as direct as a skeptic like me would like it to be, and makes it difficult to confirm that no offset has been introduced that might misrepresent the actual results.

I'm honestly not trying to be a jerk or to poo-poo your product. I really do want to understand all the issues involved, the compromises taken by the Jaguar engineers to achieve their design objectives, and the real-world differences offered by your intake design.

Thanks again for your patient replies!

Cheers,

Don

Don,

It's a personal thing, but for me you may be overthinking it. You've made two very good points in passing..

1: Increase the noise
2: It looks good

As someone that has fitted Caldoofy's intake pipe I can tell you that I like it a lot simply because of the two points above. It does increase the noise, it's not loud or obtrusive, far more subtle than that! The key point for me though is wow - its a big shiny bit of metal in an otherwise dull boring and plastic filled engine bay. I cant tell of any meaningful power increase, my foot\pants don't tell me i've strapped a twin screw supercharger on the car (nor did I expect them to), but that enhanced whine is highly addictive.

I'll be at the front of queue when he gets the stage 2 version completed which as I understand it is perhaps even more performance enhancing.

So, two fantastic reasons in themselves to get one. Perhaps if you have a greater understanding in this area than others you could do the more detailed research and share with those of us that just like the shiny noisy stuff ;-)

You've been attacked by internet worm. Sometimes it happens. Sorry, no offence to anyone.


PS It's a shame new carbon elbow is not ready yet especially when you swap to summer tires to push it hard.. :icon_playing::icon_mrgreen:

Welcome to the forum Sochi2014,

When you get a minute, please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see.

In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

Thank you!


Just done.


regards,
Alex

Beavis,

I completely agree that the stock Jaguar setup is too quiet for the taste of many, including myself, and I completely agree that caldoofy's intake is beautiful and adds a massive improvement in under-hood appearance.

I'm just trying to understand why the Jaguar engineers went to such obviously great lengths to design the intake tube with six resonance chambers (probably tuned Helmholtz resonators) if their only design objective was noise reduction. It would have been much simpler and far less expensive to simply throw a thick layer of sound-deadening insulation around a straight pipe. Based on the limited research I've done, properly-designed resonance chambers actually add horsepower and torque. The logical conclusion is that removing them does the opposite, and the replacement straight pipe must overcome that loss of horsepower and torque before it can add any incremental benefit. Sorry if this seems like "over-thinking it," but I can make some decisions strictly on "form," but for decisions involving the mechanical operation of my car, I like to understand the "function."

I'm sure caldoofy's forthcoming dyno graphs will help us all understand more clearly.

Cheers,

Don

Don,
The Jaguar engineers added cambers to tune the sound of the motor, trying to make it sound a certain way without effect performance too much. Back when the X350 came out the were targeting the car toward people who wanted a quiet fast car. The quite part being more important than the performance. With N/A the engine has to breath with atmospheric pressure only so tuning of the intake length, diameter, camber volumes, ect all effect the performance. But with a S/C motor, the less restriction the motor has to breath the better performance.

Its the same with exhaust systems. An N/A motor needs to have well tuned exhaust to manage the air flow. But turbo motors just want to get the exhaust out as quick and easy as possible, for the most part.