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  • Writer's pictureJoel Brown

Breaking down the benefits of the Banshee Screamer Intake for the X350/X358 XJR and S-Type R.

Pictured above is a shot of the Screamer next to the oem upper intake plenum paired with a 3” J-pipe intake much like what’s commonly found on the market for the X350/X358 Jaguar XJR and Jaguar S-Type R.

This writeup will hopefully do well in highlighting the differences and advantages of the Screamer -Vs- the other available intake options.

Photo Credit- Google Search 😆
Range Rover Upper Intake Plenum Shown.

The Screamer was designed to be a more readily available option to sourcing one of the plenums from the AJV8 in the Range Rover and purchasing a J-Pipe intake to piece together your own induction upgrade.

RR Intake plenum paired with commonly sold J-Pipe intake

The overall goal was to replicate the typical gains benefitted from the RR upgrade and J-Pipe intake in an easily sourced package while maintaining fit and finish and ease of install. Most importantly, it needed to be priced affordably. The screamer is priced at $250.00 USD or roughly £180.00 at the current exchange rate.

Upon researching and attempting to acquire an RR plenum ourselves, it was found that typically, when you can find one, they commonly run upwards of $100.00 USD. When pricing the available intakes on the market, we discovered that just the J-Pipe section pictured above carried a pricetag of £125.00 to £165.00 or roughly $175.00 to $230.00 USD.

When combining the cost of an RR plenum, our cheapest option to upgrade the entire intake tract was still nearly $275.00 to $330.00!

Looking at the cost of the high grade materials we wanted for our intake, plus the labor and time involved to build each intake, we came to what we believe is the fair price of $250.00 (£180).

Not only is the Screamer the only all in one solution to upgrading your intake tract but, it is also the most affordable option, and even more-so, it provides the biggest gains in Horsepower and Torque and does what the current options on the market cannot. Here’s where it gets good...

We just recently completed our first round of dyno testing where, we wanted to compare the screamer plenum to the oem plenum. For this test we used the screamer and the typical 3”(ish) J-pipe style intake found online. In our case it was my personal 3” stainless steel pipe that was my first mod 🙂. First we wanted to make sure that the plenum was worth upgrading (Why wouldn’t it be? Right? The RR produces gains... why wouldn’t this?).

To determine whether or not the upper plenum was worth pursuing over sourcing an RR upper, we needed to see what the gain was compared to stock so we could compare that to what we’ve typically seen the RR upper produce in dyno graphs found on and other online sources as we could not find an easily obtainable or reasonably priced RR upper in time for the dyno session.

As you can see in the above graph the Screamer plenum gained 20hp and 18tq in the mid range rpm band.

Also pictured is the gain made at peak rpm, this is the number most focus on... when you see an advert or post about a specific gain made on the dyno, typically more times than not, they’re referring to peak rpm gain. This part of the powerband shows overall HP in total, the figure in the midrange shows the USEABLE power band.

”What is useable power band?”

The graph shows the production of power from the time the throttle goes wide open to the time you shift. As you go up in rpm more power is made. To a certain point, once you reach an rpm where the engine loses efficiency it’s all downhill from there, this is why shift points are important But, that’s another story.

Peak power is the highest number the engine produces and usually is reached just below and sometimes in some factory nerfed vehicles, just beyond the redline.

The old saying goes “Horsepower sells cars, torque wins races” and is completely true. The more power you have below the curve (Low end and mid range) the faster the car accelerates.

To simplify things, in essence... Peak HP helps achieve a higher top speed and power made below the curve dictates how quickly you reach that top speed. I.E TORQUE.

Now that we have that out of the way... We can explain the benefits of the screamer over the Range Rover plenum with a clearer understanding.

From what we’ve gathered from scouring forums and fb groups, It’s a generally accepted fact that the Range Rover plenum provides an increase of 12-16hp in the mid range and gives no increase to peak power... Generally this is translated in some low end grunt and slightly improved acceleration off of the line. In the examples we've studied that gain falls off a couple of thousand rpm before redline. This tapering off at the threshold helps with a quicker 0-60 and throttle response with no improvement to the back half of the acceleration.

As you can see in the graph above, the screamer plenum not only crushed the typical gain made in the mid range from the Range Rover plenum but, it also gained 12hp and 10tq at peak rpm. Basically what this means is, the Screamer plenum alone outperforms the Range Rover plenum in EVERY way.

Banshee Screamer for S-Type R

How we achieved this increase across the ENTIRE powerband (Yup, your screamer will give you extra ponies from the time you floor it to the time you shift.) was by removing the inefficiencies we found in the oem style plenum and, while the RR is larger than the stock XJR/STR plenum, it still retains the factory bottlenecked pancake power killer at the back of the stock plenum.

OEM XJR/STR plenum vs Screamer Plenum

The other inefficiency we found was the inner diameter doesn’t match the outer diameter... the inner diameter is substantially smaller... Also, the inside of the OEM plenum is shaped like a D then, transitions into a pancake just before that hard 90 into the throttle body. Not a smooth path for airflow at all.


Banshee Screamer Plenum

We remedied these bottlenecks and inefficiencies by first and foremost increasing the inner diameter to 3.5” using a high grade Aluminum 2mm thick tube that was shaped into a cone to provide clearance and increased velocity and, to create a larger reserve for volume to collect in before entering the throttle body.

To do this we used a shorter tube connected to a 90 degree coupler to remove the bottleneck at the rear of the plenum and replace it with an open, free flowing elbow with a smoother transition and path for airflow.

Banshee Screamer Plenum

Phase one of our testing has produced enough data and evidence to be sure that the Screamer plenum alone not only makes more power more efficiently than any other intake on the market but, it also can be sourced more readily and easily while staying more affordable than any other option currently.

We’re not done though! The Banshee Screamer Intake is more than just the plenum! Though that specific piece of the puzzle plays the biggest role, every great performer needs a support! That support is found in the 3.5” J-Pipe.

much larger than the other J-Pipes on the market, the screamers J-Pipe opens the front end of the intake tract to recieve more airflow to feed the massive 3.5” plenum. Combined with the Screamer plenum, the gains should be further increased and we’ll have more data to share about that very soon!

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