XJ XJ6 / XJ8 / XJR ( X350 & X358 ) 2003 - 2009

My 3.5” Intake. :)

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Old Jan 10, 2021 | 02:33 PM
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Default My 3.5” Intake and RR upper alternative.

Hello everyone!

I seem to have managed to fabricate an alternative to the RR upper intake. 😁

I still need to do some dyno testing with the full 3.5” system but just the upper intake section made 12hp and 10tq at 6100rpm and picked up roughly 20hp/18tq in the mid range.





Unlike the RR which, from what I’ve seen, tends to make gains in the mid range only and they diminish near peak rpm. The tubular upper intake makes more power and torque from start to finish.

Power below the curve is great and all, but power across the entire RPM range from the time you mash the throttle to the time you shift is better. 😈

Originally, I had planned on the RR upper and one of the J-Pipe intakes on the market until I started tearing the intake tract apart and realized how restrictive the stock intake is.
The RR has a larger diameter but it also shares the same design as the oem intake.
It has the same bottlenecks and inefficiencies...

I decided I wanted more volume and smoother more even flow than what the D shaped cast intake provides, so... I made my own.

It started out as a D shaped 4” plenum, which looked decent enough, but hood clearance was trash and in order to make it fit, it had to share some similarities to the RR/OEM design. It also had a very sharp transition from the round 3” J-Pipe to the plenum and the inefficiency was felt as a flat spot near the upper rpms.



I did some working around and decided a tubular, smaller diameter tube would be more suitable design for both efficiency and clearance.

The result was the first real prototype. The tubular 3.5” upper paired with the 3” J-Pipe both fit and performed well and is the design that was used for the dyno sessions.

Unfortunately, I wasn’t able to source an RR intake or the oem plastic in time for my appointment due to tight restrictions and guidelines because of covid, so the testing for that particular session was just to see if my upper intake did better than the oem cast upper intake. Which it did!





In the dyno testing, we did pulls with both the stock cast upper intake as well as my tubular upper intake, both paired with the 3” J-Pipe.

The stock oem cast upper and 3” J-Pipe made 336whp and 358wtq.




The Tubular upper plenum and 3” J-Pipe made 348whp and 368wtq.


Finally going to the last version, I wanted to make sure I had everything I wanted in an intake, including headroom to benefit from once I go with a larger pulley later down the road. I pulled it all apart, redesigned most of it, and improved upon what I already had. The end result is a full 3.5” from TB to Airbox and not only does it look good, but it sounds amazing and performs well too. I even replaced the stock junk plastic breather tube with a more flexible, better quality solution!







Not too shabby eh? 😈










As soon as I get it back on the dyno with the new results for the full 3.5” system, I’ll post back here!
 

Last edited by Joel Brown; Jan 10, 2021 at 02:39 PM.
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Old Jan 11, 2021 | 07:23 AM
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great work! it looks amazing and the dyno shows it works. I assume it's cheaper then the RR intake listed on e bay from time to time. I'll follow this post...best of luck and i'm sure you have given me a warmer weather project too.
 
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Old Jan 11, 2021 | 08:01 AM
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Originally Posted by aceler8
great work! it looks amazing and the dyno shows it works. I assume it's cheaper then the RR intake listed on e bay from time to time. I'll follow this post...best of luck and i'm sure you have given me a warmer weather project too.
Luckily, I have a wholesaler and supplier for aluminum piping and silicone just ten minutes from my house so I do get the parts cheaper than you can find on ebay, etc... makes things more affordable for sure!

I’ve had a few Jag owners contact me to make them one so I’ve sent a few out already. ☺️
 
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Old Jan 12, 2021 | 12:50 PM
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PM sent
 
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Old Jan 12, 2021 | 01:57 PM
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Originally Posted by aceler8
PM sent
Replied
 
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Old Jan 13, 2021 | 10:05 PM
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Are they for sale?
 
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Old Jan 13, 2021 | 10:21 PM
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Originally Posted by GooseP00pXJR
Are they for sale?
They’re available to order on ebay.
 
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Old Jan 13, 2021 | 11:36 PM
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Originally Posted by Joel Brown
They’re available to order on ebay.
if you ever get your hands on a 308 let us know, we’re pretty desperate for a low effort plug and play 3.5” intake
 
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Old Jan 13, 2021 | 11:49 PM
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Originally Posted by xalty
if you ever get your hands on a 308 let us know, we’re pretty desperate for a low effort plug and play 3.5” intake
If I can find a local car to fit it on I could make it happen.
 
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Old Mar 17, 2021 | 12:06 PM
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I like your idea. So I copied it...sorry. Question. Did you have to oval the pipe at the 90 elbow to fit under the cowl? I did a test fit today. The runner that goes to the bypass valve contacts the pipe. So I'm thinking either the pipe has to be modified or the cowl? Your thoughts.
 
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Old Oct 11, 2021 | 09:07 PM
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Originally Posted by GooseP00pXJR
I like your idea. So I copied it...sorry. Question. Did you have to oval the pipe at the 90 elbow to fit under the cowl? I did a test fit today. The runner that goes to the bypass valve contacts the pipe. So I'm thinking either the pipe has to be modified or the cowl? Your thoughts.
did you figure it out?
 
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Old Oct 13, 2021 | 03:31 AM
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Originally Posted by xalty
did you figure it out?
Im going to try and fabricate one too, although I already have a caldoofy intake so will just be a matter of the upper intake
 
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Old Oct 13, 2021 | 10:09 PM
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I see eBay is flooded with the 3” intake pipes. But none of the rest of this assembly. Has anyone completed a copy of Joel Brown’s design? Looks simple enough. But definitely tight in there.
I want to keep the intake box.
 
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Old Oct 13, 2021 | 10:11 PM
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Originally Posted by Panelhead
I see eBay is flooded with the 3” intake pipes. But none of the rest of this assembly. Has anyone completed a copy of Joel Brown’s design? Looks simple enough. But definitely tight in there.
I want to keep the intake box.
i bought everything i’m going to copy and install it this week
 
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Old Oct 16, 2021 | 06:03 PM
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easy







 
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Old Oct 18, 2021 | 08:25 AM
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Xalty,
Any chance we can get some detail on your materials? I may try this for fun, but need some more details on what to purchase. Thanks! Also, i like the black color much better then the red as it blends in with the engine compartment.
 
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Old Oct 18, 2021 | 10:09 AM
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Originally Posted by aceler8
Xalty,
Any chance we can get some detail on your materials? I may try this for fun, but need some more details on what to purchase. Thanks! Also, i like the black color much better then the red as it blends in with the engine compartment.
1ft 3.5” straight pipe

90deg 3.5 coupler

3.5 to 3 coupler

3 to 3 coupler

2ft long 3” j pipe cut down

you can do the same with a 3.5 j-pipe
 

Last edited by xalty; Oct 18, 2021 at 10:11 AM.
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Old Oct 19, 2021 | 10:47 AM
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Originally Posted by aceler8
Xalty,
Any chance we can get some detail on your materials? I may try this for fun, but need some more details on what to purchase. Thanks! Also, i like the black color much better then the red as it blends in with the engine compartment.
https://www.bansheescreamerintake.co...r-intake-black
 
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Old Oct 19, 2021 | 10:48 AM
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Originally Posted by Mikehill596
Im going to try and fabricate one too, although I already have a caldoofy intake so will just be a matter of the upper intake
https://www.bansheescreamerintake.co...r-upper-plenum
 
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Old Oct 19, 2021 | 12:29 PM
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I guess they say imitation is the sincerest form of flattery lol…

My design has changed a lot since this post was originally made.

The intakes can’t be found on ebay anymore. They are only purchasable on our website Banshee Screamer Intake


 
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