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Discussion Starter #1
Upgraded my throttle body to a CFM 105mm, also have f.a.s. porting my sc snout and using their billet bearing plate. So, my JLT was undersized on the throttle body end.

I like the JLT because it has the box that separates from engine heat and has two entry points of fresh air. Also, I own it and its paid for. So I figured I would try to mod before buying an LMI or bwoody.

I believe my original inner diameter was 95mm on the throttle body end 45 degree turn. Basically I used a 4" expandable test plug for drainpipes and a heat gun. The plug can handle 30psi so it will expand pretty far. Take your time, heat it up evenly to the point the plastic starts to get shiny. Insert the test plug and inflate till tight. Continue to heat entire diameter of tube. Add more air. Repeat, repeat, repeat. Leave the plug in until completely cooled down. You may need to do two or three cycles to achieve a finished product. Keep a hose clamp on the end flange so it does not round open. Keep loosening the clamp a little to gain inner diameter. Take your time, if you go crazy it will split. I got mine open to 110mm at the smallest spot. I know it sounds odd, but it worked perfect and the inside is still nice and shiny smooth. The outside returns to the satin black finish when it cools.
You will need to buy a 4" to 5" silicone adapter for the throttle body to pipe connection and two new clamps. I am very happy with the finished product.
 

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Interesting, can't say I've ever seen this approach.
Did the IAT hole get bigger with the expansion or does it still fit nice and tight in there?
 

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Discussion Starter #3
It fits nice and tight. I tried to stay away from that area with the heat. I really focused on the turn going into the throttle body.
 

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Just seeing this item and had a question......if a 105 TB is put onto the original JLT intake, won't it mate up with a straight coupler?

What is the original measurement of the TB side of the JLT pipe?
 

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Discussion Starter #5
No it will not go onto a 105mm TB.
 

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Discussion Starter #6
I would say 95mm
 

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So I get your thoughts about the smaller end closest to the tb being what it was originally, just looking at mine and it does not appear to be much smaller.

Just thinking a straight silicone coupler would fit it 20200620_125006.jpg
 

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Discussion Starter #8
If you have a jlt, a 105 is way bigger. Look through the threads and you will see my measurements. I would say a 12mm difference or just over.
 

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So I get your thoughts about the smaller end closest to the tb being what it was originally, just looking at mine and it does not appear to be much smaller.

Just thinking a straight silicone coupler would fit it View attachment 558517
That is the way I see it in your pic. Take yours off and measure it
 

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This is off of JLT website
The intake tube is roto molded plastic with a huge 125mm for superior airflow and NO heat soak like metal tubes.
With a mouth of 4.5" at the throttle body end, it is ready for any larger throttle bodies that may come in the future.

4.5" is 114mm

Maybe you have an older JLT?

I had a '13 Mustang with a Roush supercharger and bought a used JLT intake for it. Took my tuner awhile to get it to run right. He told me they kept changed the tube and it effected the tuning more since Mustangs use mass air. The 15-16 Hellcats have mass air also but they may not depend on the reading as much from what I have read and is why they changed to speed density

 

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Am going to measure mine tomorrow morning. Not convinced I want to spend the money on a larger tb right now as I have other parts that have been going for a while stacking up.
 

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Discussion Starter #12
Bought mine in august or september of 2019.
It is 4.5 inches at the filter, not the bend.
Mine cut down well below 4 inches at the bend. If you think i have an older model or can't measure, sure, buy it and see for yourself.
 

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Discussion Starter #13
Use a telescoping gauge and see for yourself at the bend. It goes down to roughly the same size as a factory throttle body.
If your not changing out the bearing plate on the sc, i feel a tb and snout porting is a waste of cash till you do that.
 

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Not saying yours is not that small. JLT says 125mm at the filter and 114mm at the throttle body. Maybe they changed it or false info
 
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