JDL Auto Design - 2014 Exhaust Products

[2much]

Originally Posted by DocWalt

I installed my JDL overpipe and catted/resonated front pipe and drove it around a bit. Fitment of the overpipe is freaking fantastic! The frontpipe took a little bit of work, I really had to shove it towards the passenger side to not hit the tranny mount and the donut gasket that was included really put a LOT of excess tension on the frontpipe-midpipe bolts because of the way the gasket is made versus stock.

Sounds fantastic! No wooshy noise, and it's a tiny bit louder than my previous setup (ISIS overpipe and stock frontpipe) but there's no rasp and no strange tingy noise like I got with the Nameless combo pipe.

I can't wait for tomorrow so I can go out and rip around a bit with the windows down and not worry about snow in my face, hehe.

nice to hear. I have a catless header and I want to finish the rest of the exhaust, but I dont want it getting loud at all. Really considering this piece

[DocWalt]

Originally Posted by 2much

nice to hear. I have a catless header and I want to finish the rest of the exhaust, but I dont want it getting loud at all. Really considering this piece

I'm really happy with the volume level now. I now have JDL UEL (catless) with their OP and ultra quiet FP with the stock catback. Quiet enough just driving around (no drone!), and just loud enough while ripping on it.

While I sometimes wish it was as loud as my GTI... I enjoy being able to actually converse inside the car, hehe.

[DocWalt]

Excuse the mess, and my brother's project cars...

[ame="http://www.youtube.com/watch?v=tUlLAONnHOc"]BRZ with JDL exhaust and stock catback - YouTube[/ame]

[PA-86]

Meh...looks slow

Just kidding sounds awesome nice work!

Originally Posted by DocWalt

Excuse the mess, and my brother's project cars...

[CTB727]

Originally Posted by jonkim2

That's what I figured. The gaskets were in perfect condition so I used the same. I successfully installed the headers today, but I'm getting a loud flappy/clicking sound when I step on the gas. Anybody else get this? I'm going to assume a leak


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Gaskets are fine to reuse around the axleback, but I'm not sure I would reuse a header gasket. Only $17 for the pair from the dealership is worth the piece of mind.

Originally Posted by jonkim2

I called up JDL and they said that every header they've installed with the stock overpipe had produced the same sound i described earlier. Can anyone else confirm/elaborate? Many thanks


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yes, I called JDL today with the same concern. I thought I had a minor exhaust leak at the overpipe (which I did), but most of the noise is due to the header meeting the slightly smaller diameter stock overpipe. He said they had a similar problem on a car they worked on, and the noise went away with an aftermarket overpipe. If you are worried about a leak at the overpipe, apply some high temp RTV on both sides of the gasket like I did. My leak went away, but the weird raspy noise was still there.

I have a tune scheduled three weeks from now, and I also have SCCA nationals coming up that I need to be ready for. The race to find a good quality overpipe/front pipe is on...

Originally Posted by Zaneman

I installed the JDL EL catted header last night and I could only get it 2-3mm from the fan shroud. I drove it to work and noticed it had begun to melt the plasic of the shroud. What is the best way for me to adjust the header so that I can move it farther away?

Yeah, my EL is awfully close to the plastic piece underneath the intake inlet hose... the one just behind the intake resonator. I noticed it started to melt that little piece ever so slightly, so I put a piece of heat reflective tape on the plastic. I'll keep an eye out for any other heat-related issues in the engine bay.

[weederr33]

Originally Posted by CTB727

Yeah, my EL is awfully close to the plastic piece underneath the intake inlet hose... the one just behind the intake resonator. I noticed it started to melt that little piece ever so slightly, so I put a piece of heat reflective tape on the plastic. I'll keep an eye out for any other heat-related issues in the engine bay.

As I purchased the EL headers, too. This is a bit concerning for me. I didn't realize it would come so close. Do you have any sort of thermal coating on the headers?

[Zaneman]

My header is ceramic coated but that isn't enough to stop it from melting the shroud a bit. I was able to finagle it another 1-2mm away and that is all i needed to stop it from melting but I wonder how it will react when I drive for 2-3 hours or get on the dyno.

[was385]

Originally Posted by Zaneman

My header is ceramic coated but that isn't enough to stop it from melting the shroud a bit. I was able to finagle it another 1-2mm away and that is all i needed to stop it from melting but I wonder how it will react when I drive for 2-3 hours or get on the dyno.

Yikes. I ordered mine without a coating. Now I'm a little terrified at how bad it will melt mine.

[Mad_Mike]

Mines hasn't melted anything and I've driven it 2.5 hours on the highway. Mine is further than 1mm away, more like 0.25".

[BatStig]

Originally Posted by Zaneman

My header is ceramic coated but that isn't enough to stop it from melting the shroud a bit. I was able to finagle it another 1-2mm away and that is all i needed to stop it from melting but I wonder how it will react when I drive for 2-3 hours or get on the dyno.

The driving isn't going to be an issue. It's the standing still with no airflow that will be the problem.

My shroud did get a little melted, nothing serious, but that was after a session on the track. Now I just make sure to open the hood after a session and everything is wonderful.

[jonkim2]

Originally Posted by CTB727

Gaskets are fine to reuse around the axleback, but I'm not sure I would reuse a header gasket. Only $17 for the pair from the dealership is worth the piece of mind.



yes, I called JDL today with the same concern. I thought I had a minor exhaust leak at the overpipe (which I did), but most of the noise is due to the header meeting the slightly smaller diameter stock overpipe. He said they had a similar problem on a car they worked on, and the noise went away with an aftermarket overpipe. If you are worried about a leak at the overpipe, apply some high temp RTV on both sides of the gasket like I did. My leak went away, but the weird raspy noise was still there.

I have a tune scheduled three weeks from now, and I also have SCCA nationals coming up that I need to be ready for. The race to find a good quality overpipe/front pipe is on...




Yeah, my EL is awfully close to the plastic piece underneath the intake inlet hose... the one just behind the intake resonator. I noticed it started to melt that little piece ever so slightly, so I put a piece of heat reflective tape on the plastic. I'll keep an eye out for any other heat-related issues in the engine bay.

Thanks for your input.

JDL sends a new header gasket for the overpipe, which I used. I haven't yet tested for leaks but you've pretty much confirm I'll need to get a new op/fp

Scientifically, I just don't understand how the difference in diameter creates that flappy/clicky sound? Can anyone explain please?


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[DocWalt]

Originally Posted by jonkim2

Thanks for your input.

JDL sends a new header gasket for the overpipe, which I used. I haven't yet tested for leaks but you've pretty much confirm I'll need to get a new op/fp

Scientifically, I just don't understand how the difference in diameter creates that flappy/clicky sound? Can anyone explain please?


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I didn't have much of a flappy/clicky sound but it sounded awful. A LOT of wooshy noise. I stepped up to a cheap ebay overpipe to hold me over until I got the JDL pipes, and it sounded a lot better. With all the JDL pipes the wooshy noise is gone (besides the sound of the exhaust simply flowing through the header) but now it's a touch sharper tone (maybe too sharp?)

JDL Posted this pic of the header flange vs a stock flange:

[2016 Camaro SS]

Running the JDL UEL, JDL OP, and JDL catted FP, fitment was absolutely perfect. Even the custom flange to mate with the Perrin catback. Not a single leak, all Grimmspeed gaskets.

[Lee@JDLAutoDesign]

Originally Posted by jonkim2

Scientifically, I just don't understand how the difference in diameter creates that flappy/clicky sound? Can anyone explain please?

The "lip" created by the mismatch in diameter acts as a forward facing step that the flow has to go up, over and around as it enters the overpipe. This causes a really messy flow field with significant regions of reversed flow. To combat the reversed flow the flow in the center of the pipe has to accelerate, so you end up stretching and distorting the flow field, which creates all sorts of nasty acoustic disturbances at a wide range of frequencies (think of the sound a compressor makes when it surges).

Here is a CFD model I made some time ago showing 2D velocity contours of flow from a plenum entering a runner with a 0.090" radius on the entrance. In this case the flow moves from left to right. You can see that the flow in the center of the runner is accelerated and large separation bubbles form on the sides of the runner. This case is a little bit different because the diameter ratio of a plenum/runner is much larger than a collector/overpipe, but hopefully this will make the effect a bit more ~tangible.