I tried doing a search but didn't see any other mention of this. Anyway, has anyone else noticed that the factory shorty headers on the 2011 5.0 are of a Tri-Y design? The front two primary exhaust runners merge into one secondary tube while the back two merge into a separate secondary tube before both secondaries enter the collector. This is similar to the long tube Tri-Ys used on the 65 Shelby GT350. The Tri-Y design is supposed to increase low and mid range torque over more conventional 4 into 1 designs. While space limitations probably dictated tube sizes and lengths it is interesting to see that the Ford engineers didn't just slap together a typical 4 into 1 design.



http://www.popularhotrodding.com/tec...ech/index.html

 

Did you happen to see this story, which was referenced in this post in another forum thread?

 

Interesting stuff but no one has really said much about the design itself other than this quote from the engineering team:

“The greatest obstacle we faced on the 5.0-liter was getting the fabricated exhaust manifolds into the program,” said Christian. “Initial supplier prototypes failed to meet program objectives, and we were running out of time. Computational Fluid Dynamics Analyst Beth Dalrymple and I quickly finalized the computer-aided engineering (CAE) design and I built the prototype manifolds in my home workshop.”
Christian’s handcrafted manifolds were instantly installed on a development engine and dynamometer-tested, yielding an incremental increase of 6 horsepower and 14 additional ft.-lb. of torque. The home-grown headers became benchmarks for production pieces. The entire process took two weeks.

 

It is PRECISELY that quote that one might use to understand the header design was done with something special in mind. While they did not describe it as a "Tri-Y" configuration that is supposed to increase torque, the increases mentioned say to me "enthusiasts worked on this engine".

 

One of the reasons this caught my attention is that I am currently restoring a 1970 Mustang Mach 1 that came from the factory with a 428 Cobra Jet and 4-speed trans. While the factory cast iron exhaust manifolds were better than most they were still just a log type configuration and very heavy. Since I plan to drive this car the exhaust system is one of the areas I want to improve. Several aftermarket headers are available for this car but most, like the popular Hooker Super Comps, are of the 4 into 1 design and the best come with equal length primary tubes. However, this design requires a lot of space and in most cases they hang down very low taking up precious ground clearance. Enter the Tri-Y design. There are now at least two companies offering the Tri-Y design for the Cobra Jet Mustangs. While they may not have the visual appeal or high rpm horsepower of 4 into 1s they do offer better low speed torque, better clearance around and better access to things like the clutch linkage and the starter motor as well as significantly more ground clearance. All of which are important considerations on a street driven car.
I think anyone looking to improve the exhaust on the 2011 GT would be wise to think twice before replacing the factory Tri-Y headers.

 

I agree with this - I think these are probably a bigger step up than we might know at this moment!

 

Ah, good ol' engineering. And what's that sound? Is...is that the sound of my tax dollars not being wasted? Oh good, for a second there I was afraid GM might try to engineer something useful while we all paid for it. How nice to have a car from a manufacturer that can actually build something.

 

Wanna talk about clearances tolerances and such, ask me how i know. I installed those exact same Hooker super comp long tube headers on my '69 351W. What a PITA.

 

Just imagine trying the same thing on a 428.

Having said that I did see pics of a 70 where the owner was installing a 427 and 4-speed and he claims he was able to install the engine and trans with the super comps attached. Go figure.

 

I also think it is interesting that they chose stainless steel for these headers, it really doesn't leave much to be desired by the aftermarket. I have mixed feelings about this as i was planning on a full exhaust and getting rid of the sound tube.

Looks like i might not have to replace the headers, and might just go with cats and catback and have some muffler shop patch up the sound tube and remove it.

 

The sound tube is not connected to the exhaust.

 

I think there would be very little to gain with aftermarket headers, a set of high flow metallic cats and a 93 octane tune would still probably eek out 10-15hp though.

Dave

 

MMMM just had a thought I know its unusual. heheh But with the increased cubes, horsepower, and rpm high flow cats and bigger exhaust tubing might be benefical. I wonder if Ford increased the flow of the stock pieces.

 

After a lil more reasearch on the sound tube alot of people are saying to don't notice it until you have the gas pedel slammed, and someone else said it reminded them of flipping the air filter cover on the old trucks. I don't think i am going to mind the sound tube after all!!

I think it's hilarious how i had all these plans when i first heard about the 5.0's return, and now the more i learn about it the less i think i am going to change.

Still going the suspension/chassis hardening route though