Ted,

   All those graphs that you post showing the real world data rather than conjecture and urban ledgend lead me to my next foolish question. Any opinion or data on what effect on the torque curve of your test engine if an H crossover pipe or an X crossover pipe had been added to the 2 1/2 inch exhaust system with street mufflers on it.

  I am very curious to know if what I believe ( that an H pipe helps on the street) is a fact or not? Thanks in advance. Pete

That is something I'm interested to see in a back to back comparison. It doesn't look easy to set up on the dyno, though.


Lawrenceville, GA

Every comparision test I've ever read showed an increase in low end torque with the crossovers, and a slight reduction in "Droning" sound. The X pipe seems to work better than the H by a small amount and is usually easier to install. I'm very happy with the Crossover on my 57. 

Frank/Rebop

Bristol, In ( by Elkhart) 

Frank, that was my experience with the crossover pipe in toning down the sound which was much better than without the crossover. It also helped in the torque dept and my Tbird appreciated it as well.

-Gary Burnette-

There is a set of FPA headers for a Thunderbird being built and soon to be heading my way which will be dyno tested on the same engine combination as the other exhaust systems.  One of the forum members has stepped forward for this.  If there are some more header designs that have not been tested and you’d like to see how they fair against the other exhaust systems, get with me.  I’m figuring about two more weeks or thereabouts before the FPA headers show up.

 

As far as crossover pipes go, they’ve been tested to death in the Mustang magazines and the crossover and X pipes are good for additional low end torque while also mellowing out sharp exhaust notes.  But the question still remains “What are they worth on the Y?”.  So with that in mind, I’ll rig something up in the way of a crossover pipe to the Sanderson pickup headers and run that setup along with the other exhaust systems on the same day that the FPA headers are run.

 

After this last piece of the exhaust test is done, I’m crossing exhaust testing off of my bucket list.  Next on the list is a cylinder head test and will be needing a set of ECZ-C heads that are ready to run as part of the test.  Both ported and unported varieties would make for some good info.

Lorena, Texas (South of Waco)

Ted, I'm glad to hear someone has contributed the FPA's since that's what I run on my bird. It will be good to know how they do.



As far as a crossover or x pipe is concerned, all would be well and good on the dyno but I could never see how to make it practical on a street Thunderbird app. as there is such limited clearance under there. But I will differ to you GURUS to please show me how. It might be possible to cut a 2 large holes in the X member of the frame to route the pipe through?

You may not remember but I moved my mufflers back for better heat dissipation and it works well.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

Alan, my crossover pipe connects just as they go thru the frame some several inches and slightly curve under my tranny on the 56 tbird and work pretty well. They are not welded but set up so they can be removed for any reason such as removing my exhaust (one side or the other) when working with close quarters as you know these tbirds are known for.

-Gary Burnette-

The rule of thumb for crossover pipes is to place them as close to the engine as possible.  The further back they are placed, the less effective they are.

Lorena, Texas (South of Waco)

I'm waiting for my FPA's to arrive to confirm space and clearance, but am thinking similar to Gary...

... fitting/welding a three-bolt flange on each of the pipes just past the collectors (but before the X-frame), perhaps at a slightly downward angle, and then bolting a mildly u-shaped cross-over pipe (much like a cat-test pipe) between the two hopefully clearing the tranny... even if I had to squash it down a little bit for clearance, it should still have some equalizing affect, right?

Cheers... Brian

Cylinder Index = 84

Current Experiment = `57 Tbird, Grand Rapids, Michigan

Yep. If you use a vice to squish it, you can create a nice oval pipe. Universal crossover kits can be purchased straight, and bent to clear transmissions and such


Lawrenceville, GA