Fox T-Bird/Cougar Forums

Technical => Exhaust => Topic started by: jcassity on July 28, 2018, 12:11:21 PM

Title: 2 1/2'' exhaust tubing over rear axle
Post by: jcassity on July 28, 2018, 12:11:21 PM
are you guys cutting your tail pipes before the axle and making the tubing height adjustable there?

i am finding it very difficult to use off the shelf 2 1/2 '' exhaust tubing a big challenge to make it over the rear axles without bumping into things.

i end up with almost a finger width of room in any direction.
Title: 2 1/2'' exhaust tubing over rear axle
Post by: 87 T-BIRD on July 29, 2018, 01:14:54 AM
Quote from: jcassity;466541
are you guys cutting your tail pipes before the axle and making the tubing height adjustable there?

i am finding it very difficult to use off the shelf 2 1/2 '' exhaust tubing a big challenge to make it over the rear axles without bumping into things.

i end up with almost a finger width of room in any direction.


You could cut and add where you need to, or take it to an exhaust shop and have them custom bend some for you.
Title: 2 1/2'' exhaust tubing over rear axle
Post by: thunderjet302 on July 29, 2018, 10:48:26 PM
I used Dynomax 2.5" mandrel bent tail pipes for a 86-93 Mustang. They fit like a glove with room around everything. Are you bending/fabricating your own tail pipes?
Title: 2 1/2'' exhaust tubing over rear axle
Post by: Aerocoupe on July 30, 2018, 11:20:22 AM
I have 3” mandrel bent pipes from MAC and all we had to do was lengthen the tail pipes 8” or so. Tight but they fit no issues.
Title: 2 1/2'' exhaust tubing over rear axle
Post by: jcassity on July 30, 2018, 12:10:28 PM
Quote from: thunderjet302;466569
I used Dynomax 2.5" mandrel bent tail pipes for a 86-93 Mustang. They fit like a glove with room around everything. Are you bending/fabricating your own tail pipes?

no,
i am installing already bent up tubing.
i was going to buy the JD Squared tubing bender to cover 3'' down to 2'' of dies but decided its cost prohibitive for the amount of use it would get.
Haystack made a good point about this tubing a while back,, why not use off the shelf stuff ,
my pipes fit but the total height of the arch that passes over the axle is what i consider "too tall".  i think what i am saying is that particular "radius bend is too long.
in reality everything fits Like a glove.

the top of the arch of my tail pipe section is so tall that i can get one finger between:
-the top frame / beam member
-the shock
-the axle stabilizer dog bone thing

you have a triangle of sorts of free area the tail pipe passes thru in square inches of space.
my tail pipe is at the peak of that triangle.

if the tail pipe arch were shorter by 1'' it would fit nice like a loose glove.... which is what i am after.

right now if i go with what i have, if chance loads down the trunk with weight or has rear seats filled with people, i am certain the rear of the car will drop down and put the peak of these tail pipe 'humps" directly on something metal up above.
Title: 2 1/2'' exhaust tubing over rear axle
Post by: jcassity on July 30, 2018, 12:24:59 PM
the height is designated with the yellow lines.
the red line shows where i believe i should cut , expand and make a lap joint with my new pipe expansion tool.

this will lower the overall height of my arch.
[
we are going to sweep a 45deg tip about 12'' aft of the wheel well making it side exits.

thoughts?
Title: 2 1/2'' exhaust tubing over rear axle
Post by: ZondaC12 on July 30, 2018, 03:43:55 PM
I must buy the wrong shiznit too always seems like not enough room for my liking anyway. As you said, a finger or so. Never seems to have been an actual problem...but c'mon...too close for comfort.
Title: 2 1/2'' exhaust tubing over rear axle
Post by: 1BadBird on July 30, 2018, 05:20:00 PM
When you connect the exhaust, you’re not connecting it to axle, you’re connecting (hanger brackets)it to the car. Whatever weight you put in the trunk shouldn’t have any effect on the arch hitting the body as the exhaust won’t move. If you shorten the arch, there’s a really good chance of the axle hitting the bottom of said arch, if you have weight in the trunk or not.
Title: 2 1/2'' exhaust tubing over rear axle
Post by: thunderjet302 on July 30, 2018, 05:22:43 PM
You want enough of a space under the tube for the axle to move up and down, hence why the tubing is close to the frame and what not. It's bigger in diameter than the stock stuff. I've been running unmodified Dynomax tailpipes on mine for 11 years with no issues. It's close but it'll be fine. Once attached the exhaust isn't really moving around anyway.
Title: 2 1/2'' exhaust tubing over rear axle
Post by: jcassity on July 30, 2018, 10:16:31 PM
Quote from: 1BadBird;466582
When you connect the exhaust, you’re not connecting it to axle, you’re connecting (hanger brackets)it to the car. Whatever weight you put in the trunk shouldn’t have any effect on the arch hitting the body as the exhaust won’t move. If you shorten the arch, there’s a really good chance of the axle hitting the bottom of said arch, if you have weight in the trunk or not.

well,, that sure did straighten me out,, not sure what i was thinking. 
i think its one of those common sense things i never had to think about

thanks!!!!!!!!!!!!!

the pipe follows the body so up high is ok.
Title: 2 1/2'' exhaust tubing over rear axle
Post by: 1BadBird on July 31, 2018, 09:57:49 PM
Lol it’s called a brainfart. I have them waaaay to much lately :hick:
Title: 2 1/2'' exhaust tubing over rear axle
Post by: jcassity on August 01, 2018, 03:21:07 PM
so after you specifically told me what you said,, i went out and did this after toiling with "how to" get a decent support on the tubing yet not have the cats bumping the floor. 

i went out there thinking,, yeah, yeah,, ok,, the pipes follow the body,, got it....................

u bolt the pipes to the tunnel metal bar.............. yup good to go.................. NOT!!!!!!!!!

when the engine torques i suspect this principle will slowly yank all my band clamps loose.

so..
i will revise.

man why do i get all caught up in stupid stuff that ends up taking me days to make me happy ............??

its alright though,, i think i can cut that bracket into two pieces and make them just long enough to reach over each individual pipe.
secure the metal bracket(s) to thier original mounts on the floor pan but have a rubber gasket between.

keep the uBolt system and all should be well.  this will separate the torque on each pipe run and allow the pipes to twerk and tweek and move as they need.

the downside is i have to chop out that date code thats on the top of this metal bracket.

there is a net gain though because it allows more room to drop the drive shaft down when needed.
Title: 2 1/2'' exhaust tubing over rear axle
Post by: Haystack on August 01, 2018, 11:58:15 PM
You think you over complicate stuff, you need to look up project binky on YouTube