Exhaust pipes routed under rear end instead of over rear end?

[RCE1313 23]

Hey guys,

 

I'm in the process of routing my exhaust system and have come across a problem.  With the Ridetech coilover suspension system I have on my car the space is really limited to route the 2.5" exhaust system over the rear end.  I was considering going under the rear end instead of having cutoffs under the car.  Has anyone experienced this issue before?  Pros / Cons of going under rear end?  Any pictures would be great also.  thanks. 

[cavboy78 28]

Depending on how much wiggle room you have over the axle, you could look at some oval tubing. Cons would primarily be ground clearance & corresponding potential damage...oh, and looks!

[Brian Conway 264]

The cut outs in the rear valance are the only real reason to go over the axle.  If that doesn't matter to you, after all your not going to run the  stock exhaust tips, under is the best solution.  Brian 

[RPM 1,190]

When i first saw the under axle pipes I thought they had lost their minds. However, upon further review and taking into account limited room with different suspensions now being used, I get it if the car is low enough. At this point I plan on dumping the exhaust in front of the axle, but I'll attach the twin tips for the stock look. If the dumps don't cut it I just might try the under axle route, then out the back to the stock exit.

[cavboy78 28]

I guess I'm different since I don't have the valence cut outs to begin with. I personally would dump in front of the rear tires before I go under the axle. If you go under, just make sure you measure clearance with axle at full or nearly full droop, not as it sits normally.

[1969_Mach1 333]

I'm also not a big fan of under the axle exhaust on these cars.

[MikeStang 247]

I'm running under the axle on my car.

It runs out of an X-Pipe into 2 Borla's and the out.

I had a muffler shop fab up from the muffler, all the way under the axle and routed the driver side over to meet the pass side and dual exit on the pass side behind the valance.. Looks clean and is hidden.

The axle has never hit the exhaust b4, but if you jack the car up on the frame you have to pay attention and not let the rear sag down and rest on the exhaust...Altho my brackets are strong enough to easily support it, I avoid doing it.

I can get ya a pic if you like

[MikeStang 247]

1

[barnett468 418]

Well, the first question would be, do you need pipes that are bigger than 2 1/2"? . If you have a true 400 hp or less, you can get by with 2 1/2 if you have a cross over and straight thru mufflers . Keep in mind that hen you put your car on a rack that does not support your suspension, the rear axle will drop down quite a bit, therefore you would need to determine exactly how far down the rear axle will hang when it is unsupported then allow for at least 1/4" of additional clearance . This means that when the car is on the ground, the top of the pipes might be around 3 inches from the bottom of the axle, which at the very least would look a bit dorky to some if appearance was a concern.

[RCE1313 23]

1

 

I'm running under the axle on my car.

It runs out of an X-Pipe into 2 Borla's and the out.

I had a muffler shop fab up from the muffler, all the way under the axle and routed the driver side over to meet the pass side and dual exit on the pass side behind the valance.. Looks clean and is hidden.

The axle has never hit the exhaust b4, but if you jack the car up on the frame you have to pay attention and not let the rear sag down and rest on the exhaust...Altho my brackets are strong enough to easily support it, I avoid doing it.

I can get ya a pic if you like

 

Thanks for the picture and advice MikeStang. 

[1969_Mach1 333]

Eventually you will be in a situation where you have to jack up or lift the car on a hoist and let the rear suspension hang.  Then you second guess the idea of the exhaust under the rear axle.  I don't know, It just doesn't sound like a good idea.

 

NOT MY THUMBNAILS.  CAN'T THIS BE FIXED?

[RCE1313 23]

Well, the first question would be, do you need pipes that are bigger than 2 1/2"? . If you have a true 400 hp or less, you can get by with 2 1/2 if you have a cross over and straight thru mufflers . Keep in mind that hen you put your car on a rack that does not support your suspension, the rear axle will drop down quite a bit, therefore you would need to determine exactly how far down the rear axle will hang when it is unsupported then allow for at least 1/4" of additional clearance . This means that when the car is on the ground, the top of the pipes might be around 3 inches from the bottom of the axle, which at the very least would look a bit dorky to some if appearance was a concern.

 

I was told my motor is around 400 to 450 horsepower so I went with the 2.5" system.  I hope to dyno the motor in the future to get the true numbers.  I plan to put on rack to install the exhaust and make the bends to hopefully avoid any touching.  I've seen a few pictures of the mufflers running under the rear end and I thought it looked good (of course I would rather over).  My car is sitting pretty low so hopefully it's not terribly noticeable and stands out.  If so i'll change to turndowns before rear end.    

 

ALSO, NOT MY THUMBNAILS. Not sure where this came from....

[MikeStang 247]

Yeah my car sits Very low also and my headers hit long before my exhaust pipe under the axle does.

It sure makes getting the exhaust out of the way fast and easy tho.

I pull the 4 collector bolts, unbolt the 2 nuts on the hangers at the top and loosten 1 clamp and the whole exhaust falls out in 1 piece and slides out of the car.. I can do it by myself laying on my back, as well as reinstall it all alone :P

I usually jack my car up under the rear end then just put a stand under the frame and lower the rear some and put it on another stand if need be to get to things.

I honestly haven't run into a reason to Not have it under the axle LOL..not yet anyhow

[MikeStang 247]

Oh my motor made 550 at the crank on the Dyno and I went 2.5"

I noticed a bit of a power drop when I swapped from my 1-7/8" Home made shortie headers to FPA Long tubes :/

[RCE1313 23]

Oh my motor made 550 at the crank on the Dyno and I went 2.5"

I noticed a bit of a power drop when I swapped from my 1-7/8" Home made shortie headers to FPA Long tubes :/

 

Powerdrop?!?! that's no good haha.  Where did you get your motor dyno'd?  You are in BR area, right?  Any good places to get my car dyno'd once I get it going?