So I'm going to be running a 3" turbo back exhaust And I was wondering if anyone has run their exhaust under the axle? I know Mazda ran under axle on the IMSA cars. 3" is kinda big under a solid axle. If the Car was n/a and i was running 2-1/4" it wouldn't be an issue. So has anyone run under axle at all? If so what were your experiances and was the risk of scrapping worth the benifits. For those of you who don't know usually under axle on a turbo car is good for 4-5 whp. 3 less bends in an exhaust.

 

If myou have a system built out of mandrels it should be just fine to go over the axle

 

you have to make sure the axle cant hit it, kinda limits the suspension travel a tad. dual 2.5"'s arent that bad, 3" you prolly have to pay attention to speed bumps and stuff.



going over the axle is a 3-5hp loss on an na car, on a turbo its not gonna be as big a deal

 

This is way off the wall, but I thought I'd chime in since I've thought about this problem as well. No idea about the legality of this, but when I had my rear wheel wells cut out to get rid of some rust, I had an idea about routing the exhaust through the wheel well into the cabin and then out through the area between the tail lights. It'd be loud as hell and hot in the car, but less bends and no worries about hitting anything.

I've also thought about just dumping the exhaust out the side in front of the passengers rear tire, but I think that might be too close to the ground. Anyway, just some food for thought.

 

I have 3" over the axle in my FB and no problems just really catious when i built it to make sure it cleared everything ok

 

I'm running dual 2 1/4" exhaust under the axle on my 12A half-bridge and I have plenty of clearance for street driving. If you're worried you might consider buying some ex-NASCAR oval tubing from www.musclemotorsports.com or making your own by squashing larger tubing.

 

3" exhaust under the axle is a great idea! on a turbo car, you cant go too big with the exhaust.. straight as possible helps too,,

 

This would be very illegal as an exhaust leak could be potentially fatal.

 

plus the heat

 

I would run oval pipe if you are going to go under the axle.