Just searching threw some threads and read a couple people ran open down pipe, open catback,or something of that nature. I also read that there was some fumes inside the cabin or flames of some sort comming out the back end.
I am about to receive my new HKS Hi-power in a couple days but can't wait for it to get here and was wanting to try this little trick out. I am a little hesitant as to if i should fool around with fire tho and was wanting to see what some others thoughts were as to this. It's only for sound i know that and am not going to make it a long term thing just a little fun for the weekend.

So my question is would "open" or no axleback be harm less or would it cause problems of some sort i'm not aware of?

Any info or comments would be much needed and appreciated.

Thanks-

 

You might get away with it as long as you have adequate ventilation and the mid-pipe is supported properly underneath the car. Almost all cars and trucks have exhaust systems that terminate at the rear of the car to get exhaust fumes as far away from the passengers as possible. There might be a few exceptions like some older Corvette Sting Rays and Viper roadsters with side pipes, but even these two terminate with the tips directing exhaust away from the body. The fumes aren't as bad as long as you retain at least one factory cat and the car is fully warmed up but you don't really want to inhale ANY exhaust gases for very long. These aren't zero emission vehicles.

Also, the exhaust gases are warmer the closer you get to the turbo/downpipe. I don't know how much warmer it would be with just the axleback missing but it would be aiming toward the front of the gas tank, would it not?

Personally, I'd just wait until you've installed the complete exhaust. Why risk problems for little gain?

--
0==WW==0
"…axles of evil…" - george w. bush

 

I can only think of a couple things:

1: With no axleback, there will be a lot of heat building up under the trunk/spare tire area when you are not moving. This can't be good.

2: Noise. I ran without one for about 10 minutes one night, to see what it sounds like. It's fierce, but I can imagine that doing so for the whole weekend would attract some unwanted attention if you are foolish about it. Similar to running straight pipe. Drive smart and you will be ok, other than point number one.

 

Well thats one of the thing i was thinking about, what would this do to my gas tank,or even my drive shaft or links. I know it's gonna be hot, but the question is how hot and what the risk factors would be, maybe a little spark or a little gas leak. That might be a disaster waiting to happen. So i thought i'd better ask first. Don't wanna see on the news " Subaru driver was killed as his car burst into flames only 3 miles from his house.....what a dumbass..........ok back to you Bob." Ok maybe not that extreme but " what if"?

As for wingless wonders's reply to an "adequate ventilation and the mid-pipe is supported properly underneath the car." That was no where in my plans. Something to think about tonight, got any ideas as to how this might be done, If i do this that is. Might wait til the hi-power gets here. And also how about if i just role the windows down? Would this be an adequate source for fumes to escape?


And for cdawd's reply: I was thinking about all weekend then switched to only one day, then a couple hours, then one hour. Now maybe not at all. You brought up some good points thanks.

Thanks for the non flamed replys and info, i will consider this threw the weekend.

And also thanks for the quick reply's i greatly appreciat them.

 

ive been driving with the stock catback off for almost a year now, ive never had any problems with any fumes, and the sound is easily controlled since its coming from underneath and not behind the car...the only problem ive experienced has been that the bottom of the center cosole gets warm on long trips ( 1 hr +), other than that its a good free mod and helps your motor exhale a bit around 3k-4k rpm and a lil bit there afterwards.. just try it, take the axle back off, it ends right in front of your rear left axle, if that tickles your fancy then stick with that ( i did for a few months) if you want to realy unleash the boxer rumble and feel a bit more power then take the mid pipe off, its literally a 5-10 min job to take the mid pipe off, and prolly a whole 30 mins to take the stock cat back off lol, its a good free mod just like takeing you intake silencer off, no harm done

 

i ran my car without the axleback for quite awhile, even on long road trips....never had any problems. it can get pretty loud though

 

Oh, it's been awhile since I posted here.

So here's the up date.
Saturday there was nothing to do so I un-bolted my Axel back. It wasn’t as loud as I thought it was, ( I thought like NHRA straight pipes, hehe ) It was pretty muffled, well I guess the cats helped out too.
So I went for a little ride down to Home Depot and picked up a few things, and headed back. ( Only about 5 miles both ways.) It wasn’t bad and sounded pretty good too. Very enjoyable. I checked under the car around the spare tire and it wasn’t smoking hot but a little warm. It really made my day with the rumble going, gotta love the boxer.
So Monday rolled around and a knock came from my door. YESSSSSSSS, its here.
The Hi-power sounds great, and was pretty easy to install. If you have a lift. The only thing I have concerns with from the HKS is that it raddles from time to time. Like if I turn a corner and give it some throttle, you hear a lite shaking, almost from the back end. I checked the hangers and bolts and looks ok, any have a guess as to what it might be?

I would suggest this to anyone who is eager to here there exhaust a little better. Plus it's free.

Life is that much better when you have heard the boxer rumble-

 

The way the HKS Hi-power is routed causes it to rub against the rear diff housing and could probably be the source of your rattling sound. New hangers wont help. If this is the case with yours, get a square of tough rubber padding (like half the length but same width as a stick of gum) and epoxy it to the spot on the diff where the pipe is making contact. Worked for me.

 

I might try that but after i read your post i took at look at the diff housing and it checked out as ok. It's close but reasonable.
However, i looked at the very first hanger on the right side of the muffler and it had some marking on it from rubbing on.... the sway-bar!?!?!? I stuck my finger inbetween to try to see how much space i had and my finger could not fit. If i had to guess as to how much space there was, i'd say about 1 cm. I know this can't be good. My sway-bar's not bent or anything like that. So i guess thats why i hear noise when i go over something rough or take corners at a good speed. Is there something i could do to try to do, like...bend the hanger maybe? I was going to get some new sway-bars soon but i guees thats gonna have to wait.

Got any advice as to what i might do/try?

 

ive been running an open midpipe for a while now...its located right after the downpipe connects to the midpipe and mannn that thing growls like no other....sets off alarms left and right, makes the old people on my block stare at me like they wanna shoot me, and attracts cops like crazy...finally getting sick of it and gonna just go with full turbo back...but if you wanna run the "open downpipe" setup be ready to attract alotta attention...