Exhaust dump right before axle? Any issues?
#1
Exhaust dump right before axle? Any issues?
...so I've been kickin around making some changes. I've got the electronic cut out I never use, the fancy polished dual dual tips out back....I just wanna go simple. I measured, and have room for a smaller muffler (spintech for example) to go right below the cat heat shield. Then I could take the normal route back to the axle, and dump.
Any reason NOT to do this?
Any reason NOT to do this?
#3
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Car: '89 Firebird
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Re: Exhaust dump right before axle? Any issues?
It isn't clear to me what your goal is. Are you just trying to incorporate a cutout, or are you wanting to eliminate the tailpipes showing in the back?
Last edited by QwkTrip; 11-16-2017 at 04:57 AM.
#4
Re: Exhaust dump right before axle? Any issues?
It isn't clear to me what your goal is. Are you just trying to incorporate a cutout, or are you wanting to eliminate the tailpipes showing in the back?
No, seriously though, I mention the cut out only to illustrate that I feel my current set up is over thought. I'd like to go simple. Simple appearing with no tail pipes out back, simple functioning with no fancy cut out, simple fab, with minimal bends. I've had the car for 20 years, and feelings, ideas and opinions change. I just wanna go simple. ....the cost in actual dollars and labor hours to swap exhaust systems, when spread over that time in minimal. I figure what the heck, try something new.
I'm just looking to see if there's legitimate reasons NOT to do it. mgg4591 mentioned drone, which is of course a possibility. I thought about fumes too. I dunno....just looking for feedback I guess.
#5
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Re: Exhaust dump right before axle? Any issues?
I've had mine dumped before the axle for the last decade. As long as as you use a turn down that points the exhaust down you don't have any real problems. If it points straight back you will have the rear components and floor pan covered in black.
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Car: 92 Firebird
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Re: Exhaust dump right before axle? Any issues?
I don't like seeing the exhaust tips out the back also. I have a Borla system on my car, and if I ever get around to it, I plan on removing the dual/dual tips and just putting slash cut straight pipes in to replace the tip, and tuck them so you can't really see them from the back. IMO that would be the least amount of work for you, just leave what you have and "fix" it
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#8
Re: Exhaust dump right before axle? Any issues?
IMO that would be the least amount of work for you, just leave what you have and "fix" it
#9
Re: Exhaust dump right before axle? Any issues?
Turn downs before the axle are simple and light, but the exhaust resonates between the ground and the floor pan, almost effectively turning the floor pan into a massive sub woofer and there is NO way to make them quiet (If you've ever stood next to a car with a healthy engine and turn downs you'll notice that you _feel_ the bass in the exhuast note much more than if the same exhaust was pointed out the back or the side) . In the car with a full muffler they'll be louder than out the back with no muffler.
The disadvantage with what you're suggesting otherwise is that the further forward in the exhaust you mount a muffler the more affect it has on power. You are best off running as much exhaust as you're going to run, muffler and then tip.
My exhaust for years (on 4 different f-bodies, it literally got swapped from one to the next) probably meets your requirements- Headers/y appropriate to the car, large diameter intermediate pipe, Dynomax Ultraflow Welded behind the axle and a short tailpipe and turndown right before the bumper. You can't see it from behind, it's quiet (my car is quieter than most stock/near stock f-bodys with any cat back, most people think it's stockish, simple and flows better than I'd bet 90% of the exhausts on here. I've recently added a cutout to the intermediate pipe, dumping right in front of the axle for strictly superficial reasons, I got tired of being the quietest guy every time a bunch of my car guy/f-body friends got together, but I still mostly drive it closed.
Last edited by 83 Crossfire TA; 11-16-2017 at 04:43 PM.
#10
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Re: Exhaust dump right before axle? Any issues?
I have no tips showing on my car. At one point I thought the tips out the back was bad ***. But taste changes and now I like the clean look of no pipes showing... at least for now. I modified my old hooker catback and welded in an slp muffler to a 90 degree bend. Then used a 3 inch steel turn down from autozone and welded it all together.
#11
Re: Exhaust dump right before axle? Any issues?
83 Crossfire - I hear ya...thanks for the feedback. Do you really think a muffled dump under the car would be louder than open pipes out the back? Not arguing, I really don't know.
I may do something to what you or mgg4591 have.
mgg4591 - dude, that looks AWESOME. As you say, I bet you can't really see anything from regular viewing angles. Not a huge fan of the SLP (been there) but I love the way you did that.
I may do something to what you or mgg4591 have.
mgg4591 - dude, that looks AWESOME. As you say, I bet you can't really see anything from regular viewing angles. Not a huge fan of the SLP (been there) but I love the way you did that.
#12
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Re: Exhaust dump right before axle? Any issues?
83 Crossfire - I hear ya...thanks for the feedback. Do you really think a muffled dump under the car would be louder than open pipes out the back? Not arguing, I really don't know.
I may do something to what you or mgg4591 have.
mgg4591 - dude, that looks AWESOME. As you say, I bet you can't really see anything from regular viewing angles. Not a huge fan of the SLP (been there) but I love the way you did that.
I may do something to what you or mgg4591 have.
mgg4591 - dude, that looks AWESOME. As you say, I bet you can't really see anything from regular viewing angles. Not a huge fan of the SLP (been there) but I love the way you did that.
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Re: Exhaust dump right before axle? Any issues?
Full exhaust is the way to go (fumes and sound). When I see a dump before axle it just leaves me with the impression of cheap, half-*** work, boy-racer kind of stuff.
Just do a single in/out muffler in the back with a hidden turn down tucked behind the bumper. Sound bouncing off the ground will make the interior more loud but that's the sacrifice for a clean look.
Hawks Motorsports sells a fantastic 3.5" system with V-band flanges for LS swapped cars. Not sure if they sell it for SBC or not. If not, then check with Stainless Works who manufactures the kit. There is a good view of the tailpipe in the video below.
As far as sound, you just never know what you'll get until it is done. As long as you can avoid the "rap brap brap brap brap" noise then it's a win. And there is one universal truth --- build a fast car and it will sound good. I have an stroker LS with sizable cam, you have a stroker SBC with very mild cam... I guarantee they will sound different. But one thing will be consistent and that is that Stainless Works manages to keep idle sound very strong while not being too loud (like Magnaflow) at wide open throttle. It's a good system for being noticed cruising the parking lot but not blowing out your ears on the way home. It's not quiet though. I sure wouldn't want to be any louder. A quick rev or WOT can bother my ears. It is quite a bit louder than the video would lead you to believe.
Just do a single in/out muffler in the back with a hidden turn down tucked behind the bumper. Sound bouncing off the ground will make the interior more loud but that's the sacrifice for a clean look.
Hawks Motorsports sells a fantastic 3.5" system with V-band flanges for LS swapped cars. Not sure if they sell it for SBC or not. If not, then check with Stainless Works who manufactures the kit. There is a good view of the tailpipe in the video below.
As far as sound, you just never know what you'll get until it is done. As long as you can avoid the "rap brap brap brap brap" noise then it's a win. And there is one universal truth --- build a fast car and it will sound good. I have an stroker LS with sizable cam, you have a stroker SBC with very mild cam... I guarantee they will sound different. But one thing will be consistent and that is that Stainless Works manages to keep idle sound very strong while not being too loud (like Magnaflow) at wide open throttle. It's a good system for being noticed cruising the parking lot but not blowing out your ears on the way home. It's not quiet though. I sure wouldn't want to be any louder. A quick rev or WOT can bother my ears. It is quite a bit louder than the video would lead you to believe.
Last edited by QwkTrip; 11-17-2017 at 01:20 AM.
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Re: Exhaust dump right before axle? Any issues?
I like the pipes semi hidden like the factory did it, unless you have a SLP totl.
No matter how they are angled, dumps under the car will coat things black over time and under certain conditions you'll have fumes in the cabin.
No matter how they are angled, dumps under the car will coat things black over time and under certain conditions you'll have fumes in the cabin.
#17
Re: Exhaust dump right before axle? Any issues?
During this inspection , no emissions are checked because the car is too old for that (in my State , pre OBD2 are safety inspection only) and safety items only are checked .
One of the biggest safety items they check for on an old car , especially an old racy looking car , is a "factory proper" exhaust system , in other words one that is not loud and , the important part here ; One that runs to the back of the car . Any exhaust that dumps under the car or even in front of the rear axle is verbotten and will earn the car a "rejection" sticker , and since this is a safety and not emissions deficiency the car is illegal to drive till the safety issue is rectified (emissions rejection has 30 days to be repaired but the car IS legal to drive during those 30 days)
So I ask the Original Poster , DO you register and insure your car for road use ? And ARE you required to get an inspection sticker every year ? And if yes to both DO you have a friend in the inspection place that'll let an improper exhaust system slide and give you the sticker anyway ?
Where I live (Taxachusetts) , If your car isn't inspected within 30 days of the due date , the RMV (Registry of Motor Vehicles) sends a nasty letter threatening to cancel the vehicle's registration within the next 30 days if the vehicle isn't inspected (gotta love the fact that the inspection stations are all tied into the RMV so they know which cars have active registrations with no inspection on record) .
Land of the free huh ? Not when it comes to modifications to your car , at least not in the "People's Republic of Massachusetts"
#18
Re: Exhaust dump right before axle? Any issues?
That's EXACTLY how I want to re-do my tips on my car.
So I ask the Original Poster , DO you register and insure your car for road use ? And ARE you required to get an inspection sticker every year ? And if yes to both DO you have a friend in the inspection place that'll let an improper exhaust system slide and give you the sticker anyway ?
It's funny because growing up in NY/NJ you just assume "that's the way it is". It's not til you get out that you realize that most of the country is actually pretty normal. I'll never go back!
Last edited by Abubaca; 11-18-2017 at 03:16 PM.
#19
Re: Exhaust dump right before axle? Any issues?
Agreed. I like that.
I'm in North Carolina. It's pretty loose. Pre OBD2, you basically just go to cashier at the inspection station and pay. They've been considering dropping it all together, but it hasn't quite happened just yet.
It's funny because growing up in NY/NJ you just assume "that's the way it is". It's not til you get out that you realize that most of the country is actually pretty normal. I'll never go back!
I'm in North Carolina. It's pretty loose. Pre OBD2, you basically just go to cashier at the inspection station and pay. They've been considering dropping it all together, but it hasn't quite happened just yet.
It's funny because growing up in NY/NJ you just assume "that's the way it is". It's not til you get out that you realize that most of the country is actually pretty normal. I'll never go back!
God Bless North Carolina and any other State that's cool with old cars !
#20
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Re: Exhaust dump right before axle? Any issues?
I've had no problems dumping in front of the rear axle and it does not drone in the car on the highway.
#21
Re: Exhaust dump right before axle? Any issues?
Ha thanks. Yea Im always swapping out mufflers. Went from a magnaflow, to a hooker, to a flowmaster 40, to a flowmaster 10, then to the loudmouth 2. Before the loudmouth a had the same pipe routing but just straight with no muffler. Idle sounds INSANE with the cam, but driving is unreal loud at wot. I swap back to the straight pipe from time to time, but what i really need is a cutout. Here’s a shot of just the straight pipe, and the slp off the car. Same tucked away routing.
If I remember right my intermediate pipe started as a stainless SLP pipe, though it's been cut up and modified a few times, and cut it and put a standard 3 bolt flange in the back before the muffler.
The Dynomax Ultra flow welded is my default muffler, but I've run an SLP TTL muffler, stock 4th gen TA muffler/tailpipes, glasspack/bullet, aerochamber, magnaflow, a couple of homemade setups with different tailpipes configurations, a turn down right at the flange, a tailpipe all the way like he has it... I'm sure tons of others. I usually paint my back section black to hide it even better.
#22
Re: Exhaust dump right before axle? Any issues?
i had a 70 1/2 camaro with a tpi motor and 2 chamber flomasters dualed out with 3 inch pipe and turn downs before the rear end and it was loud but then it was loud before the turn downs also but at a certain speed you picked up up droning or like was mentioned before like bass but i like to hear my exhaust and never had problems with fumes either