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Re: Why just fix the leak when you can eliminate the choke points?
Posted: Thu Oct 08, 2020 5:34 pm
by CapriceX2
Welds weren’t too pretty but they ground down ok.
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Re: Why just fix the leak when you can eliminate the choke points?
Posted: Thu Oct 08, 2020 7:16 pm
by lastcall190
I welded a couple times and the phrase I channeled was "A grinder and paint make me the welder i ain't"
I think it looks good along with the downpipe. Reminds me of the homemade intercooler pipes on my previous vehicles, good times.
My center section muffler looked the same (rusted and separated) and my axle back muffler had a hole in it. Cats and rest of the pipes were fine, strangely enough
-J
Re: Why just fix the leak when you can eliminate the choke points?
Posted: Fri Oct 09, 2020 7:25 am
by CapriceX2
kevink wrote: ↑Thu Oct 08, 2020 5:08 pm
1/16" rod is your problem. Use 0.035".
I haven't found smaller than 1/16" rod for SMAW (stick welding). It isn't too bad. Took some effort to get the current set just right, I can only make short stitches, and the arc blow is unreal at times; but with the right technique it isn't going too bad.
At 0.035", I assume your are talking TIG rod? I've just barely scratched the surface with TIG. I suppose I should put some effort into learning it, but I'll do that on some mild steel scrap. I'm too cheap to learn on stainless!
Re: Why just fix the leak when you can eliminate the choke points?
Posted: Fri Oct 09, 2020 4:37 pm
by Fandango
Cool.
I wonder about those flat sections vibrating from the exhaust pulses and causing some noise. I think that's why most exhaust stuff is oval/round. Either way, looking forward to the progress.
Re: Why just fix the leak when you can eliminate the choke points?
Posted: Sat Oct 10, 2020 8:45 am
by CapriceX2
Fandango wrote: ↑Fri Oct 09, 2020 4:37 pm
Cool.
I wonder about those flat sections vibrating from the exhaust pulses and causing some noise. I think that's why most exhaust stuff is oval/round. Either way, looking forward to the progress.
Yeah, I have the same concerns.
Even without the end plates installed, I can stand on it. Does that mean it is strong/stiff enough to not vibrate with exhaust pulses? No idea.
I got one end plate cut out last night. I’ll get it cleaned up and add some photos in a bit.
Re: Why just fix the leak when you can eliminate the choke points?
Posted: Sat Oct 10, 2020 10:42 am
by CapriceX2
Look what showed up a couple days early!
Guess I won’t run out of things to do this weekend. Like that ever happens.
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Re: Why just fix the leak when you can eliminate the choke points?
Posted: Sat Oct 10, 2020 6:21 pm
by CapriceX2
The first end plate is welded to the expansion chamber. Pulled out the old exhaust.
And the project grows...
Both mufflers are also shot. Seams are splitting and rust has opened them up.
I’ve got a set of Borla ProXS on hand that were supposed to go on the wagon. Guess I’ll try them here.
Guess the exhaust just got louder.
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Re: Why just fix the leak when you can eliminate the choke points?
Posted: Sun Oct 11, 2020 9:07 am
by CapriceX2
The outlet of the exhaust manifolds have a step down to about 2 1/8. I started smoothing this out before my compressor died last night. I’ll need to swap compressors around before I can finish the blending.
Here’s how it looked when the compressor died:
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And here is where it started:
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I have the other end of the expansion chamber cut out and tacked in. No photos yet.
Re: Why just fix the leak when you can eliminate the choke points?
Posted: Mon Oct 12, 2020 11:20 am
by storm9c1
Interesting restriction there. Almost looks intentional and not a casting flaw. I wonder if that was engineered into the manifolds to either increase velocity or create some turbulence before entering the cats.
Just guessing, but I'm wondering if the AFM (or other part-throttle condition) was causing some popping in the manifolds and keeping the velocity up would smooth it.
FWIW, unsure if this applies here, but properly engineered restrictions in an exhaust system can have a significant bearing on gas velocity. Which can also lower unwanted noises. For example, it's reasonable to have a larger pipe at the manifolds, then gently reduce to the cats, then smaller pipes after the mufflers, with the theory being that as the gasses cool, they no longer need the same larger diameter to maintain the same velocity. Keeping the velocity up as the gasses cool helps with scavenging, but perhaps more importantly, helps with unwanted noise, drone, etc. With low velocity, big pipes become echo chambers.
I'm not an exhaust engineer, so this is all just spit balling as far as I'm concerned. Although I do work for a software company that produces software to simulate just about anything in engineering... including the flow of gasses and liquids through pipes, and some of the simulations are pretty neat.
Re: Why just fix the leak when you can eliminate the choke points?
Posted: Mon Oct 12, 2020 1:57 pm
by CapriceX2
storm9c1 wrote: ↑Mon Oct 12, 2020 11:20 am
Interesting restriction there. Almost looks intentional and not a casting flaw. I wonder if that was engineered into the manifolds to either increase velocity or create some turbulence before entering the cats.
Just guessing, but I'm wondering if the AFM (or other part-throttle condition) was causing some popping in the manifolds and keeping the velocity up would smooth it.
FWIW, unsure if this applies here, but properly engineered restrictions in an exhaust system can have a significant bearing on gas velocity. Which can also lower unwanted noises. For example, it's reasonable to have a larger pipe at the manifolds, then gently reduce to the cats, then smaller pipes after the mufflers, with the theory being that as the gasses cool, they no longer need the same larger diameter to maintain the same velocity. Keeping the velocity up as the gasses cool helps with scavenging, but perhaps more importantly, helps with unwanted noise, drone, etc. With low velocity, big pipes become echo chambers.
I'm not an exhaust engineer, so this is all just spit balling as far as I'm concerned. Although I do work for a software company that produces software to simulate just about anything in engineering... including the flow of gasses and liquids through pipes, and some of the simulations are pretty neat.
My guess is that this step is intended for an exhaust donut. Our application doesn't use one, but these manifolds are used in other places. Wondering if they designed the manifold to be able to seal in different ways depending on application.
Here is a photo of a spare manifold for my truck. Looks very similar to me.
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Here is the donut and how it fits into that recess.
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