[quote author=AlpineRAM link=board=7;threadid=14778;start=60#140302 date=1053456327]<br>I think you left out where I said in correlation to the diameter of the exhaust pipe. ..[/quote]<br>well I didn't just &quot;leave it out&quot; -- I assumed that it &quot;goes without saying&quot;! seriously, I agree with you, and I know that the gas will travel faster in the pipe than the piston's max speed. I was trying to show that reality checks all fit nicely with your explanations. All the numbers (both yours and mine) make sense nicely.

 

[quote author=Gary - KJ6Q link=board=7;threadid=14778;start=75#140337 date=1053465106]<br>I may have missed something above - [/quote]<br>relax guys, the calculation was not trying to predict the speed of the gas in the pipe! Alpine mentioned that the speed of the piston was part of the equation and the only thing I did was provide that part

 

Well I do believe that the stuff we can hang on there post turbo can make a difference. This difference will be bigger when we go way up in fuel and HP. (And we'll notice 25F below or above meltdown much more than 750 to 800 F ;D )<br>What I didn't see yet were exhaust manifolds that were of a radically differend design than stock . Aren't there any or did I sleep through something ???<br><br>I think it's great to have threads like this. I do not expect anybody to search for hard tech facts or quick help in a thread called &quot;some trivial musings re: exhaust pipes (sound and EGTs)&quot; <br>But maybe it's threads like these that give some folks a push to research in a certain direction. Or this may have killed some exhaust vortex only 299,95$ myths. <br><br>Thanks for this nice and informative thread and for bearing with my musings ;D <br>AlpineRAM

 

All you guy's need to do about learning everything there is to know about exhaust systems, is talk to Jerry Jardine. He's been building and designing them for over 40 years and says there's some good improvements to be made by putting the turbo on the end of a shorty header.

 

I think that it might be nice to invite this guy to comment on our musings. <br>Maybe he could write an article.....<br><br>AlpineRAM

 

I would imagine there would an advantage to putting the turbo on the end of a short header.<br><br>The problem is that it would have to be VERY short. Turbos need heat to be efficient, and moving it further downstream won't help that any. If you stuck your turbo down by where the muffler is, it would NEVER spool!! Well, maybe but it would be a total dog.<br><br>Katoom, why so hasty to dump this thread? If you feel it's not your style, then you have other viewing options. Maybe you could just periodically summarize the thread as you did so succinctly in your last post?<br><br>Here's an interesting idea: wouldn't the IDEAL system (if not the most impractical) have one little turbo bolted to each exhaust port? I mean, eliminating the manifold all together, even! OF course, the problem is then how do you spool a turbo when it only sees one exhaust pulse every other revolution. Scratch that-- you NEED the manifold.<br><br>Now that you think about it, it would seem our CTDs have an advantage in turbo spooling over many turbo apps, but not other diesels. First, we have 6 cylinders feeding one turbo. Most turbo cars are only 4cyl. Turbo v-8s usually have two turbos, so they're in the same boat as the 4-cyl guys. Wouldn't it help the turbo to have a more frequent series of smaller pulses (more cylinders of smaller displacement) for a given engine size? logic would SEEM to say this would help the turbo spool faster. Thus, the DMAX and PSD guys would have an advantage over us. Too bad they can't capitalize on it.<br> As for manifold designs, I would think that a 6-into-3-into-1 manifold would be better. Kind of like the old tri-Y headers. Isn't that how the ATS manifold is?<br><br>Good thread fellas. Thanks for the education.<br><br>HOHN

 

The manifold on these trucks are not that important because they arent relying on the scavenging effect of a header design. This is the beauty of a aritificialy aspirated motor. As for the Tri-Y design, these were to build torque, not total horsepwer by using the pulses to scavenge eachother. The manifold on our trucks work fine because the cylinders are firing at opposite sides of the manifold. So they dont run into eachother causing restriction. <br><br> My views havent changed. You guys seem to be doing fine without me. Just let me know when you need my summerizing. As for dumping the post...well I do have a life and to be honest if I spend much more time plugged into this computer my wife going to cut the cord!!! ;D I feel like a closet computer junky.<br>

 

Have yall ever thought about taking up a hobby? Like fishing or stamp collecting?

 

Hypothesis:<br>Current conditions = stock 12v<br>Remove the &quot;scrubber&quot; and muffler.<br>Install a piece of 4 in so the progression would be 3 in to 4 in then back to a 3 in. Essentially a resonance chamber with the added effect of allowing the exhaust gases to mix before exiting?<br><br>The questions raised by this hypothesis is:<br>1, Will the &quot;whooshing&quot; noise exiting a straight piped 3 in system be reduced?<br>2. Would the &quot;chamber&quot; create or reduce the dreaded cab drone?<br>3. What would the performance gains or reductions be?<br><br>Thoughts?

 

[quote author=rookie73 link=board=7;threadid=14778;start=75#148333 date=1055368467]<br>Hypothesis:<br>Current conditions = stock 12v<br>Remove the &quot;scrubber&quot; and muffler.<br>Install a piece of 4 in so the progression would be 3 in to 4 in then back to a 3 in. Essentially a resonance chamber with the added effect of allowing the exhaust gases to mix before exiting?<br><br>The questions raised by this hypothesis is:<br>1, Will the &quot;whooshing&quot; noise exiting a straight piped 3 in system be reduced?<br>2. Would the &quot;chamber&quot; create or reduce the dreaded cab drone?<br>3. What would the performance gains or reductions be?<br><br>Thoughts?<br>[/quote]<br>I will comment to the best of my knowledge:<br>ad 1. whooshing- don't know<br>ad2. The cab drone seems to be the resonance of the pipe being transferred through the frame into the body- some people claim success in eliminating the drone by clamping pieces of angle iron to the pipe- this seems to alter frequencies.<br>3. With stock fueling the effects of changing anything on the exhaust are marginal. You could possibly see an EGT reduction and better spoolup compared to the stock system, but I doubt any real performance gain.<br><br>HTH<br><br>AlpineRAM

 

Geez, now I wish I stayed awake in Thermodynamics at school! I blew off the Diesel discussion thinking, &quot;when am I ever going to use this?&quot; <br>Thanks, Doug and all for the quick recap!<br>Now I'm gonna take a Tylenol and a nap!

 

Thanks for the info AlpineRAM.<br><br>[quote author=AlpineRAM link=board=7;threadid=14778;start=75#148465 date=1055400877]<br>3. With stock fueling the effects of changing anything on the exhaust are marginal. You could possibly see an EGT reduction and better spoolup compared to the stock system, but I doubt any real performance gain.<br>[/quote]<br><br><br>I would have to disagree on this comment.<br><br>Since straight piping my truck it has some REAL get up and go. For example, I have some CD's in the overhead console and now if I floor it. I have to reach up and hold onto the CD's or they end up in the back seat!!! (Not scientific, but the evidence speaks for it's self.)

 

[quote author=rookie73 link=board=7;threadid=14778;start=75#148333 date=1055368467]<br>Hypothesis:<br>Current conditions = stock 12v<br>Remove the &quot;scrubber&quot; and muffler.<br>Install a piece of 4 in so the progression would be 3 in to 4 in then back to a 3 in. Essentially a resonance chamber with the added effect of allowing the exhaust gases to mix before exiting?<br>[/quote]<br><br>my thoughts (from a theoretical perspecitve. I've not experimented with any of this stuff): this creates an &quot;expansion&quot; chamber or resonator with a couple of interesting consequences. The sudden increase in diameter causes the exhaust gases to slow down, cool, and to increase in density. As seen from upstream in the pipe, this change in density will create acoustic reflections and might result in a change in the sonic signature of your system (it will probably sound slightly different with the chamber than without it). It will certainly be louder, but I'm talking about the sonic signature, not the loudness.<br><br>I don't think so. The sound changes introduced by the expansion chamber or resonator I expect are lower in frequency than &quot;whooshes&quot;, which are really the sound of air passing through a restriction which is present in the 3&quot; straight pipe. <br><br>I doubt it, but its possible that the new resonator, depending on it's placement and mechanical properties, would break up what would otherwise be a mechanical resonance in the pipe. just expanding on what Alpine said here -- the drone is not caused by the acoustics of the air inside the pipe, it is caused by the mechanical resonance properties of the pipe itself. <br>The new expansion chamber itself I doubt would net you anything (it would act as a &quot;resonator&quot;, affecting sound as upposed to performance). Removing the stock air restrictions in the 3&quot; system (mainly the muffler) might net some small improvments in turbo spoolup, depending on the condition of the stock muffler you are removing. if the muffler is falling apart inside then you probably will see a big performance improvement and maybe a reduction in the 'whoosh' nosie. That possibillity aside I wouldn't expect to see an obvious performance improvement in terms of measurable HP gain on a dyno, for example. What you might see is a faster turbo spoolup, such as what Alpine suggests, and you might perceivce this as a performance improvement, even though there is no substantial net increase in net HP.<br><br>You may see reduced EGTs caused by better air flow as a consequence of removing the stock restrictions in the pipe (just as with any other straight pipe system with or without a resonator). Average air flow (liters per second) is what keeps things cool. But again, with stock fueling, EGTs are not an issue anyway. My thought here is that if you see a noticable improvement in performance, then you have proven that the stock exhaust system is the air flow bottleneck, and you can acheive the same improvement by simply removing the muffler (no expansion chamber). <br><br>There was a while back some voodoo snake oil outfit trying to sell a &quot;chamber&quot; like thing as a performance enhancer. some fancy sounding technobable name with the word &quot;vortex&quot; in it, if memory serves. Anyway, I think their add campaign must have run out of money as I haven't seen this foolishness pop up for some time. I wrote them asking for some good solid technical or experimental data and received no ressponse. My point is that these expansion chambers or resonators are effective at changing the sound of the system, but not the engine performance.