My manifold is all welded...see it on the car!
01-16-03, 01:11 AM
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My manifold is all welded...see it on the car!
01-16-03, 11:03 AM
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Originally posted by GLHS
Very nice work, could make more power with longer straight out tubing from the manifold.
Very nice work, could make more power with longer straight out tubing from the manifold.
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01-16-03, 11:39 AM
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Sorry sir.. I have great respect for you and what you have done, but you are are wrong...
I have seen manifolds with 3" straight out from the block and they made more power than any other setup made..to be exact.. 15 hp more to the wheels...
There is also a good site, I think its Paul Yaws site, he also has been testing the exhaust harmonics, and found that 3" straight out is also the best power producer, with the flatest TQ curve.
I have seen manifolds with 3" straight out from the block and they made more power than any other setup made..to be exact.. 15 hp more to the wheels...
There is also a good site, I think its Paul Yaws site, he also has been testing the exhaust harmonics, and found that 3" straight out is also the best power producer, with the flatest TQ curve.
01-16-03, 02:42 PM
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What I meant was that there was a point of deminishing returns. His manifold looked pretty long already from the pictures (though maybe I didn't see it at the right angles? I only looked at a few of them).
01-16-03, 06:42 PM
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Can you tell me what the hell you guy's are talking about? Cuz all the guys in the turbo section are saying to make the runners about 11-13 inches long, and one guy says he makes .81 bar at a free rev with no load on the motor and he is running 28" runners....Oh and his runners are 2.5"dia.
01-16-03, 09:05 PM
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Don't mind GLHS, I honestly don't know where he gets all of his *information*. Cake is on the right track, as usual. Keep the tubing as small as it has to be (3" is rediculous) or else you'll create weird flow turbulence and such. Also, keep all the bends nice and smooth as to not create head loss. Another problem when you use HUGE tubing is that the air will expand into the pipe and cool as it travels and have a lower velocity...not exactly what you want for a turbo car. As for optimum length? I don't really know, but 11-12 inches sounds like it'd work. I'd really like to calculate out for a tuned manifold and I can do it for a boinger, but I'm not too sure how it works out with a rotary. If anyone knows some good reference materials, I'd really like to get ahold of some. All in all, I think trying to keep it equal length, smooth and as short as possible is the true key. Good luck, it looks good.
01-16-03, 10:09 PM
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It sounds like some people making ALOT of power are using 11-12" or in the mid 20s" for the length of the turbo primaries.
Very probably the 11-12" figure is the right length that the exhaust pressure wave reflecting off of the turbo and back at the exhaust port hits the port when it is closed. Then the mid 20" figure would hit do the same, but on the next engine rotation.
If you just stick the turbo as close to the engine as possible you will reflect a lot of exhaust pressure waves right back at the open exhaust port- forcing some exhaust back into the engine thus largely reducing the benifits of thermal efficiency (having the turbo as close to the engine as possible.)
It just struck me as more than coincidence that these two lengths are mentioned. Ian
Very probably the 11-12" figure is the right length that the exhaust pressure wave reflecting off of the turbo and back at the exhaust port hits the port when it is closed. Then the mid 20" figure would hit do the same, but on the next engine rotation.
If you just stick the turbo as close to the engine as possible you will reflect a lot of exhaust pressure waves right back at the open exhaust port- forcing some exhaust back into the engine thus largely reducing the benifits of thermal efficiency (having the turbo as close to the engine as possible.)
It just struck me as more than coincidence that these two lengths are mentioned. Ian
01-17-03, 06:02 AM
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Originally posted by cbrock
Don't mind GLHS, I honestly don't know where he gets all of his *information*. Cake is on the right track, as usual. Keep the tubing as small as it has to be (3" is rediculous) or else you'll create weird flow turbulence and such. Also, keep all the bends nice and smooth as to not create head loss. Another problem when you use HUGE tubing is that the air will expand into the pipe and cool as it travels and have a lower velocity...not exactly what you want for a turbo car. As for optimum length? I don't really know, but 11-12 inches sounds like it'd work. I'd really like to calculate out for a tuned manifold and I can do it for a boinger, but I'm not too sure how it works out with a rotary. If anyone knows some good reference materials, I'd really like to get ahold of some. All in all, I think trying to keep it equal length, smooth and as short as possible is the true key. Good luck, it looks good.
Don't mind GLHS, I honestly don't know where he gets all of his *information*. Cake is on the right track, as usual. Keep the tubing as small as it has to be (3" is rediculous) or else you'll create weird flow turbulence and such. Also, keep all the bends nice and smooth as to not create head loss. Another problem when you use HUGE tubing is that the air will expand into the pipe and cool as it travels and have a lower velocity...not exactly what you want for a turbo car. As for optimum length? I don't really know, but 11-12 inches sounds like it'd work. I'd really like to calculate out for a tuned manifold and I can do it for a boinger, but I'm not too sure how it works out with a rotary. If anyone knows some good reference materials, I'd really like to get ahold of some. All in all, I think trying to keep it equal length, smooth and as short as possible is the true key. Good luck, it looks good.
Last edited by GLHS; 01-17-03 at 06:04 AM.
01-17-03, 12:06 PM
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If you look at intercooler pipe design, bigger isn't always better. GLHS, have you been through any design class or theory on pipe flow???? You have to calculate out for how much CFM, velocity..etc etc that you are dealing with. Another thing to look at is the size of the exhaust port on the housing. What happens when you try to go from that to a 3" pipe without a smooth transition? You'll create turbulence (bad flow). So perhaps 3" pipe is the size to go with, we all know that it's an option. What about 4" pipe or 5"...you know where I'm going with this. At some point you hit deminishing returns. So perhaps you run 3" pipe, I would think you'd need quite a long section of tube to flare out to the 3" and by that time you will have lost any gains, let alone trying to mount that in a car. From everything I know about turbo design, you need heat and velocity. You go too big and you won't get either. GLHS, all you provide is hearsay. I'd have to seem so cold hard #'s backed up by COMPLETE vehicle setups. Change one thing and the amount of air moved by the motor will change. See ya later..TOOL.
01-17-03, 12:49 PM
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Dude what is your problem. I should have never helped you with your Dodge, your such a jerk, and for no reason.. Thanks.
Now since your so smart. I said 3" of straight piping from the block, not 3" ID... get it right and maybe you will understand what was being said.
And if you can't read other posts about this, go and check Pauls page, he has tested this also and says the exact same thing I have been saying for a while now.
Also I have been doing CAD designing for almost 10 years, and you know nothing about anything... you wrench..
Now since your so smart. I said 3" of straight piping from the block, not 3" ID... get it right and maybe you will understand what was being said.
And if you can't read other posts about this, go and check Pauls page, he has tested this also and says the exact same thing I have been saying for a while now.
Also I have been doing CAD designing for almost 10 years, and you know nothing about anything... you wrench..
01-17-03, 07:23 PM
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Originally posted by Bad2ndgen
So you draw pictures huh? That doesn't make you a flow dynamics engineer....Please people Im looking for good info not a battle of wits.
So you draw pictures huh? That doesn't make you a flow dynamics engineer....Please people Im looking for good info not a battle of wits.
I'm not gonna to participate in "this battle of wits" but I do like your manifold amd I respect Paul Yaws work. I do however take offense at your "you draw pictures" remark. I am a 3D Nuclear Glovebox Designer, I have 20+ years Experience in Design, Operation, Maintenance, and Quality Asurance Inspection Experience in Nuclear Powered Submarines and Nuclear Facilities (I could tell you which ones, but then I would have to KILL you!
). CADD is more than drawing pictures, Lets talk Flow Dynamics sometime, but you don't get to have a college text in front of you, Lets Discuss hmmmmm......... Ultra-low vacuum flow of tritium gas.....yeah, thats the ticket...How about Cryrogenic distillation???? How many Thermal-Cyclic Absorption Vessels have you designed? How many MILLIONs of $$$ projects and contracts have you been responsible for? (LAST GLOVEBOX contract was 400 MILLION, the current one is 500 Million +) What Cadd programs are you PROFICIENT in? DO NOT include those that you have taken classes in only, Include those where you have 2000+ hours of PRODUCTIVE seat time...Next time you shoot off about someones PROFESSION and LIVELYHOOD, be prepared for the Shitball to roll down hill!
01-17-03, 08:13 PM
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I read just fine, but your lack of english skills lends me to believe that you meant 3" diameter pipes. As for a lack of skills, I'm currently working in the advanced product design group for a small company called TRW...perhaps you've heard of them??? I also worked on Formula SAE. Last I checked I was designing parts in solidworks and running FEA's. As for being a jerk, I think I have every right to be. You ask questions and if the answer wasn't what you were looking for, you get pissed and call me a ricer and a tool. Instead of calling me names you could have said, "Chuck, I'm sorry, I meant the length of the pipe to be 3" not the diameter". Simple mistake. Simple reply.
Now 3" LONG pipe makes since. There will be different lengths at which the manifold will be efficient. Obviously for a turbo you want to be as short as possible, but still allow for proper packaging. I think this is why most people say 11-12 inches...that's the next length that will flow well. Also believe someone said 20 or 28"..but that seems waaay too long. What we really need to do is tune for optimum length based off exhaust pulses...but we'll need a bunch of different manifolds and a lot of dyno time. That would cost $$$$, so I think I'm going to pattern my manifold off of the HPI that soul was running. They probably had quite a few engineers work on that..so I'll trust it.
As for the dodge....the kid blew the head gasket. I told him not to run it hard till he got that fixed. Someone cut him off, he punched...spooled hard but as soon as he passed..POP.
Now 3" LONG pipe makes since. There will be different lengths at which the manifold will be efficient. Obviously for a turbo you want to be as short as possible, but still allow for proper packaging. I think this is why most people say 11-12 inches...that's the next length that will flow well. Also believe someone said 20 or 28"..but that seems waaay too long. What we really need to do is tune for optimum length based off exhaust pulses...but we'll need a bunch of different manifolds and a lot of dyno time. That would cost $$$$, so I think I'm going to pattern my manifold off of the HPI that soul was running. They probably had quite a few engineers work on that..so I'll trust it.
As for the dodge....the kid blew the head gasket. I told him not to run it hard till he got that fixed. Someone cut him off, he punched...spooled hard but as soon as he passed..POP.