Exhaust Manifold Design ??'s - and pics of one we made.
10-29-2004, 09:21 AM
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Exhaust Manifold Design ??'s - and pics of one we made.
If anyone is familiar with exhaust manifold design, I have a few questions.
A: Equal length... is this a hit or miss? I mean... is it "the closer the better" or if you are not within 1/10" inch on each runner is there no more benefit than there is at 1" or 2" difference?
B: Stress Relief... what are some methods for this to help prevent cracking? I think that using a saw to put some slits in the flange might help take a little of the tweaking out... also from what I have read about cyro treating it sounds like that would be a very good way to stress relief it and improve longevity.
C: Manifold Support. Say your manifold has about 12" runners. If you braced the turbine flange to the head flange would this be bad? Will this make the manifold more likely to crack by taking out some of the space for expansion... or is it ok to try and brace the **** out of it?
Thats all really.
I ask these because we recently built an exhaust manifold for a customers car here at the shop... its our first effort at it and I think we did an excellent job. We are setting up jigs to replicate it and sell.
I am extremely confident in our fabrication skills and material selection and design... but I ask these things to see if there are other ways I can improve on the manifold before trying to sell them to people. 3 of the runners are almost perfect equal length, and the one that is not we have room to adjust to bring it into spec but it would slightly change the even appearance of the manifold... but if it is a hit or miss then we can make the adjustment.
Here are some pics (The turbo pictured is not the one we are using, its just there to demonstrate placement):
Modified by mister2racer at 1:01 PM 10/29/2004
A: Equal length... is this a hit or miss? I mean... is it "the closer the better" or if you are not within 1/10" inch on each runner is there no more benefit than there is at 1" or 2" difference?
B: Stress Relief... what are some methods for this to help prevent cracking? I think that using a saw to put some slits in the flange might help take a little of the tweaking out... also from what I have read about cyro treating it sounds like that would be a very good way to stress relief it and improve longevity.
C: Manifold Support. Say your manifold has about 12" runners. If you braced the turbine flange to the head flange would this be bad? Will this make the manifold more likely to crack by taking out some of the space for expansion... or is it ok to try and brace the **** out of it?
Thats all really.
I ask these because we recently built an exhaust manifold for a customers car here at the shop... its our first effort at it and I think we did an excellent job. We are setting up jigs to replicate it and sell.
I am extremely confident in our fabrication skills and material selection and design... but I ask these things to see if there are other ways I can improve on the manifold before trying to sell them to people. 3 of the runners are almost perfect equal length, and the one that is not we have room to adjust to bring it into spec but it would slightly change the even appearance of the manifold... but if it is a hit or miss then we can make the adjustment.
Here are some pics (The turbo pictured is not the one we are using, its just there to demonstrate placement):
Modified by mister2racer at 1:01 PM 10/29/2004
10-29-2004, 09:46 AM
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Re: Exhaust Manifold Design ??'s - and pics of one we made. (mister2racer)
A) the length must be calculated, not measured
B) heat treat, cryo, many other options. All in all, everything comes down to the quality of the weld, and the quality of the weld comes down to many factors.
C) If the weld quality is good with a thickwall manifold, no braces are necessary. If you arent sure, definately brace it. From the looks of these pictures i would brace it.
thickwall manfiolds have a learning curve, they are very different than thinwall.
B) heat treat, cryo, many other options. All in all, everything comes down to the quality of the weld, and the quality of the weld comes down to many factors.
C) If the weld quality is good with a thickwall manifold, no braces are necessary. If you arent sure, definately brace it. From the looks of these pictures i would brace it.
thickwall manfiolds have a learning curve, they are very different than thinwall.
10-29-2004, 09:51 AM
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Thanks for reply!
A) i have considered a few ways to try and figure it out. I actually considered using fluid to calculate it since I know the ID of the piping... but once again can you tell me if it is hit or miss?
C) if you mean that you would brace it based on the weld quality you see in the pics - well... i wouldnt judge on prototype tack welds
my welder chris worked at a pure fabrication shop for several years before coming here... welding is what he does best... If you are referring to something else... what would it be?
Modified by mister2racer at 1:04 PM 10/29/2004
A) i have considered a few ways to try and figure it out. I actually considered using fluid to calculate it since I know the ID of the piping... but once again can you tell me if it is hit or miss?
C) if you mean that you would brace it based on the weld quality you see in the pics - well... i wouldnt judge on prototype tack welds
my welder chris worked at a pure fabrication shop for several years before coming here... welding is what he does best... If you are referring to something else... what would it be?Modified by mister2racer at 1:04 PM 10/29/2004
10-29-2004, 09:54 AM
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Re: Exhaust Manifold Design ??'s - and pics of one we made. (mister2racer)
some of your bends look "cheated" you might want to work on that....they are not condusive to good flow
10-29-2004, 09:57 AM
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only one joint just slightly is, and this was just a layout prototype... next one will not be like that. The collector jig we made is setup to make the collectors just a hair longer and smoother, and by keeping the T3 flange in the same spot it gives more vertical space to make the bend on the #4 runner which must be the one your looking at since it is the only cheated bend. thanks!
10-29-2004, 10:11 AM
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Re: (mister2racer)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mister2racer »</TD></TR><TR><TD CLASS="quote">If you are referring to something else...</TD></TR></TABLE>
yes, referring to something else.
yes, referring to something else.
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10-29-2004, 10:17 AM
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Re: (Full-Race Geoff)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Full-Race Geoff »</TD></TR><TR><TD CLASS="quote">
yes, referring to something else.</TD></TR></TABLE>
???
yes, referring to something else.</TD></TR></TABLE>
???
10-29-2004, 10:20 AM
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Re: (mister2racer)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mister2racer »</TD></TR><TR><TD CLASS="quote">
???</TD></TR></TABLE>
Methinks mister full race thinks its a bad design..
???</TD></TR></TABLE>
Methinks mister full race thinks its a bad design..
10-29-2004, 10:26 AM
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Re: (91civicDXdude)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91civicDXdude »</TD></TR><TR><TD CLASS="quote">
Methinks mister full race thinks its a bad design..</TD></TR></TABLE>
could be... there is not much room to call it bad... its got a mint collector, no harsh radius bends, and its very close to equal length and it will be even more so once we figure out exactly where it is and make adjustment... so if someone thought it was a bad design that would be pretty wack...
im just trying to get any recommendations for improving reliability... but i havent got any yet... and I am asking if anyone can tell me to what accuracy equal length is required to be functional as an equal length.... but it doesnt look like anyone has any answers here yet.. hoping for more replies.
Methinks mister full race thinks its a bad design..</TD></TR></TABLE>
could be... there is not much room to call it bad... its got a mint collector, no harsh radius bends, and its very close to equal length and it will be even more so once we figure out exactly where it is and make adjustment... so if someone thought it was a bad design that would be pretty wack...
im just trying to get any recommendations for improving reliability... but i havent got any yet... and I am asking if anyone can tell me to what accuracy equal length is required to be functional as an equal length.... but it doesnt look like anyone has any answers here yet.. hoping for more replies.
10-29-2004, 10:30 AM
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Re: (FOrSfEd)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FOrSfEd »</TD></TR><TR><TD CLASS="quote">I wish I could be of more help cause I like the design, more replies from people with input I would like to know also.</TD></TR></TABLE>
yes... there are probably not many others besides geoff who could answer any of these questions... and he probably is not going to get any less vague.
yes... there are probably not many others besides geoff who could answer any of these questions... and he probably is not going to get any less vague.
10-29-2004, 10:38 AM
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Re: (Full-Race Geoff)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Full-Race Geoff »</TD></TR><TR><TD CLASS="quote">
yes, referring to something else.</TD></TR></TABLE>
LOL!
I think he means that you should brace it.
yes, referring to something else.</TD></TR></TABLE>
LOL!
I think he means that you should brace it.
10-29-2004, 10:39 AM
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Re: (mister2racer)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mister2racer »</TD></TR><TR><TD CLASS="quote">
im just trying to get any recommendations for improving reliability... but i havent got any yet... and I am asking if anyone can tell me to what accuracy equal length is required to be functional as an equal length.... but it doesnt look like anyone has any answers here yet.. hoping for more replies.</TD></TR></TABLE>
The Design Looks Fairly Straight forward. There does Seem to be some Sharp or cheated bends that could have been possibly avoided.
True Equal Length Is hard to come by, Full-race's manifold seems to be off by a good 2 inches or so between 2 of the runners. My standard b series has about 1.5" difference in one of the runners. 95% of the manifolds you see still have some Variance between the runners in length
They are Obvisouly refferred to as being equal Length, but If you Define it truly, they aren't .
im just trying to get any recommendations for improving reliability... but i havent got any yet... and I am asking if anyone can tell me to what accuracy equal length is required to be functional as an equal length.... but it doesnt look like anyone has any answers here yet.. hoping for more replies.</TD></TR></TABLE>
The Design Looks Fairly Straight forward. There does Seem to be some Sharp or cheated bends that could have been possibly avoided.
True Equal Length Is hard to come by, Full-race's manifold seems to be off by a good 2 inches or so between 2 of the runners. My standard b series has about 1.5" difference in one of the runners. 95% of the manifolds you see still have some Variance between the runners in length
They are Obvisouly refferred to as being equal Length, but If you Define it truly, they aren't .
10-29-2004, 10:56 AM
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This One: Thanks for the reply... it is pretty straight forward. One thing that was kind of funny is that we wanted the manifold to look unique... and it did... but once we turn it over we noticed that it strongly resembled another manifold we have seen!!! I guess there are just only so many ways to run 4 tubes.
As for the cheated bends... like I said before there honestly is only 1, and it is very very slight and it will not be in the next version because the collectors we build now are a little longer, and by keeping the turbine flange in the same spot it gives more vertical space to make that bend without cutting the elbows.
I too have noticed that there seems to really be no true equal length... but then again without actually calculating it its impossibel to guess by looking at it. THis manifold we have here... the 2,3,4 runners are less then half inch in measurable length but like Geoff said we have to really calculate it to know for sure.... and I think that perhaps using fluid might be the best/easiest way to do it... but I have to do some thinking about if that would be accurate or not. We have room to adjust the #1 runner to bring it right in with the other 3.
As for the cheated bends... like I said before there honestly is only 1, and it is very very slight and it will not be in the next version because the collectors we build now are a little longer, and by keeping the turbine flange in the same spot it gives more vertical space to make that bend without cutting the elbows.
I too have noticed that there seems to really be no true equal length... but then again without actually calculating it its impossibel to guess by looking at it. THis manifold we have here... the 2,3,4 runners are less then half inch in measurable length but like Geoff said we have to really calculate it to know for sure.... and I think that perhaps using fluid might be the best/easiest way to do it... but I have to do some thinking about if that would be accurate or not. We have room to adjust the #1 runner to bring it right in with the other 3.
10-29-2004, 11:42 AM
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Re: (91civicDXdude)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91civicDXdude »</TD></TR><TR><TD CLASS="quote">
Methinks mister full race thinks its a bad design..</TD></TR></TABLE>
no not saying its a bad design. just saying there is a learning curve to making these manifolds perfect.
Methinks mister full race thinks its a bad design..</TD></TR></TABLE>
no not saying its a bad design. just saying there is a learning curve to making these manifolds perfect.
10-30-2004, 11:41 PM
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Re: Exhaust Manifold Design ??'s - and pics of one we made. (mister2racer)
If you do decide to brace the manifold, make sure you use the same material brace as the material your manifold is made from.
The thermal expansion rates of metal X compared to metal Z may be different... meaning metal X expands faster than the metal of your manifold thus causing increased stress to the points of union (brace will be in tension). If it's the opposite way, the brace will go into compression.
The thermal expansion rates of metal X compared to metal Z may be different... meaning metal X expands faster than the metal of your manifold thus causing increased stress to the points of union (brace will be in tension). If it's the opposite way, the brace will go into compression.
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