I was wondering if there is some sort of guideline to how much volume an intake manifold for our 2.0 engines should have? Is it based on RPM, displacement, overall airflow through the engine, turbo size or all of the above. As well as how long the runners should be. I am looking to make one here soon and want to have it designed properly. Any help would be great!
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Dialcaliper
Well-known member
The plenum size is dependent on overall airflow as well as boost pressure (to the extent that it affects mass airflow).
Your overall airflow is dependent on displacement, your *true* volumetric efficiency (dependent on head flow, pressure drop, cam overlap, etc), not your "turbocharged" VE, which is greater than 1.
The runner length is dependent on where you want the "hotspots" to be. In other words, just like headers, the length is dependent on a pseudo standing wave being present at a resonant frequency that corresponds to valve opening events. (Once per 2 revolutions, divide by 60 to convert to Hz from RPM)
The idea for the intake is that the plenum is maintaining a constant, or near constant air pressure at a given flow rate. Naturally, this means the one you want is larger in volume than the stock one. Big enough that the pressure remains fairly constant, small enough that your turbo can actually keep it pressurized. I honestly don't know the math off the top of my head for that calculation, but that's the basic idea.
On the other end, you want to have another high pressure point right outside the intake valves. Since this requires a standing wave, you have to "tune" it for specific RPM ranges
The formula for resonant frequency is pretty simple at first glance. Frequency in Hz = V/2L.
L = length of runners.
V = Speed of Sound in the medium. 331 m/s at 21 degrees C. (Temperature is delta from 21 C)
V = 331.3 + (.606 * T)
The last part is where it gets tricky. Luckily, the speed of sound is almost independent of air pressure, which seems counterintuitive when you're talking about setting up pressure waves. It's best, unless you want to get really really hardcore, to assume that air is an ideal gas.
Even if you assume an ideal gas, you still need to start looking at compressor maps and intercooler efficiency and pressure drop, so that you can arrive at:
A) The actual output pressure of the turbo (your boost pressure + the pressure drop of your intercooler system), which you can then use to find:
B) Your intake charge temperature, based on the pressure ratio and efficiency that your turbo is running at.
From there, you can then calculate the speed of sound in your intake, and then choose your target rpm range. If you get fancy, you can try and tune it for two different frequencies for both for off-boost (ambient temperature) and full boost (intake charge temp), since the resonant frequency is increased at higher temperature.
It is also important to remember that the speed of the pressure/sound waves through the runners is *independent* of the actual speed of the air moving through it. Also, humidity has a slight effect of increasing the speed of sound in the medium.
Now, I'll give you a little hint. Similar to header design, you're dealing with frequencies of 75 Hz or less. You'll soon realize that the tube length required for an ideal runner is much longer than will fit in your car. This is where we exploit the fact that waves can reflect, even in open ended tubes. In other words, the wave will run up and down the runner multiple times between each valve opening. The open end in the plenum effectively increases the tube length by .6*radius. Also, include the length from the head to the intake valve in the tube length, and assume it is closed (It should actually correspond to the high pressure wave peaking at maximum valve lift, but good luck doing the calculation and having it be accurate unless you want to start doing non-ideal gas behavior and airflow around the valve, etc. I guess you could add your valve lift to the length of the very last wave arrival too, but it doesn't seem reliable)
Anyway, you'll want to cut your ideal wave in an odd number of segments to get your runner length, so that the high pressure wave arrives at the valve at the right time. Since it isn't a true standing wave, the effect will not be as pronounced as a full length tube would be, but it has the added side effect that any wave that passes through the tube exactly an odd number of times will have a similar effect.
As far as runner diameter goes, it's basically a tradeoff between air velocity and pressure drop. The simplest way is to keep it the same cross sectional area as the intake valves.
Other variables to think about are having a slightly tapered plenum to keep the pressure equalized between the four runners, adding tapered "horns" to the runners inside the plenum to produce a ram-air effect (increases the effective pressure at the runner mouth).
These formulas are identical to the ones you'd use to calculate exhaust runner length for a manifold. The only difference is that you're tuning for the low pressure standing wave to promote scavenging between cylinders rather than using the plenum as positive pressure. Substitute EGT for intake charge temperature and you're there, assuming you use the exhaust valve diameter. The only funky part about exhaust is the voodoo involved in collector diameters, but since you're doing a turbo manifold instead of a N/A one, you can probably just taper to your turbo inlet.
Good luck!
There are some good books out there on turbocharged engine design:
Winterbone and Pearson; Design Techniques for Engine Manifolds, Wave Action Methods for IC Engines; Society of Automotive Engineers, Inc; 1999; ISBN 0-7680-0482-9
That book is quite expensive, which is why I don't own it yet.
Also, a book that's OOP:
Watson and Janota; Turbocharging the Internal Combustion Engine; The Macmillan Press Ltd; 1982; ISBN 0 333 24290 4
Your overall airflow is dependent on displacement, your *true* volumetric efficiency (dependent on head flow, pressure drop, cam overlap, etc), not your "turbocharged" VE, which is greater than 1.
The runner length is dependent on where you want the "hotspots" to be. In other words, just like headers, the length is dependent on a pseudo standing wave being present at a resonant frequency that corresponds to valve opening events. (Once per 2 revolutions, divide by 60 to convert to Hz from RPM)
The idea for the intake is that the plenum is maintaining a constant, or near constant air pressure at a given flow rate. Naturally, this means the one you want is larger in volume than the stock one. Big enough that the pressure remains fairly constant, small enough that your turbo can actually keep it pressurized. I honestly don't know the math off the top of my head for that calculation, but that's the basic idea.
On the other end, you want to have another high pressure point right outside the intake valves. Since this requires a standing wave, you have to "tune" it for specific RPM ranges
The formula for resonant frequency is pretty simple at first glance. Frequency in Hz = V/2L.
L = length of runners.
V = Speed of Sound in the medium. 331 m/s at 21 degrees C. (Temperature is delta from 21 C)
V = 331.3 + (.606 * T)
The last part is where it gets tricky. Luckily, the speed of sound is almost independent of air pressure, which seems counterintuitive when you're talking about setting up pressure waves. It's best, unless you want to get really really hardcore, to assume that air is an ideal gas.
Even if you assume an ideal gas, you still need to start looking at compressor maps and intercooler efficiency and pressure drop, so that you can arrive at:
A) The actual output pressure of the turbo (your boost pressure + the pressure drop of your intercooler system), which you can then use to find:
B) Your intake charge temperature, based on the pressure ratio and efficiency that your turbo is running at.
From there, you can then calculate the speed of sound in your intake, and then choose your target rpm range. If you get fancy, you can try and tune it for two different frequencies for both for off-boost (ambient temperature) and full boost (intake charge temp), since the resonant frequency is increased at higher temperature.
It is also important to remember that the speed of the pressure/sound waves through the runners is *independent* of the actual speed of the air moving through it. Also, humidity has a slight effect of increasing the speed of sound in the medium.
Now, I'll give you a little hint. Similar to header design, you're dealing with frequencies of 75 Hz or less. You'll soon realize that the tube length required for an ideal runner is much longer than will fit in your car. This is where we exploit the fact that waves can reflect, even in open ended tubes. In other words, the wave will run up and down the runner multiple times between each valve opening. The open end in the plenum effectively increases the tube length by .6*radius. Also, include the length from the head to the intake valve in the tube length, and assume it is closed (It should actually correspond to the high pressure wave peaking at maximum valve lift, but good luck doing the calculation and having it be accurate unless you want to start doing non-ideal gas behavior and airflow around the valve, etc. I guess you could add your valve lift to the length of the very last wave arrival too, but it doesn't seem reliable)
Anyway, you'll want to cut your ideal wave in an odd number of segments to get your runner length, so that the high pressure wave arrives at the valve at the right time. Since it isn't a true standing wave, the effect will not be as pronounced as a full length tube would be, but it has the added side effect that any wave that passes through the tube exactly an odd number of times will have a similar effect.
As far as runner diameter goes, it's basically a tradeoff between air velocity and pressure drop. The simplest way is to keep it the same cross sectional area as the intake valves.
Other variables to think about are having a slightly tapered plenum to keep the pressure equalized between the four runners, adding tapered "horns" to the runners inside the plenum to produce a ram-air effect (increases the effective pressure at the runner mouth).
These formulas are identical to the ones you'd use to calculate exhaust runner length for a manifold. The only difference is that you're tuning for the low pressure standing wave to promote scavenging between cylinders rather than using the plenum as positive pressure. Substitute EGT for intake charge temperature and you're there, assuming you use the exhaust valve diameter. The only funky part about exhaust is the voodoo involved in collector diameters, but since you're doing a turbo manifold instead of a N/A one, you can probably just taper to your turbo inlet.
Good luck!
There are some good books out there on turbocharged engine design:
Winterbone and Pearson; Design Techniques for Engine Manifolds, Wave Action Methods for IC Engines; Society of Automotive Engineers, Inc; 1999; ISBN 0-7680-0482-9
That book is quite expensive, which is why I don't own it yet.
Also, a book that's OOP:
Watson and Janota; Turbocharging the Internal Combustion Engine; The Macmillan Press Ltd; 1982; ISBN 0 333 24290 4
Last edited:
Dialcaliper
Well-known member
Also, assuming that you already have your car running with the mods you want to design the intake manifold for, if you don't want to do all the compressor/intercooler math, you can set up a thermocouple or thermistor (you can easily get one cheap for a computer from an electronics store) and actually just measure the intake charge temperature at WOT.
Another comment about the plenum - although the airflow through the MAF and the airflow into the engine are technically equivalent, the plenum basically acts like a damper to keep the airflow through the throttle body constant, preventing the pressure drop from cylinders opening from affecting other cylinders as well as from propogating back up the line.
Another comment about the plenum - although the airflow through the MAF and the airflow into the engine are technically equivalent, the plenum basically acts like a damper to keep the airflow through the throttle body constant, preventing the pressure drop from cylinders opening from affecting other cylinders as well as from propogating back up the line.
Wow! I think Im in over my head. I have read what you wrote three times and still dont understand it. How do you read the output of the thermistor you spoke about? Is it in volts or is there a gauge or display of some kind? Thanks for the reply!
I suppose I am looking for an easy way to design it. Does anyone have an aftermarket intake manifold that they could give the approximate dimensions of so I can figure out some proven plenum volumes and runner lengths?
i assume you are making a sheet metal manifold?
Quote:
I suppose I am looking for an easy way to design it. Does anyone have an aftermarket intake manifold that they could give the approximate dimensions of so I can figure out some proven plenum volumes and runner lengths?
You mean you are looking for a way to do no work with no knowledge and find a manifold that someone has already done all the work, research, design and testing on and copy it for yourself. Not sure the reason behind this would be since it would cost less just to buy a version of the manifold you would be copying.
I suppose I am looking for an easy way to design it. Does anyone have an aftermarket intake manifold that they could give the approximate dimensions of so I can figure out some proven plenum volumes and runner lengths?
You mean you are looking for a way to do no work with no knowledge and find a manifold that someone has already done all the work, research, design and testing on and copy it for yourself. Not sure the reason behind this would be since it would cost less just to buy a version of the manifold you would be copying.
85tr
Well-known member
how would it cost less when you own a welder ??? and materials cost about 200 bucks .
4orced4door
Moderator
There's more involved than having a welder and materials. You think you're gonna nail it on your first try?
curtis
Well-known member
First to the moderators this needs to go to the how to when its all done in a few weeks.
Basic rules of thumb.
Air acts as a liquid, it has mass and should be treated as such.
Longer small runners are for torque
Fat short ones are for top end.
Runner cross section areas should be the same from the ve stack to the head.
Most turbo intake builders design the plenum to be 70% of the volume of the engine.
It is usually better to have a square runner from the head to the plenum and have a ve stack that is square with radiused corners. Air doesn't like to change shape at at the speed of sound and causes internal friction.
As above. Air moves back and forth in the intake before and after the valves close. Hemholts ram resonance is what the term is. For more on this read here..... tech articles
In a nut shell, as the column of air moves from the plenum to the valves it has a certain velocity. Energy is conserved and redirected back up the runner as the valve closes. In a perfect design you would want the air to remain laminar and bounch back and recollide with the valves when they are just beginning to open to add a ram effect and have a high pressure wave behind it to drag in more air. This needs to be at the torque peak.
Now for some measurements.
This is the measurements of a popular 4G63 intake manifold. To add this is one of the best flowing and highest HP intakes out.
Ask Plesko he tested it.
04 intake manifold test.
flange thickness at the head to manifold. 10mm
plenum is 90mm across the ve.stack area.
plenum is 82mm from the ve stack area to the back.
plenum is 114mm across at a diagonal
Cross section look of this.... looks like a slice of bread with the back having a radius and the bottom being flat.
runner is 68 mm wide
runner is 64.20mm tall
runner is 131mm long to the base of the ve stack area to the head surface.
Runnner is designed with two pieces of c channel with radiused corners. The bottom one mid point down is the same height from top to bottom, then the top one is cut at an angle with the back being taller than the front.
Nos nozzles position is 93 mm from the head surface.
/ubbthreads/images//graemlins/grin.gif
Basic rules of thumb.
Air acts as a liquid, it has mass and should be treated as such.
Longer small runners are for torque
Fat short ones are for top end.
Runner cross section areas should be the same from the ve stack to the head.
Most turbo intake builders design the plenum to be 70% of the volume of the engine.
It is usually better to have a square runner from the head to the plenum and have a ve stack that is square with radiused corners. Air doesn't like to change shape at at the speed of sound and causes internal friction.
As above. Air moves back and forth in the intake before and after the valves close. Hemholts ram resonance is what the term is. For more on this read here..... tech articles
In a nut shell, as the column of air moves from the plenum to the valves it has a certain velocity. Energy is conserved and redirected back up the runner as the valve closes. In a perfect design you would want the air to remain laminar and bounch back and recollide with the valves when they are just beginning to open to add a ram effect and have a high pressure wave behind it to drag in more air. This needs to be at the torque peak.
Now for some measurements.
This is the measurements of a popular 4G63 intake manifold. To add this is one of the best flowing and highest HP intakes out.
Ask Plesko he tested it.
04 intake manifold test.
flange thickness at the head to manifold. 10mm
plenum is 90mm across the ve.stack area.
plenum is 82mm from the ve stack area to the back.
plenum is 114mm across at a diagonal
Cross section look of this.... looks like a slice of bread with the back having a radius and the bottom being flat.
runner is 68 mm wide
runner is 64.20mm tall
runner is 131mm long to the base of the ve stack area to the head surface.
Runnner is designed with two pieces of c channel with radiused corners. The bottom one mid point down is the same height from top to bottom, then the top one is cut at an angle with the back being taller than the front.
Nos nozzles position is 93 mm from the head surface.
/ubbthreads/images//graemlins/grin.gif
Quote:
how would it cost less when you own a welder ??? and materials cost about 200 bucks .
Well lets see. Bare metal prices might be 200 but most people don't have a brake for bending the plenum design, band saw for cutting the tubing used for runners to get the right taper, plus both flanges CNC cut, you'll spend over 100 alone on the 4 velocity stacks, on top of the cost of the argon(to weld and to purge the whole setup during the welding process) and filler rod needed to complete the job. The only reason you get magnus, jmf, etc is cause they have all the equipment for them and do them in mas production.
If you have not built one yourself, don't try quoting how much it would cost to make one.
how would it cost less when you own a welder ??? and materials cost about 200 bucks .
Well lets see. Bare metal prices might be 200 but most people don't have a brake for bending the plenum design, band saw for cutting the tubing used for runners to get the right taper, plus both flanges CNC cut, you'll spend over 100 alone on the 4 velocity stacks, on top of the cost of the argon(to weld and to purge the whole setup during the welding process) and filler rod needed to complete the job. The only reason you get magnus, jmf, etc is cause they have all the equipment for them and do them in mas production.
If you have not built one yourself, don't try quoting how much it would cost to make one.
curtis
Well-known member
To add to what Ian said. Mig welding is cheap compaired to Tig. Mig is a 2 pound roll of wire and a 40 dollar bottle of gas that goes forever. Tig welders figure an hour to weld everything at 5 times the gas flow. Then 20 dollars worth of rod. CNC flanges are going to be at least 150 considering set-up costs and machine time.
The hardest part to get correct is the pulse tuning that Dial caliper is talking about. It is very easy to blow up an engine if your pusles are happening at the wrong time and there is to much air going into one cylinder and allot less air going to the next. This would show up on your plugs and if you are pushing your engine to the limit is is very easy to go right passed the edge and blow it up. Just buy one thats been proven and you will be better off. But if still decide to build one I wish you the best of luck, and I will give you as much advice as I can.
Galantvr41062
Well-known member
I would just buy a JMF, Magnus, AMS, Forrester, or slimilar SMIM. Unless you are trying to run 8s over the shelf parts will provide the potential to run in the 9s no problem. I have made a few SMIM for dsms, the one I have on my car after material, labor, welding supplies would cost over $850, or for most people a over the shelf $3-$400 manifold will do the trick for sure. A lot of people forget about or do not care about the labor end in this industry.
~John
~John
Before I get started thank you Dialcaliper, Curtis, and Boostin hard I appreciate the advice and TECHNICAL info you have given me I appreciate it.
Now to Digit! This pisses me off. You do not know me or what I have in mind to build you have not contributed anything useful to this thread and I am not freakin looking to copy anyones manifold I like doing my own work I like building things and learning how to do things on my own all I want are some general guidelines. I dont care about your useless bratty opinions.
"You mean you are looking for a way to do no work with no knowledge and find a manifold that someone has already done all the work, research, design and testing on and copy it for yourself. Not sure the reason behind this would be since it would cost less just to buy a version of the manifold you would be copying."
I am not using cnc flanges I am making my own flanges out of 1/2 inch aluminum, a drill press and some porting tools I am going to be cutting the runners on my band saw And I dont plan on it being perfect on the first try. Practice makes perfect.
All I want is some help, advice and maybe a little encouragement.
Now to Digit! This pisses me off. You do not know me or what I have in mind to build you have not contributed anything useful to this thread and I am not freakin looking to copy anyones manifold I like doing my own work I like building things and learning how to do things on my own all I want are some general guidelines. I dont care about your useless bratty opinions.
"You mean you are looking for a way to do no work with no knowledge and find a manifold that someone has already done all the work, research, design and testing on and copy it for yourself. Not sure the reason behind this would be since it would cost less just to buy a version of the manifold you would be copying."
I am not using cnc flanges I am making my own flanges out of 1/2 inch aluminum, a drill press and some porting tools I am going to be cutting the runners on my band saw And I dont plan on it being perfect on the first try. Practice makes perfect.
All I want is some help, advice and maybe a little encouragement.
Dialcaliper
Well-known member
I wholeheartedly endorse the "do-it-yourself" attitude. First and foremost, you learn something that you never do from just buying something. Second, it usually is cheaper, provided you have access to the right equipment. Third, even if it's not cheaper, there's a certain satisfaction gained from the simple act of doing something yourself.
I mean, we're talking about this all in the context of customized cars. If you can learn how an engine works, and build one up from parts that someoone else made and get it to work, its a very short step away from custom parts for your custom car. All you need is a little more theory, a little more math and some tools and know-how. It just depends on how much time and effort you want to put in, and how much you enjoy working on your car as well as being able to drive it.
Now for something technical:
click
The link is a class lecture on induction tuning. It goes way more in depth than I first described, and may actually contradict some of the things I had assumed. However, the very last page has some interesting rules of thumb for designing intake runners, at least as a starting point. David Vizard seems to have been a guy that did a lot of experimentation tuning chevys, fords and minis, as well as messing around with nitrous (presumably feeding it into his engine...).
Keep in mind, these numbers are only applicable for normally aspirated engines. Use them with a hot intake charge and you'll probably end up with the wrong lengths, but they might make a good starting point.
Runner Length = 7" for 10,000 RPM. Add 1.7" for every 1000 RPM lower you're targeting.
Runner Diameter = Multiply Displacement, Target RPM band and estimated engine volumetric efficiency. Divide by 3330, and then take the square root of the whole thing.
Now, If you combine those with a simple temperature measurement at the throttle body, and you can probably adjust using the other formulas to get a runner length and diameter pretty close to what you'd come up with by doing much more extensive calculations. At least you could probably get within 1000 rpm of where you're looking to shoot for.
Also, it turns out that my initial assumption was not quite correct. Apparently:
"The tuning peak will occur when the natural Helmholtz resonance of the cylinder and runner is about twice the piston frequency."
Now this method requires you to sum up all kinds of wacky "inductances" based on the cross sectional areas and lengths of specific sections, with the valve *open* and the cylinder at half height.
Makes the head spin a little
I mean, we're talking about this all in the context of customized cars. If you can learn how an engine works, and build one up from parts that someoone else made and get it to work, its a very short step away from custom parts for your custom car. All you need is a little more theory, a little more math and some tools and know-how. It just depends on how much time and effort you want to put in, and how much you enjoy working on your car as well as being able to drive it.
Now for something technical:
click
The link is a class lecture on induction tuning. It goes way more in depth than I first described, and may actually contradict some of the things I had assumed. However, the very last page has some interesting rules of thumb for designing intake runners, at least as a starting point. David Vizard seems to have been a guy that did a lot of experimentation tuning chevys, fords and minis, as well as messing around with nitrous (presumably feeding it into his engine...).
Keep in mind, these numbers are only applicable for normally aspirated engines. Use them with a hot intake charge and you'll probably end up with the wrong lengths, but they might make a good starting point.
Runner Length = 7" for 10,000 RPM. Add 1.7" for every 1000 RPM lower you're targeting.
Runner Diameter = Multiply Displacement, Target RPM band and estimated engine volumetric efficiency. Divide by 3330, and then take the square root of the whole thing.
Now, If you combine those with a simple temperature measurement at the throttle body, and you can probably adjust using the other formulas to get a runner length and diameter pretty close to what you'd come up with by doing much more extensive calculations. At least you could probably get within 1000 rpm of where you're looking to shoot for.
Also, it turns out that my initial assumption was not quite correct. Apparently:
"The tuning peak will occur when the natural Helmholtz resonance of the cylinder and runner is about twice the piston frequency."
Now this method requires you to sum up all kinds of wacky "inductances" based on the cross sectional areas and lengths of specific sections, with the valve *open* and the cylinder at half height.
Makes the head spin a little
Last edited:
Okay so here's one thing I have been wondering, every turbo DSM/GVR4 aftermarket intake manifold has the throttle body side much larger than the non-throttle body side of the intake plenum. My thought is that it is to compinsate for the air that is being taken by the cylinders to help equalize pressure/volume, mainly for cylinder 1 and 4, but also 2 and 3, am I right on this, or is it just cheaper to make that way? Also isn't designing a turbo and N/A intake manifold totally differnt or are they still similar enough?
GVR-4
Well-known member
Quote:
Now to Digit! This pisses me off. You do not know me or what I have in mind to build you have not contributed anything useful to this thread and I am not freakin looking to copy anyones manifold I like doing my own work I like building things and learning how to do things on my own all I want are some general guidelines. I dont care about your useless bratty opinions.
"You mean you are looking for a way to do no work with no knowledge and find a manifold that someone has already done all the work, research, design and testing on and copy it for yourself. Not sure the reason behind this would be since it would cost less just to buy a version of the manifold you would be copying."
I am not using cnc flanges I am making my own flanges out of 1/2 inch aluminum, a drill press and some porting tools I am going to be cutting the runners on my band saw And I dont plan on it being perfect on the first try. Practice makes perfect.
All I want is some help, advice and maybe a little encouragement.
Don't let Digit's lack of maturity and uncouthness discourage you. If money were the only factor in us working on our cars, we would have a different hobby.
Now to Digit! This pisses me off. You do not know me or what I have in mind to build you have not contributed anything useful to this thread and I am not freakin looking to copy anyones manifold I like doing my own work I like building things and learning how to do things on my own all I want are some general guidelines. I dont care about your useless bratty opinions.
"You mean you are looking for a way to do no work with no knowledge and find a manifold that someone has already done all the work, research, design and testing on and copy it for yourself. Not sure the reason behind this would be since it would cost less just to buy a version of the manifold you would be copying."
I am not using cnc flanges I am making my own flanges out of 1/2 inch aluminum, a drill press and some porting tools I am going to be cutting the runners on my band saw And I dont plan on it being perfect on the first try. Practice makes perfect.
All I want is some help, advice and maybe a little encouragement.
Don't let Digit's lack of maturity and uncouthness discourage you. If money were the only factor in us working on our cars, we would have a different hobby.
Dialcaliper
Well-known member
You're spot on about the taper - the idea is to keep the pressure to each cylinder more even. And it isn't cheaper. The cheapest way, which works for some is to just use a big 4" tube as the plenum, cap the end, and weld the runners to it.
The method for designing a N/A and Turbo intake are similar, the difference is mainly that Turbo manifolds deal with much wider temperatures, which changes the tuning, and supposedly the plenum volume on a N/A engine is much more important.
Quote:
Okay so here's one thing I have been wondering, every turbo DSM/GVR4 aftermarket intake manifold has the throttle body side much larger than the non-throttle body side of the intake plenum. My thought is that it is to compinsate for the air that is being taken by the cylinders to help equalize pressure/volume, mainly for cylinder 1 and 4, but also 2 and 3, am I right on this, or is it just cheaper to make that way? Also isn't designing a turbo and N/A intake manifold totally differnt or are they still similar enough?
The method for designing a N/A and Turbo intake are similar, the difference is mainly that Turbo manifolds deal with much wider temperatures, which changes the tuning, and supposedly the plenum volume on a N/A engine is much more important.
Quote:
Okay so here's one thing I have been wondering, every turbo DSM/GVR4 aftermarket intake manifold has the throttle body side much larger than the non-throttle body side of the intake plenum. My thought is that it is to compinsate for the air that is being taken by the cylinders to help equalize pressure/volume, mainly for cylinder 1 and 4, but also 2 and 3, am I right on this, or is it just cheaper to make that way? Also isn't designing a turbo and N/A intake manifold totally differnt or are they still similar enough?
Quote:
Quote:
Now to Digit! This pisses me off. You do not know me or what I have in mind to build you have not contributed anything useful to this thread and I am not freakin looking to copy anyones manifold I like doing my own work I like building things and learning how to do things on my own all I want are some general guidelines. I dont care about your useless bratty opinions.
"You mean you are looking for a way to do no work with no knowledge and find a manifold that someone has already done all the work, research, design and testing on and copy it for yourself. Not sure the reason behind this would be since it would cost less just to buy a version of the manifold you would be copying."
I am not using cnc flanges I am making my own flanges out of 1/2 inch aluminum, a drill press and some porting tools I am going to be cutting the runners on my band saw And I dont plan on it being perfect on the first try. Practice makes perfect.
All I want is some help, advice and maybe a little encouragement.
Don't let Digit's lack of maturity and uncouthness discourage you. If money were the only factor in us working on our cars, we would have a different hobby.
You mean sanity and honesty? Give me a break.
What kind of welder do you have? What Material will you be making the manifold out of? What filler rod? Pure argon or argon/oxy mix? How are you going to mill the flanges after welding the manifold together? What tungsten are you using? What kind of brake do you have for bending the plenum up or are you going to just cut all the sides and weld them together? If so what shier will you be using? Since you are not going to use VS how do you plan on doing the plenum plate/runner area?
From the looks of your original and 3rd post it just seemed like you wanted the dimensions of an already proven manifold so you could just copy it and make your own and try to save a few bucks, not "guidelines". If I'm wrong about that then I apologize. Make sure to post pictures and a final cost when all is said and done, as I would be interested to see the results.
For something constructive, why not just cut off the stock plenum and design your own and weld it to the stock runner setup. If done right you would probably get close to what you are looking for anyways and save the trouble of the runner situation which is the hardest part of the whole design/fabrication.
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Now to Digit! This pisses me off. You do not know me or what I have in mind to build you have not contributed anything useful to this thread and I am not freakin looking to copy anyones manifold I like doing my own work I like building things and learning how to do things on my own all I want are some general guidelines. I dont care about your useless bratty opinions.
"You mean you are looking for a way to do no work with no knowledge and find a manifold that someone has already done all the work, research, design and testing on and copy it for yourself. Not sure the reason behind this would be since it would cost less just to buy a version of the manifold you would be copying."
I am not using cnc flanges I am making my own flanges out of 1/2 inch aluminum, a drill press and some porting tools I am going to be cutting the runners on my band saw And I dont plan on it being perfect on the first try. Practice makes perfect.
All I want is some help, advice and maybe a little encouragement.
Don't let Digit's lack of maturity and uncouthness discourage you. If money were the only factor in us working on our cars, we would have a different hobby.
You mean sanity and honesty? Give me a break.
What kind of welder do you have? What Material will you be making the manifold out of? What filler rod? Pure argon or argon/oxy mix? How are you going to mill the flanges after welding the manifold together? What tungsten are you using? What kind of brake do you have for bending the plenum up or are you going to just cut all the sides and weld them together? If so what shier will you be using? Since you are not going to use VS how do you plan on doing the plenum plate/runner area?
From the looks of your original and 3rd post it just seemed like you wanted the dimensions of an already proven manifold so you could just copy it and make your own and try to save a few bucks, not "guidelines". If I'm wrong about that then I apologize. Make sure to post pictures and a final cost when all is said and done, as I would be interested to see the results.
For something constructive, why not just cut off the stock plenum and design your own and weld it to the stock runner setup. If done right you would probably get close to what you are looking for anyways and save the trouble of the runner situation which is the hardest part of the whole design/fabrication.
