Does a cold air intake improve gas mileage?
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Originally Posted By: mechanicx
The throttlebody size can affect lower RPM torque at WOT. I still say the intake tube size can have some affect on low end torque due to inertia. The thing is the intake tube size matches the TB size. If you enlarge both too much, you may see a loss of low end torque. Also for example I've seen dyno tests where the stock snorkel air cleaner housing made more low end torque torque and power than an open element aircleaner with the same filter.
Since the TB is the gateway to the plenum and enlarging it beyond a reasonable point could theoretically decrease any velocity-based fill going on within the plenum, I would agree.
I still don't agree on the tubing though
The throttlebody size can affect lower RPM torque at WOT. I still say the intake tube size can have some affect on low end torque due to inertia. The thing is the intake tube size matches the TB size. If you enlarge both too much, you may see a loss of low end torque. Also for example I've seen dyno tests where the stock snorkel air cleaner housing made more low end torque torque and power than an open element aircleaner with the same filter.
Since the TB is the gateway to the plenum and enlarging it beyond a reasonable point could theoretically decrease any velocity-based fill going on within the plenum, I would agree.
I still don't agree on the tubing though
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Originally Posted By: eljefino
Why bring exhaust pipes into this? They have no throttles.
I know you are intentionally being an [censored] for whatever reason, but there is a HUGE difference between the column of air flowing through the intake tubing, which is being REGULATED by the throttle body before it is able to go inside the plenum and the engine's exhaust system.
The TB, in conjunction with load, controls the amount of VACUUM that exists within that body (plenum) that the cylinders draw from. This is why I feel that the pipe sizing in FRONT of the TB (remember, I am NOT downplaying the role of ANY of the components BEHIND the TB), unless imposing a significant restriction, is not instrumental in whether the engine makes decent low-end power or not. On the other hand, plenum FILL is controlled by the TB, which is why I agree with the point mechanix made about TB sizing.
The exhaust SYSTEM, if properly designed will help an engine make MORE power. This is why long-tubed headers exist, tri-Y's, H and X pipes. Scavenging, collector diameter and length... these are all things that racers play with in order to get more power out of their combo. And I'm not talking some one-run K&N 5HP gain, I'm talking 20+HP through much of the engine's power band verifiable via multiple runs and reduced ET and increased MPH.
Look at it this way: The more air you can move through an engine, the more power it is going to make. The intake tract is REGULATED by the throttle body. It has to be for reasons I should not have to explain. Everything BEHIND the throttle body has to be tuned and optimized for the engine's intended use. This includes the exhaust system. Camshaft design plays a key role here too. The throttle body is the gateway to this entire system.
If you could control low-end torque by simply changing the airflow through the piping in FRONT of the throttle body, do you not think OEM's would do that? Rather than implementing much more complex systems like IMRC to control runner length and modulate low-end torque production and high-end output?
Instead of making sarcastic jabs at me, perhaps try to enlighten me as to why you disagree with my logic?
I have spent a lot of time researching and thinking about this stuff because I am into drag racing. But the cars we drive are also driven on the street regularly, hence the term street/strip. The goal is always to retain good streetability while getting the most out of a given combo.
Having a camshaft optimized for a given setup in conjunction with a good tune ultimately yields the best of both worlds. This is one of the topics we have beat to death on SBFTech.
Why bring exhaust pipes into this? They have no throttles.
I know you are intentionally being an [censored] for whatever reason, but there is a HUGE difference between the column of air flowing through the intake tubing, which is being REGULATED by the throttle body before it is able to go inside the plenum and the engine's exhaust system.
The TB, in conjunction with load, controls the amount of VACUUM that exists within that body (plenum) that the cylinders draw from. This is why I feel that the pipe sizing in FRONT of the TB (remember, I am NOT downplaying the role of ANY of the components BEHIND the TB), unless imposing a significant restriction, is not instrumental in whether the engine makes decent low-end power or not. On the other hand, plenum FILL is controlled by the TB, which is why I agree with the point mechanix made about TB sizing.
The exhaust SYSTEM, if properly designed will help an engine make MORE power. This is why long-tubed headers exist, tri-Y's, H and X pipes. Scavenging, collector diameter and length... these are all things that racers play with in order to get more power out of their combo. And I'm not talking some one-run K&N 5HP gain, I'm talking 20+HP through much of the engine's power band verifiable via multiple runs and reduced ET and increased MPH.
Look at it this way: The more air you can move through an engine, the more power it is going to make. The intake tract is REGULATED by the throttle body. It has to be for reasons I should not have to explain. Everything BEHIND the throttle body has to be tuned and optimized for the engine's intended use. This includes the exhaust system. Camshaft design plays a key role here too. The throttle body is the gateway to this entire system.
If you could control low-end torque by simply changing the airflow through the piping in FRONT of the throttle body, do you not think OEM's would do that? Rather than implementing much more complex systems like IMRC to control runner length and modulate low-end torque production and high-end output?
Instead of making sarcastic jabs at me, perhaps try to enlighten me as to why you disagree with my logic?
I have spent a lot of time researching and thinking about this stuff because I am into drag racing. But the cars we drive are also driven on the street regularly, hence the term street/strip. The goal is always to retain good streetability while getting the most out of a given combo.
Having a camshaft optimized for a given setup in conjunction with a good tune ultimately yields the best of both worlds. This is one of the topics we have beat to death on SBFTech.
Originally Posted By: OVERK1LL
Originally Posted By: mechanicx
The throttlebody size can affect lower RPM torque at WOT. I still say the intake tube size can have some affect on low end torque due to inertia. The thing is the intake tube size matches the TB size. If you enlarge both too much, you may see a loss of low end torque. Also for example I've seen dyno tests where the stock snorkel air cleaner housing made more low end torque torque and power than an open element aircleaner with the same filter.
Since the TB is the gateway to the plenum and enlarging it beyond a reasonable point could theoretically decrease any velocity-based fill going on within the plenum, I would agree.
I still don't agree on the tubing though
OK but you have to consider the complexities of the valve timing and the pressure changes behind the throttle. Not to mention at WOT the throttle valve isn't really the gatekeeper any longer. How different really is the TB and the intake tube from an intake runner and the valve. I don't think the intake tube makes as much different as TB size but they usually go hand in hand.
Originally Posted By: mechanicx
The throttlebody size can affect lower RPM torque at WOT. I still say the intake tube size can have some affect on low end torque due to inertia. The thing is the intake tube size matches the TB size. If you enlarge both too much, you may see a loss of low end torque. Also for example I've seen dyno tests where the stock snorkel air cleaner housing made more low end torque torque and power than an open element aircleaner with the same filter.
Since the TB is the gateway to the plenum and enlarging it beyond a reasonable point could theoretically decrease any velocity-based fill going on within the plenum, I would agree.
I still don't agree on the tubing though
OK but you have to consider the complexities of the valve timing and the pressure changes behind the throttle. Not to mention at WOT the throttle valve isn't really the gatekeeper any longer. How different really is the TB and the intake tube from an intake runner and the valve. I don't think the intake tube makes as much different as TB size but they usually go hand in hand.
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Originally Posted By: mechanicx
Originally Posted By: OVERK1LL
Originally Posted By: mechanicx
The throttlebody size can affect lower RPM torque at WOT. I still say the intake tube size can have some affect on low end torque due to inertia. The thing is the intake tube size matches the TB size. If you enlarge both too much, you may see a loss of low end torque. Also for example I've seen dyno tests where the stock snorkel air cleaner housing made more low end torque torque and power than an open element aircleaner with the same filter.
Since the TB is the gateway to the plenum and enlarging it beyond a reasonable point could theoretically decrease any velocity-based fill going on within the plenum, I would agree.
I still don't agree on the tubing though
OK but you have to consider the complexities of the valve timing and the pressure changes behind the throttle. Not to mention at WOT the throttle valve isn't really the gatekeeper any longer. How different really is the TB and the intake tube from an intake runner and the valve. I don't think the intake tube makes as much different as TB size but they usually go hand in hand.
Runner and valve come AFTER the plenum, TB and the piping come BEFORE the plenum.
As I said earlier, as I understand it: The cylinders draw from the plenum, not the carb/TB. The TB simply feeds the plenum or restricts the available quantity of air in it.
I think we can agree to disagree on this one, though I do think we are in COMPLETE agreement as to what happens after the air enters the TB and the affects the design of the components after the TB has on how the engine behaves.
Originally Posted By: OVERK1LL
Originally Posted By: mechanicx
The throttlebody size can affect lower RPM torque at WOT. I still say the intake tube size can have some affect on low end torque due to inertia. The thing is the intake tube size matches the TB size. If you enlarge both too much, you may see a loss of low end torque. Also for example I've seen dyno tests where the stock snorkel air cleaner housing made more low end torque torque and power than an open element aircleaner with the same filter.
Since the TB is the gateway to the plenum and enlarging it beyond a reasonable point could theoretically decrease any velocity-based fill going on within the plenum, I would agree.
I still don't agree on the tubing though
OK but you have to consider the complexities of the valve timing and the pressure changes behind the throttle. Not to mention at WOT the throttle valve isn't really the gatekeeper any longer. How different really is the TB and the intake tube from an intake runner and the valve. I don't think the intake tube makes as much different as TB size but they usually go hand in hand.
Runner and valve come AFTER the plenum, TB and the piping come BEFORE the plenum.
As I said earlier, as I understand it: The cylinders draw from the plenum, not the carb/TB. The TB simply feeds the plenum or restricts the available quantity of air in it.
I think we can agree to disagree on this one, though I do think we are in COMPLETE agreement as to what happens after the air enters the TB and the affects the design of the components after the TB has on how the engine behaves.
I agree mostly, just that the size of the TB and the intake duct ahead of the TB can have some affect in plenum filling and directing air with inertia through the TB and plenum. So in that way it can have an effect on lower speed WOT torque. A bigger plenum could reduce vaccuum because of valve timing, overlap and reversion. It's not a huge difference and most drag racers will trade a bit of low speed torque for horsepower gains. to some degree everything from the airfilter to the exhaust tip can sometimes be a factor to an engine, however small.
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Originally Posted By: mechanicx
I agree mostly, just that the size of the TB and the intake duct ahead of the TB can have some affect in plenum filling and directing air with inertia through the TB and plenum. So in that way it can have an effect on lower speed WOT torque. A bigger plenum could reduce vaccuum because of valve timing, overlap and reversion. It's not a huge difference and most drag racers will trade a bit of low speed torque for horsepower gains. to some degree everything from the airfilter to the exhaust tip can sometimes be a factor to an engine, however small.
Definitely agree with you on the size of the TB, as well as plenum sizing. The latter is critical in carb setups.
This has been a good discussion.
I agree mostly, just that the size of the TB and the intake duct ahead of the TB can have some affect in plenum filling and directing air with inertia through the TB and plenum. So in that way it can have an effect on lower speed WOT torque. A bigger plenum could reduce vaccuum because of valve timing, overlap and reversion. It's not a huge difference and most drag racers will trade a bit of low speed torque for horsepower gains. to some degree everything from the airfilter to the exhaust tip can sometimes be a factor to an engine, however small.
Definitely agree with you on the size of the TB, as well as plenum sizing. The latter is critical in carb setups.
This has been a good discussion.
Many guys report better throttle response with a large TB. They are fooling themselves - all that is happening is that the throttle is opened more for the same depth of gas pedal travel.
AT WOT, a larger TB can help. For normal unmodified street cars, good luck in observing a HP difference.
As to intake piping affecting operation under part throttle vacuum conditions, I have observed in my own car pinging at light throttle after modifying the intake - immediately and with no other mods. it did not do this before. Somehow the cylinders were being charged better.
AT WOT, a larger TB can help. For normal unmodified street cars, good luck in observing a HP difference.
As to intake piping affecting operation under part throttle vacuum conditions, I have observed in my own car pinging at light throttle after modifying the intake - immediately and with no other mods. it did not do this before. Somehow the cylinders were being charged better.
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Originally Posted By: mechtech2
Many guys report better throttle response with a large TB. They are fooling themselves - all that is happening is that the throttle is opened more for the same depth of gas pedal travel.
AT WOT, a larger TB can help. For normal unmodified street cars, good luck in observing a HP difference.
As to intake piping affecting operation under part throttle vacuum conditions, I have observed in my own car pinging at light throttle after modifying the intake - immediately and with no other mods. it did not do this before. Somehow the cylinders were being charged better.
Or if the car is MAF, the tubing is now skewing the reading. This was a big problem on Mustangs. We had to "clock" the MAF in the tubing to get it correct again.
Many guys report better throttle response with a large TB. They are fooling themselves - all that is happening is that the throttle is opened more for the same depth of gas pedal travel.
AT WOT, a larger TB can help. For normal unmodified street cars, good luck in observing a HP difference.
As to intake piping affecting operation under part throttle vacuum conditions, I have observed in my own car pinging at light throttle after modifying the intake - immediately and with no other mods. it did not do this before. Somehow the cylinders were being charged better.
Or if the car is MAF, the tubing is now skewing the reading. This was a big problem on Mustangs. We had to "clock" the MAF in the tubing to get it correct again.
Now a bigger MAF sensor makes sense to me because they can be a bit more restrictive than a straight pipe. If you placed a larger MAP sensor in the intake tube, recalibrated the PCM for it, and blended the intake tube entrance and exit, I don't think it would have any negative effect on low-speed torque.
MAFS are indeed often the 'cork' in the system.
The problem is that a larger one does not meter as well for idle and low RPMs.
This is what Mfrs. are after, esp for emissions.
I have heard about orienting the MAF on some cars having an effect.
I suppose anomalies in the air flow could warrant a MAF position/rotation change for the better.
The problem is that a larger one does not meter as well for idle and low RPMs.
This is what Mfrs. are after, esp for emissions.
I have heard about orienting the MAF on some cars having an effect.
I suppose anomalies in the air flow could warrant a MAF position/rotation change for the better.
i think a larger intake before the TB will increase torque and responsiveness because there is a volume of air already filtered in reserve,
and less instantaneous demand (vacuum) on the air filter itself. that's why my K&N intake looks like a black orca rising out of the sea
vs. this
and less instantaneous demand (vacuum) on the air filter itself. that's why my K&N intake looks like a black orca rising out of the sea
vs. this
After reading this thread I wonder if any of you can answer these two questions?
1. What do you think of products such as the Tornado? And what about using a similar product in both your intake tubing and exhaust?
I always thought the concept made sense without any real or further look into it.
2. Is there a product that can change it's aperture to limit or open the amount of air that can enter the intake by reading engine RPMs and be programmed for any particular engine?
Just an interesting idea after reading through this thread ...
Looking forward to all of your comments ...
~J
1. What do you think of products such as the Tornado? And what about using a similar product in both your intake tubing and exhaust?
I always thought the concept made sense without any real or further look into it.
2. Is there a product that can change it's aperture to limit or open the amount of air that can enter the intake by reading engine RPMs and be programmed for any particular engine?
Just an interesting idea after reading through this thread ...
Looking forward to all of your comments ...
~J
Originally Posted By: Juhsga
What do you think of products such as the Tornado? And what about using a similar product in both your intake tubing and exhaust?
Whether on the intake or the exhaust, it is nothing but a flow restriction. If there were any benefit to creating a swirl in the airflow going through the valves, having a Tornado in the intake isn't going to do it. The swirl would not survive across the throttle, plenum, and runners. I'm sure the air becomes plenty turbulent as it goes through the intake valves anyway. I can't think of any possible reason that swirly flow would be beneficial in the exhaust. It would do nothing but increase friction along the pipe walls.
Originally Posted By: Juhsga
Is there a product that can change it's aperture to limit or open the amount of air that can enter the intake by reading engine RPMs and be programmed for any particular engine?
There's no benefit to restricting the intake air. Ideally, the air should flow as smoothly as possible through both the intake and the exhaust. Mufflers, filters, throttles, catalytic converters, and sensors are necessary evils. You can tune by changing length and diameter, but you don't want to introduce restrictions.
What do you think of products such as the Tornado? And what about using a similar product in both your intake tubing and exhaust?
Whether on the intake or the exhaust, it is nothing but a flow restriction. If there were any benefit to creating a swirl in the airflow going through the valves, having a Tornado in the intake isn't going to do it. The swirl would not survive across the throttle, plenum, and runners. I'm sure the air becomes plenty turbulent as it goes through the intake valves anyway. I can't think of any possible reason that swirly flow would be beneficial in the exhaust. It would do nothing but increase friction along the pipe walls.
Originally Posted By: Juhsga
Is there a product that can change it's aperture to limit or open the amount of air that can enter the intake by reading engine RPMs and be programmed for any particular engine?
There's no benefit to restricting the intake air. Ideally, the air should flow as smoothly as possible through both the intake and the exhaust. Mufflers, filters, throttles, catalytic converters, and sensors are necessary evils. You can tune by changing length and diameter, but you don't want to introduce restrictions.
Originally Posted By: rpn453
Originally Posted By: Juhsga
Is there a product that can change it's aperture to limit or open the amount of air that can enter the intake by reading engine RPMs and be programmed for any particular engine?
There's no benefit to restricting the intake air. Ideally, the air should flow as smoothly as possible through both the intake and the exhaust. Mufflers, filters, throttles, catalytic converters, and sensors are necessary evils. You can tune by changing length and diameter, but you don't want to introduce restrictions.
I agree. I think the airflow through intake duct should be smooth or laminar. This is one of the reason I didn't believe a bigger intake tube would help at lower RPM where it's not a restriction because of possibly more turburlence. Ideally you probably want a straight shot tube into the TB to provide smooth unrestricted flow. I could be wrong but the idea shape a cone or horn converging on the throttle body, but that's not the same thing as a bigger than the TB straight tube.
Originally Posted By: Juhsga
Is there a product that can change it's aperture to limit or open the amount of air that can enter the intake by reading engine RPMs and be programmed for any particular engine?
There's no benefit to restricting the intake air. Ideally, the air should flow as smoothly as possible through both the intake and the exhaust. Mufflers, filters, throttles, catalytic converters, and sensors are necessary evils. You can tune by changing length and diameter, but you don't want to introduce restrictions.
I agree. I think the airflow through intake duct should be smooth or laminar. This is one of the reason I didn't believe a bigger intake tube would help at lower RPM where it's not a restriction because of possibly more turburlence. Ideally you probably want a straight shot tube into the TB to provide smooth unrestricted flow. I could be wrong but the idea shape a cone or horn converging on the throttle body, but that's not the same thing as a bigger than the TB straight tube.
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yeah bends are not good but hard to correct the design unless you create inlet in front of the hood or under. transverse mounted engines just have to live w/ it.
the honeycomb screens on the back of the MAF are supposed to smooth out the airflow before the throttle body.
the honeycomb screens on the back of the MAF are supposed to smooth out the airflow before the throttle body.
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