The exception is the air intake on the LS2 cars.
Truth or BS?
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WOW !! You sound like one of them there "Experts". You got me totally confused on the fact that headers are scavengers ?? Are you suggesting that the power increase they provide is due to them "scavenging" something from the combustion chamber that then ads more power to the rear wheels after the exhaust has left the combustion chamber ? Or are you suggesting that headers help the engine breath better by drawing out more gases due to scavenging ? Or are you trying to say that headers usually have better flow simply due to their porting design ? And let us not forget one of the main advantages of headers....that pesky little thing called excess weight. Help us Mr. Wizard !!!!....
Well first off someone making power with headers doesn't have one Ioda to with weight. It is all about the scavenging effect that the long tube had on the cylinder and in doing so increasing the VE on the engine. Do I need to explain to you how it work, I know your in CA and you all know better than everyone else, but by reading your response earlier I am not so sure.
Last edited by Zip Corvettes; Feb 23, 2018 at 03:16 PM.
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At low speeds of course the shroud works. At those speeds conduction plays a bigger role than convection. But as soon as you get up to speed (real speed, where your CAI is arguably a more important upgrade), the temperature differences are going to be minute.
Let me use your example: with shroud the highest temps you saw was 95ºF (308 K), 120ºF (322 K) without the shroud.
Now let's use the ideal gas law to figure out density of air. After all, the goal of a CAI is to have colder (more dense) air enter the combustion chamber to increase our volumetric efficiency.
Let's see how these temperature differences really affect the final density of the air as it is entering the intake:
Ideal gas law: PV = nRT
P= pressure, V= volume, n= quantity (mass) of air, R = constant, T= temperature, n/V= density, p = density
Rearrange to get on the order of density (mass per unit volume):
(n/V) = (P/(RT))
But pressure in the atmosphere is relatively constant, and the R is also constant so we can transform to:
p=(1/T)*k; where k is some constant
Now the goal is to figure what 1/T is at both temperatures measured above:
1/308= .00325; 1/322 = .00311.
So what was the increase in density? .00014 g/ml or 4.5%.
Now this may sound like a huge improvement, but at traffic speeds there is usually an easier, cheaper way to increase your volumetric efficiency: depress the accelerator further.
Note that this density improvement only decreases as your speed increases, because convection due to the rapid relative velocity of air will maintain your intake temperature closer to ambient with or without a shroud.
In any case, this is just a simplification of a much more complicated problem. Thanks for reading.
.
Let me use your example: with shroud the highest temps you saw was 95ºF (308 K), 120ºF (322 K) without the shroud.
Now let's use the ideal gas law to figure out density of air. After all, the goal of a CAI is to have colder (more dense) air enter the combustion chamber to increase our volumetric efficiency.
Let's see how these temperature differences really affect the final density of the air as it is entering the intake:
Ideal gas law: PV = nRT
P= pressure, V= volume, n= quantity (mass) of air, R = constant, T= temperature, n/V= density, p = density
Rearrange to get on the order of density (mass per unit volume):
(n/V) = (P/(RT))
But pressure in the atmosphere is relatively constant, and the R is also constant so we can transform to:
p=(1/T)*k; where k is some constant
Now the goal is to figure what 1/T is at both temperatures measured above:
1/308= .00325; 1/322 = .00311.
So what was the increase in density? .00014 g/ml or 4.5%.
Now this may sound like a huge improvement, but at traffic speeds there is usually an easier, cheaper way to increase your volumetric efficiency: depress the accelerator further.
Note that this density improvement only decreases as your speed increases, because convection due to the rapid relative velocity of air will maintain your intake temperature closer to ambient with or without a shroud.
In any case, this is just a simplification of a much more complicated problem. Thanks for reading.
.
Also the throttle is absolutely the answer, we did not design our box around increasing any power at say 20% throttle, if we did then a guy with a stock airbox and 30% throttle will exceed any improvement. Our only agenda was at 100% throttle all the way through the curve. There is a lot to be gained in a C6, but it is also easy to lose power if not done properly. The other thing that is often not looked at is the abilitly of the box to keep the IAT down and it's affect on the timing table. Even 2 degrees can really set you back depending on what combination you are running.
Last edited by Zip Corvettes; Feb 23, 2018 at 03:54 PM.
Melting Slicks
Joined: May 2007
Posts: 3,248
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From: Lindenhurst, IL
When I put a cold air intake on my previous BMW 540i, the results were immediately apparent. The increase in horsepower was very noticeable. I found myself accidentally spinning the tires, when I never did before.
On my C6 Corvette, I noticed no change whatsoever. I have a Halltech Killer Bee, with a Bee Hive enclosure, and another scoop that pushes air into the intake enclosure. It did nothing that I could feel. However - I felt, initially, that since I opened up the back end with a freer flowing exhaust, that it made sense to open it up a the front end. I figure that I may have added up to 20 horsepower, but I could not tell the difference before/after.
On my C6 Corvette, I noticed no change whatsoever. I have a Halltech Killer Bee, with a Bee Hive enclosure, and another scoop that pushes air into the intake enclosure. It did nothing that I could feel. However - I felt, initially, that since I opened up the back end with a freer flowing exhaust, that it made sense to open it up a the front end. I figure that I may have added up to 20 horsepower, but I could not tell the difference before/after.
Safety Car
Joined: Jan 2011
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Wow, you think because you can throw around part of the equation for the VE table you can call other people names? Oops your not that guy, I'm going with this subject is over your head.
Well first off someone making power with headers doesn't have one Ioda to with weight. It is all about the scavenging effect that the long tube had on the cylinder and in doing so increasing the VE on the engine. Do I need to explain to you how it work, I know your in CA and you all know better than everyone else, but by reading your response earlier I am not so sure.
Well first off someone making power with headers doesn't have one Ioda to with weight. It is all about the scavenging effect that the long tube had on the cylinder and in doing so increasing the VE on the engine. Do I need to explain to you how it work, I know your in CA and you all know better than everyone else, but by reading your response earlier I am not so sure.
Pro
Joined: Nov 2016
Posts: 647
Likes: 103
From: Aurora IL
When I put a cold air intake on my previous BMW 540i, the results were immediately apparent. The increase in horsepower was very noticeable. I found myself accidentally spinning the tires, when I never did before.
On my C6 Corvette, I noticed no change whatsoever. I have a Halltech Killer Bee, with a Bee Hive enclosure, and another scoop that pushes air into the intake enclosure. It did nothing that I could feel. However - I felt, initially, that since I opened up the back end with a freer flowing exhaust, that it made sense to open it up a the front end. I figure that I may have added up to 20 horsepower, but I could not tell the difference before/after.
On my C6 Corvette, I noticed no change whatsoever. I have a Halltech Killer Bee, with a Bee Hive enclosure, and another scoop that pushes air into the intake enclosure. It did nothing that I could feel. However - I felt, initially, that since I opened up the back end with a freer flowing exhaust, that it made sense to open it up a the front end. I figure that I may have added up to 20 horsepower, but I could not tell the difference before/after.
Le Mans Master
Joined: Jan 2001
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From: Maryville TN
St. Jude Donor '06-13,'16-'17, '19
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From: SoCal
I like you are using the equation to solve for this. You can figure out any performance aspect of a car with a calculator if needed. The problem with your equation is you are only focusing on the effect the box has on cooling the air temp inside the box. That absolutely has an effect, but it's not the whole story. You really only need the equation for VE or GMVE to solve this. I hope you realize though everything you posted 99% of anyone on here is not going to understand it.
Also the throttle is absolutely the answer, we did not design our box around increasing any power at say 20% throttle, if we did then a guy with a stock airbox and 30% throttle will exceed any improvement. Our only agenda was at 100% throttle all the way through the curve. There is a lot to be gained in a C6, but it is also easy to lose power if not done properly. The other thing that is often not looked at is the abilitly of the box to keep the IAT down and it's affect on the timing table. Even 2 degrees can really set you back depending on what combination you are running.
Also the throttle is absolutely the answer, we did not design our box around increasing any power at say 20% throttle, if we did then a guy with a stock airbox and 30% throttle will exceed any improvement. Our only agenda was at 100% throttle all the way through the curve. There is a lot to be gained in a C6, but it is also easy to lose power if not done properly. The other thing that is often not looked at is the abilitly of the box to keep the IAT down and it's affect on the timing table. Even 2 degrees can really set you back depending on what combination you are running.
Of course if I were to purchase a CAI, I'd be from a manufacturer who has data proving lower IAT using actual use temperature graphs at a minimum. Not dyno, I don't believe convection is accurately modeled at most dynos. Flow benches, to prove improved air flow, would be my next requirement. Too many CAI sellers out there peddling gains with no relevant data to back it up, that's my biggest qualms with them.
Last edited by kevinjm; Feb 23, 2018 at 06:53 PM.
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Joined: Jan 2008
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From: corpus christi Texas
Le Mans Master
Joined: Jan 2008
Posts: 6,457
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From: corpus christi Texas
A true CAI allows fresh and cooler air into your engine on a good day when the dew point is low (Less Water Grains) in the air which has more oxygen in it.Bottom line is,
the cooler the air that you can get flowing into the intake your engine will love it.You can add NOS or Meth (Not The **** You Smoke)
and it will damm near freeze the air going into the combustion chamber.
the cooler the air that you can get flowing into the intake your engine will love it.You can add NOS or Meth (Not The **** You Smoke)
and it will damm near freeze the air going into the combustion chamber.
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Joined: Mar 2014
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From: Below the bottom of Berby Hollow, NYS
Ok, I'll spell it out in scientific terms, which should have been done in the beginning. And FWIW, I am not a scientist nor do I pretend to be one on TV or the internet.
Hypothesis/claim: "A cold air intake will increase horsepower."
The skeptic asks: "On a test model of your choice, which should be bone-stock, how much power increase is there and under what conditions?
"What are the exact mechanisms that you claim increase horsepower? There can be only two that I'm aware of: 1) The air entering the engine is enough cooler to produce horsepower gains; and/or 2) the air is being compressed enough to produce more intake charge than it otherwise would get."
Claimant: "Yes, that's it. Both of them."
Skeptic: "Fine! Prove that it produces more horsepower, and how much?"
That's how it works.
Claimant: "I have a car that runs on water, will do 200 MPH, gets 50 MPG, seats four comfortably, and will pass all US emission and safety tests."
"Fine. Prove it."
Claimant: "I have a pill that will cure all cancer."
"Fine. Prove it."
Claimant: "I have invented a perpetual motion machine."
"Prove it."
The burden of proof is always on those making the claim, never on the skeptic.
EDIT: Wanting something to be so, doesn't make it so.
Hypothesis/claim: "A cold air intake will increase horsepower."
The skeptic asks: "On a test model of your choice, which should be bone-stock, how much power increase is there and under what conditions?
"What are the exact mechanisms that you claim increase horsepower? There can be only two that I'm aware of: 1) The air entering the engine is enough cooler to produce horsepower gains; and/or 2) the air is being compressed enough to produce more intake charge than it otherwise would get."
Claimant: "Yes, that's it. Both of them."
Skeptic: "Fine! Prove that it produces more horsepower, and how much?"
That's how it works.
Claimant: "I have a car that runs on water, will do 200 MPH, gets 50 MPG, seats four comfortably, and will pass all US emission and safety tests."
"Fine. Prove it."
Claimant: "I have a pill that will cure all cancer."
"Fine. Prove it."
Claimant: "I have invented a perpetual motion machine."
"Prove it."
The burden of proof is always on those making the claim, never on the skeptic.
EDIT: Wanting something to be so, doesn't make it so.
Last edited by Bruze; Feb 24, 2018 at 02:30 AM.
Team Owner
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From: Below the bottom of Berby Hollow, NYS
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From: corpus christi Texas
That's my exact argument. I doubt these boxes can do much, 2 degrees might even be pushing it when the car's at speed. Huge amounts of convection taking place.
Of course if I were to purchase a CAI, I'd be from a manufacturer who has data proving lower IAT using actual use temperature graphs at a minimum. Not dyno, I don't believe convection is accurately modeled at most dynos. Flow benches, to prove improved air flow, would be my next requirement. Too many CAI sellers out there peddling gains with no relevant data to back it up, that's my biggest qualms with them.
Of course if I were to purchase a CAI, I'd be from a manufacturer who has data proving lower IAT using actual use temperature graphs at a minimum. Not dyno, I don't believe convection is accurately modeled at most dynos. Flow benches, to prove improved air flow, would be my next requirement. Too many CAI sellers out there peddling gains with no relevant data to back it up, that's my biggest qualms with them.
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That's my exact argument. I doubt these boxes can do much, 2 degrees might even be pushing it when the car's at speed. Huge amounts of convection taking place.
Of course if I were to purchase a CAI, I'd be from a manufacturer who has data proving lower IAT using actual use temperature graphs at a minimum. Not dyno, I don't believe convection is accurately modeled at most dynos. Flow benches, to prove improved air flow, would be my next requirement. Too many CAI sellers out there peddling gains with no relevant data to back it up, that's my biggest qualms with them.
Of course if I were to purchase a CAI, I'd be from a manufacturer who has data proving lower IAT using actual use temperature graphs at a minimum. Not dyno, I don't believe convection is accurately modeled at most dynos. Flow benches, to prove improved air flow, would be my next requirement. Too many CAI sellers out there peddling gains with no relevant data to back it up, that's my biggest qualms with them.
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Ok you can stop calling me names and you can stop putting words in my mouth. First headers and weight savings are NOT the benefit of headers. Have you weighed a set of stainless long tubes and not chinease ones? There if very little different in the overall weight. The performance behind headers is the scavenging effect of the long header tube on the cylinder and creating a much better VE which makes more power. You can also add some timing with headers because of the better VE in the cylinder. If you want to make a difference in weight then if you have aftermarket wheels, they better be Forgelines or CCW's or along those lines, not re production wheels and I hope you are using our brake rotors that are 10lbs lighter per rotor then a stock rotor or better yet most of the drivers can lose weight. So if the gain is weight, why change the calibration when adding headers?
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That's my exact argument. I doubt these boxes can do much, 2 degrees might even be pushing it when the car's at speed. Huge amounts of convection taking place.
Of course if I were to purchase a CAI, I'd be from a manufacturer who has data proving lower IAT using actual use temperature graphs at a minimum. Not dyno, I don't believe convection is accurately modeled at most dynos. Flow benches, to prove improved air flow, would be my next requirement. Too many CAI sellers out there peddling gains with no relevant data to back it up, that's my biggest qualms with them.
Of course if I were to purchase a CAI, I'd be from a manufacturer who has data proving lower IAT using actual use temperature graphs at a minimum. Not dyno, I don't believe convection is accurately modeled at most dynos. Flow benches, to prove improved air flow, would be my next requirement. Too many CAI sellers out there peddling gains with no relevant data to back it up, that's my biggest qualms with them.
Kind of like motocross, everyone is trying to make their's faster with performance pipes and parts but if you watch them on the track the throttle is never pinned. Watch a factory rider on a stock bike and it goes way faster than most on modified bikes. Cars are no different, we were up at VIR with Johnny Miller and at the time had a 05 T1 car, he was killing modified ZO6's except for the back straight, but as soon as they hit down hill section he was gone. He had a fairly stock 05 that was set up as a T1 car. The difference is they backed off the throttle and his was on the floor. The throttle pedal makes a huge difference, but we are operating on the performance gain once that part of the equation is maxed out.
Le Mans Master
Joined: Jan 2008
Posts: 6,457
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From: corpus christi Texas
I like you are using the equation to solve for this. You can figure out any performance aspect of a car with a calculator if needed. The problem with your equation is you are only focusing on the effect the box has on cooling the air temp inside the box. That absolutely has an effect, but it's not the whole story. You really only need the equation for VE or GMVE to solve this. I hope you realize though everything you posted 99% of anyone on here is not going to understand it.
Also the throttle is absolutely the answer, we did not design our box around increasing any power at say 20% throttle, if we did then a guy with a stock airbox and 30% throttle will exceed any improvement. Our only agenda was at 100% throttle all the way through the curve. There is a lot to be gained in a C6, but it is also easy to lose power if not done properly. The other thing that is often not looked at is the abilitly of the box to keep the IAT down and it's affect on the timing table. Even 2 degrees can really set you back depending on what combination you are running.
Also the throttle is absolutely the answer, we did not design our box around increasing any power at say 20% throttle, if we did then a guy with a stock airbox and 30% throttle will exceed any improvement. Our only agenda was at 100% throttle all the way through the curve. There is a lot to be gained in a C6, but it is also easy to lose power if not done properly. The other thing that is often not looked at is the abilitly of the box to keep the IAT down and it's affect on the timing table. Even 2 degrees can really set you back depending on what combination you are running.
