-
Protip: Profile posts are public! Use Conversations to message other members privately. Everyone can see the content of a profile post.
Downforce i take vs cold air intake
- Thread starter makija
- Start date
Downforce would be nice but the stock box will be better.. Short ram will look nice but will suck in hot air and that probably won't be good for the SC.
The CT carbon air box would work best for your SC, as it allows more airflow than the stock box.
- Joined
- 22 April 2012
- Messages
- 665
Don't get the short ram intake, its inside the engine bay so it'll just suck in the hot air. The best intake for a CTSC would be the CT-E Carbon Fiber lower airbox. The CF lid is just for show. If you're on a budget then just get the drop in Uni-Filter, since the stock airbox is really well designed.
I make an aluminum tube (polished) intake that puts the filter directly behind the vent on the driver's side. Cold air. Simple. Made 13whp over the CT carbon air box (more volume) and cost my customer only 200 bucks. If you know anyone who can do two aluminum beads around some 3 inch mandrel bent pipe get it done! 
- Joined
- 22 April 2012
- Messages
- 665
Is this it ???
Yes, that is the one.
Unless there are dynos to prove otherwise, the stock air box with a better flowing filter will be your best bet IMO. The Comptech piece definitely looks nice, but functionally it works the same as the stock air box.
Just FYI, the stock airbox is "cold air" and "ram air", as it draws air from the side vent, and it is sealed so it will only draw outside air.
A "short ram" intake for the NSX would most definitely be a step down in performance due to the design, as it'd mainly be drawing in hot air from the engine bay.
Just FYI, the stock airbox is "cold air" and "ram air", as it draws air from the side vent, and it is sealed so it will only draw outside air.
A "short ram" intake for the NSX would most definitely be a step down in performance due to the design, as it'd mainly be drawing in hot air from the engine bay.
Last edited:
Here is the dyno sheet to prove otherwise: This removal of said better carbon airbox with K&N panel filter and installation of a simple aluminum intake pipe. It was not a ram air. It was a "cold air" that placed the filter directly behind the driver's side vent. This vehicle had 1.6L whipple with high boost pulley
This was the same vehicle with removal of comptech exhaust and fabrication of three inch custom stainless exhaust and then tuned with AEM FIC: Any questions?
Last edited:
The first chart yes that makes sense but you cannot compare adding the fic to the equation without putting back the carbon box. Unless I missed something. Those are good numbers btw
The second graph added for the purpose of showing how much more the intake could potentially provide if it was tuned VIA FIC after it was installed Vs just installed like the first graph represents. Collectively, with tuning those pieces bring more to the table vs one part alone, if that makes sense to you.
- Joined
- 8 April 2012
- Messages
- 675
Are you saying that the car had been tuned with an AEM FIC in the first graph as well?
as we all know that these type of modifications can improve performance on theire own yet to maximize its potential, a proper tune with FIC can/will make a big difference.
as we all know that these type of modifications can improve performance on theire own yet to maximize its potential, a proper tune with FIC can/will make a big difference.
Nope, it was exactly opposite your statement. The intake was installed without tuning. (first graph) The second graph shows what is possible with tuning along with supporting mods. Make sense? The FIC was added later because the exhaust mod leaned out the mixture to the point that bigger injectors were needed and tuning afterwards was the icing on the cake. I cannot say for sure what the gains would have been on the intake alone with the FIC, but the second graph points in the direction that the gains on the intake alone with FIC tuning could have had a much higher yield. Make sense?
- - - Updated - - -
I'll throw up a few pics as soon as I can upload them
... i am looking into cold air intake what is better downforce or a shortram intake i am planing on getting a sos supercharger next spring so i am buying parts now any info would help
The OEM airbox/intake snorkel is a "cold air" intake system that only inhales cold air from outside the engine compartment. The exit of the airbox has a nice bellmouth (aka "velocity stack") cast into it and its diameter is matched to the bellows behind it. For feeding air to the stock throttle body, that combination is going to be hard to beat. Exit opening in OEM airbox lid:
The entrance of the airbox is 10% larger than the exit so it sounds like a well balanced design. The stock intake snorkel that feeds the airbox doesn't seem ideal from a horsepower perspective, however. The OEM intake opening of the snorkel (where it sucks air in) is smaller than its exit so for the airbox, it's a bit like breathing through a straw. Also, the relatively tight curves of the snorkel are more difficult for the air to flow through than straighter designs. Despite that, the diameter of the OEM snorkel is still large enough that stock NSXs supposedly see no gains by replacing it with other snorkels and the OEM design will keep more dirt and water away from your air filter than any other "cold air" design I've seen.
To give you an idea where bottlenecks could be, here's an overview of the cross sections along various points of an NSX's intake tract:
Replacing the OEM intake snorkel with the Downforce air intake scoop will funnel all air entering the side intake into your airbox. With that, you'll have not only a "cold air" intake like stock but what could be called a "ram air" intake as well. You supposedly don’t really get a "ram air" effect at road car speeds but the entrance of the Downforce intake scoop is a lot larger than its exit and the flow into the airbox will be as smooth as possible. So whatever weaknesses the OEM intake snorkel has from a horsepower perspective should be cured with the Downforce scoop and it'll make the car's induction sound a lot louder. On the negative side, it will not only channel air into your airbox as efficiently as possible, but also dirt and water as well.
Comptech's offering not only modifies the intake snorkel but also the airbox itself by increasing the size of the airbox's entrance opening. Entrance opening in bottom half of Comptech airbox:
With a Comptech airbox, the engine doesn't only breathe through the round opening in the side wall you can see above but also through the opening around the gas tank pipe. How much it really helps if the airbox's entrance is that much larger than its exit, I don't know. There's an extension to the airbox that seals it against the side wall so like OEM, it's a true "cold air" design that only breathes cool air from outside the engine compartment. Inside the fender, there's a little hood but not a funnel like the Downforce air intake scoop so the Comptech offering shouldn't be called a "ram air" design.
Other offerings like the Downforce STACK intake system get rid of the airbox completely. Considering the smooth air path, gently increasing cross section, and bellmouths in a stock airbox/Downforce intake snorkel combination, the only way I can see how the STACK intake system is going to pose less of a restriction is if the filter itself lets air through more easily. Since the surface area of the STACK filter looks smaller than that of the stock filter, that's probably only going to happen if the filter element doesn't filter as well.
Other designs don't only inhale cold air from the fender but also warm air from the engine compartment. By definition, those are neither "cold air" nor "ram air" intakes. Inhaling air in the engine compartment probably doesn't make much of a difference on a dyno when the engine compartment lid is open. When you're actually driving on the road with the engine compartment lid closed it may be another story. Warm air is less dense, contains less oxygen, and produces less horsepower.
For the sake of my engine, I don't want it to inhale dirt and dust that will increase wear and decrease its lifespan. If I were planning on getting a supercharger, I'd want a cold air intake that minimizes the intake restriction as far as possible while still filtering the air well. If I didn't care how quickly the filter gets dirty, I'd keep the stock airbox and just slap on a Downforce air intake scoop. If that turned out to be too loud, I'd modify the OEM intake scoop and put that back on. If you unplug the resonator from the stock intake snorkel, you'll get a second intake opening. Put a bellmouth over that to smooth the airflow and your two intake openings together will be larger than the exit, reducing the restriction. It won't be as loud as the Downforce snorkel but it will be louder than stock, have less restriction than stock, be a true cold air intake, and still filter the air well.
If you're staying naturally aspirated, another area to consider beyond intake air temperature and restriction is the resonant frequency of the airbox/air filter system. Resonances can help push more air into the cylinders as the intake valves open. Perhaps the stock airbox doesn't have an ideal resonant frequency and if that's the case, perhaps it's because of packaging or servicing considerations - don't know. I do know that ProSpeed calculated what they thought would be a good resonant frequency and a designed an air filter/intake snorkel to deliver that. It's a long tube that snakes into the fender well and places a conical air filter behind the rear wheel. It looks like it should have a low restriction and breathe cold air plus have a different resonant frequency than stock. It also looks like it will be more difficult to service and might get dirty more quickly. If there's a supercharger in front of the intake valves, I don't think the resonant frequency of the air filtration system is going to help push more air into the cylinders. If done right, it could in a naturally aspirated engine - and maybe the OEM airbox leaves some horsepower on the table in that regard. Don't know.
Last edited:
The OEM airbox/intake snorkel is a "cold air" intake system that only inhales cold air from outside the engine compartment. The exit of the airbox has a nice bellmouth (aka "velocity stack") cast into it and its diameter is matched to the bellows behind it. For feeding air to the stock throttle body, that combination is going to be hard to beat. Exit opening in OEM airbox lid:
The entrance of the airbox is 10% larger than the exit so it sounds like a well balanced design. The stock intake snorkel that feeds the airbox doesn't seem ideal from a horsepower perspective, however. The OEM intake opening of the snorkel (where it sucks air in) is smaller than its exit so for the airbox, it's a bit like breathing through a straw. Also, the relatively tight curves of the snorkel are more difficult for the air to flow through than straighter designs. Despite that, the diameter of the OEM snorkel is still large enough that stock NSXs supposedly see no gains by replacing it with other snorkels and the OEM design will keep more dirt and water away from your air filter than any other "cold air" design I've seen.
To give you an idea where bottlenecks could be, here's an overview of the cross sections along various points of an NSX's intake tract:
Replacing the OEM intake snorkel with the Downforce air intake scoop will funnel all air entering the side intake into your airbox. With that, you'll have not only a "cold air" intake like stock but what could be called a "ram air" intake as well. You supposedly don’t really get a "ram air" effect at road car speeds but the entrance of the Downforce intake scoop is a lot larger than its exit and the flow into the airbox will be as smooth as possible. So whatever weaknesses the OEM intake snorkel has from a horsepower perspective should be cured with the Downforce scoop and it'll make the car's induction sound a lot louder. On the negative side, it will not only channel air into your airbox as efficiently as possible, but also dirt and water as well.
Comptech's offering not only modifies the intake snorkel but also the airbox itself by increasing the size of the airbox's entrance opening. Entrance opening in bottom half of Comptech airbox:
With a Comptech airbox, the engine doesn't only breathe through the round opening in the side wall you can see above but also through the opening around the gas tank pipe. How much it really helps if the airbox's entrance is that much larger than its exit, I don't know. There's an extension to the airbox that seals it against the side wall so like OEM, it's a true "cold air" design that only breathes cool air from outside the engine compartment. Inside the fender, there's a little hood but not a funnel like the Downforce air intake scoop so the Comptech offering shouldn't be called a "ram air" design.
Other offerings like the Downforce STACK intake system get rid of the airbox completely. Considering the smooth air path, gently increasing cross section, and bellmouths in a stock airbox/Downforce intake snorkel combination, the only way I can see how the STACK intake system is going to pose less of a restriction is if the filter itself lets air through more easily. Since the surface area of the STACK filter looks smaller than that of the stock filter, that's probably only going to happen if the filter element doesn't filter as well.
Other designs don't only inhale cold air from the fender but also warm air from the engine compartment. By definition, those are neither "cold air" nor "ram air" intakes. Inhaling air in the engine compartment probably doesn't make much of a difference on a dyno when the engine compartment lid is open. When you're actually driving on the road with the engine compartment lid closed it may be another story. Warm air is less dense, contains less oxygen, and produces less horsepower.
For the sake of my engine, I don't want it to inhale dirt and dust that will increase wear and decrease its lifespan. If I were planning on getting a supercharger, I'd want a cold air intake that minimizes the intake restriction as far as possible while still filtering the air well. If I didn't care how quickly the filter gets dirty, I'd keep the stock airbox and just slap on a Downforce air intake scoop. If that turned out to be too loud, I'd modify the OEM intake scoop and put that back on. If you unplug the resonator from the stock intake snorkel, you'll get a second intake opening. Put a bellmouth over that to smooth the airflow and your two intake openings together will be larger than the exit, reducing the restriction. It won't be as loud as the Downforce snorkel but it will be louder than stock, have less restriction than stock, be a true cold air intake, and still filter the air well.
If you're staying naturally aspirated, another area to consider beyond intake air temperature and restriction is the resonant frequency of the airbox/air filter system. Resonances can help push more air into the cylinders as the intake valves open. Perhaps the stock airbox doesn't have an ideal resonant frequency and if that's the case, perhaps it's because of packaging or servicing considerations - don't know. I do know that ProSpeed calculated what they thought would be a good resonant frequency and a designed an air filter/intake snorkel to deliver that. It's a long tube that snakes into the fender well and places a conical air filter behind the rear wheel. It looks like it should have a low restriction and breathe cold air plus have a different resonant frequency than stock. It also looks like it will be more difficult to service and might get dirty more quickly. If there's a supercharger in front of the intake valves, I don't think the resonant frequency of the air filtration system is going to help push more air into the cylinders. If done right, it could in a naturally aspirated engine - and maybe the OEM airbox leaves some horsepower on the table in that regard. Don't know.
Wow thank you for this def cleared alot of my questions this was a well detailed explanation, if you have a second take a look at the http://www.blinemotorsports.com/ and their intake for nsx where its just a pipe going into fender with a filter thats what i am considering now or a downforce, i mean i wilm get all this when spring comes due to canadian awesome winters and ... A dog tearing his acl and that setting me back 2700
)) once again thx alot and take a look at that page let me know what you think
B-Line introduced their NSX Cold Air Intake in this thread on Prime: http://www.nsxprime.com/forum/showthread.php/156468-B-Line-Motorsports-NSX-Cold-Air-Intake. There's interesting information about it but unfortunately, no dyno measurements were carried out on the same dyno on the same day to see what gains it brings compared to stock and no measurements were carried out of the pressure drop caused by their intake compared to stock. So there's no hard data to show that your engine can breathe easier with their intake.
In the first post of that thread, they mention that the tubing they use has a 3.00” diameter. Look at the diameter of the stock airbox entrance and exit in the table above. The B-Line intake has a smaller diameter than stock.
In post #57 on page 3, they mention that the OEM bellows between the airbox and the throttle body does not transition well and has kind of a wall in it. Exit of OEM airbox and entrance of bellows leading to throttle body:
The OEM bellows has a bellmouth in it to smoothly transition to the throttle body, the airbox has a bellmouth to smoothly transition into the bellows, and all of the transitions are port matched. That does not look bad.
When using the B-Line intake, there is also a step that needs to be transitioned between the 3.00” intake tube and the 2.68” throttle body. Looking at the pictures on B-Line's website, it looks like that transition is effected with a crease or a kink in a coupling instead of with a Honda-like bellmouth. B-Line use a conical filter in the fender instead of a filter in an airbox – will the conical filter really pose less restriction in that location when it can only breathe well through one side? Then there's the issue of its smaller-than-stock diameter. Overall, it's hard to predict whether the B-Line intake it will pose a higher or lower restriction than stock and unfortunately, there is no data to back up their claims.
To make horsepower, your engine needs to breathe cold air through an intake with little restriction that, if possible, resonates at the correct frequency. The B-Line intake breathes cold air in any case and will definitely funnel the intake noise out into the open better than the OEM setup.
In the first post of that thread, they mention that the tubing they use has a 3.00” diameter. Look at the diameter of the stock airbox entrance and exit in the table above. The B-Line intake has a smaller diameter than stock.
In post #57 on page 3, they mention that the OEM bellows between the airbox and the throttle body does not transition well and has kind of a wall in it. Exit of OEM airbox and entrance of bellows leading to throttle body:
The OEM bellows has a bellmouth in it to smoothly transition to the throttle body, the airbox has a bellmouth to smoothly transition into the bellows, and all of the transitions are port matched. That does not look bad.
When using the B-Line intake, there is also a step that needs to be transitioned between the 3.00” intake tube and the 2.68” throttle body. Looking at the pictures on B-Line's website, it looks like that transition is effected with a crease or a kink in a coupling instead of with a Honda-like bellmouth. B-Line use a conical filter in the fender instead of a filter in an airbox – will the conical filter really pose less restriction in that location when it can only breathe well through one side? Then there's the issue of its smaller-than-stock diameter. Overall, it's hard to predict whether the B-Line intake it will pose a higher or lower restriction than stock and unfortunately, there is no data to back up their claims.
To make horsepower, your engine needs to breathe cold air through an intake with little restriction that, if possible, resonates at the correct frequency. The B-Line intake breathes cold air in any case and will definitely funnel the intake noise out into the open better than the OEM setup.
I just installed a bline CAI. I'll be hopefully on the dyno soon and post before after. I have a compact exhaust, Pride RTP, DC headers. I'm really curious too. Plus side, is it looks nice in the engine bay and sound great. Now if it improves pony's... Find out soon I guess.
Cool! Is there any way you could be coaxed into doing before/after runs on the same dyno on the same day, measuring the engine rpm from the tachometer pickup loop in the engine compartment? Cody from LoveFab found out the hard way that measuring the same car on the same dyno but on different days makes the results hard to compare.
These are typically what I make in regards to my "cold air" intake systems. Sometimes I hook the DF scoop directly to the pipe with a foam filter in front and sometimes I use additional pipe with the typical large style cone filter instead of the scoop. One is a "ram air type" and the other would be a normal "cold air" type (depends on customer preference). Either way shows similar dyno results to the ones I posted earlier in this thread. I do not make short ram types for these vehicles.
Check the dyno graphs on this post. I can't vouch for what it will do naturally aspirated as I have not done back to back on that regard, but SC has shown a decent gain.
One thing I know from my motorcycle days is that Honda spent lots of time tuning the air intakes of their motors to optimize the charge using the sound waves of the intake.
I would think that Honda decided for the NSX engine, that they would build a tuned intake system as well, so would guess there was research done on the design of the NSX intake.
Here in BC we get a lot of rain so the large Downforce type air scoops don't work well in the wet.
An air filter placed directly behind the side air intake as mentioned by dmscrx would get soaked and plugged with road dirt almost immediately.
The oem intake works well in all climate conditions but perhaps is a compromise and in sunny dry desert climes improvements can be made
I would think that Honda decided for the NSX engine, that they would build a tuned intake system as well, so would guess there was research done on the design of the NSX intake.
Here in BC we get a lot of rain so the large Downforce type air scoops don't work well in the wet.
An air filter placed directly behind the side air intake as mentioned by dmscrx would get soaked and plugged with road dirt almost immediately.
The oem intake works well in all climate conditions but perhaps is a compromise and in sunny dry desert climes improvements can be made
I am in winnipeg manitoba heh but ya bc is def mire rain then us
Similar threads
