In my scenario, there is no direct ducting from a hatch intake to a sealed enclosure around the airhorns of the ITBs. Thus, no ram-air affect, to benefit induction. Though I think a view like this is so worth the loss in HP. IMHO.
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ScienceofSpeed next generation Individual Throttle Body System for NSX
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Ram air is an interesting angle I hadn't considered. Could have a roof scoop that transitions into large sealed transparent feed under window to ITBs. But those of us with bonnet scoop may loose out, with hot radiator air coming over roof into scoop.
BTW...
who's car is that, with mesh screens on each ITB?
BTW...
who's car is that, with mesh screens on each ITB?
For the umpteenth time, ram air has zero effect below 230 mph. None. Zero.
Cooler air, yes... Ram air, zero.
sent from my Evo4
Cooler air, yes... Ram air, zero.
sent from my Evo4
I wondered about this myself, but unfortunately I missed the umpteen-minus-one explanations. 230mph sounds kinda arbitrary.... and increased air pressure on inlet side must have a benefit if engineered correctly (after all, that's what turbo or superchargers do). For example ram air and trumpet resonance would interact, so trumpet design may have to change to extract max benefit from increased intake pressure.
Even if ram air has minimal or no effect, intake over roof looks horn
The biggest issue you (and I for that matter) are dealing with is having the airbox big enough to provide unimpeded airflow yet small enough so that rear view is unobstructed. I believe this is what Chris is working on now.
IIRC, general displacement of the airbox should be roughly 2x the displacement of the engine itself. So in my case, it's 7.2 liters for the airbox. In your case, it's 7.6 liters.
I'll have to dig through some of my engineering books to find the exact reference though.
I wondered about this myself, but unfortunately I missed the umpteen-minus-one explanations. 230mph sounds kinda arbitrary.... and increased air pressure on inlet side must have a benefit if engineered correctly (after all, that's what turbo or superchargers do). For example ram air and trumpet resonance would interact, so trumpet design may have to change to extract max benefit from increased intake pressure.
Even if ram air has minimal or no effect, intake over roof looks horn
Sorry, it's actually 320 mph (not 230)....
"...the extensive tests that NACA did in 1948 provided
both the math and the test results to show that the Ram Air effect is nearly useless below about 320 mph. It seems that
Ram Air is a dynamic function that is proportional to the square of the air velocity. As such, at 75 mph the gain in air
density is about 7/10ths of one percent, or .007 percent. At sea level you'll be getting 14.8 PSI instead of the standard
14.7 PSI. But that's in a perfect world. Ram Air is generally considered to be only about 75% efficient, so in truth at
75mph you are gaining only about 1/2 of one percent.
This begins to ramp up as you get faster. At 150 mph the density increase is 2.75% (2.06% adjusted) which is probably
helpful in some way but is still in the "nearly impossible to measure" category.
At 350 mph the increase in density is in the 15% range and this is where Ram Air becomes usable.
So unfortunately at normal highway speeds and even at drag strip speeds, Ram Air just doesn't add anything to the
performance of your car."
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Chris did a baseline a few months ago and the engine dyno'd 338rwhp and 278rwftlbs. Considering that the ITBs are basically installed and we're just waiting for the finishing touches on the airbox to be completed, this is about as close together as the dynos are going to be for comparision purposes. That said, the dyno software does the whole SAE correction thing so I'm not too worried about dramatic environmental swings.
Here's the most recent pic:
Does any one know if the valve covers are stripped and polished or are they aftemarket? Also will the brace from the the T-roof work with the ITB's
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Valve covers are powder coated and the coil pack covers are the stock color.
http://www.nsxprime.com/forums/showthread.php?t=91546&highlight=Valve+covers+powder+coated
I don't believe the strut bar from the T will work with the ITBs.
Hope that helps.
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I'm in for the group buy Chris
Count me in if there is a group buy for this ITB kit.
There's a reason race teams go to the umph-degree to ensure as high of a pressure is formed in the airbox of a motor. While maybe not "Ram-Air" by definition, any positive pressure in the airbox will increase power while any vacuum in the same airbox/engine inlet will result in less power.
0.02
Hey Chris do you know if these will work with the brace and clamshell for the T's. I really want them bad and fiqured I could put the roof panel in the trunk so I tried it out and I could not manage to get it in and still have any usable trunk left.
Sorry, this is not compatible with the factory targa brace or engine cover.
cheers,
-- Chris
cheers,
-- Chris
I've thought of this and wondered why doesn't someone just make a clear duct out of lexan? It would then let you look at the rear window without having a big obstruction in your line of sight. I've attached a very basic concept drawing made in paint lol.
Attachments
I suggest there's an even better design solution - seal/enclose the entire volume under glass and above engine cover by creating sealed edging all round (capable of separating/opening, like a door rubber seal). Then, with air filter in stock location, feed filterered air up into the enclosed window area. bingo - perfection.
and yes, I'm serious
and yes, I'm serious
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It is important to remember that the air box also functions has as a distribution for the positive crankcase ventilation system. Hot oily vapors will not make a clear enclosure look great with time. However the throttles could be modified to port the PCV directly into the intake tract if this is a concern.
-- Chris
-- Chris
Chris, how is your carbon airbox development going? That one just comes in through the usual fender intake without all these rear hatch shenanigans right?
Chris, a few questions. Excuse me if they seem to be "noobish".
- Is this kit plug and play? will we need anything additional to make this kit functional/tune-able?
- I remember back in my FI days i was constantly worried about cracking ring lands and blown motors. What are the drawback(s) of using ITB's?
- How will my fuel economy be affected by the use of ITB's? I understand it's all based on tuning, but overall, how much lower, on average, will I lose?
- What are some ways we can "hide" the ITB's from being seen so we don't get into trouble with the law? I wouldn't think the clamshell/standard engine cover would fit with these bad boys installed.
- Would it be better to have back pressure (cats/highflow cats) installed rather than test pipes?
- Have you taken decibel readings to see how much louder the car is with the rear hatch down and driving normally?
- Will this kit work with the stock airbox kit? I currently have the DF "Mugen" air intake. Wondering if i still can use that.
and last but certainly not least,
- Will a group buy be available, and if so, how soon can we see the group buy and pricing?
I know there are a lot of people interested in the ITB kit. So lets start a list. If we're able to get enough people, it may persuade SOS to get a group buy going.
1. Sicarius82
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
- Is this kit plug and play? will we need anything additional to make this kit functional/tune-able?
- I remember back in my FI days i was constantly worried about cracking ring lands and blown motors. What are the drawback(s) of using ITB's?
- How will my fuel economy be affected by the use of ITB's? I understand it's all based on tuning, but overall, how much lower, on average, will I lose?
- What are some ways we can "hide" the ITB's from being seen so we don't get into trouble with the law? I wouldn't think the clamshell/standard engine cover would fit with these bad boys installed.
- Would it be better to have back pressure (cats/highflow cats) installed rather than test pipes?
- Have you taken decibel readings to see how much louder the car is with the rear hatch down and driving normally?
- Will this kit work with the stock airbox kit? I currently have the DF "Mugen" air intake. Wondering if i still can use that.
and last but certainly not least,
- Will a group buy be available, and if so, how soon can we see the group buy and pricing?
I know there are a lot of people interested in the ITB kit. So lets start a list. If we're able to get enough people, it may persuade SOS to get a group buy going.
1. Sicarius82
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
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Long, you do realize that this is technically not CA smog legal, right?
It's easier to get a SOS SC and fool the people in a smog check by referencing an existing CARB EO# from the Comptech days.
The average smog tech ain't going to break out a tape measure to figure out that one Autorotor is smaller than the other......
If I may be so bold; re: help w/ questions on the carbon airbox: http://nsxprime.com/forum/showthread.php?t=85793&page=8
posts #186 and #189 for pics of the box.
posts #186 and #189 for pics of the box.
yes alain, i do. but we all install parts that aren't "technically smog legal" all the time. you're very fortunate to have an existing CARB EO#.
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