no!docurley wrote:One second, is not the top snorkel a ram air feed
Carbon intake Vs standard airbox power.
Re: Carbon intake Vs standard airbox power.
Re: Carbon intake Vs standard airbox power.
And what about the wing vent that faces backwards?docurley wrote:bam_bam wrote:That looks like a CAF to me (and a pretty good one), nothing to do with ram air.docurley wrote:This is a good build right-up on a Ram Air setup on a V8 car, but just have a hunt around on the net will confirm the advantages of having a Ram Air system and hence why most car makers have the system fitted to there cars.
http://planetsoarer.com/BFI3/bfi3.htm
Ram Air effect is caused by a sealed system to direct the air in to one location and this is what he did, mine for instance is the CAI fitted to the flap on the stock air box leading to the bottom grill and still using the stock snorkel behind the middle grill.
basically channeling the air in to a box unlike the open air filters just sitting in the air. If I added a CAI to that it would be just a cold air feed no Ram effect as the filter is not in a sealed unit (other than the CAI) so only allowing what the engine can suck in rather than ramming air in to the engine.
I hope that made sense
Re: Carbon intake Vs standard airbox power.
utter tosh.docurley wrote:Just thought of another way to explain.
You travel in your car at say 70mph window shut and air con on, you breath normally because nothing is forcing air in to your lungs but you feel the chill as you breath. now open the window stick a funnel in your gob and stick you head out the window...... you lungs will have been forced to inflate (You will probably die Lol) but for those few seconds you will have felt Ram Air effect.
Try it - I have a car with no doors, windscreen or roof. on the motorway I have driven without full face crash helmet and am still here.
I can categorically state that if you open your mouth you ingest flies and not much else. There is no difficulty breathing and you certainly don't explode.
- RossDagley
- Top Gear
- Posts: 2334
- Joined: Mon Mar 17, 2014 11:53 pm
- Location: Bedford, UK
Re: Carbon intake Vs standard airbox power.
And on that subject, I've taken wind in the face at over 150mph sustained for several hours continuously with no ill effects (other than the worst bed hair imaginable). It's fine 

Believe only the man who has nothing to gain from what he says.
2017 BMW M4 Competition Pack - Mineral Grey - 530ps by bootmod3, JCWeldfab exhaust.
Previously:
Renault Megane R26 - Liquid Yellow - 275ps.
2015 Audi Exclusive RS4 B8 - Merlin Purple - JCWF Exhaust
2009 Audi RS6 C6 - Phantom Black - 730ps MRC Tuned
2008 Audi RS4 B7 - Phantom Black - 449ps MRC Tuned
2002 Peugeot 106 Gti - Mauritius blue - 430ps Home built.
2017 BMW M4 Competition Pack - Mineral Grey - 530ps by bootmod3, JCWeldfab exhaust.
Previously:
Renault Megane R26 - Liquid Yellow - 275ps.
2015 Audi Exclusive RS4 B8 - Merlin Purple - JCWF Exhaust
2009 Audi RS6 C6 - Phantom Black - 730ps MRC Tuned
2008 Audi RS4 B7 - Phantom Black - 449ps MRC Tuned
2002 Peugeot 106 Gti - Mauritius blue - 430ps Home built.
Re: Carbon intake Vs standard airbox power.
Note "funnel" to stop the gagging reflex kicking in to prevent this from happening, but hay this is all hypothetical anyways and I never mentioned explode, but if I took a guess you would suffocate.
Avus Audi RS4 2076|Black optic |Carbon Airbag surround|LED'S inside|RNS-E style Android Stereo with DAB+ dongle|
Re: Carbon intake Vs standard airbox power.
Its not hypothetical - it's well established facts.
The problem is that you are equating "force" with "pressure" and they are fundamentally different things.
So for example putting your arm in a fast moving stream of air (say 100mph) has the effect of you experiencing a lot of force on your arm from the air hitting it. However what isn't happening is the air compressing by a huge degree.
Similarly if you put a paper bag and hold it open it doesn't break from the air pressure in the bag but from the force of the air molecules slamming into it at high speed.
It's pretty easy to work out as the formula for dynamic pressure is (d x v^2)/2.
d = air density kg/m^3 (usually about 1.2)
v = 44.7 m/s (100mph).
So the dynamic air pressure (in pascals) is 1199 or about 0.17 psi.
Given that the air is already forcing air into the cylinders at 14.7 psi you are looking at a difference of about 1%
Now importantly, this is not taking into account the fact that the engine is reducing this air by allowing some to enter into the combustion chambers. This is why "ram air" on large displacement engines doesn't have as much impact as say motorcycles as the bikes are not using as much.
If we calculate how much air the rs4 V8 needs at 8000 rpm (assuming 10cm air intake diameter) then the .17 psi drops to 0.008 psi.
Plug the numbers in for a kawasaki ninja and it's about 0.1psi... Take an old 2.4 v8 f1 car at 19000 then at 200 it's 0.5psi from air alone (not including the effect of the large air box)
The problem is that you are equating "force" with "pressure" and they are fundamentally different things.
So for example putting your arm in a fast moving stream of air (say 100mph) has the effect of you experiencing a lot of force on your arm from the air hitting it. However what isn't happening is the air compressing by a huge degree.
Similarly if you put a paper bag and hold it open it doesn't break from the air pressure in the bag but from the force of the air molecules slamming into it at high speed.
It's pretty easy to work out as the formula for dynamic pressure is (d x v^2)/2.
d = air density kg/m^3 (usually about 1.2)
v = 44.7 m/s (100mph).
So the dynamic air pressure (in pascals) is 1199 or about 0.17 psi.
Given that the air is already forcing air into the cylinders at 14.7 psi you are looking at a difference of about 1%
Now importantly, this is not taking into account the fact that the engine is reducing this air by allowing some to enter into the combustion chambers. This is why "ram air" on large displacement engines doesn't have as much impact as say motorcycles as the bikes are not using as much.
If we calculate how much air the rs4 V8 needs at 8000 rpm (assuming 10cm air intake diameter) then the .17 psi drops to 0.008 psi.
Plug the numbers in for a kawasaki ninja and it's about 0.1psi... Take an old 2.4 v8 f1 car at 19000 then at 200 it's 0.5psi from air alone (not including the effect of the large air box)
Re: Carbon intake Vs standard airbox power.
I found some old on line articles on Ram-air feed and I struggle to see why a CAI like mine is not a ram-air
http://www.autospeed.com/cms/article.html?&A=110824
http://www.autospeed.com/cms/article.html?&A=110824
Avus Audi RS4 2076|Black optic |Carbon Airbag surround|LED'S inside|RNS-E style Android Stereo with DAB+ dongle|
- PetrolDave
- Cruising
- Posts: 7599
- Joined: Mon Nov 07, 2005 11:28 am
- Location: Southampton, Hampshire UK
Re: Carbon intake Vs standard airbox power.
This is another one of those subjects that comes up each year or so on here, and even when the maths proves that there ain't no more than a miniscule ram air effect (atmospheric pressure changes more from day to day...) the "debate" always drags onadsgreen wrote:<sigh>
This one never goes away.

Gone: 2006 B7 RS4 Avant (Phantom Black)
Re: Carbon intake Vs standard airbox power.
Yes it may get a 'ram air' effect but even if it was perfect you gain not very much if anything at all.docurley wrote:I found some old on line articles on Ram-air feed and I struggle to see why a CAI like mine is not a ram-air
http://www.autospeed.com/cms/article.html?&A=110824
Re: Carbon intake Vs standard airbox power.
RS4 B7
MRC stage2 436ps-487nm
Revolution intake, custom CAF, carbon clean, deflaped manifold, JHM manifold spacers, Forge oil cooler, Forge spacers, full de-cat, Scorpion cat back, Trup's LED's, 20' S5 wheels, KW V3's.
Launch control & flat shift
MRC stage2 436ps-487nm
Revolution intake, custom CAF, carbon clean, deflaped manifold, JHM manifold spacers, Forge oil cooler, Forge spacers, full de-cat, Scorpion cat back, Trup's LED's, 20' S5 wheels, KW V3's.
Launch control & flat shift

Re: Carbon intake Vs standard airbox power.
I 've been reading this thread and it has been floating around 1 or 2 pages long for a while now and I check back a few hours later and it's on 4 pages, so I think 'wow, whta's happened here?', then I read the word 'RAM' and knew exactly why it had got to 4 pages!
I have cut away the mesh from my foglight grilles so the bare end of the tube looks a bit nasty and wanted to smarten it up a bit but I'm struggling to find anything nice enough. I ideally want a rectangular funnel, bit like a bit of guttering but prettier.
Where did you get the trumpet from? Is it a subwoofer port?docurley wrote:
I have cut away the mesh from my foglight grilles so the bare end of the tube looks a bit nasty and wanted to smarten it up a bit but I'm struggling to find anything nice enough. I ideally want a rectangular funnel, bit like a bit of guttering but prettier.
-
- 2nd Gear
- Posts: 154
- Joined: Sun Oct 03, 2010 12:06 pm
Re: Carbon intake Vs standard airbox power.
Well you nearly sucked that Peugeot into your air intake the other day after the mini meet....MikeFish wrote:I 've been reading this thread and it has been floating around 1 or 2 pages long for a while now and I check back a few hours later and it's on 4 pages, so I think 'wow, whta's happened here?', then I read the word 'RAM' and knew exactly why it had got to 4 pages!
Where did you get the trumpet from? Is it a subwoofer port?docurley wrote:
I have cut away the mesh from my foglight grilles so the bare end of the tube looks a bit nasty and wanted to smarten it up a bit but I'm struggling to find anything nice enough. I ideally want a rectangular funnel, bit like a bit of guttering but prettier.


Re: Carbon intake Vs standard airbox power.
He did it again at the roundabout!
-
- 2nd Gear
- Posts: 154
- Joined: Sun Oct 03, 2010 12:06 pm
Re: Carbon intake Vs standard airbox power.
I backed up that much i never even made the lights... An let me guess you hit the loud pedal and he got sucked in.. 

Re: Carbon intake Vs standard airbox power.
No I let him in again so he didn't take my wing off.
Who is online
Users browsing this forum: Google Adsense [Bot] and 95 guests