lol evan sif u need to do that, anyone with half a brain could figure it out if they know 14.7psi is 100 kpa, 1 bar, 1000mbar!
then again we have a few nissan ppl here, so we better make it nice and simple for them
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lol evan sif u need to do that, anyone with half a brain could figure it out if they know 14.7psi is 100 kpa, 1 bar, 1000mbar!
then again we have a few nissan ppl here, so we better make it nice and simple for them
Yeah you know how it is, Honours Maths grads cant do simple maths!
wow I like this pissing contest more than my one =D (jk)
Last time I checked I believe most air ram designes (attached to normal cars, not ones with specially made intakes) didn't manage to show any ram effect until about 150kph (or so, this could be very wrong)
BUT
not only is this possible, it looks like it's going to be part of the future of powered flight. lol, maybe it's hubris to try and use it for ground bound designs .. =)
http://en.wikipedia.org/wiki/Ramjet
http://en.wikipedia.org/wiki/Scramjet
yeah, i dont think anyone is doubting that ram-air has an effect...Quote:
Originally Posted by 2ds
the unresolved question is regarding whether the ram-air can create manifold pressure higher than 14.7psi...
(i stopped looking for info on this at about midday and decided to do some work...)
It definately can, the question is, can the car reach the speed required to do it.
-2ds
im not sure if u guys missed my last post, but clearly if u account the speeds that the car has to be going for such a large effect of this so called "ram air" the revolutions would be way too high to allow the cylinder to fill with enough air to get past 100% VE.
I just dont see if being physically possible
lol, i say we convert your car into a ramjet and do some testing =)
-2ds
this is my thoughts of Pornstars questions
I have no proof to back this so Grill me if you want.
I know the MAP sensor mesures Manifold pressure so Im not talking about what happens in the chamber. , say your driving at 110KM/h at WOT ( wide Open Throttle ) you manifold presuure will become atmospheric, your valves are opening and closing thus causing a restriction of for the air to freely flow past. now add ram air intake and the curved intake runners of your manifold. we know air can be compressed so with the restrictions from the valves causing a flow restrictionr ram air can build up in the intake manifold. also the inertia of the air passing the curved intake runners helps draw more air in.
do an experiment. drive down the street and hold a paper cup out the window with the opening of the cup facing the front. you will feal the air building up in the cup. of you cut a hole in the cup the air will escape from the back but as long as the hole in front of the cup where the air first enters is larger than the hole in the back of the cup where it escapes there will be a build up of air waiting to escape. this would be air compressing ram style would it not, and compressed air reprisents a positive pressure.
maybee this is a question for DR Karl :)
Ill be listening on Thursday :)
Ecu-man the logic/thought process that u have described i agree with. The only problem is this, at say one rpm, that is one engine revolution per minute, which is 360degrees of the crank shaft turning. think about that for one second and keep that in mind.
now lets say for arguments sake that we would have to be going at 110kmph like ur suggestion at WOT. what gear would u be in to be at 110kpmh at WOT? 3rd gear or so id imagine? lets say 3rd gear in a honda and not gear 17 in a nissan. at 3rd gear in our average 4 cylinder, what rpms is that? for arguments sake, lets say 6k rpms.
at 6krpms, thats 6000 revolutions of 360 degrees of crankshaft rotation ( could be wrong im not sure how u want to express rpm, cos strictly the rpm = 720degrees of crankshaft rotation) per minute. lets divide 1 minute by 6000 to get the time it takes to get to 1 rpm.
1minute = 60 seconds therefore divide 6000 by 60 seconds to get rpms per second. i got no calculator so correct me if im wrong but by my honda brain and not my dumb nissan side that would take me to 100rpms per second. Expressed as the time for one rpm, that would be 1/100th of a second for the engine to do one rpm at 6k rpms at wot at 110mph. Now hold that thought for one second, the intake stroke of the engine is only for 1/2 of the rpms if im corect in defintion that one rpm = 360 degrees rotation. or if by defination im wrong and that one rpm is actually 720degrees od crankshaft rotation, then u divide the rpms by 4. im pretty sure that one rpm = 720degress od crank shaft, but to give ur argument a better chance ;), ;lets say its 360 degrees, so divide that 1/100th of a second for that one rpm to get the intake stroke of the engine. that is 0.005 of a second time that the engine will take in air to fill in teh chamber.... as u can see, i jsut dont see it happening....
Another argument that I have not raised is this. If speed did help with creating positive pressure with ram air or not, because it creates as u think a positive pressure built up against the intake valves, then any car after 110kmph would see positive pressure or 100+kpa right? Cos by the same reasoning, the speed of the car is the force or the main contribution to compacting the air.
It leads me to believe that unless that air is already precompacted, I dont think it would work. Ram air or mini electric fan supercharged air. For me, the intake valves on the intake when lifted create a vibrational resonance that can be used to help better atomise the fuel mix in the chamber for a better and thus stronger burn, but the drawback is that it serves as a restriction. By following my thought process I think its not possible.
Again this is a technical discussion and I am only putting my argument up. Im open to be corrected or proven wrong. I enjoy reading input from others as it really keeps the honda aftermarket weed out the bull$hit that happens in other aftermarkets, ie 13s stock silvias, claims of stock Ball bearing turbos that they saw when they "opened theirs up" when they never did and u know the usual dumbshit stuff u see from internet mechanics.
To be honest, I think the ram air thing would serve to be a restriction to the air flow at high rpm. Thats why when dyno tested, most of those electric supercharger fans that claim to make boost lsoe power. IMO it robs the air of a free passage.
maybe we could sell it to a nissan owner? ;)
lol. read the two links i posted earlier, ram air serves as a restriction when the vehicle reaches mach 5.
-2ds
read what i wrote. teh restriction at high rpms is the head
some good reading here:
http://www.yawpower.com/techindx.html