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Well the filter finally made it in from a AFE took a few weeks for these guys obviously is not on the Shelf it's the exact same dimensions as the filter for the Rogue MAF
I will be reinstalling the fender liner, so in effect it's the same air intake point as the OE snorkel.
Trouble is, the factory location for the intake snorkle is not very good: Best intake position would be at the aerodynamic stagnation point at the front of the car, basically where the license plate is. Air stacks up there, then whips up over the hood or around the fenders, accelerating and losing pressure (per Bernoulli) in the process, so by the time it gets to the wheel well, pressure has dropped. Plus lots of turbulence, although the fender liner would attenuate this problem.
Autospeed (the Australian online car fixit/mod magazine) did a study ( http://www.autospeed.com/cms/article.html?&A=113157) on this and found that properly applied ram air can slightly overcome and therefore offset the internal line drag from the plumbing, filter, etc., so it's a worthwhile effort if done correctly. OTOH, putting the intake snorkle at a low pressure point could worsen the problem by reducing ambient pressure at the point of intake.
Make a simple manometer using clear plastic tubing, and water with food coloring inside, to test ambient pressure at various points around the car, and you'd soon see the front license plate location (or just below it) is about the best. Put some gauze or a bit of sponge at the intake end of the tube to dampen pressure fluctuations, and mark the tube with a felt tip pen to note standing and moving pressure levels of the water.
Or, use scotch tape and put pits of ~3" yarn or dental floss like freckles on the face of the car, and have an assistant with a camera take pics of the nose at highway speed, to see the stagnation point.
Trouble is, the factory location for the intake snorkle is not very good: Best intake position would be at the aerodynamic stagnation point at the front of the car, basically where the license plate is. Air stacks up there, then whips up over the hood or around the fenders, accelerating and losing pressure (per Bernoulli) in the process, so by the time it gets to the wheel well, pressure has dropped. Plus lots of turbulence, although the fender liner would attenuate this problem.
Autospeed (the Australian online car fixit/mod magazine) did a study ( http://www.autospeed.com/cms/article.html?&A=113157) on this and found that properly applied ram air can slightly overcome and therefore offset the internal line drag from the plumbing, filter, etc., so it's a worthwhile effort if done correctly. OTOH, putting the intake snorkle at a low pressure point could worsen the problem by reducing ambient pressure at the point of intake.
Make a simple manometer using clear plastic tubing, and water with food coloring inside, to test ambient pressure at various points around the car, and you'd soon see the front license plate location (or just below it) is about the best. Put some gauze or a bit of sponge at the intake end of the tube to dampen pressure fluctuations, and mark the tube with a felt tip pen to note standing and moving pressure levels of the water.
Or, use scotch tape and put pits of ~3" yarn or dental floss like freckles on the face of the car, and have an assistant with a camera take pics of the nose at highway speed, to see the stagnation point.
This is good info.
I will soon be empirically testing intake setups (including the factory airbox) using a Bosch TMAP (MAP sensor with temp sensor built in) sensor mounted in the J-boot/turbo inlet to monitor intake temp and pressure. I think I have a couple of free analog sensor input channels available on my VEMS engine management system, so I will be able to datalog the turbo inlet temp and pressure along with MAP, MAT, RPM, etc to see the how these variables affect turbo spool and engine output, and I will post the results in a new thread.
seems to me about as conveniently located and aerodynamically "good" a place you could do an air intake would be where the 951 turn signals are.
on the "peak" of the nose and high enough above ground to maybe not suck up debris off the road.
seems to me about as conveniently located and aerodynamically "good" a place you could do an air intake would be where the 951 turn signals are.
on the "peak" of the nose and high enough above ground to maybe not suck up debris off the road.
This can be determined by placing said TMAP sensor in various locations and datalogging the results in similar barometric/ambient conditions (but of course higher is better for minimizing debris, etc).
I hope to make some headway on this during the weekend, but if not it will be soon . . . .
I experimented putting the air filter in the fender a few years ago. I made similar piping but cut the rear of the side marker to install the air filter vertically.
I didnt see a huge difference aside from noise, and considering its always flooding around here, I scrapped it and used Lindseys MAF air dam and vented headlight and called it a day. A larger intercooler would be far better than a "cold air intake" for lowering intake air temps, considering that compressing air heats it to over 300 degrees after leaving the turbo would make the ambient temp a moot point.
I experimented putting the air filter in the fender a few years ago. I made similar piping but cut the rear of the side marker to install the air filter vertically.
I didnt see a huge difference aside from noise, and considering its always flooding around here, I scrapped it and used Lindseys MAF air dam and vented headlight and called it a day. A larger intercooler would be far better than a "cold air intake" for lowering intake air temps, considering that compressing air heats it to over 300 degrees after leaving the turbo would make the ambient temp a moot point.
Or, keep using the stock intercooler, but provide proper exit ducting so the ambient air (which has excellent factory intake geometry at the nose) can rejoin the slipstream aft of the intercooler efficiently, thereby cooling it much more effectively. Somehow, despite excellent inlet geometry, the factory basically forgot to provide a good outlet pathway, so the cooling air just jams into the already hot engine bay. Or, given jamming of the flow, there is too little through-flow and the stock setup is far less efficient than it otherwise could be. NACA studied and tested all this during WW2 for aircraft purposes, and found that the exit geometry is equally important to the inlet geometry: Without a good exit path, cooling air pretty much won't go in or through the heat exchanger, defeating its purpose.
I've been slammed at work and haven't had time to finish this. Didn't quite fit in the top of the fender well, needed about another inch for the fender liner to fit back in. So...new plan is to relocate lower under the foglight. Should have so tie this afternoon, I'll get some pics.
02-10-2018, 09:11 PM
using clear plastic tubing, and water with food coloring inside, to test ambient pressure at various points around the car, and you'd soon see the front license plate location (or just below it) is about the best. Put some gauze or a bit of sponge at the intake end of the tube to dampen pressure fluctuations, and mark the tube with a felt tip pen to note standing and moving pressure levels of the water.
