so,
i can't help but continue to wonder about this.
the stock SVT air intake
draws from the front (upper) grill,
not from the engine bay in general.
however,
the piping and whatnot
is all squished and takes lots of tight turns
to get around the battery.
i went down the AEM CAI route some years ago,
and three throttle pressure sensors and a throttle body later,
i took it back off and went back to stock.
it seems to me,
that going to a ram air is pointless,
as you'd be traded restricted cold air
for unrestricted hot air,
and that seems like its got to be either a wash, or a loss
(i could see going with a ram on a base model but not an SVT).
has anyone designed a CAI for mass production
that uses the stock location for drawing in the air
(up away from rain and road spray)
rather than going down in front of the driver side front tire?
this seems like such an obvious thing to do.
i'd look into designing my own,
but i am guessing that a PVC-based set of pipes
would end up being way too heavy,
and i have no way of properly bending an aluminium pipe.
by keeping my over-all speed down,
and maximizing use of cruise control,
i'm really improving my mpg on my (now very long) daily commute.
i'm thinking
that freeing up even more (cold) air flow
would help even more,
but i'm not willing to risk reliability
by going back to the more traditional CAI
located 6 inches from the ground.
any thoughts?
____________________ it is smarter to be lucky
than
it is lucky to be smart.
Get a short ram intake, a heat shield, and cut a hole in the hood above the air filter, and put a scoop on the top of it (to stop debris and so forth from getting in).
I would guess even cold air restricted would have more benifits then hot air. The cooler the air the better your gains, I don't think the stock system is that restricted to lose hp.
Cutting a hole in the hood is not a bad idea but you have to come up with plan to keep water out of the scoop.
the problem is,
the SVT stock
draws from right in the front grill.
so,
it's not drawing hot air.
going to a short ram
would actually be hotter air,
although probably less restricted.
not sure that's worth the trade.
i'd love to sit down
and design a way
to re-locate the battery where the stock air box is
and then route a less restricted pipe
to the stock SVT location
but using a cone filter.
i wonder what it would run me
to get someone to bend and cut all the pipes...
____________________ it is smarter to be lucky
than
it is lucky to be smart.
Well there are several considerations in your intake system. I thought I understood the principles pretty well myself until I got a rude awakening from stepping into the forced induction world.
I had a short ram intake on my Focus and I can tell you that there were issues with heat soaking, but I felt that is primarily from the tube being metal. So I later switched to an ABS (plastic) tube and that helped.
I personally refused to use a CAI because I certainly didnt want to be ingesting water and as a storm chaser this was a real possiblity.
I think what most fail to realize is that while the engine bay does get hot, more so in stop-n-go traffic and city driving, you have quite a bit of air flow under the hood. Air comes in through the grille area, comes in from underneath the car and of course through the opening between the hood. Unless the back side of the hood is completely sealed off you also have the effect of wind blowing over the hood sucking air out through that side. A principle I have only ever seen taken advantage of in the Grand Prix. They have an aftermarket hood for it that has ram air openings up front for the ram effect (however effective it may be) and then there are openings on the back side for the sole purpose of sucking out air from the engine bay.
I would think, particularly with a high revving 4cyl engine, that the Focus would particularly benefit from this. I'll see if I can get a picture up of the hood so you see what I mean.
Next, we have the efficiency of the intake system. Bends are the absolute enemy of intake efficiency. That is to say the amount of air being taken in that actually makes it to the intake system (i.e., throttle body, intake manifold, etc). The focus suffers from two horrible, unavoidable, points that affect air flow.
First, the throttle body location mandates a 90* bend, which can reduce air flow up to about 10% or more depeding on the conditions. Second the horrible bend in the intake runners. The air comes down the TB into the intake manifold and does a 180 to get back up into the combustion chamber.
CAI's for the Focus add even more bends to it and I really wonder if the benefit of the colde air there out weighs the reduction in air flow with the bends used to get to the cold air.
So in designing an intake, you already got two radical bends to deal with so I would personally design one as straight as possible, which all but rules out any type of currently available CAI for the Focus. Next, you want it to be as heat resistant as possible which almost mandates the use of ABS or Plastic or even PVC. I would even go further and use some type of wrap after that. I wouldnt be concerned with any type of turbulence because there is already going to be plenty added by the intake manifold and no matter what you do, as long as you have that manifold, its going to be pretty much in vain.
Next, the air filter are is going to be a source of low pressure (read: vacuum) so as long as you have it near a source of colder air, such as outside the engine bay air, you are going to pretty much be pulling in predominatly colder air. The other thing that could be done and would be much safer it to just 'route' some outside air up to the filter. You wouldnt have to deal with water ingestion and it would avoid the bends in the intake itself.
My only concern with an intake, and thus the filter, place near the front of the engine bay would be the possibility of the filter becoming rain soaked in a storm but I would think a simple shield of some type would take care of that.
Just some things to consider in the intake design. If you have any capability to do some type of flow testing (which its not all that difficult to do) I would highly recommend that being done as well so that you get the best air flow.
Here is a picture of the 4-Vent hood I mentioned:
You can seehow the front vents serve as the ram for the incoming air and it is ported over to the intake that is on the front drivers side of the engine bay. The vents on the back side serve as an outlet. The air going over hood creates a low pressur point at the vent and it sucks out the hot engine bay air. Quite the innovative use of that principle I think and if it could somehow be taken advantage of in the Focus it would solve some of the intake issues.
____________________ My car is a synner! It uses Amsoil Synthetic Lubricants.
2001 Pontiac Grand Prix GTP
It whines a lot, but I like it
i had the AEM CAI for about a year when i first got the car.
it made a huge difference,
not necessarily in horse power,
but in the responsiveness of the car.
it was just kind of all around "perkier".
but, i didn't put in a bypass valve (stupid)
and 3 throttle pressure sensors and a throttle body later,
i took the system off again
(probably also stupid,
should have just gotten the bypass valve).
when i got the stock system back in,
that was when i really looked closely at it
and realized it was already attempting to draw "external" air,
unlike most stock air systems.
but it's that stupid, rectangular, corrogated plastic tubing
and there's just no way that (or the stock filter) are good for air flow
(especially with the insane way they have it routing around the battery)
and i doubt it's doing much to insulate that air from engine heat.
there are some bends in the system you can't avoid.
there are going to be bends on any car, i suspect,
that you can't avoid.
i'm just looking to create an improvement over what's there
not necessarily create the world's most ideal system.
my only concern with pvc is the weight of it,
which might require fabricating new supports,
which would be well beyond my skills
(then again, so will be re-locating the battery).
for all i know,
i'll be moving to cambridge or NYC in less than a year
and i'll end up selling the car anyway...
____________________ it is smarter to be lucky
than
it is lucky to be smart.
Well the AEM Short Ram intake avoids all the bends that you have control over, so there is something that can be done but it is, unfortunately, at the cost IAT.
My intake on the GTP is 4" dia. and made of PVC and I dont have any weight issues, though I would love to bolt it up just for the comfort factor. But on the Focus you may need some support due to the length of the tube. But fabricating some support brackets would be easy enough.
I also eliminated the bends with the exception of one that amounts to about 20* bend and that is simply because I used 4" tubing and had to make a bend slightly to clear some components.
Its pointless for me even to attempt to try and eliminate turbulence since I have the blower and no matter how straight I make the air, the blower is just going to mess it all up anyway.
I still think the Short Ram intake, coupled with some type of heat shield and some type of tubing porting outside air up to the filter is about as good as it is going to get. Though, you could leave the stock air box in and connect up some tubing to it that pulled in outside air, I have heard of people doing that. I dont think trying to reduce turbulence in the focus is worthwhile either due to the 90* bend into the TB and the U turn the air makes in the intake manifold. If I were to make anything for the Focus it would be something that would eliminate that manifold so that the air was more direct to the engine.
I even once though of trying to use the shape and design of some V8 exhaust manifolds turned upside down. The exhaust ports would be the ports into the motor and the collocter would serve as the base for the TB. I wouldnt necessarily do it out of metal, but it would be easier to do with that.
Anyway, just some more thoughts.
____________________ My car is a synner! It uses Amsoil Synthetic Lubricants.
2001 Pontiac Grand Prix GTP
It whines a lot, but I like it
I still think the Short Ram intake, coupled with some type of heat shield and some type of tubing porting outside air up to the filter is about as good as it is going to get.
i guess i don't get why it would make more sense to do that
rather than to simply run the tubing
directly from the TB to the front grill
with the filter down at that end,
and skip the need to construct the heat shielding.
it would seem to be the same result
with a lot fewer steps.
____________________ it is smarter to be lucky
than
it is lucky to be smart.
