Stepping out for fresh air??

[TechHeavy]

Should the K&N air filter "step out" of the engine compartment, (or be "blown" in some way such as ram-air) for better performance?

That question sums up the topic of this thread... I wanted to be clear about the topic since I have so many thoughts on this, and many more questions... but I'll try to put them all together in some cohesive manner. While I started to post this thread in the Trilogy forum, (since I have Trilogy kit #58 installed) but I didn't want any MM.net member to feel excluded from the discussion since I really need the collective wisdom of the entire membership. My knowledge of air exchange is limited, and I'm guessing that at some point someone will read my ramblings and think me an idiot, but I learned long ago that you won't learn unless you ask.... so here goes.

We all know that the cooler temperatures help our cars run faster, (as much as 3 or 4 or more tenths at the track) but my recent experience at the speedway caused me to wonder.. What is it about the colder air that makes cars run faster? What if we could make the air going into the engine 50 or 60 degrees all the time... even in the summer? Artificially cool the air, somehow, as it goes in.
I gave up on this idea as being HP, weight, and cost prohibitive.
Next I considered the air filter itself being housed inside that oven called an engine compartment. I wondered just how hot it got in there, and what a difference the temp would be compared to the outside temp. So I tested it.
Today it was 47 degrees outside. I placed a digital thermometer sensor directly on the K&N air filter, closed the hood, and watched the temperature rise. At 131 degrees I pulled the sensor off as I was afraid it might melt, (although it was still climbing). Thats a difference of 84 degees! Would not the car perform better with the cooler air outside the engine compartment?

Question 1) If the air filter were outside the car, (it doesn't matter how you envision it for this question as this is hypothetical... on a smoke stack if you like) does that equate to an 84 degree drop in temperature for engine/track performance? Is there a formula for this?

Now I know guys pull their headlights. I know some ricers put elbows on their K&N filters and route them to stick out of the fender well. Still not good enough. What is the ultimate best performance for the air filter, (fair weather driving of course)? Out in the open with no heat from the engine, and plenty of cool fresh air to suck up?
It seems to me, (although laughable at first) that the ricer logic may be true. What I can't calculate though, is how much a performance gain I could experience with a mod of this type. I just haven't been doing this long enough. Does anyone have an idea?

My next thought was to have a custom hood scoop made that will force fresh cool air directly down onto the K&N filter... sort of a quasi-ram-air effect. Though I don't know how effective this would be either.

In summary I'd like to know if this logic is sound, and what performance gains could be expected from either, a) extending the air filter outside the engine compartment, or b) building a functional hood scoop that forces cool air directly onto the filter.

Thanks for listening guys. Your comments will be appreciated.

[snowbird]

I'm not an expert but i would risk this: the colder the air, the more HP so in principle, those cold air setup should help. Now, if your goal is more mileage to the gallon, then it's the opposite, finding a way to use the engine radiant heat for preheating the intake air would then be the correct goal.

In your particular application, Eaton type superchargers are known to be more affected by intake restriction before the supercharging unit itself (because they suck more than they blow i believe, and YES i'm still talking superchargers !!), i.e. throttle body or filter. Also to consider, the mass air reaction to velocity, i.e. the proximity and angle of the filter and adjacent piping (and angle) to fresh air could also alter the reading of the MAF and disturb it some ways. I read somewhere that a MAF want straight through air, not a 90 degree angle just before.

In any case, the gains are usually pretty slim but still worth considering if you start from a very bad design. My opinion is based 30 years of extreme weather change in the latitude i'm living in. In the winter any car is more powerfull but drink at least 15% more and in the summer, the mileage is better but the engine is just plain lazy.

Finally, for all the reasons listed above, intake track enhancements are not IMO, a piece of cake but could be done adequatly by doing little research and digging.

[TechHeavy]

Originally Posted by snowbird

I'm not an expert but i would risk this: the colder the air, the more HP so in principle, those cold air setup should help. Now, if your goal is more mileage to the gallon, then it's the opposite, finding a way to use the engine radiant heat for preheating the intake air would then be the correct goal.

In your particular application, Eaton type superchargers are known to be more affected by intake restriction before the supercharging unit itself (because they suck more than they blow i believe, and YES i'm still talking superchargers !!), i.e. throttle body or filter. Also to consider, the mass air reaction to velocity, i.e. the proximity and angle of the filter and adjacent piping (and angle) to fresh air could also alter the reading of the MAF and disturb it some ways. I read somewhere that a MAF want straight through air, not a 90 degree angle just before.

In any case, the gains are usually pretty slim but still worth considering if you start from a very bad design. My opinion is based 30 years of extreme weather change in the latitude i'm living in. In the winter any car is more powerfull but drink at least 15% more and in the summer, the mileage is better but the engine is just plain lazy.

Finally, for all the reasons listed above, intake track enhancements are not IMO, a piece of cake but could be done adequatly by doing little research and digging.

Thanks snowbird for your response. I wasn't aware of the better/less mileage during summer/winter months.

I recently had explained to me by a "racing" friend of mine that cold air to the intake is not the entire equation to this question.
He explained that colder ambient temperature also effects the fuel. Although I was aware of how heat causes expansion and colder temps cause contraction I had not applied this principle to fuel. Apparently when cold temps interact with fuel it causes the molecules in fuel to contract and to better perform, (uhmmmm... ok)... and when the warm temps interact with fuel it causes the molecules in the fuel to expand and perform not as well as when contracted... Oh, ok. I'm not a chemical or automotive engineer... I'm just trying to understand....
Maybe all this expansion and contraction could explain the mileage increase in the summer over the winter as you described?

Anyway, it's become apparent to me that there is a whole lot more involved with the, "reasons for running faster in colder temperatures" than just the air intake at the engine.
I would still like to force cool, fresh air to the K&N air filter at some point in the future... just to test what performance benefits may arise.
But for now my curiousity has been sated. I guess there really are no more original ideas?

[Mike Poore]

Dave, you know, of course, the trilogy has an intercooler, which purpose is, I believe, to cool the air before it enters the engine.

The approach I like, and one I'm begging some to photochop is the Mach-1 shaker hood scoop on the MM. One of those gadgets would do two things: cool the air, and provide some ram effect.

The thing about static temps measured at the air box, is that you're measuring stagnant air, compared to the air that is rushing into the plenum at a fairly high velocity from outside. Does it have time to get hot?

[SergntMac]

Originally Posted by Mike Poore

The approach I like, and one I'm begging some to photochop is the Mach-1 shaker hood scoop on the MM. One of those gadgets would do two things: cool the air, and provide some ram effect.

Umm...Not entirely true, Mike, take a peek at this.

http://www.karkraft.com/46_engine_wshaker3.jpg

That's a Mach 1 shaker hood kit from Kar Kraft. As you can see, the scooped air is redirected into the OEM air box (not seen in this photo) for filtering, then on to the throttle body. IMHO, that air suffers the same engine bay heating as our OEM air path provides, and any "ram" effect is diluted by filtration. But, it looks neat when it wiggles.

[fastblackmerc]

Originally Posted by SergntMac

Umm...Not entirely true, Mike, take a peek at this.

http://www.karkraft.com/46_engine_wshaker3.jpg

That's a Mach 1 shaker hood kit from Kar Kraft. As you can see, the scooped air is redirected into the OEM air box (not seen in this photo) for filtering, then on to the throttle body. IMHO, that air suffers the same engine bay heating as our OEM air path provides, and any "ram" effect is diluted by filtration. But, it looks neat when it wiggles.

Gee that would fit on our engine.... just got to bend the tube to the left intead of the right...

[Mike Poore]

Originally Posted by SergntMac

Umm...Not entirely true, Mike, take a peek at this.

http://www.karkraft.com/46_engine_wshaker3.jpg

That's a Mach 1 shaker hood kit from Kar Kraft. As you can see, the scooped air is redirected into the OEM air box (not seen in this photo) for filtering, then on to the throttle body. IMHO, that air suffers the same engine bay heating as our OEM air path provides, and any "ram" effect is diluted by filtration. But, it looks neat when it wiggles.

Darn, Mac, I guess I knew it directed the air into the bottomless pit so it could heat it up, and kill the ram effect. Son John has one on his '94 Mach-1, and complained it didn't do much but look way cool. And, of course, everyone knows how we love stuff that wiggles.

Thing is, though, with our air box way up high, just like fastblackmerc pointed out, it might do something for the MM, ........if there's room for all that plumbing.

I wish one of our Photo Shop wizzards would put one of those on an MM.