I've been working on an alternative CAI for the xfire for a while and I think I've found the most promising solution (so far)... It took a while to get my first sample, but the Apollo CIS Systems available from K&N look great. They are a sealed enclosure around a K&N cone filter that is designed to clamp intake hosing to.

I chose these because I'm trying to maintain everything in a close-to-stock location while maintaining the symmetry that makes our engines look good. The first CIS arrived in my hands today, and I'd have to say that I'm more than pleased with it... Although our cars should only need one of these, for symmetry I order 2. The second CIS should arrive in about 2 more weeks, so it'll probably be 4 weeks or more before I have the whole system worked out. But anyways here are the pics and dimensions.

Looking inside:


Whole Kit:


Side View with nose cose snapped on:



Dims:

 

https://www.crossfireforum.org/forum...ad.php?t=15298

Here is my version I can't quiet see what your going for, I hope your not going through the air box with two covered filters and thinking its going to be a CAI.

 

Of course not, there would be no purpose to use the old airbox if I'm using the K&N inline filters. Basically the system would be sealed from the intake holes in front of the radiator all the way to the intake manifold, but with inline K&N air filters.

Here is an "artists" rendition:


Oh, and yeah, HDDP, thanks for the engine shot.

 

Looks like a good idea...

 

If HDDP says something good about it then it's got to be a great idea!

Just kidding, HDDP.

 

For $125 a pop for the filters there better be some proven dyno results. I was thinking of doing the same thing with using he existing snorkels driving right up into the filters I have (cause they fit perfectly). I just haven't gotten around to it.

I would like to get a hold of the splitter HDDP has (though I know it's probably custom).

 

you guys have way too much time on your hands.

 

Once I get everything measured out, I'm probably going to order the splitter from Spectre. They come in all sae sizes, so it'll require an adaptor. But for $12, you can't beat them.

 

Save money and just run one. The mass can be relocated to keep the bend from being to tight.
Looks like a fun project.

 

The air intake at the front behind the grill is still the most restricted area - you should look at enlarging or removing them if you're spending all that cash.

 

Looks good keep us posted.

 

I still like my way better, Keep the air box + put on 2 K&M filters in it + Keep it connected to the bumper for cooler air + 1.7 PSI of air pressure With the super e-RAMs when you floor the gas pedal + paint the pipes red...
ps. sorry about the SRT stickers they're gone now!!!

 

Looks expensive and complex. I hope everything works out I am just happy other people are also taking the time to figure something out.

 

One question: Are you concerned about losing the airbox? Here's a snippet of an article that describes how air boxes work. This particular piece is from a paper on motorcycles but the underlying theory is the same for automotive applications as well:

The combination of a box and tube is a system with a resonance. Exactly as a child's swing has a resonant frequency, exactly as a ported speaker enclosure has a resonant frequency, so does your air box. A system at resonance is nearly perfect - there are small frictional losses in any system, but at resonance these are the only losses. Imagine pushing a child on a swing - it takes very little energy to keep her going at the natural frequency of the swing, just a little push each swing is enough. The only thing slowing her down is air resistance and a little friction in the chains. So at resonance, air flows through a tuned air box almost without resistance. This is as close as we can get to a superconductor of air.
A modern engine with valve overlap will naturally have a dip in the torque at about a third to a half the red line rpm. If the air box is tuned to have minimum resistance to air flow at this rpm, the dip in the torque curve will be partially filled in by the ease of pulling air into the engine.
So, your air box is most likely designed to add horsepower in the mid-range. The air box will have little or no effect on peak hp.
Years ago, before air boxes were designed as resonant systems, it used to be popular to cut additional holes in the air box to allow more air flow for high rpm. This is no longer a good idea. Modern air boxes can flow much more air than the engine will ever use. Modern engines have throttle bodies or carburetors with throats that are typically about 45mm in diameter, about 16 sq.cm in area. The inlet snorkel to a modern air box will be roughly 300 to 800 sq.cm - much larger than the throttle body or carburetor throat. The idea that the snorkel makes for a significant impediment to air flow into the engine is questionable at best. Drilling holes to let in more air is exactly equivalent to drilling holes in your speaker cabinets to let out more sound. Removing the snorkel from your air box is the exact same thing as removing the port in your speakers, the tube that's carefully engineered to have just the right diameter and length to reinforce the bass on your speakers at low frequencies. By altering your air box in any significant fashion, you're most likely going to cost yourself three to five hp in the mid range, and gain nothing measurable at high rpms.

The full article along with the accompanying math is here:

http://www.calsci.com/motorcycleinfo/Airboxes.html

 

Hmm, interesting article - maybe I'd better reassemble the engine bay!!!
I've read the full article, and double checking all the equations in 'Theory I', I concur.

 

You've raised some very valid points about the resonance of intakes. I've just started to research this, however what I've found so far is that most of the tuning done before the intake manifold is "tuned" to acoustically reduce engine and intake noise from being heard outside the car.

However a lot of effort is placed on NA engines to acoustically charge the air while inside the intake runners to aid in the filling of cylinders as soon as the valve opens. Another good site about this is here: http://www.team-integra.net/sections...?ArticleID=466

I may be completely out of line, but since the throttle body and MAF should be the most restrictive points prior to the intake manifold, I would think that any work that improves airflow to the throttle body wouldn't greatly disrupt the resonating frequency in the intake runners.

Basically to bring this back to the speaker metaphor: Improving airflow to the throttle body would by metaphorically equivalent to moving the ported speaker from your example into a larger room. Sure in a larger room, it may not seem quite as loud, but that definitely doesn't mean the speaker's efficiency is reduced...

As this is all new to me (as is the crossfire's engine), I'm going to have to bring this topic to some local engine tuners around here. I have an OBDII reader that can tell me the absolute intake manifold pressure, so I'll be able to accurately gauge whether or not this intake design "flows better", but if you're right about the intake resonance... ..."flowing better" might not mean "improved performance"...

...more to come...

 

Maybe I'll have to one up you and add the e-rams to my intake design.

 

I talked to a friend of mine who builds high performance engines and posed the "acoustically tuned" airbox question to him. Well, he looked at me like I was crazy and said, "I doubt that you will have any issues there as the new '08 vettes are just getting acoustically tuned manifolds and the crossfire's engine is a much older design."

So I decided to finally use my B.S. degree and examine the equations the motorcycle guy had up on his page...

According to him (or her?), for our engines (V6):
Resonant RPM = 28650 sqrt (116.5 A / VL)

But in our case, since we have dual snorkels that are 70mm and round, cross sectional areas are doubled.

V = (Left intake area + Right intake area) L

V = 2 * A * L

Simplifying we get:
Resonant RPM = 28650 sqrt (116.5 A / (2AL) L)

Resonant RPM = 28650 sqrt (116.5 / 2LL)

Resonant RPM = 28650 sqrt (58.25 / LL)

Resonant RPM = 28650 sqrt (58.25) / L

Resonant RPM = 218661 / Length

Or in our case:

Intake Length = 218661 / RPM

if we solve for an RPM less than or equal to our red line... We can see for our airbox to be "acoustically tuned" to our engines (6,000 RPM or less), the intake plenum length would have to be over 36 meters (or 118 feet) long!

 

 

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