Welsh 350Z N

Sorry if this has been discussed in detail already - I did search posts but couldn't find a satisfactory answer. Can someone please explain to me the difference between the AEM CAI and the Short Ram ? I see the obvious difference visually and in terms of cost but what is the difference in functionality and impact on performance ? Hope someone can help. Thanks.

Chebosto

iTrader: (43)

Short Ram is just the upper pipe tubing from the throttle body -> maf sensor and then putting the filter right after the MAF..

the full CAI is the weirdo-bend pipe that comes AFTER the maf that goes into the inner fender walling..

i'm impartial to short ram intakes.. the bendpiping no matter how neat it looks or where its place to suck air in, always affects the speed of the air flow into the engine at high rpms due to the curvature of the piping and the resonance of the air banging the sides of the curved piping...




--Cheston

Welsh 350Z N

Thanks Cheston but if, as you say, "the bendpiping always affects the speed of the air flow into the engine at high rpms due to the curvature of the piping and the resonance of the air banging the sides of the curved piping" how does that same rule not apply to the CAI which has even more tubing and even more bends ?

indulf

lots of people poo-poo the effects of bent pipe before an inlet of some sort, but it is definitely something to think about.

for anyone that knows anything about HVAC, code (and manufacturer's requirements) usually specify a piece of straight duct at least 1.5x the diameter of a Variable Air Volume box in order to smooth the flow sufficiently before the metering device.

trane uses a flow ring metering device not unlike our MAF sensors. if they are worried about it on medium pressure duct work before a VAV box, then Id worry about it in my intake system. if the air is "bunched up" on one side of the intake, the MAF sensor can produce false readings, usually ending up in wacko fuel/timing changes.

my .02

indulf

Welsh 350Z N

Thanks indulf but I gotta tell ya'...I'm not an engineer and all that means practically nothing to me. I'm trying to get a definitive answer for the difference between the CAI and the Short Ram and to me, they both look bent...the CAI just looks longer than the Ram. Are you saying that these concerns you describe are only applicable to the Short Ram or are they also applicable to the CAI ?

indulf

i would say that the same principle applies to the intake as applies to the HVAC stuff i was talking about.

i know you cant get around the bend before the intake, so dont worry about that. for air metering purposes, i would go for the one that has the longest straight pipe before the MAFS.

indulf

slickZ

Just think of it this way what you have on your car is a short ram...What you want is a cold air intake.The colder the air the more power!!It pulls air from under the car instead of next to the engine.Only downside of a cold air is the chance of sucking in water when you go through high water areas.Get a water bypass valve and you will be ok.Hope this helps

Welsh 350Z N

Thanks guys. I guess it comes down to air temp !

D'oh

The Z's stock intake is a CAI with some ram effects as well. It sucks the air straight from the front of the car, not anywhere near the engine. From what I've seen, there has not been a significant, consistant, benefit from any aftermarket intake when compared to the stock version. Some cars seem to show a couple HP, while some seem to show no gain at all. There might be some benefit if you can get a higher airflow filter, but there is pretty much no way you will get air that is colder than what the stock intake gives.

The intent of the short ram intake is to pressurize the intake tube and the goal of the CAI is to provide colder air. The RAM will only work at higher speeds and if there is good air pressure reaching the entrance to the intake. Because the Z's intake is blocked by the hood and front bumper, the ram air effect is marginal on the stock intake, but it is still there.

So, on the Z:
Because the aftermarket ram intakes on the Z are enclosed in the engine compartment, they will not provide much benefit over the stock intake because there is no direct line of airflow directly into the filter except what is coming thru the stock airbox. Because the CAI is not bringing air in that is colder than stock (at least significantly) there won't be much benefit there either. I would say both mods are tied for a very slight benefit over stock, and are mainly cool from a looks perspective and a personalization perspective.

If you really wanted a ram air to work on the Z, you would want to cut a hole in the leading edge of the bumper (where the greatest build up of air is) and funnel that directly into the opening of the stock airbox. I think some aftermarket bumper has a hole like that already, but from what I recall, it looks kinda bad.

Just my opinion, based on what I've seen here so far and what I know of engineering.

-D'oh!

GaryK

The stock airbox is technically a "cold air" intake as it does not pull air directly from the hot engine compartment. Rather, it pulls air from behind the bumper cover, just up higher than most aftermarket cold air intakes.

Indulf has a good point about straightening of the air flow before the MAS. Because of this, and the fact that you will lose some velocity with the longer piping for a CAI, I'm very skeptical of any benefits from a CAI. The gain, if any, comes from the free flowing air filter in my opinion.

Welsh 350Z N

After reading the very useful info. posted by everyone in direct response to this thread and eventually finding more and more discussion on the subject in other threads I have made my decision..................I am staying stock with my K&N filter. I now understand the benefits but I think I can find other MOD's to spend a couple of hundred bucks on that'll do more for me than either a CAI or Short Ram.

zxsaint

This weekend I'm going to do a little experiment.

I have a few digital thermometers that i'm going to place in various locations in the front. After some 'spirited driving' i'll record the temperature readings, as well as the ambient temperature.

The locations i'll be measuring will be the injen and AEM CAI filter locations, stock intake port, and also one from within the engine bay (near the driver side headlight housing)

Chebosto

iTrader: (43)

this was referring to the CAI bends..





im putting the full INjen kit on an air flow bench test next week to see how much 'better' it is versus the stock air box when it comes to sucking in air....

the stock air box is already a 'cold' air box because of the chamber the filter is enclosed in..

as for the leading edge theory.. i address that in a thread a LONNNnnng time ago...

i think i have a pict... still

Chebosto

iTrader: (43)

....

blascelles

iTrader: (3)

It all come down down to pressure waves, bottom line. If you can take advantage of the motor's overlap then you are gonna make maximum power with that modification.

Welsh 350Z N

Thanks again guys. I will be very interested in the outcome of the experiments performed by zxsaint and Cheston. As I mentioned above I am not an engineer - but I am a scientist. I need data to base my decisions upon so let's see the data. Keep us all posted men.