original message posted on m|u

how do the NAM users feel about this? are intakes purely for sound purposes but actually slows your car down low end-to-midrange?

 

Its all bling and sound.

 

On an R53 we've dyno'd gains with just an intake to be 3-10 HP. But on an R56 I'm still waiting on the gain. So for an R53 definetly do an intake.

 

Sure makes it sound mean! Installed the Alta CAI last weekend. It sounds great!

 

Do I run a $200 CAI? Yes. So it therefore on some level must be worht it to me, as it did increase MPG to a point where it paid for itself in about 6 months of driving.

But I've also done and compared notes with others that have done similar testing, and found that CAIs aren't exactly cold, and that HAIs are just as effective. So $40 (check out the "operation hot air intake" thread) will be a much faster return on investment, and yield near equal gains. The stock intake traps heat for a very long time, and the flat panel filter allows less air in and gets dirty fast and is expensive to replace frequently.

So would I say do an intake, but I wouldn't say you necessarily have to go the CAI route, though it has worked out well for me.

 

I believe that yes you do need to swap out the Stock one as Motor On said for a description. As to which one, I believe that they are all about equal. Anything is better than stock. But my main thing that I look for is how well it is heat shielded. Therefore I prefer the boxes that are full closed and draw the air from the window cowl. They also help with S/C whine!!!!

 

Careful about the heat shielding, the stock box does the best at keeping heat out, but it holds it in the longest. Insulation works both ways, the key is finding the proper balance or not worrying about that first 2seconds of cooler air.

Might I suggest reading this whole thread.
https://www.northamericanmotoring.co...-findings.html

 

Interesting thread. So which cai is that which you got motor on? And are you saying cai such as the jcw airbox and dave.f holds heat in for longer? As they both use a similar design to the stock airbox, the dave.f uses the stock airbox just modified. What are you on about though? Once the car is moving there is a constant feed of air directing it through to the airbox.

 

I've got the ALTA CAI, and I made a top for it (I'm cheap and hand with tools it cost me about $1) and then used roofing material to insulate it, and I tested it both before and after, it preformed better in terms of effect of heatsoak when insulated, results were the same after 5min of cruising and the stock airbox had a slower climb than both on heatsoak but it retained that heat for much longer when driving and when sitting eventually would reach the same levels as the other boxes, so for stop and go traffic it would see the most effect and take the longest to get cold air back into it again.

The JCW box provides more openings and better airflow than the stock box, so I actually wouldn't be surprised if it preformed better, I don't know of anyone having tested temps at the filter with it though.

But again, moving for an extended period of time (highway driving or long country roads that have lots of twisties and few lights or stop signs or a tack session lasting more than a few laps) and I think that most any conical filter will preform equally temperature wise. But then again if we're looking in those practical applications speed wise, it's going to be more river than car dependent, and same amount of air at the same temperature should have the same effect on MPG.

I haven't been able to find the link to it, but years ago I do remember a well respected member that was doing regular dyno testing comment that gains with all aftermarket conical filters where the same because of the weak links further down the system, and the difference between them was subtle enough to only be noticeable on a dedicated engine dyno and changing the filters between runs in the same session, and even then is was a 1-2hp adjustment. Which brings us back to changing the intake is just part of the larger package for those seeking significant performance gains.

 

One other thing to add....
Since Dino tests do not take into account ram air ( the stock does have that little snorkel, and some set-ups reuse it..others use other methods to get higher preasure cold air...like hood scoops), and do not have as much airflow as when a car is actually moving, some CAI that incorporate a ram air intake of some type may have even better performance in the real world. The only way to know for sure would be a Dino in a wind-tunnel.

 

Which brings me back to saying that pretty much all the CAI are equal, it just depends on what you want to spend on it, how it looks to you in the engine bay and to add the S/C whine

 

ZippyNH: some tests were done many years ago about the front grille duct that pipes air to the airbox. It only creates positive pressure in the airbox (as in air begins to flow through it to the airbox) above 50mph. So it works, and shouldn't be thrown away without consideration, but it's no ram air device. I know of one true ram air device...

 

True...I know of a few guys running scoops on the grills by the windshield too....to funnel/force more air to the CAI's......

 

So can we say that intakes such as DINAN, Dave.F and JCW are the best intakes in terms of performance?

 

me:


Does it work? Hell, I dunno, looks cool though.

 

As to ramming air into the airbox: there's been many threads on this over the years. I know of no-one who has actually tested the cowl scoops and published the results. I did tests on my FAD when I first designed it. I did simple up-hill runs with the FAD open and blocked. While airbox temps were initially lower, they stabilized to be the same. Where the ram air had an effect was the rate at which the temps fell after the "sitting" period. Airbox temps fell faster with the FAD.
I believe this modification is unique, and have not seen anything similar over the last 5 years I've been on NAM. That said, I still believe we're talking turd-polishing here...

 

Hey Doc, old subject. Seems like everything "temperature" = Dr Phil.

Bottom line: How does the "CAI" mod effect the AIT at the T-MAP and which 1 is best????? Does the benifit of an HAI outweigh the cost of a CAI in relationship to AIT? I don't believe there is a wrong answer. True - the "CAI" has some merrit but if you go to almost anything, related to this subject, on this site, there are minimal gains. We, in the NE, can see some TE with most of the CAI mods, not 7 - 10 hp but some.....

 

Steve: your questions are interesting, for sure. I don't think anyone has ever formally addressed the "gains per dollar" issue (I'd call it economic efficiency, but that's because I'm a geeky economics professor - haha.) Other than in the most broadest and casual (in an academics sense) way, that is.
After 5 years of workin' the Mini, I'd say that the goal is increasing the rate at which temperatures (ultimately IAT) fall. Under-bonnet temps are always going to be high, and vary considerably. The "toughest" goal is to maintain performance in heavy, commuter type traffic (of course, why you'd want this is another, crazy question.) This is where engine bay temps rise due to long periods spent idling, or moving slowly. It's common to see IATs in the 150F range.
Given the developments that have been made over time (most in the early days of course) in CAIs, and the relatively stagnation in the way the HAI works, I'd say that CAI systems offer the greatest potential to improve temperature recovery. A few basic principles can be enunciated:
1. Thermally inert material is best for the airbox (resin boxes such as the Dinan, JCW and others nowdays fall in this category).
2. Opening the back of the airbox to the cowl is critical.
3. Sealing the top of the airbox is critical--but a separate top is inherently no better than sealing against the bonnet.
4. Sealing the bottom of the airbox is also important and often forgotten.
5. Enjoying the resulting increase in SC noise is the icing on the cake...

 

Excuse my ignorance, still new to this but does the cowl mod not give entrance to the "ram air effect" aswell as the snorkel from the grille??

 

I see searching around the cai that K&N actually has a dyno graph and a guarantee hp increase with their systems. [FONT=Arial][SIZE=5][/SIZE][/FONT][FONT=Arial][SIZE=5]
[/SIZE][/FONT]

 

thats what they all say.

 

What I'm saying is that there's no data to prove (or disprove) that there's any significant "ram air effect" due to the cowl scoops. There was evidence published on NAM years ago about the effect of the front grille duct above 50mph. Since no one is taking pressure readings (I've only ever taken temperature readings) inside the airbox, it's hard to know what's going on with all these openings. There's armchair theorizing, and speculation, for sure.
And keep in mind that when the pressure inside the inlet manifold is below barometric pressure, the engine is essentially "sucking" air into the airbox. All that's needed is sufficient unrestricted air supply to provide the engine with the amount of air it needs at the time to properly combine with the fuel to deliver the power. Ramming more air into the airbox is not going to do anything once the cylinder has all the air it needs. And in a Cooper S, the SC is doing most of the pressure build-up work regardless of what's being rammed into the airbox.
It's more about the temperature of the air in the airbox than the pressure. If you can get the air to be close to ambient you've done just about all that's needed.
In my case (and I'm speculating here), the FAD is producing enough air to the airbox that any excess pressure is going to be released *out* the cowl opening. If as is common, there is negative pressure at the base of the windshield, air will be sucked out of the airbox at this point.
Check out some really old posts by Dr Obnxs on the air demands of the Cooper S engine. It's good supplemental reading.

 

To work it would need to be facing the opposite direction, the positive air pressure on the cowl area is caused by build up and push back from the windshield, if you look at the post recall (no foam) OEM cowl covers, you may notice the slats angled to take advantage of that airflow.
Without testing it I can't tell you. But if it inspires someone else to test it out then all the better. The theory behind it is certainly solid, based on what I've seen, so I wouldn't discredit them; however these cars are complex machines and what's good on paper isn't always what's good in practice.

 

^This is true. However the wiper blades really mess up the air flow. If you use the yarn test, 8 - 10" @ 4" work best - not to be used when rain is present....

Dr Phil - #5 works for me. did someone give you a new polishing rag??? Yet? Under hood temp is my area of insanity. Sombody once said you need to identify the heat source........ the correct answer everything.....

There is some advantage having a large column of air to feed an HAI.
Also the same from "CAI" ( should read SCIA - somewhat cool air intake ) with a smooth charge pipe, with a slight AIT advantage.

 

Hmm, I do remember my Firebird in High school, and I ran a hood scoop open at the back to to grab air from in front of the windshield. Now, how would I test that. (I was an Aerospace engineer in a previous career ...)