Hi all, I did some data logging on a HAI vs Stock intake and found some pretty interesting stuff... Here goes.

I bought a new K&N filter, and a new stock MCS filter so dirtyness doesn't come into it. My car is an 02 with some of the standard mods:

HAI,
15% Pulley,
OBX Header,
One-Ball Exhaust,
JCW Injectors,
M7 thermostat
Pilo Coil Pack
Kingborne Wires
MTH Tuner

I think that's it....

It is very important to note that I didn't open up the hole in the front of the car to increase cold air flow, nor have I done anything to the bulkhead divider at the rear of the engine compartment. This does effect the results. How much, I'm not sure.

Anyway, I put on the stock intake with the new filter, and measured air temps by inserting a temp probe through the side of the rubber air-box to TB tube. I stuck the temp probe through the rubber on the K&N as well.

I did runs to 70 in second gear to get the data, and then set the cruise control at 70 in 4th to look at more "steady state" conditions....

So, first off, the pressure singnal from the MAP sensor (logged with BiM-COM).

So this is the data we're used to seeing, no big deal hear. The use of the HAI in place of a stock intake gives you about a half a PSI more pressure at red-line. So far so good.

But if we look at the pre-and post SC pressures, something screwy starts to happen.

Post SC, the HAI is losing out over stock until 6500 RPMS! WTF?

But wait, there's more. The T-MAP sensor has a temp reading feature, and looking at intake manifold air density (basically P/T in absolute units) one gets...

Now, the HAI is WORSE than the stock airbox at all RPMS! So what's the deal?

1) Heat soak. The HAI is more susceptable to it, plain and simple. This makes sense, because if the car is at rest, there is no cool air flowing anywhere due to the motion of the car. This is bad news for 1/4 mile runs, as the HAI is at it's worst when the car just starts moving.

2) Car speed. These were second gear testes. In third, there will be more airflow, just as in first there will be less. This means the relative difference is vehicle speed dependant.

3) Other mods. Like I mentioned earlier, opening up the front and rear bulkheads will greatly improve airflow, and increase the benefit of the HAI. But I don't know if I'm gonna test these other configurations... I sold off the K&N after I'd logged my data.

There was one effect I couldn't log. Throttle response. While the HAI may be crappy when it comes to heat soak, it sure removes tones of volume in the intake path. Any time you change the throttle position, the car has to wait for the air to accelerate. So while the stock intake was a good performer from the perspective of air density, when I was driving around in stock configuration, it sure felt like the car was stuck in molasses!

So, what did I learn?

1) HAIs are more prone to heat soak.
2) For the HAI, you should remove the rear bulkhead divider.
3) If you're going to stay with it, you should open the front bulkhead up as well.
4) Depending on how you drive, the HAI may or may not be the intake for you. If you're a 1/4 mile rat, then this will suck because of the heat soak. If you're a track rat, moving mostly at speed, it can provide benefit.
5) The HAI sure is more responsive. Bodes well for the AGS design, which ditches all that upstream plumbing as well. Also, this makes me think that the heat shield you can get with the AGS is a must, not an option.

So what am I gonna do? I'm going to take out the rear bulkhead divider and see how I like the sound. If it's not too much, I'll go with that. But cutting the front bulkhead makes this a very expensive proposition if you ever want to return to stock.....

Matt

 

Looks like I'll be sticking to stock

 

but I gotta say the throttle response whas very, very different. Even after logging the data, the HAI is staying on the car.

Matt

 

great stuff matt. A good read. Glad i've got my CAI

 

Well done Matt, as always!

The stock box is probably the best "CAI" out there. I've said this before... because the stock box, compared to the aftermkt, is probably the best insulator. That's just part of the equation though... Your pressure findings are interesting.

Look forward to hearing more. Thank you.

 

Roland on Mini2 is posting lots of interesting stuff on intake pressures. Insulating effects will only dominate at initial launch... I think when the car is swallowing a couple of hundred CFM of air, that won't make much difference.

But as always, the truth is in the numbers. More measurements to make....

Matt

 

Imagine that.....MINI's engineers had it right to begin with.

 

As far as the actual benefit of slightly cooler air, all things considered, probably insignificant. I think we'll be hard pressed to find a unit that blocks-out the engine bay heat better than the stock box. The path, access to fresh air, and filter element might not be best though...

 

nice job Matt...... bodes well for AGS...we'll see

 

The good Dr continues to amaze me.

TonyB - assuming the stock box as the best CAI - is there any benefit to a K&N type cone
in the stock box. And on that thought, is there a cone that will fit the stock box?

 

Thanks for the #s all seems fairly logical, kinda wish we could see those other results just to comapre another set of #s; its nice to see some hard data.

Another thing, you mentioned something that really stood out, BiM-COM, How do I get my hands on it?

 

If you take a look in the stoct box you'd need to make alterations as there is nothing to attach a cone type filter to, now the JCW or DInian on the other hand....

 

Nice stuff. As always.

But.....there's always a butt isn't there ? :D

I disagree with the removing the bulkhead idea for 2 reasons.

1. Underhood flow is quite good even with it in place. Reference this old thread

2. I'm even getting tired of hearing myself on this one Once you open that rear wall you are allowing direct underhood air into your HVAC system. Noxious fumes entering your cabin space being one thing and increasing summertime heat loads on your AC being another.
I've spent an inordinate amount of time plugging the little gaps associated with the Alta and HDI kits.
I used to build HVAC and realize there is an acceptable limit to the amount of leakage allowed but I'm pretty sure a gaping 6x12" hole exceeds these limits

Discuss amongst yourselves...or throw stones... or whatever.

 

What if one were to open it up, and still manage to blok off the HVAC system, what would your opinon be then?

 

To fit a cone in there you'd have to remove the top... do some cutting here and there... a little bit of sealing against the bonnet... knock out the back firewall...

Or... go buy a Helix, Alta, etc... CAI and get the same results.

 

Shankrabbit - motor on Thanks for the clarification. I thought I read someone had done it, but didn't know what was involved.

Short money is nice - simplicity and convenience is nicer

 

That would be a good thing.

Not easy to do though.

 

So then we just need to determine if its worth it.

 

A higher flow filter in the stock box location seems to have its merits, and I think a few have done it. I pondered it sometime ago... It would look stock, which is desirable to some...

As Matt said, there's something to be said for throttle response though, esp with our cars. A shorter path is what I want, and ideally a larger one, which the AGS addresses...

Having a cooler temp at the filter or TB is not quite what it would be on an NA car. Just a foot or so away that air gets compressed or displaced, and heated quite a bit by the SC...

My thinking has evolved to... focus on volume of air into the SC, not making temp the highest priority (HAI mentality), but focus on dropping the temp afterwards, as that will be our IAT. The DFIC is showing signs of doing this very well...

The AGS V.3, with heat shield, coupled with a very effective/efficient IC should be a really nice set-up. It's no secret that I'm an M7 fan, but there's a reason why. They just keep delivering innovative products, and I really appreciate that... And without saying too much, the M7 pipeline is certainly not dry; so expect more appealing stuff in the coming weeks... including something quite relevant to this discussion .

 

i'm certainly not an M7 fan ( yet) as i have none of their stuff on my car (yet), but i definately agree with all the above.

The only concern is that while IAT's will be the same, the fact is that the hotter the air that enters the SC, the hotter the SC will get while compressing this already hot air. With a small enough pulley, this will provide a significant amount of extra and unwanted stress to the SC, perhaps causing it to crack. Now this might be an exaggeration in terms of short term effects, but what about long term, especially for those of us who live in hotter climates.

 

Darned right

 

Cooler air into the SC, should make for cooler air out, so it should not be totally ignored. But, if we are talking only a couple or few degrees pre SC, the benefit of the increased volume seems like a better trade-off for slightly higher temps pre SC... The ticket is what we have post IC, or what I think Matt referred to as charge density... a combo of pressure and temp.

 

again, i was only talking about hotter intake temps damaging the actual SC itself. This would only happen under heat soak while the car was stationary. Hopefully the AGS Heatshield will prevent this.

While on the move, the HAI/AGS won't ingest any hot air

 

Sorry if I've misunderstood this discussion, but...

In my CAI (Alta) installation (done by Steve's Auto Clinic) the rear wall has an opening cut just large enough to accomodate fresh air going into Alta's metal CAI airbox alone (probably 5x5 inches). The rest of the rear wall remains intact and sealed...

So the question: Is there underhood air going *out of* the CAI cone (which I had thought would actually be a relative vaccuum going the other way), and if not, where does the bulk of "bad air" pass out to get into the HVAC?

Now I'm not assuming the CAI itself is air-tight, there is some leakage I'm sure, but given the direction of unrestricted fresh airflow and the nature of rubber seals against the hood, isn't the "bad air" less of an issue this way?

Musing, maybe the biggest problem is we know there is leakage, but have no real numbers to represent it.

Just an aside, I'm reading forum discussion of benefits related to mpg with intakes (including CAIs) but not necessarily related to hp... Any of you learned folk care to share an opinion? (And sorry if this part is too off-topic, feel free to ignore if needed.)

 

And if you read the MINI2 thread after a short amount of time on start-up from say a long stop light it can be a huge differance in intial temp and the amount of time it takes to get back to the 5 degree difference. I have a CAI and am now working on adding insulation. In orginal form the ALTA is 5 degrees (assuming F scale) cooler than the engine bay while traveling in excess of 30 MPH, I'd like to get that differance to exceed 10 degrees with the insulation. Also there was an aproximate 40 differance after sitting for a few minutes in traffic, the goal of the insulation is also to increase that gap over ~2 min. from 30-40 to 50+ degrees. Only problem with all of this is nobody can tell me how to get a copy of BiM-COM, and I need to go out and pick up an inexpensive thermomter to get some readings.