I know one of our fine forum members got a K-thermocouple and placed it at the air inlet (or you could log IAT with ATAP,HPT, etc...) , and on the outside of a stock car with the foglights in, it took a couple of seconds of driving to clear hot air out that stacked up in the engine compartment and get to the same temperature as outside ambient.

If someone could find that post it would be nice, but it is pretty old.

Anyhow, with the screens out (like a Z06) the time to get a cool intake charge went down even quicker. Like in a few seconds ( I think the car was at 10-15 mph). So you can imagine how long that takes in your car....

I used to work in the Filter industry, and the comments about Donaldson were correct. They are in the filter business, and they do know how to make filters. I never bought a Blackwing as it was reported to cause issue with the stock unscreened MAF on the 2002 and later Z06's. Anyhow, most folks know I use a stock GM airbox with the lid off, and I use a factory paper air filter.

I do this for two reasons. It filters far better than a K&N or many of the other filters out there. Paper filters might not be as free flowing as oiled cotton, but they are much more efficent in their filtration (and they are cheap to replace).

It has been dyno and track tested to be just as fast as any of the aftermarket filters I have put it up against. So, no gain for all this money seems pointless to me.... But thats just me.


I do agree that cooler inlet air will make more power. The question key to this point is how quickly is hot inlet air exchanged for cooler outside air? If folks spent 10 minutes with a dremel tool on the foglight surrounds on non Z06, and used a couple of zip ties and a hood seal they'd have 100% of the gains of a high dollar aftermarket "ram-air" system with no basic outlay of cash.

But hey do as you will. Cold air does make more HP though... But I do agree many of the "gains" people have reported are more than likely a placebo effect.

 

Assuming that this statement is true:
At 95-degrees IAT, the Blackwing will lose 1 degree of timing. At 135-degrees a full 12 degrees is pulled on the LS1 which equals 10 RWHP

and assuming that the intake air temperature readings that I obtained from the OBDIIdata acquisition device (before I had my cold air mod in-place) is accurate, those who have Blackwing or other aftermarket filters without either opening up the foglight panels or (better yet) directing cold air from underneath, via a cutout in the lower radiator cover are losing 10 HP on warm days after a short period of time (10 minutes or so, based upon my data).

In other words, negating any "RAM AIR" effects, the biggest gain from introducing cold air is to prevent the 10 HP loss that occurs frequently to non-cold-air C5s.

Does everyone understand this now?

 

One other thing. Rather than taking a lot of stuff at face value. Here is the actual spark retard vs IAT table from a stock 2002. The tables are in Celcius. You can see that @ 35C (95F) its -1. at 40C (104 F) -2, etc... look at the table for yourself. It doesn't do it down low only above .2G/cyl does it pull any timing at all. So, depending on how fast you are moving, etc... you may see 0 retard. Like I said, with open foglight surrounds you see little if any retard except for possibly below 10mph or so...



Now here is the stock spark advance table for the same car


As you can see the car has plenty of advance... If you look at the g/cyl vs RPM, and correlate that to spark retard, unless it is the dead of summer and you shouldn't see spark retard once the car is moving.

 

I used a water manometer and took readings of the pressure difference between the enclosed duct from the license plate and cockpit, (windows up or down did not change the results). There was no pressure difference between the cockpit and location of the unducted filter area. The cockpit is also vented at the rear quarter panel. The choice of the relative pressure difference was more for convenience on my part.

To construct a water manometer requires a ruler and several feet of clear tube along with the water, not a lot of money. I have a remoter temperature meter along with 4 transducers that I used to measure temperature everywhere under the hood, there is very little heat gain between the hood and the engine. Air seems to move over the top of the engine and then down the firewall cooling the headers.

Another way to measure a change in performance is to monitor (log) the MAF vs RPM (Mass Air Flow) before and after changes in the ducting. I saw no significant increase in the MAF from ducting the air filter. The reported MAF was not influenced by a 0.2% increase in inlet pressure.

 

This whole post is interesting. Thanks for sharing. A question I would have is, did you log ducted, and unducted, MAF readings while stopped and at a slow roll? Those are the areas where it seems to me a CAI may have a significant benefit in launch capability, both because of the increased combustion efficiency (denser air=more fuel) because of that (relatively) cold intake air, and no rolling back of timing because of that cold intake air.
Ed

 

Best way to measure this is to wait for the second yellow light, stomp it and then look at your time slip. More fun than a manometer, or colored graph.

 

Evil Twin you have such a sick sense of humor. You engineer guys really know how to cut up.

 

Hmmmm let me see, No.

 

I keep reading in posts people talking about gains from a vararam or a cold air intake being a placebo effect. Two problems with that, one we are looking at time slips nothing psychological about it. Two, the placebo effect is the measurable, observable, or felt improvement in health not attributable to treatment. This effect is believed by many people to be due to the placebo itself in some mysterious way.
So if it is a placebo, after one bolts on a vararam goes to the strip on a similar weather day and runs two tenths faster and three mph faster through the lights, we must assume it was not the CAI that did it. It was some mysterious force we can not explain. Nope sorry I will stick with the CAI.

 

This is one of the reasons why I want to use corrected numbers.

http://www.modulardepot.com/density.php

If I plug in my numbers for the day I ran the 12.53 it corrects out to a 12.39.

Going about it this way should give you more accurate assessment of real vs perceived (placebo) gains.

 

Aw, that was cheating. I think this thread should rank up there on the sheer intricacy of the debate alone. Who knew?!

 

90 Droptop.... Now, now.. be nice! Those smog techs just might hide a bunch of mattress tags in your glove box, so watch out for the next time you go through Border Patrol check points!

Kidding aside, would you mind PM`ing me the smog people`s ph or address that your`re using?

Cheers, Rick

 

Border check points, I don't stop for no stinking Border Check points.


P.M. sent.

 

Bump

 

If the track had been hooking at all yesterday, you would be opening your wallet to buy that Vararam. My best 60' was 1.86.

I came to within 0.11 of making it to 12.29.

That 0.11 is within my reach. A high 1.7x 60' which I feel is attainable should do it.

 

Ok...jog my memmory.

Exactly how much gain did you get. Was the track prepped better on your runs before the VRam, where your 60' the same??

Are you satisfied that the VRam is the best performnace CAI?

 

maybe this will help out results

 

Thanks

I missed this....I have been waiting for the results