Well, I finally was able to borrow the Car Chip OBD II data acquisition device again to measure
Intake temperature
Coolant temperature
Vehicle speed
Long term fuel trim(both banks)
Elapsed engine operation time

I ran the "Chip" before installing my cold air mod to the Halltech Stinger-R intake one year ago and was eager to collect more data, now that cold air is surging through my C5's veins. What I found really made me smile. In summation:

1. Steady speed from cold start in morning: During steady speeds and after a cold startup in the morning (ambient temps i the high 50s - mid 60s), the non-cold air setup stays fairly cool. I recorded intake temps that never exceeded 86F on the way to work. Coolant temps reached about 200F during this time. Average intake temp was 84-85F.

The same trip after C.A.I. yielded an average intake temp of about 67-68F (quite a bit cooler, I'd say!)

2. After heat-soak: After the engine has been run and allowed to sit (heat soak) for many hours, the intake air temps in a non-C.A.I. system have a really hard time coming down. Example: With a startup coolant temp of 154F and intake air temp of 122F, slow driving (20-35 MPH) does nothing to cool down the intake air, which stayed at 122F after 5 minutes of slow-go and some stop&go driving. In fact, after sitting at a light for one minute, followed by 30-40 MPH driving , the intake temps hit 135F (hot!). Even after driving at 80+ MPH for one minute, the intake temp only dropped to 122F. After a total of 16 minutes of slow-go and stop&go driving, the air intake temps hit a whopping 147 degrees F!
During this time, coolant temps hit 219F.

By contrast, the "after-C.A.I." setup, which saw startup coolant temp at 140F and air intake temp at 104F, very quickly brought air intake temps plummeting after the car started moving. Average intake temps over 17 minutes was about 80F and even after a 1-minute stop light, the intake temp rose to only 104. A 1-minute drive at only 40 MPH dropped the intake temp down to 82F.

Fuel trim: Long-term fuel trim with C.A.I. is consistently more positive (correcting for lean conditions) but since there are no lean codes, this means that the computer's limits of adjustment were not reached (a good thing).

Remember, at 135-degrees F. a full 12 degrees is pulled on the LS1 which equals 10 RWHP. My Cold Air Intake mod kept intake air temps well below this number, effectively preventing a 10 HP loss during slow moving or stop & go driving.

All-in-all, I am very happy with the combination of the Halltech Stinger-R intake and cold air mod. If any of have not seen how this is done, check out http://www.conceptualpolymer.com/corvette_c5_corner.htm

 

Thank you so much for the write up

Your results are consistent with my own informal results since I have installed the Vararam. I have made a few trips using the hand held Predator since then, and I have seen readings in line with your own overall observations. And tonite with HP tuners again the same thing.

On steady state cruising however I have seen it go both ways with the fuel trims. A couple of weeks ago, I noticed slightly positive LTFTs in the +2 and no higher than the +4 range, but mostly in the +1 to 0 range. (An average is usually the best way to get a feel for this and the Predator for GM has no logging capability, so you sort of have to wing it)

Lately however I have not seen anything higher than a +2. They are usually at 0 or down to -1 or -2 on steady state cruising at say 65 MPH and up.

Intake temps get very close to if not outright equal to ambient air temps in a very short time with the Vararam.

Anyone else want to argue that there is no such thing as cold air????

 

Nice writeup Dave.

Check your post....you have BORLA instead of HALTECH

How do you think my TRAP would have fared.....


DH

 

Great job and awesome job! Thanks!
Dave

 

Nothing like some hard data to prove up common sense!

Good work Dave.

 

I wonder about the "depressurization" mod...

We have large vent holes molded into our fenders. Although there is not a direct path, they should vent the engine compartment and make cutting the weatherstrip not required.

Thoughts?

 

Great info!! It do wonder if you opened up the vents in the front facia if this would have an effect on a stock like setup. I know is won't be as good as a vararam or trap, but I wonder if it could at least reduce the heat soak. Is there any easy way of doing this with the tools you have Dave68?

 

I'm using a Blackwing. As the Z06 came without foglight shrouds of any kind, to allow cooler outside air in near the filter, when I had my heads, cam, longtubes, etc., installed, I had several large holes drilled into each foglight shroud. I then mounted Z06 front screens over the openings. Obviously not as efficient as a Vararam, but I derive some of the benefit without the downsides.
Ed

 

Korreck? We are waiting

 

He will be here. He is now a cold air disciple himself, although he won't admit it. He likes to use the term "ambient". I am sure that you have seen his CAI and heard about his results .

"Ambient"...... I like it.......sort of like a stripper referring to herself as an "exotic" dancer. Or a used car being referred to as "pre owned"

 

I have a RM twin flow intake and opened up the fog light area before installing the Z06 screens. I monitor the air intake temp. continuously via a temp. probe in the air filter that is hooked to a digital readout on my visor.I have very simular results.My intake temp. is within 1* of ambient during highway driving. It also comes down very quickly after a hot soak, usally takes about a minute. I have also opened the area behind the license plate and this has cut the cool down time in half. I use this procedure at the dragstrip. The wait in the staging area causes the inlet temp. to rise and this extra cooling helps to get it down quickly. Last week in 78* ambient I was going through the traps with a intake temp. of 82*. My trap speeds are in the 113 mph range. Three weeks ago with a 60* ambient I ran several 114 mph trap speeds with a best of 114.5. My only mods are intake and headers.Plus I have a SS3600 TC and a 3.73 gears. Cold air does work.

 

Halltech - that's what I said! Your TRAP should do just as well if you have any of these two:
1) Tunnel Port opening in front fascia
2) Fog light panel openings


The depressurization mod is really for getting rid of large volumes of air. More than likely, the opening I installed doesn't warrant it, but I always intended to make it larger. You'll notice that many racing-type aftermarket hoods are vented to allow hot underhood air to escape. That's the idea of the depressurization mod on a much smaller scale. One of these days, I'll try a before-and-after hood vent cut temperature test to see if there is any difference. However for those who don't drive in pouring rain, I see no harm in a little more venting.

Yes, that would definitely help, as indicated here by yaankeevette. The reason why I didn't do this are two fold.

1) I wanted to retain the front-end look and

2) The engine bay should stay cleaner with my mod. Some of the inrushing air cools off the engine bay, but most is fed directly to the filter - kinda the best of both worlds in a sense.

 

Good to hear. I haven't measured inlet air at the filter, but suspected the exact results you got. That's the reason I had my foglight shrouds drilled out. Thanks!
Ed

 

Not suprised in the least

 

We're the He!! is Korreck when you need him??? This has the makings of a good debate. He's probably outside flipping hamburgers or something. Maybe he needs to change the name of the thread to "Paging Korreck: Cold air intake data is here."

BTW, there's a guy asking about a K&N filter for the Vararam and another dude is asking about 2.73, 3.15 and 3.42 gears. Boy, he's going to have a field day with this stuff.

 

I think Korreck might be racing today. It rained here again so another weekend on the sidelines for me.

 

He's at the track for a 3 day event I think he said he will be home late Monday afternoon.

 

Sorry, good write up, but incomplete. Now, go out and measure the mass of air being read in at IDLE and at WOT by the MAF. Then come back and tell me what it says. Aftermarket airboxes throw off the MAF's ability to measure air due to unexpected turbulence, that was my conclusion and included ZIP tie, VARARAM, HALLTECH, and at least one other air box. SAME RESULTS for each one, less reported air by teh MAF at IDLE and WOT (though yes, more air avail).
If a guy is lucky, this leaning of the engine will cause more power and will show up immediately on fuel trims. In all cases, IATs were slightly lower than stock. If you were seeking lower air temps, I agree with you, but to suggest the box is effective without tuning is another thing. The only possible way these airboxes gain power without tuning, is to lean out the engine because of the fact the maf is not working correctly. These facts were only derived from my car of course. I would love to see more from yours. NOW, after retuning the engine, or effectively lieing to the pcm by skewing the injector curve to get the fuel trims correct at idle, the car ran stronger and fuel trims somewhat back in line.

My only point to this post is to suggest that yes, IATs are decreased, but the power comes from leaning the engine by corrupting mass air flow or should I say air flowing across the maf sensor in an unexpected way. Air boxes work, but MUST be tuned for, even the zip tie mod, which by the way, my car was slower with at the track.

Ok, flame suit is on.

 

Are you saying that cooler air does not produce more power? If you are you are dead wrong. I agree the maf may be off but not enough to cause any problems. My car has run quicker times with my cold air setup and I did not retune it. Cold air produces denser air and hence more power.Standard engine testing by all automotive companies use a correction factor for inlet air temp. This is not a arguable point it is FACT.

 

I agree that tuning will in almost all cases optimize HP output. However, to suggest that an aftermarket airbox doesn't increase HP significantly is incorrect, as is evidenced by my dyno numbers. Remember too, that during most dyno runs, air velocity to the air filter (C.A.R. systems) does not parallel real-life runs. If anything, a wimpy fan's 20 MPH breeze will limit actual RWHP numbers.