Tom400CFI

For those who haven't noticed, I prefer to seek out fact, rather than make stuff up and post bullsh!t. So that's what I worked on today; fact finding.

I started by taking a better pic of my front end in bright, day light. Still looking for that orifice for air...





...Maybe I need glasses. I'm just not seeing it.

My Blue Point MT586 DVOM has a temp function and a temp probe. I ran that to the inlet of my air cleaner, added some wire so it would reach into my car so I could take pics of the air temp in the filter housing area while under way. Got it all set up;






I measured the ambient air temp at 71*F, then closed the hood. Started the car and drove off. I drive about 2 min to get out of my neighborhood, then I'm on the highway, basically coasting down hill to Salt Lake; 13 miles, 2500' drop. So I'm at high speed, engine idling...that is about as good a scenario as I can imagine for "cold air" while under way.

Anyway, once up to speed and on the highway for ~5 minutes, I turned the DVOM on again; 86*F. I'd already increased temps at my filter 15* and the car wasn't even warmed up or under load. And I was traveling 75 mph. But now I'm confused, b/c I swear that BTG said;
...so that being the case, I should have been reading ~71*F temps then. Right? I'm going to do some more testing, b/c right after that, my DVOM malfunctioned.

I finished my trip in SLC got back to my house and threw a regular thermometer on the air filter, and let it sit, idling for a few minutes. Ambient temp was about 80* at that point, engine temp was 185*, car was parked in the garage (shaded) w/the garage doors open. Here was the reading;



^Thermometer is pegged, -over 120*F, or over 40* higher than ambient...that ain't "Cold" air. Like I said; I'm going to do more precise/controlled measuring once I get my DVOM fixed and report back, but maybe we need to more clearly define what "cold air" is. I don't call that cold air.


.

1stVetteFinally

Hey Tom, when you do more testing, can you also check the under hood temps to compare with the air filter temps? That would settle it once and for all.

blackozvet

I think some people might be focussing too much on the trees and arent seeing the forest !

Remember that this early c4 intake was designed at the beginning of computer controlled fuel injection, at that stage it was about sufficient air volume to feed the TPI, which was around 550 cfm, that the engineers wanted. This can be achieved with stocksetup.

People in search of increased airflow have talked a lot about "cold air intake"
without getting into that concept too much, lets think about how all the manufacturers have developed the air intake in later years ? They have an air intake from the front of the car and funnel it into a box surrounding the air filter. This captures the air and causes a pressure at the face of the filter that it can easily draw the air from.
Performance motorcycles have gone one step further and they use this system with an airbox that creates a pressurized system.

So for the c4 system to work as a real cold air system it needs to take the air from the front and feed it into a captured air system enclosing the filter. If you just feed air from the front towards the air filter that just sits in its own void it would simply just keep on going elsewhere into the engine compartment. Air isnt that smart that it can recognise an air filter and go into it !

To understand it, look at modern efi air intakes and look at the aftermarket cold air intakes and see how they are designed.

Tom400CFI

That's a great idea. I can't measure both simultaneously -don't have enough thermocouples...but I can measure each space independently, under the same conditions. I'll give that a try and write it all down so I can post.


BINGO!! Someone (else) gets it too! Modern systems physically segregate the cold air from the front of the car (front bumper/grill area, typically -which is a separate compartment than the engine compartment, unlike the 'Vette), to the throttle body. In those systems, heated air from under the hood CAN'T enter the air stream. The 'Vette's system doesn't do that. IMO, the 'Vettes intake -the later 'Vettes at any rate, is not much better than a typical inlet on a carb'ed car. It's an open element filter w/it's inlet inside the engine compartment.

In my '96 Silverado...and in my wife's V, the inlet to the intake system is right behind the turnsignal light...which is completely outside the engine compartment. From that inlet, there is molded plastic pipe to the air filter box...and of course a molded plastic or rubber pipe from the bod, the the TB. So no air that is influenced by engine heat can get into that air stream. Not at speed, not at rest, not at idle...never. THAT, to me, is a "cold air intake. Anything that allows the mixing of inlet air, which is all C4, 5 and 6 intakes...is not that.

91 black convert

It appears to me, (not a fact), that the C4 engineers found it to be more important for the ambient air to get to the a/c condenser and the radiator than it was to get it to the engine intake. Therefore they built the shroud around them to get the ambient air directly to them, and not to the air filter.

jsmn4vu

Assumptions will get us every time. Based purely on external evidence, I'm assuming most of you haven't noticed the rubber sealing strip between the hood and the top of the air filter that restricts airflow from the engine compartment to the intake when the hood is down.

And it may be that some of you are assuming no such airflow preventer is present.

Film at 11:00 after I can dig into it a bit deeper.

bow tie guy

I'm still trying to fathom the idea of hot air from behind the condensor and radiator making its way foward to the air boxes inlet while the car is in motion

"Hey Tom you want an aspirin or something"


and get a load of those pics I see the same opening ("deliberate path") as in my pics

if it serves no purpose what are the louvers or vents for

91 -96 use the same bumper reinforcement bar

and I guess they put the water diverter on the later higher horsepower higher compression engines help get more hot air from under the semi sealed under hood area into those hungry LT4 and LT5 engines

Tom400CFI

If there is no opening ahead, below, beside above the filter for cold air to enter...then there is really only one other place air can come from; the over the top and around the sides of the radiator shroud.

If you looked at my pics, you'll see that there is no opening ahead, below, beside above the filter for cold air to enter.




Look again. Look more carefully. Use glasses if you need to. Look especially closely at the pic I posted, where I noted that I had a shop spot light under the car shining up...you can't see it at all. There is no opening at all.





IDK what the louvers are for. IDK what the "water diverter" is. Is there such a thing? Or is that a name you gave to a "thing" on the filter inlet? IDK.As far as *I* am concerned, the radiator shroud would "divert" water just fine. Maybe those devices are for induction noise attenuation? Dust (like on heavy equipment inlets?) IDK. But using that as "proof"...as "FACT, TOM" is a pretty **** poor way to conclude something.

I also don't follow the "asprin" comment...nor do I understand why you keep quoting (in bold, of course) the "semi sealed hood area". Is that a hard concept to understand? The hood has seals around select areas of it's "flange". Around the wheel wells, along the cowl, for example. Other areas are not sealed: around the bottom/sides/front of engine, the bumper to hood panel gap....not sealed. Hence, my use of the term, "semi sealed". Part of it is sealed....the rest is not.


.

Tom400CFI

My car has no such rubber strip. Pics please.


So I figured out the issue w/my DVOM. I took my boy down to watch Nitro World Games in SLC tonight. On the way home, I wanted to take observations but the DVOM isn't back lit. So, I got off the highway, cruised through our neighborhood at about 35 mph (less than two minutes off the highway to my garage). Pulled in the garage and flipped on the DVOM which I could now read w/the garage door light on. Here is some bold face for you, BTG: Ambient temp was/is 60*F. Temp at my filter was 159*F.

That's not a cold air intake.

.

Tom400CFI

Say what? What are you talking about? My cut filter lid? You're going to poke fun of me for that are you? Previous owner did that...not me. Nice diversion.



I know. *I* was one of the TWO people who posted IAT data. You haven't. Where is YOUR data. Only thing you contribute to this topic is bullsh!t and conflict.

If you knew anything about tools, you'd know how accurate the Blue Point MT586 is, and you wouldn't be slandering it. Oooor, you probably would, because your role here in this thread doesn't appear to be in seeking out fact. You seem to have other, less noble motives. A shame a fellow forum member behaves this way.


.

Tom400CFI

Nicest month on this forum.


Your data wasn't data. It was a pic. That is something, but it's not data.

*I* acknowledged that the car in the pics you posted does appear to have some kind of port/hole...whatever you want to call it. FYI, that is not a "deliberate path of cold air". A "deliberate path" would be a formed tubing from the filter housing, to the hole that your pic depicted -like my Silverado, and V has. Anyway, why can't you admit that my pics show no opening? It's incredibly clear. Anyone w/eyeballs can see that there is no hole. I asked you what you make of that. You lied and said that you can see a hole, but we all know that ya can't. There isn't one to see.
If you can see a hole, do this; use photoshop or some similar program, and draw an arrow pointing toward the hole in my shroud. You won't, because there isn't a hole to point to. Now....I don't know why the car in the pics you posted and Ron's pics apparently have an opening. Mine definitely doesn't (FACT, BTG -as you like to say), so why the diff? 91 Black convert's car doesn't have one, he says. The car in the pic that you posted should have the same shroud as mine, I think. Why the diff between cars?

Now I post real air filter temps. I admit that the data thus far isn't the best -more controlled testing is in order. You contribute by saying that "my pot is full of holes". That is a bullsh!t statement. Tell this forum HOW, specifically, a temp probe at the filter element, measuring 159*F on a 60* night, how is that full of holes? it's way more data than you're contributing...


.

Tom400CFI

Why are you re-posting the same irrelevant posts...that you already posted?

The car in the link appears to be an '84. This thread is about late C4's. At least, that is what *I* have been talking about. Try to keep up. If I'm making a "dog and pony show" I have no fear of being the only one, with you posting your drivel here.

If you can see a hole, do this; use photoshop or some similar program, and draw an arrow pointing toward the hole in my shroud.

Why the diff between cars?

Tell this forum HOW, specifically, a temp probe at the filter element, measuring 159*F on a 60* night, how is that full of holes?

Tom400CFI

What does "jamf" mean?
You already posted that. This is the third time. Why do you keep posting the same posts, over and over again? I guess that I have to repeat myself. That is an early car -an '84 I believe. Different shroud, front end, induction system, etc. Anyway, I did get similar readings to his...right after I started driving my car w/a cold engine, and coasting down hill at highway speeds at idle. In other conditions, I got different results. Why the diff between cars?

You said you saw a hole in my shroud. That was either a lie...or you're blind.



If you can see a hole, do this; use photoshop or some similar program, and draw an arrow pointing toward the hole in my shroud.

Why the diff between cars?

Tell this forum HOW, specifically, a temp probe at the filter element, measuring 159*F on a 60* night, how is that full of holes?


I don't know what your "mission" is in this thread...but it certainly doesn't appear to be for the benefit of knowledge.

.

bow tie guy

https://www.corvetteforum.com/forums...-cold-air.html



ps the car is a 1990 model try and focus Tom



Your figures don't JIBE

Tom400CFI

More repeat posts...no answers. I see a pattern here. AMF.

bow tie guy

yes Tom more posts with links to real IAT results

jsmn4vu

I think you're on the right track measuring temperatures to get to the bottom of this, but you've got a thermally conductive wire going through a hot zone (the engine compartment). The tip (which works well for point contact against a surface) WILL get raised to that temperature, without something to cool it that's more effective than airflow past something the size of a pin head.

IOW, to get a valid reading, you need something better suited for the application. Absent the proper instrument, I would suggest an RF indoor-outdoor thermometer with
o the hood down and
o the car moving.

Those two conditions are essential for any valid reading.

Tom400CFI

Good points. Thanks for the constructive input. I'll see what I can do to get something meaningful. I spent a good bit of time taking measurements today, but none of the data was any good, I didn't feel.

pologreen1

I have nothing in front of my radiator anymore, and I cut open the shroud in front for a mod suiting the car in the past. I may close it back up at some point, but I have no problems with cooling on my car even with Chinese radiator cooling my larger than stock motor.

In stock form my car has an angled radiator that has an ac condenser in front of it, both of these units sit under a radiator shroud or almost cowl. The air filter sits in front and gets it's own air up to the intake.

People have said over and over "bottom feeder' take a minute and go look at your car or read posts from the 90's even on the net and figure it out. It's simple and nobody said it was the best design but it worked well enough to sell many thousands of cars and still have them be drivable decades later.

If you had a sealed off bottom of the car it would need a different design.

Can I ask what makes you so intrigued by this simple design concept?

PatternDayTrader

Leave me out of your nonsense tom. I have always treated you fairly.

Even if you were right about whos "hucking slander" (your not), then it wouldn't be slander anyway. It would be Libel, but I'm not surprised you don't know the difference.

Did you ever try to deform the trim pieces as to create an air gap, similar to the earlier cars ?? I know we had talked about it in the other thread but it may have been too much hassle ...