QUICK, Do you work for NASA! If it is the same temp or cooler I don't care! It will look WAYYYYYYYY better powder coated then the stock grey IMO. I hope to be able to do it before the Spring Flingy................. Adam and Dave thanks for the info and the headache:drugs:
Lets get back to the volumetric flow through the manifold and answer that question first. It just might not make a difference if your manifold has frost on it or is glowing red hot. I have no idea, anyone want to guess at the volume inside the manifold? 6.1L = ~372 cubic inches At 4000 rpm the engine is moving about 744,000 cubic inches of air through the manifold per minute Thats about 12,400 cubic inches of air a second? The inside surface area of the manifold is not a perfect cylinder so it would be a bit more than that but there is a good bit of room in there (think about your radiator. It wouldn't work as well if it was just a big tank instead of a very long thin tube with fins). Surface area is important. I'm guessing that at 4000 rpm it takes less than a second to completely change the air in the manifold -- all the air coming in the throttle body is in the cylinders within 1 second. So this is where it would get a little technical. Given the inside surface area of the manifold and the difference between the entering intake air and the tempurature of the inside manifold surface, how much of an air temperature increase would we expect?
I've seen where some racers paint the underside white or silver and the tops black. Lighter blocks the heat and black disipates it out. They used the Duplicolor hi temp engine paint on Horsepower TV because it has the "ceramic plates" in the paint.
I wonder if there's any science behind that? Different colors reflect or absorb different wavelengths... but isn't that mainly in the visible spectrum? Energy transmitted by the sun is mostly in the visible or infra red spectrum isn't it? So color is very effective in the sunlight. So is all heat in this spectrum and does something white stay cooler than something black if it's pitch dark? (yes, the light ALWAYS goes off when you close the fridge door). Or is it primarily the material itself that makes the main difference in our application?
Yea, all questions and no answers:sorry:. This thread happened once before (sort of) and died without any real answers that time. I'm hoping we get some resolution this time. Anybody know the volume of the intake manifold? Take an extra one, turn it upside down, fill it with water, pour that into a bucket and measure it? Get a rough idea of the inside surface area. maybe guess what it would be if it was just a long tube. Measure the diameter and length of the runners and the plenum to figure a rough average diameter and length to estimate the surface area. Then.... someone has to know somebody in the physics department. We know the volume. We know the flow (let's say at 4,000 rpm) We know the intake air temp (let's say 75*) We know the manifold temp (let's say 200* (probably too high) -- unless someone has measurements) We know the surface area the air is flowing over (??) Given that I think someone could tell us the average air temperature rise passing through the manifold. Should be able to get a formula to plug in any IAT and any manifold temp and get the air temp rise to the cylinder. Then we'd know if it's worth doing anything to the manifold at all and how much. It could be a big deal or it could be insignificant.
Yo Quick, looks like you and I could go on and on for a few hours on this subject. Give me a couple days and I do have some answers for you. But right now is not the right time for me. BTW, my manifold that Adam is refering too is barrier coated. The original powder coated manifold was not. I have all the tests showing head, manifold, coolant, and intake charge temps. When I recently conducted the heat gain test on the new BT spacers, I was very surprised to see that even though we maintained the differentual temp between the head and manifold, the top of the runner increased. This particular manifold will be going out for powder coating new week and when she gets home, I will conduct the test again. I also have the ability to test the actual intake charge temp just prior to entering the cylinder. Let me handle some other stuff and I'll be back this weekend with some data for you.
OK, I'll ask. What's the difference between regular powder coated and barrier powder coated? Is the barrier coating a common coating, ie will my local place likely have it?
The barrier coating is on the inside of the manifold. It's the same theory as having the inside ceramic coated. Isolating external heat gain on the intake charge.
Woohoo! can't wait. Intake charge temp at the throttle body and intake charge temp at the cylinder is all we need. It all boils (<--pun) down to that. Adam, it's probably the case that a thermal barrier would only make sense on the inside of the manifold unless you had almost perfect phenolic spacers. If the entire inside of the manifold was coated with a perfect thermal barrier you wouldn't care what kind of heat was transferred to or through the manifold housing since it would be outside the barrier. Even phenolic spacers would be pointless. Unfortunately I don't think you can come close to a really efficient, really thin, thermal barrier (that's not to say it won't make a large difference) so we're back to the spacers and manifold housing temp is a concern. All this is assuming that the rise in intake charge temp through the manifold is significant. I'm guessing it may be or Cam would have quit testing after getting the data from the stock setup?
HHmmmm must stay posted to this thread I have a spacer in my trunk right now and have simply been waiting for the results on the coating of the manifold tests.
Sorry guys, all the info is on my office computer and I haven't spent anytime free time there since I teased ya'll. I will take care of this tomorrow afternoon, promise. :fart: BTW, that little experiment of getting runner temp readings ain't gonna happen for my intake. Between the exterior smoothing and interior porting, I have deemed the runner to thin to drill and tap. So sorry, I can't pull that off.
Promises, promises... lol. Runner temp readings ain't gonna happen? Crap, went from a 5 minute test to building the space shuttle. Maybe you could just borrow someone else's manifold and drill that? :angel:
