andy-gts

I heard this shape changed the resonance and therefore quieted the intake sound

auzivision

I've heard two resonant theories. One is the already mentioned standing wave tuned for sound and another tuned to aid with flow. I know some modern cars have dead end chambers that are used to tune for sound. Then I heard a third theory that it’s a venturi used to create a low pressure spot intended to aid timing belt cooling/ventilation. So that part is still a mystery to me.

While I’ll agree that some of this look pretty cool, I’m still wondering how effective these solutions really are. Say the engine sucks in 2.5 liters per revolution and revolves roughly 10 times per second at idle. That would be 25 liters per second at idle. Then looking at the tubes, I’d estimate they hold less than 10 liters of air.

Then I ask myself, how much heat will be transferred to the air during the fraction of a second it resides in these tubes. My guess is this amount is insignificant when compared to variations that occur with ambient inlet temps. I know my car runs so much stronger on cool crisp mornings than it does in hot humid afternoons.

Mike Frye

+1, I'd love to see this data.
Intuitively this sounds right. I can't imagine that the plastic intake tubes transfer enough heat to the intake air to have any effect whatsoever, even at idle but especially at speed.

Also, is anyone aware of the 'golf ball effect'? I wouldn't be surprised if there's actually a layer of air that sits along the inside of the intake tubes that acts as a cushion in between the tube and the intake air that actually makes it to the engine. It has to do with the turbulence created by a rough surface like the dimples of a golf ball or (IMO) by the ridges on the inside of the intake tubes.

I'd love to see some temp data taken from the MAF or farther downstream to see a comparison.

Imo000

I was waiting for you to ask this.

SnakeFeeder

Awesome! Glad to have been of service. I know there's lingering doubt about the effectiveness of this, but when it comes to sitting in traffic in a Queensland summer this definitely makes a difference - at least on the initial pickup.

I actually ditched my old tapered ones and went with some of Roger's straight merc tubes. No detectable difference in sound...

hacker-pschorr

Who me???

Always good to know what other people are doing that works. A lot of false positives when it comes to measuring air temp.

Maleficio

That's a very interesting theory. I have no data save for what I've gotten from my Budtt Dyno. The car runs very strongly now regardless of time of day or traffic conditions (so far). I'll report back any other observations.

I plan on wrapping my entire intake system: airbox top and bottom, plenum and runners. I'm sure most will say it's overkill, but I'm on a mission.

mark kibort

GUYS! thats ALL a bunch of BS. Sorry, there is no scientific fact, research or even theory that can substantiate a 31 degree drop in intake tempurature by wrapping the tubes. thats a near 2% HP gain if it was true.

Look, as was said, the transient time of the air through the tubes is VERY VERY short. in fact, the speed of the air is near 25 to 30mph through the tube, depending on the size. The neck down area is a venturi, but it has NOTHING to do with flow enhancement. It is only a sound trick for resonance. a venturi in an intake tract, lowers the pressure, increases the speed, and then returns the speed to the air to what it was before the venturi, at a COST of a pressure drop (i.e. HP loss)

Getting back to wrapping tubes. ever bake a potato in aluminum foil? try this wrap, with fiberglass backing, felcro, etc as was mentioned. it will still bake. maybe up front the potato would not get hot for the first few mins, but after that, the heat will FULLY penetrate the potato. Just like the intake tubes, the heat penetrates the tubes in traffic. under WOT, all the tubes will be cooled by the incoming air and the only heat that will be transfered is what can be transfered through the tube. plastic, almost immediately, steel or aluminum, a little longer, and with wrapped plastic tubes, longer still, BUT what are you really gaining? you cant transfer enough heat in a 3ft section of 3" diameter tubes to make ANY difference in intake air temp. want to test the theory? take a tube heat it up in the oven to about 175 degrees ( about what the tubes will be in the engine bay). then, take a hair drier and put on cool and point through the tube. turn it on. feel that the air coming down the tube is still very cool, in fact, almost no difference. I would be surprised in that test, if there is even a 1-5 degree difference. WHY?? because there is very little surface area to transfer heat. also the boundary layers also insulate the the air flow from faster heat transfer.

if you really want to help your intake air temps by a REAL 31 degrees, make it out of CF, go WOT for a minute or so, and then do a drag race or dyno run. the entire intake, if cooled could probabably reduce the intake temps by 10 or more degrees, getting that extra 1 hp you have been looking for

mark kibort

Jim,

How did you measure, and over what time period. where did you measure.

If you use a good sunx temp sensor, and put it at the top of the air filter, you will see NO noticeable difference on a 105 texas day vs not wrapping the tubes. eventually, they all willl be heat soaked. sure, it will take longer to heat soak again if you go WOT, but we are talking the difference in sitting in traffic on a hot day. the next question is, if you do go WOT for a min and then tubes are cool what is the temp difference vs hot tubes during a WOT run. Im pretty sure you only did a temp test of the car just sitting there and that is really not a test at all now, is it?

mark kibort

Better get your butt dyno calibrated!

Hey, all you need to do is some 60 to 100mph timed runs. Ive been doing them for years on the same stretch of hyway. I can detect larger changes in HP, like 10 to 15hp, and have matched those issues on the dyno as well. as far as butt dyno, it doesnt work so well sometimes the car feels faster and in the end, racing against my competitors at the track, its alway the same. always the same on the dyno as well.

you are chasing your tail. the intake is heat sunk against the engine heads. (over 250 degrees) you cant do ANYTHING to stop the engine from heating the intake system. you may even do yourself a diservice, as when you do go WOT, all the heat will go into the intake, and wont be able to dissipate out the surface area, because now its insulated.

Maleficio

If it's all BS, why is my car running so much better now? What you're saying about the eventual heat soak is exactly what happened with Gorilla duct tape, but so far it's not happening with this tape I bought.

http://store.newlevelmotorsports.com/heheshta2wi5.html

Maleficio

This is a good point. This is why I cleaned the living crap out of the engine surfaces when I first bought the car. It was covered in 28 years of grime and slime, and I knew the engine wasn't radiating efficiently through it's surfaces. It helped.

mark kibort

because its in your head. you cant make the car run better by wrapping the intake tubes. what do you think is happening?? under idle, after they are heat soaked. (maybe now that will take 5 mins instead of 2 mins), but in traffic, there is NOTHING you can do to perminately insulate the intake tubes, and even if you could, there is NO potential for gains. trust me on this. Or if you dont trust me. get a temp gauge and put it on the top of the intake and do two tests. WOT after heat soak with insulation, and WOT before heat soak, and then WOT with no mods. you havent done this, I can tell, and you are only going on BUTT dyno, which is total BS. Keep in mind how long I have been racing WOT and feeling every little possiblilby of HP gain and loss. to feel the gains that you think you are feeling, you would have to be going back and forth with 10hp, and that is not going to happen unless you ran the air through an ICE intercooler (a real one) and were able to drop your intake temps by 60 degrees.

mark kibort

good idea, and every little bit helps, but no amount of grime is truely going to "help" radiate heat to make a cooling difference. maybe a degree or two at most.

Maleficio

How about this: I'm not gaining ANY horsepower, but now I'm not losing as much as quickly.