Rxseven7

i have a 88 t11 and i wana get the alium. shroud that gose around it instead of the plastic, we can i get it?

TehMonkay

iTrader: (-1)

if you mean a cold air box there is no inexpensive or even reasonable place to get one, much easier to make it yourself.

RotaryEvolution

iTrader: (30)

there is only 1 or 2 aftermarket sources for "cold air intake boxes", one costs $400 and is carbon fiber and the other i haven't seen in forever, aside from that the only option is to be creative and make one yourself.


the only question i have to ask is: "why bother?"

there is no cold air flowing anywhere near that area and even the ones i have seen that were done well will barely make it worth the effort.

incubuseva

iTrader: (13)

^That's not entirely true. There are lots of cracks from the hood + lights. There's also that hole where the washer fluid filler neck is. If you take that out then you'll have a decent amount of air that is colder than the surrounding air that's hot from the engine.

Rxseven7

dose anyone have one that they wana sell

micah

Aluminum is a terrible material to make an intake out of. Make your own out of cardboard for better results. (I wish I was kidding)

Evil Aviator

http://www.mariahmotorsports.com/
http://corksport.com/

I assume that's because you think that the aluminum will cause massive heat transfer to the intake charge. In actuality, there is very little heat transfer because straight-wall metal doesn't transfer heat very well, and at the typical rotary engine's flow rate of 250-400cfm there is little time for the heat transfer to take place. Aluminum is a very good material because it is cheap, light, corrosion resistant, malleable, weldable, and it is easily fastened with rivets, screws, or bolts. Cardboard is great for making a mock-up of an intake for planning, but it is too moisture sensitive and fragile for permanent use.

micah

I was mostly kidding about the cardboard... however, I DID think aluminum would cause excessive heat soak for intake tubing and air-boxes. Thanks for inserting your knowledge into me. My plan was to fiberglass/CF a box for my car or vacuum form one out of ABS/Acrylic. I'm assuming those would heat-soak less than aluminum. And in an NA.. every ounce of improvement is needed.

micah

Hey aviator... Having thought about it some more....I have a question... Why, if aluminum doesn't heat soak very well, are most heat sinks made from arrays of sraight-walled aluminum? The purpose of a heat-sink is to heat-soak. Seems like the same think we are trying to avoid...

clokker

iTrader: (2)

Heat sinks are NOT made to heatsoak, they are designed to transfer heat from a concentrated area (the CPU) to a larger surface (hence, the fins) where it can be disbursed, usually by forced air (i.e., a fan).

chatchie

iTrader: (22)

Aluminum dissapates heat very quickly, steel and cast iron tend to hold, I would assume that a plexiglass or acrylic would be the best way to block off the filter assuming that it would hold upto the heat in the engine bay.

micah

They are designed to ABSORB heat as fast as possible so the fan/ambient air can pull it off.

Yes... dissipates it very quickly.. which means that it would dissipate it right into your air-stream.

I'm not saying I'm right.. I'm just saying, the logic of heatsinks makes me think aluminum is a bad material to use.

Rxseven7

well thanks guys this is great so it is worth gettin one.

Tsuka

Gonna have to agree with micaheli... the way you explained heat sinks make this idea sound even worse.

"They are designed to transfer heat from a concentrated area (the engine) to a larger surface (the aluminum box) where it can be disbursed, usually by forced air (i.e., the intake air) resulting in a hotter intake air."

RotaMan99

^ My aluminum intake piping gets very warm and sometimes hot to the touch. Im pretty sure its effecting the intake temps. Especially the intake manifolds as well.

Unseen24-7

Though not asthetically pleasing, would heatwrapping the intake pipe be a good idea?

clokker

iTrader: (2)

Both of you are missing (or ignoring) a very important factor about heatsinks though.
Heatsinks are in direct contact with a very hot heatsource- in fact, extra care is taken to maximize this contact (thermal paste/lapping the CPU).
The heatsink is then designed to maximize the surface area available to force cooling air through it.

I did not make the analogy that an aluminum heatsink was comparable to an intake shroud/box, I was simply commenting on micaheli's statement about heatsinks in general.

Evil Aviator was absolutely correct about the general nature of heat transfer as it relates to sheet metal -of any composition- basically, it's not a factor.

@Tsuka- where did you get the idea that heatsoak- to whatever degree that it IS occurring- is coming from the attachment of the intake box to the engine?
My understanding is that air, heated by passage through the radiator, is the culprit.

chatchie

iTrader: (22)

Lots of auto makers are using plastic to make their intake manifolds now, this has gotta tell you somethin. Even my Slk, which is supercharged, has a partially plastic intake manifold.



"Plastics Make It Possible" I know you've seen tyhe commercial.

micah

True enough, but the temperature differential between both sides of the aluminum CAUSES heat transfer in metals. It doesn't matter how hot the heatsource is, it doesn't alter the properties of the material. The aluminum is in direct contact with the hot-hot-air, and the moving air inside the intake would be acting EXACTLY like a heatsink. Carrying off the heated air. The ONLY thing cooling down the intake piping/cold air box would be the air moving through it. Heatsinks are exactly that.

We're all friends here. no worries
Sheet metal, bumpy metal, cast metal, it doesn't matter.. the only difference is the efficiency that it dissipates heat due to the amount of surface area created by the shape of the metal. The fact is that it DOES transfer heat and that affects intake temperatures and air density. Making cardboard (sarcastically, but accurately) a better insulator than aluminum... although definately not a practical material. Something like corrugated plastic would be great, but highly oversized.

Again... I might be wrong.. but I have yet to see real data indicating this. So, feel free to prove me wrong. I live for it. Perhaps we need to take this offline and let this guy have his thread back too.

OP: sorry for the hijack!

Evil Aviator

The heat soak isn't significant, but I do not see anything wrong with using other material.

When I was a very young boy, many toys were made out of metal. Now toys are mostly made out of plastic. It must be because of heat soak.

I can't teach you 4 years of thermodynamics in one internet thread. I would if it were possible, but I'm afraid that you are going to need to either take my word for it, take some college courses on your own, or just keep your own incorrect yet harmless opinion on the subject.

BTW, what are you going to do about the metal upper intake manifold, lower intake manifold, and throttle body that are all made out of ... METAL ... and would obviously "heat soak" much more than a little intake box?

micah

I see your point, but I'm pretty sure you just called an SLK a toy.


Oh.... playing the "I took this in college" card eh? Thats cool. I took psychology for 4 years too... doesn't make me an expert, but I'm pretty sure you are what they call in "the biz" a "dick". Hehe. okay.. I don't really think that.. but it sounded funny in my head.

I painted them black... so they LOOK cool. And honestly, I'm not looking to make a HUGE difference with the material I make the box out of.. or the intake piping... but, I have an NA right now, every teeny bit of power/efficiency I can muster up counts. Any NA owner will agree with that I think.

micah

Upon "finding" some more information, I admit defeat! clokker sent me this: http://www.specjm.com/toolbox/engine...n/81-1-ISD.pdf

Great information about exactly what Evil Aviator was talking about.... Heat soak would occur, but in such small amounts it'd be virtually unmeasurable. Good stuff to know. but I'll probably still use fiberglass/CF due to ease of shaping and availability (I have a bunch somewhere).

Good job EA, looks like your 4 years of classes paid off. You stinking jerk. j/k, we'll all friends here.

clokker

iTrader: (2)

To be more accurate Micah, I don't believe that data I sent you addresses the amount of potential heatsoak- which is at least partially dependent on the delta T between ambient and intake air- so much as the difference that the duct material would make.
A small point to be sure, but it can't be denied that any intake will suffer from some degree of temp increase- it's just that the material the intake is made from isn't going to be very significant.

Once reasonable steps have been taken to introduce the coolest possible air, I think the next most beneficial move would be to concentrate on engine bay air extraction.
In other words...more bang for the buck trying to lower engine bay temps rather than insulating against them.
Nip the problem in the bud as it were.

micah

Right, right that data you sent me made me realize I should be focused more on the design of the air-box rather than the material its made of.

Evil Aviator

That was a multi-level remark. Congratulations on picking up on the most sophisticated point.

BTW, I was actually considering a SLK myself. It's the only new car that I like. However, I decided to drive my truck for a few more years and wait and see if a new RX-7 hits the market.

No, it's the "I'm not a professor, and I can't see how it is possible to explain the concept in a single internet post" card.

Black absorbs heat!

Sorry, I couldn't resist.

I disagree with that plan. I don't care much about engine bay temps as long as components are not getting ruined by the heat. My focus would be on pressure, which is where most homemade CAI's fail miserably.