You don't need a heat shield, and don't have to get one at the same time, even if you do want one. You can always get it later and add it on.

 

It was not a general opinion it is pretty much a fact given his car's current state (stock). This topic has been covered 100 times over on this forum just search it I won't waste time explaining it to you.

 

if you don't put in a heat shield however you will get heat soak and the whole cold air intake purpose is defeated. if your gonna do it, do the whole job. the heat shield shouldn't be too hard to put it. it can be a fun lil project for you and your audi.

 

On an N/A motor you may see a slight benefit from a heat shield, but on his car (1.8T), the turbo's gonna heat the air up before it gets to the engine. The minor difference in intake air temperature isn't going to matter for the turbo car, because any advantage the heat shield may impart will be negated by that smoking hot turbocharger that the air has to pass through. As for the naturally aspirated engine, like the 30v, the intakes really don't increase power production anyhow, so you can heat shield the intake, but it really doesn't make any discernable difference. That's just how it is on the A4, which is why he actually doesn't need the heat shield.

 

Wrong, the lower you make your iats the better you cant argue with physics my friend and Air intake temperature is used to correct fuel quantity (pulse width) since air temperature effects air density. (colder air is much more dense) Approximately 70°F is generally used for 0 correction, temperatures above will result in less fuel to compensate for the lower air density, and conversely temperatures below 70° will result in steadily richer (by volume) mixtures. Bad readings will effect ECM attempts to keep the air to fuel ratio proportional

 

You're missing the point here. I understand very well about relative oxygen density compared to air temperatures. What my point is (and I apologize for not spelling it out more in-depth), is that when you consider the engine bay to be a largely enclosed metal chamber, with a great big, hot metal lump in it (engine), heating up all that surrounding air, your ambient underhood temperature is going to be pretty warm. In the case of a 1.8T motor, it'll be even warmer due to radiant heat coming off the scalding hot turbo and downpipe.[/align][/align]Now, you can fab up a heat shield and put it in place to try and block some of that heat, and you'll probably have a little success. I'd be willing to bet that the air on the filter side of the heat shield may be as much as ten degrees cooler than the air on the engine side (maybe even 15 degrees or so). That's hardly a "cold" intake, and really doesn't change much in the thermodynamics. Ingesting 120 degree air instead of 130 degree air will not give you a noticeable power bump.[/align][/align]Now, the biggest factor, and the one that I was getting at in my original post. Take that intake air (whether or not it's coming from a shielded filter), and suck it through a hot turbocharger (because anyone with a functioning brain knows that although the turbine side is considered the "hot" side of the turbo, you wouldn't want to touch your pecker to the compressor side anytime it's been running). That act alone will dramatically increase the temperature of the intake charge. Then of course, you're compressing the air, heating it further. Yes, the car has an intercooler, and it's probably a halfway decent design, but face facts - the OEMs invest just enough money to give a functioning part with a little safety margin, so they can maximize their profits, so it's safe to assume that we aren't talking about a fantastic heat exchanger. The result is the same - whether or not you use a heat shield on your air intake, you're still going to drastically raise the intake temperature of the air, and if you were to measure the charge temperature at the throttle body, I'd bet that you'd see very little difference between the temps in a car with a shield and one without.[/align][/align]My point on the NA car possibly seeing a better gain from a shield is simple - you're starting with cooler air anyhow, and that cooler air, once pulled into the intake tract of the engine, is not being supercompressed and ambiently heated by a turbo, so the overall charge temp increase would be much less. Because the temperature increase is much less as the air passes from filter to throttle body (relative to a turbo car), any starting difference in intake charge temperature is likely to be more of a factor once the air actually enters the combustion chambers.[/align][/align]You just have to think about it a little and it will make sense - you'll see what I mean if you think of it in this way.[/align]

 

You actually took the time to write all that why? I am not missing the pointI do beleive you are. Like you said in your post yes you are starting with cooler temps on a NA engine but its all relative. By taking extra measuresI.E. heat sheild, intercooleryou will be able to lower your iat on a turbo engine and you can not tell me otherwise its plain and simple. Do not respond to this because I am sone with you

 

First off, let's drop the "I'm done with you" crap - it sounds ridiculous and childish, and this whole discussion will actually have a point if the debate continues intelligently without resorting to playground behavior. [/align][/align]It sounds like we're not seeing eye to eye on our points of view. I understand completely that lower IATs mean more power. Absolutely they do, and no one with the most basic understanding would argue that. My point is, you're glossing over the fact that you may be able to get a slightly lower IAT with a heat shield, but it's only a marginal improvement, and one that is most likely negated by how much more the air is reheated (or further heated) by the turbo's ambient heat and the compression of the intake charge by the turbo. The heat shields we're talking about are not a fully-encased, outside-air-fed, fully heat-shielded encasing of the air intake filter. It's a metal partition blocking some of the engine's radiant heat from the filter, using thin sheetmetal and what amounts to duct-work insulation. This isn't F1 technology being put to use in our street cars.[/align][/align]If you were talking about a true cold air intake, down somewhere in the nose of the car, drawing outside air instead of heat-soaked engine bay air, there would probablybe a tangible difference. But simply puttingin a partition such as the common-designheat shield that we are talking about isn't going to lower your IAT enough to make a real difference (that's my point about the fact that it may drop the temps by 10-15 degrees or so). If you were to make back to back dyno pulls, with and without the heat shield, on these particular cars, you might see a couple hp at best. It's nothing you're going to feel out on the street. [/align][/align]So the case I am trying to make is, effectively, the heat shield isn't going to really help you - it's not going to make much difference whether you make 200whp or 202whp in a 3400 lb street car at the track. Technically yes, there's an improvement in engine output, but when we're talking about cars like the A4, with the curb weight it has and the engine output it makes, does a couple hp really matter?[/align]

 

I knew it, you are missing the point. No where in this post did I say you would have significant horsepower gains from a heat shield, I actually do not agree with putting the cai on a stock 1.8 and you will see I wrote that as well. Your points are moot and this debate is getting no where so just drop it and do some research please

 

I'm putting this to rest after this post as well, but seriously man (and this is not me trying to be a *****) but you need to get the chip off your shoulder and not make some of your posts so snotty. There's nothing wrong with people putting up valid opinions, and in the case of our "conversation", my point was made and so was yours. I don't need to do any "research" on the topic. We were both talking about the same idea with different angles, and neither was wrong or invalid. But making comments to people like the one saying that they're just posting to get their post count up - is that necessary? It accomplishes nothing escept to generate hostility. Just relax a little and let things go instead of getting defensive and it'll keep everything a little nicer on here.