Cold Air Intake

Tjr2550

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2001 TDI beetle & 2002 TDI golf
Not sure if I posted in the right category but, I'd like to put a cold air intake into my 2002 tdi golf, but the only thing I've been wondering is what do I do with the MAF sensor, is there some type of manifold you have to buy so that you can still put it between the filter and the hose?
 

Ol'Rattler

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Couldn't he just cut the MAF sensor plug off and splice the wires together or would that make the ECU think the intake air velocity is 1,000 MPH?
 

jmodge

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You can have your MAF deleted with a tune. Unless there is a legal issue where you live.
 

oilhammer

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outside St Louis, MO
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There are just too many to list....
"Warm air intake"

Hehe, yep. I had to prove this to some kid once on a V6 Audi A4. Luckily, you can PROVE the difference by scan tool data. Just logging IAT and timing correction with his dumb-assed cone air filter nonsense then doing the same thing once we put it back to stock. I think there was something crazy like a 25 C IAT value difference! :eek: But it didn't "sound" as cool stock, despite it CLEARLY making more power that way. :rolleyes:
 

eddieleephd

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2002 jetta Wagon
Thehe OEM intake is a true CAI (cold air intake) and you would be hard pressed to find an aftermarket CAI that would be able to get cold air, however, it is possible.
You're going to have to do a lot of research and spend something around $500 and do a good bit of work to install and ensure it is sealed and only pulling cold air.
I just upgraded to the 1.8t air box bottom with the ALH top, and this is only an upgrade because there's a spring loaded flap on the bottom, pointed towards the engine to allow more air to enter if there's more resistance than the spring can withstand. It lets in warm air at that point, however, will meet the demand.
Your better off spending money on a cat back that will actually improve power than messing around with intake unless you want a larger turbo, then you still use the OEM air box.
On the other hand, if you were to install a FMIC instead of the OEM SMIC you could install the CAI in the bumper area, not that there's any room, and easily have a true aftermarket CAI. That'll set you back a good bit and only be worth it if you wanted to create a new race car running the largest turbo possible and R520 injectors with a stage 5 tune. Total cost doing this yourself is somewhere near the $3000.00 range.
So unless you really want to make a race car I highly recommend paying attention to the advice given. Most people (myself included) who come from the gasser world to the VW diesel world think about the CAI possibly to increase power, however, diesel is a totally different machine and plays by very different rules. More often than not the factory air box on any vehicle since the 90's has been engineered with a true CAI and most people throw their money away when installing an aftermarket CAI as they don't truly understand why it's called a CAI to begin with and leave it in the engine compartment where it never seems to be able to get cold air, only warm/hot air.
On a natural aspiration engine the CAI may make sense, however, on a boosted engine it makes very little sense.

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Ol'Rattler

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Taking retardation to a new level. It does look like it is a CAI, but using the hood as the top cover for the air box? Really? I'll bet new owners are foaming at the mouth in anticipation of dropping a K&N in that bad boy. :rolleyes:

 

eddieleephd

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2002 jetta Wagon
Welcome to the
!!! OEM COLD AIR INTAKE !!!
Below is the best possible routing and design for a cold air I take on a VW diesel unless modified some ungodly HP!
Reality is that having a vacuum within the air box for air to expand cools it down. This is accomplished by utilizing a sealed box that you control the dynamics and operation.
Below is the tube that wraps around the battery, it's sized larger than the lower boost pancake tube. (which is a far better place to consider an upgrade to the OEM system with an OEM designed part using the upgrade metal lower boost pancake tube.)
This tube is specific flow rates being considered and on a stock to slightly modified engine is more than adequate.
The tube on the upgraded plenum box (in one of the last pictures below) that points towards the engine is the OEM upgrade for vehicles with greater modifications that might occasionally need to draw a bit more air than the tube around the battery.

Where it comes out in front of the battery and behind the headlight

This is the area beside the battery and to the right is the opening for air to enter.

The same picture as above with the rear cover below installed creating the completed cold air intake.

The inside of the rear cover

This is the bottom of the 1.8T air box to the left you have the added volume air valve tube that points towards the engine above trans.

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This is the CAI installed

The picture below show's the bottom of the original ALH CAI filter plenum which only has one inlet for air.
 
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bobbiemartin

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There is an upgrade from the stock TDI cold air intake. Some R32s had a larger snorkle. It's easy to fit and looks stock. You can also get a larger MAF sensor and a PD150 turbo inlet tube if you want a larger path to the turbo. I like using factory parts over aftermarket when possible as they usually fit better. Not all cars are so designed, but fortunately the air inlets on MKIV VWs are well engineered and easy to upgrade with factory parts should the need arise. Here is a picture of the R32 snorkle I fit to my Golf, scroll down to post #29.
 

jmodge

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Taking retardation to a new level. It does look like it is a CAI, but using the hood as the top cover for the air box? Really? I'll bet new owners are foaming at the mouth in anticipation of dropping a K&N in that bad boy. :rolleyes:
Actually using the hood for a top cover is nothing new, quite common on large trucks. Performance cars of the late 60's and early 70's such as Ram Air Firebirds and Super Bees used that also.
 

eddieleephd

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Actually using the hood for a top cover is nothing new, quite common on large trucks. Performance cars of the late 60's and early 70's such as Ram Air Firebirds and Super Bees used that also.
Most of the trucks you speak of aren't too concerned with the sealing of the air box. Many More that are OEM have a cylinder and intake port/tube that draws cold air from the fender area.

It must seal and be controlled to have a vacuum cooling the air to meet OEM design minimum. As well it must draw fresh cool air in order to be considered a cold air intake.
I remember pulling the air filter off the top of my '75 Nova. Wasn't a cold air intake.
Using the hood creates certain challenge to getting a good tight seal which is capable of causing a low enough pressure to actually cool the air as well.
That's the purpose of the OEM air box. It was designed to allow the maximum amount of air and also have enough resistance to create the amount of vacuum needed to cool the incoming air as it filters.
The air filter itself was designed to be effective and efficient in it's function and minimize the resistance of air passing through it. This is done with pleating to increase the surface area so that plenty of air can flow through it, even when used for it's full service life.

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jmodge

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I was just uselessly pointing out that hoods for the top of an airbox is nothing new, been around awhile
 

eddieleephd

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I was just uselessly pointing out that hoods for the top of an airbox is nothing new, been around awhile
You definitely made a valid point. I just picked it apart because other people might think it was a good point.
A few manufacturers make a filter plenum, however, the best I have seen for a VW is a replacement top with filter and outlet tube, retaining factory inlets and restrictions. Otherwise, they're all warm air Intakes.

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Ol'Rattler

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I was just uselessly pointing out that hoods for the top of an airbox is nothing new, been around awhile
Didn't imply that it was something new. It just seems ridiculous to unseal the airbox every time you open the hood. Plus over time I would suspect the hood to airbox seal would develop leaks.

In It's defense it appears to be an actual CAI, just not as well designed as one that totally encloses the filter and uses the air filter gasket to seal the top cover.
 

bobbiemartin

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Didn't imply that it was something new. It just seems ridiculous to unseal the airbox every time you open the hood. Plus over time I would suspect the hood to airbox seal would develop leaks.
In It's defense it appears to be an actual CAI, just not as well designed as one that totally encloses the filter and uses the air filter gasket to seal the top cover.
You do know that is the factory setup on a Ford Mustang Shelby GT350 that makes in excess of 500 HP?
 

jmodge

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Didn't imply that it was something new. It just seems ridiculous to unseal the airbox every time you open the hood. Plus over time I would suspect the hood to airbox seal would develop leaks.
In It's defense it appears to be an actual CAI, just not as well designed as one that totally encloses the filter and uses the air filter gasket to seal the top cover.
Yup, see your point. Enclosed boxes I would think to be more trouble free. And harder for gawkers to spill something into.:D
 

Ol'Rattler

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You do know that is the factory setup on a Ford Mustang Shelby GT350 that makes in excess of 500 HP?
What does that have to do with anything? Did you know that 99% of the people that buy that car or most any other car will never drive it to it's full potential anyway? So ya. The more horsepower you have, the less critical half baked designs ideas become. Just make it stout enough so the customer can't break it.
 

Ol'Rattler

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Yup, see your point. Enclosed boxes I would think to be more trouble free. And harder for gawkers to spill something into.:D
Debris, that's what I was thinking. The filter would be a great place for hardware, small tools, pine needles, Cheeto's and other small debris to hide under.

If it rains or someone turns on the sprinkler while you have the hood open your filter would get soaked.
 

eddieleephd

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What does that have to do with anything? Did you know that 99% of the people that buy that car or most any other car will never drive it to it's full potential anyway? So ya. The more horsepower you have, the less critical half baked designs ideas become. Just make it stout enough so the customer can't break it.
If they made them that well, how would they sell parts?

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Ol'Rattler

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If they made them that well, how would they sell parts?

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More so parts are made stout enough so that the owner can't destroy them through normal use. You won't see a pinto transmission in say a Lincoln Navigator, but you will see a Lincoln Navigator transmission that might need to be replace 3 times in 100K miles, not because it couldn't handle the load put on it by the Navigator, but because it was just a plain old a craptastic design poorly manufactured.

I'm sure there is plenty in the design of the Mustang that will keep the parts replacement industry happy. For what it needs to do, the Mustang air cleaner will flow air and filter just fine and who knows? it might cause people the change their air cleaner once in a while.
 
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Votblindub

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Yup, see your point. Enclosed boxes I would think to be more trouble free. And harder for gawkers to spill something into.:D
AFAIK, the filters can handle some fluid well enough. I'm talking small amounts. Average rain/snow/car wash type situations where you have a bit of water splashing around. Definitely not submerging that intake or filter in water. I'm sure even if some water hits the filter media, it will spread out due to capillary action and will evaporate. If some makes it into the intake past the filter as a full droplet, it will likely hit one of the sides of the tubing somewhere on the way to engine. Or even if a completely intact droplet makes it past the filter, past the intake, past the the compressor, past the intercooler, past more ducting, past the throttle body, past the intake manifold and past the valves, i highly doubt it can damage anything.
The new Ford Focus RS has the same thing under it's hood
http://i.wheelsage.org/image/format...w-large/f/ford/focus_rs/ford_focus_rs_126.jpg
Seems to be effective enough, but how well will that insulate long term when that gasket will deteriorate some? Age, hot/cold cycles, dirt, debris, moisture, all kinds of fluids and chemicals on it. We'll see in a decade, but it seems to work for now. I agree, the enclosed box design seems to be less trouble prone. The filter can act as a gasket between the top and bottom of the airbox halves. Following the manufacturer indicated intervals, you'd have it changed out before it doesn't seal well(provided it's installed correctly and has no defects), so it's a non-issue.

Side-note: Do you guys remember those by-pass valves on cold air intakes?
 
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