Easy 25% Intercooler Upgrade for NB & Jetta W/Pics

An easy, cheap. and effective way to gain 25% more flow though your OEM intercooler assembly is to simply cut out the crappy OEM plastic blocking the airflow into the intercooler vent. A propane torch applied to a red-hot steel knife blade works wonders in cutting out the excess flab in a sort of lipo-flambe type arrangement. Piece of cake for even the most mechanically challenged TDI affectionaco!

The rewards are instant and constant, Yankees worried about snow shouldn't be, step on the throttle to MELT any snow that would accumulate! LOL I did this to my beautiful TDIs the minute I got home with them off the lot after I paid for them.

Here is the plastic surgery on the JettaIV TDI:


Here is the plastic surgery on the NB TDI:


Here is my collection of famous European marques on the car-port log pole that I pray to each day:

Sure Beats Walkin'!

[This message has been edited by SkyPup (edited August 01, 2000).]

Great idea, SkyPup!

Are u sure that 25% isn't an exaggeration?

When I went braless, I noticed no increase in power due to extra air flow (the bra had a screen by the intercooler).

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Ric Woodruff

1998 Jetta TDI Sport

[This message has been edited by Ric Woodruff (edited August 01, 2000).]

Ric, you have an A3 which seems to have better air flow around the intercooler.

-brian

I would estimate that the airflow through the OEM plastic grids to decrease the airflow by at least 20-25% minimum at a speed of 60 mph. remember that intercooler are rated at an airspeed of only 10 mph through the fins, since that is the average they get during a normal driving cycle not on a race track. Needless to say, the difference is very great during the winter time when the ambient temps under the hood are highly contrasted to the outside lower temps. During the summer the differential is not so great, however it is just as important in keeping combustion temps down on a 1:1 basis for less stress and strain on the engine and oil.

Instead of cutting oem piece, what you could do is get a greedspeed grille for it. It enhances the air flow and the look of the car.
How are you sure you have experienced a power gain when doing this mod anyways???


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Satin Silver Mk4 Golf TDi
Hella Optilux
Reactive cold air system
35% tint

VW club of Vancouver

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by A R T:
Instead of cutting oem piece, what you could do is get a greedspeed grille for it. It enhances the air flow and the look of the car.
How are you sure you have experienced a power gain when doing this mod anyways???

<HR></BLOCKQUOTE>

How are you sure that I haven't? Perhaps you can share with us your performance mods and your associated power gains so that we can learn something new here?

Boy I am glad I have a Golf. They juts have the grill, nothing blocking it though, you can see right into the IC.

Yeah, the intake air vent on the NB is about 1/2 the cross sectional area of the Jetta's, so it is even more important on a NB. Even gauged out, the NB's still is only about 1/2

I can look straight through the plastic grid on mine and see the IC. Yours was completely blocked?

Maybe I'm missing something here.

The entire passenger side vent simply pulls out. In June, I removed it for a day to use the tow hook to help stablize a canoe on my roof rack--the car didn't need to be towed.

Wouldn't removing the entire vent be even easier, cheaper, and more effective than torching it?


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Rob
2000 Golf GLS TDI (Wetted ECU, VNT 1-turn tweak, K&N, MAF & lower airbox screens removed, spare Relay 109, euro badge (red "DI"))
2000 Passat GLS Variant 1.8T (K&N)

Rob,

you're being too practical

BTW, this characteristically ultra simple and super cheap mod is on par with the super simple highly effective intake air screen and snorkel removal. 99% of TDI owners never knew anything about it before someone told them about it here on Fred's TDI Forums. There are still hundreds of thousands of uninformed TDIs around the world trying to suck something through that POC.

That's what we try to do around here, inform people and let them make their own choices.

Here is the "BEFORE" VW Jetta IV OEM POC grille cover completely clogged with polyvinyl so that NO air enters whatsoever:


Another shot of the same OEM stocker with ZERO airflow:


Any more questions?

Removing it is fine too. Painting the rim around the vent deep black would look good. I just cut mine out and stuck it back in for the black outlined rim effect, otherwise I would have left it out entirely.

It appears that since these cars are all built at the same place on the same assembly line, there may be some foul-ups between the 2.0L and VR-6 gassers (NO INTERCOOLER) and the 1.8T gasser and TDI (INTERCOOLER) when it comes to the installation of these vents.

Which works better, a blocked intercooler vent or a totally open intercooler is in itself a NO-BRAINER

I AM THE NEW TDI PERFORMANCE MEISTER!!!!
THE KING IS DEAD! LONG LIVE THE KING!

Rob,

Why limit yourself like that? How about something simple, elegant, and all-encompassing?

I would suggest:

Eve ein haar dieselmeister!

dc

May I ask what in the heck are you all talking about? Excuse my ignorance on the subject. I've only had my 2001 TDI about three weeks so I'm still learning.

Where is the grill or whatever you claim is blocked? Please email me at n5cs@tyler.net if it would be best.

Do you recommend purchasing the VW Beetle Service Manual by Bentley?

Thanks.

Ha, you guys are funny!!!! SkyPup, yes it would make a difference if the vent is entirely closed but mine was not, so sorry! But really, after doing a minor mod like this, how are you SURE of the effects that it has? It's because of this problem so I don't know how to measure the power gains of my mods...

Take it easy...

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Satin Silver Mk4 Golf TDi
Hella Optilux
Reactive cold air system
35% tint

VW club of Vancouver

Well, removal of the screen will surely get more air to the intercooler, but why not consider a much better looking sollution?
With the front spoiler of Caractere (go see http://www.caractere.be, and look for 'Bora' not 'Jetta IV') you get an awesome front spoiler with bigger air intakes!

Just a thought.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by A R T:
Ha, you guys are funny!!!! SkyPup, yes it would make a difference if the vent is entirely closed but mine was not, so sorry! But really, after doing a minor mod like this, how are you SURE of the effects that it has? It's because of this problem so I don't know how to measure the power gains of my mods...

Take it easy...

<HR></BLOCKQUOTE>

It is called the placebo effect. If you think a mod is having a positive affect, then it is! (in your mind)



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Ric Woodruff

Everyone should believe in something...
I believe I'll have another beer!

1998 Jetta TDI Sport

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ric Woodruff:
It is called the placebo effect. If you think a mod is having a positive affect, then it is! (in your mind)

<HR></BLOCKQUOTE>

How right INDEED Especially in Ric's very own case evidenced here in his very own words. He doesn't have it, he doesn't know what it is, and he never will since he is hopelessly lost in his own imagination - IT IS ALL A DREAM FOR HIM!! hehehehe, but what a joke his post is for me!

Ric - dream away and post all your dreams here, we love to hear about your imagination.

If anyone in the Performance Board is really serious about increasing the Performance of their VW TDI, the very best thing they can do is listen to everything that Ric dreams of and then do THE EXACT OPPOSITE. His frontal cerebellum operates as a inverse consciousness interperter for him, everything that he thinks is the direct opposite of reality.

Hey Ric, GET A LIFE BUD! maybe cut back on the ethanol intake some so you can think better! Hahahaha......what a joke your dreams are........

These personal attacks are stupid. I really wish you'd cut it out. Ignore the guy if he irritates you.

Agreed, now back to the original topic before I was so rudely interrupted:
--------------------------------------------

Have you ever noticed how a cold drink warms faster on a hot day in summer than on a cold day in winter? Or how a warm cup of coffee cools faster on a cold winter day than on a hot summer day? If you have, you've experienced the basic concept of heat transfer.

Heat flows from hot to cold. On a hot summer day, heat flows through the glass of a cold drink, warming the fluid within. On a cold winter morning, the heat from a cup of coffee flows through the mug and into the cold air. It is the difference between the air temperature and the fluid temperature that allows the temperature to flow.

The term used to describe the difference in temperature between the two mediums is Temperature Differential. When sizing a heat exchanger, this difference is measured at the point each initially enters the heat exchanger. From this comes the term Initial Temperature Differential (ITD). A more formal definition of ITD would be the difference in temperature between the fluid being cooled and the cooling medium.

Just as pressure difference pushes flow along at a certain flow rate, temperature difference acts to push heat along at a certain rate. High temperature difference moves heat faster (higher Btu/hr) and lower ITD moves heat more slowly (lower Btu/hr). ITD is the basic cornerstone of heat transfer.

For any heat exchanger to work there must be a difference in temperature between that which is being cooled and the cooling medium. The greater the ITD, the more efficiently a heat exchanger transfers heat. It is the concept of ITD that allows for the proper sizing of a heat exchanger.

As you may have guessed, the compressed air leaving the compressor wheel housing is very hot as a result of both compression and friction. So what's needed is a way to cool that air down before it enters the combustion chambers.

That's where an intercooler heat exchanger comes in. It reduces the temperature of the compressed air so that it is denser when it enters the chamber (heat causes things to expand, as we all have learned in science class). The charge-air cooler also helps to keep the temperature down in the combustion chamber. The result is more power, better performance, less thermal stress on engine components, and less emissions. Taken together, the engine, turbocharger and charge-air cooler form what is known as a the "charge-air system" since the engine is a basic air pump, however now it is capable of pumping more than ambient conditions would allow.

For anyone still hopelessly confused about the entire system on their TDI, here is a good overall pic;

My TDI Jetta came with the vent open to the IC and seems to provide plenty of flow. I added the Audi TT inner fender vent to that 'cause it makes sense that getting more air through the IC may help (certainly can't hurt). I think if you already have the vent to the IC open, there is not much to be gained by cutting out the little plastic grille entirely. I have yet to see anyone who has done this mod, taped their exhaust, etc. post any before/after G-Tech or dyno measurements to prove their performance claim. Without quantifiable evidence, I am not convinced. This is not a slam against anyone, so please don't take it personally. I just think that we all will do our forum brothers and sisters a greater benefit if we (myself included) back up our claims with provable/measurable data. "Seat of the pants" doesn't count.

The chip comparison that Gary just did is the most useful testing I've seen done here - especially if he can post his graphs.

East Texan, to answer your other question, of course you should get the Bentley manual! Get it on CD, BTW.

http://www.robertbentley.com/resource.htm?subject=21

I am also skeptical when it comes to this mod. There is nothing blocking the grill on my TDI. As a matter of fact I use my pressure washer every time I wash the car to blow off all dead bugs smashed on the intercooler. The grill doesn’t look that restrictive to me. You would have the same effect, if not better by mounting a small fan behind the IC. If I recall correctly this only improved the performance by 0.5 hp. Who done that? Howard?

Someone suggested replacing the plastic inner fender with one from AudiTT that has vents allowing the air to go through. In my opinion this is by far the best you can do for increasing the flow.


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George Manolov
2000 Jetta TDI

well thanks to you guys, i am just going to remove the damn IC all together...so there
and ric doesn't need on either seeing as he never goes over 1500 rpm anyway
skypup said a 25% increase in air flow not HP. do you guys realise how ram air increases air flow??? i would have to guess that cutting out the blocked area would increase air flow and taking the vent cover out all together would increase air flow even more. whenever something is removed that "spoils" there air even slightly, there will be an increase in air flow.

taking mine out right now.
garrett P.

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2000 JEDI TDI
Sub-Commander of the Epsilonian Contingent Nothern Hemisphere: Earth

As can be seen from the documentary photos above of both my TDIs, the entire air flow tract to the intercoolers on both TDIs are as CLEAR as it possibly can be in the OEM set-up. There is NO DOWN SIDE to this mod besides fear itself and the total benefit package with all my other mods is just icing on the beautiful cake!

Of course, I need more intercooler capacity with the present and planned mods, so this will only get better as time goes by.

It is simply amazing how afraid and confused some folks are of things they cannot understand.