Nice Intercooler Article

Its all about gassers but that doesn't matter , the physics of the intake air and the compressor are still the same:

http://autoweb.autospeed.com/A_0084/P_1/feature.html

"Many factory-fitted intercoolers are undersized. Air/air cores no larger than a paperback book can be found in turbo cars with a nominal maximum output of 150kW. Cars equipped with this type of intercooler can be held at peak power for only a very short time before the increasing inlet air temperature causes the ECU to retard timing or decrease boost. A car fitted with this type of tiny factory intercooler is almost impossible to dyno test - the intake air temp rises so fast that rarely can more than one consecutive dyno run be made before the intake air temp is so high that the engine detonates... On the other hand, the aforesaid Skyline GT-R has a measured intake temp of 45C on a 35C day at 1 Bar boost and a sustained full-throttle 250 km/h!"

SkyPup, wouldn't it be unusual circumstances where you need peak power for more than a short time?

For instance, wouldn't quickly accelerating from a dead stop to say, 75 MPH be a short time?

I can see that if you were ascending a long, steep grade, heavily loaded or with a sizeable trailer, your intercooler may be inadequate, but wouldn't ours be just fine under normal conditions?

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Ric Woodruff

Braumeister von Sehr Gutem Bier
Since the Last Millennium

1998 Jetta TDI

[This message has been edited by Ric Woodruff (edited March 31, 2000).]

You are right on! For a normal OEM car like yours putting out max boost of 12-13 psi the OEM intercooler (as long as it is clean and not gunked up) is perfectly adequate for any and all operations encountered. No one here in the US is going to hold the throttle wide open for greater than 20 seconds of so anyhow.

However, adding 4-5 pounds more boost raises the compressed air temperature over 350 F. (up from 300) and then the intercooler is maxed out, especially during the summer. Increased boost demands increased intercooler performance, otherwise what raised turbo boost is achieved is lost by being converted to heat, so it is a lose lose situation.

The only OEM people that could benefit from increased intercooler capacity are those opearating at high altitudes (above 3,000 feet), towing (up moderate grades), or desert conditions over 95 F. (including Florida!).

My car, for one, could benefit from increased intercooler capacity ... and this was accomplished by trimming the bottom 3 inches off the left inner fender liner which in stock form leaves only a very small opening for the hot air to get out. (You have to leave enough of the liner there so that junk flying off the wheel can't hit the finned part of the intercooler.) Cost of this modification: $0. Can't lose!

Why would this benefit me? Because I pull a trailer. When I'm slogging up a long hill with the trailer behind, I know that last year before I did this, it was floored. The lower the intake temp under those conditions, the better. I'll find out in a couple of weeks how effective this mod was.

As for why VW left so little room for airflow behind the i/c, I have no idea.

Brian P.
'96 Passat TDI

Here are couple more pics from the momentum website.

This is one of 2000 golf 1.8t before the intercooler was installed.
http://www.momentummotor.com/cars/golf%204%201.8t/nobum001.jpg

Here is one of a 1.8 A2 jetta that they completed. Not sure about I want a rear end anybody with this setup though (not that I would want to rear end anybody )
http://www.momentummotor.com/cars/brians%201.8t%20jetta/BRIAN020.jpg

I would think that this would work well in Golf's & Jetta's, having the intercooler down there (apart from road crap). Not sure about the Beete though. I think Momentum has put one on (or it could have been HPA).

I would love to see under the hood on a Audi TT to see where they mounted the 2 intercoolers. Does any one know how they are hooked up? Could be something useful there.

J.

As for the plumbing on your new intercooler ideas, I saw an ad in one of the turbo mags..or was it sport compact car that said they would build you custom silicon hoses almost anything you wanted. Might be expensive but if anyone is interested I'll see if I can find the ad.

Skypup,

Is this the size of intercooler you are looking for?
http://www.momentummotor.com/cars/golf%204%201.8t/inter001.jpg

It is being done my Momemntum Motorsport (very close to RPI) on a 2000 Golf 1.8T. That would be good for Golf/Jetta TDI's wouldn't you think?

Now the only problem would be the plumbing which could get quite extreme. I know in my case, in mounting the intercooler some of the bends can be quite tight.

J.

Nice pic, it certainly looks about the same size as the OEM TDI unit. You are right, the hookup would be the most difficult.

We need a water/air intercooler - much more efficient - this is what will work best and comes in a small package. I am still working with the swedish company to make it for us. I plan to keep the existing air/air intercooler and add this water/air intercooler. I hope I won't need earplugs when the diesel pedal is pushed down.