It begins....

Got the car up to the shop this morning. They looked it over and here's the plan of attack on the oil/water temps.

#1 Move the current oil cooler out from in front of the radiator
#2 Go back to a side mounted oil cooler, most likely run two of them in series, one on either corner of the car.
#3 Build a shroud for the radiator fans
#4 Add two side mounted radiators
#5 Add two more reverse louver vents, more on the center line of the hood behind the main radiator

This should hopefully fix the issue of oil/water temps on track and in 100F stop n go traffic

OK, time for another update.

Two more reverse louver hood vents are on their way to the shop, they'll be mounted just behind the radiator to help pull air through.

I've decided to add one additional side mounted radiator right now, they're coming from C&R and well, cost is a bit of a factor. It'll be plumbed to run parallel to my current RD radiator and plumbing will be redone to eliminate all the 90 degree turns I currently have. This is a modular system and I can add another radiator if I need to. This will get custom ducted and get air from the fog light opening as well as the grill opening below the fog light.

On the other side will be my current PS cooler and a V mounted oil cooler that's 13x15. It'll be mounted behind the crash bar, so I'll gain some protection for it. Again custom sealed ducting from the fog light and grill opening.

Hopefully this takes care of water/oil temps while on track in altitude and close to triple digit ambient temps...

Hope this works for you.

Not much else I can do. I like the way the new shop is thinking, a bit outside the box. They build Porsche race cars and their comment on my cooling system is that while the RD radiator is thick, it doesn't have enough surface area. Hence the idea of going with an additional radiator, like how the Caymans add a third radiator for track work.

All I really need is a 20 degree change, gotta think adding a second radiator, plus better shrouding, plus hood vents, plus moving the oil cooler from in front of the main radiator will get me that.

Sounds like you are on the right track. Adding a second radiator worked well for me, though I am using the original Turbo radiator and I only sit in 100 degree traffic.

Though you may have covered this: How is your electrical system, specifically power to the oil and coolant gauges? All my gauges were reading high due to increased resistance in the positive and ground cables; a typical issue for these cars as the get older... Turning on my headlights would bump the oil temp up 20 degrees. A supplemental positive cable to the cabin helped this enormously.

I'm running seperate water and oil temp gauges in the center console made by Autometer. Compared to OBD2 port readings the water temp gauge seems to read 10 degree high, but that may just be a difference in where the two sensors are.

I'm going back to my large 16" single Spal fan for the main radiator and will shroud it. Then we'll be using my current 11" Spal fans for the auxiliary radiator and the oil cooler, one fan on each, both tied into the main radiator fan so they'll get triggered by the PCM.

What auxiliary radiator did you end up using and where did you mount it?

Yes, please post a few pics of extra radiator mounting.

My pictures disapeared with the previous 944 hybrid forum.....I can dig around a little if you like?

After pricing several custom radiators to fit in various locations I went searching for a cheap substitute to test out the idea of an aux radiator, without spending big money.....heater cores came to mind. Though I know they are not the best radiator, they are cost effective.
I found that the rear heater core from a 1995 E350 was almost a perfect fit, approximately 20 x 3 x 2. I took two, $50 each at the time, and stacked one behind the other and fit them in the area where my intercooler was. I was able to use the factory intercooler ducting and mounting points with some modification; that was about 4 years ago. It has worked so well that I can't see any good reason to replace them with a custom made radiator.

Google "9010001 heater core" for images

docwyte wrote:.I'm going back to my large 16" single Spal fan for the main radiator and will shroud it.

If your cooling issues are when you are at speed, on the track, I would advise against adding a shroud as it will only add more restriction to air flow.

Shop and I have talked about that. We need to strike a balance. Cooling issues right now are both on the street and at the track.

So the shroud and fan should be well off the surface of the rad and have one-way louvers in as much of the shroud surface as possible; meaning you can have the best of both worlds.

Have you thought about running Evans Coolant?

948 wrote:So the shroud and fan should be well off the surface of the rad and have one-way louvers in as much of the shroud surface as possible; meaning you can have the best of both worlds.

Heres a pic of the c7 corvette shroud/fan assembly. Has little doors all over it that open at speed.  Cute aint it?

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That's not a bad idea. Obviously they open when the air is pushing through them...

I'm waiting for C&R to build and ship my radiator. Unfortunately that means my car won't be ready for the PCA Club Race in 2 weeks.

All the other parts are there, shop can get their hands on the oil cooler at any moment. Hopefully will have the car back towards the end of the month.

Another dud for a season between the late snow/cold we had and then resolving these cooling issues.

That fan is cheap too. $399.00 at corvettemods.com

I'm not sure if this has come up in this thread before, but I believe I talked about the concept in a thread in the cooling sub-forum.

What makes a radiator actually function is the pressure differential between the air on the front side of the radiator and the air on the rear. Air actually flows through the radiator because of that pressure differential. Maximize that differential, and you should be able to increase your cooling capacity. If your is having trouble building pressure in front of the radiator, or creating a low pressure zone behind it, then you will have very little airflow through the radiator. Also look to avoid holes that let airflow bypass the radiator. Also un-shrouded fan s can sometimes let air just loop continuously through the radiator, especially if there is minimal pressure differential between the front and back sides of the radiator.

I'm sure you're aware of all of this, but figured I'd toss it out since you're kind of going back to the basics to sort your colling problems out.

A good pressure differential is the root of all cooling.

Well the project that was ahead of mine in the shop is finally completed so my car can get worked on.

Here's what's getting installed...

Auxiliary radiator from a 2004-2007 Audi S4 V mounted in the passenger side, ducted from the fog light and grill

11x13 Setrab oil cooler V mounted on the drivers side ducted from the fog light and grill

2 hood vent/louvers directly behind the radiator to create a suction pulling through the radiator

Removing the dual 11" Spal radiator fans and replacing them with my single 16" Spal fan

Installing the 951 Master Cylinder and hydroboost adapter

Hopefully that takes care of the water temperatures and also gives me back proper brake bias and brake pedal stroke.

Really hoping to get the car back no later than this coming Friday so I can hit the track next weekend...

951 Master cylinder is mounted, had to turn around the coil pack on cylinder #6 to make clearance for the reservoir.

Swapped the two 11" Spal fans for my 16" Spal fan.

Next up is mounting the S4 auxiliary radiator and side mounting the new oil cooler, then putting in the two hood louver vents...

Another update.  Can't say I'm entirely happy with how long this process is taking.  I'm sure the work is top notch and all will be awesome when I get the car, but I'm beginning to get a bit impatient to get the car back in my garage.  This is just part of owning a project car though, everything takes alot longer and costs much more than if the car was stock.

Anyways, some work was needed to get done to the 2004-2007 Audi S4 auxiliary radiator to get it to fit.  Left alone the frame rail would've needed to have been notched to get it to fit and that's not something I wanted to have done.  

So new end tanks were fabbed and welded up.  Hopefully this ends the major fabrication stage and it's more assembly now.  The radiator and oil cooler need to get mounted and plumbed, along with filled and burped.  Then shrouds to both made, then the two hood vents installed.  Then everything tested to make sure all is well...

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Yikes, I think notching the fram would be better. Not much structural integrity needed beyond the strut towers. But at least its a step in the right direction.

I disagree. I never want to touch a structural part of my car. Nipping some sheet metal here and there I have no issue with, but something that'll potentially involved the integrity of the chassis I won't want to do.

I watch the shows on TV where they're cutting frame rails and then boxing them in but that's easily as much, if not more work than what we did to make a new end tank...

Yeah, I guess without seeing it I wouldn't know. Hopefully next season we can both enjoy our cars fully. It never seems to end... Do you have any pics of how they or where they plan to mount this stuff?

Not yet hopefully I'll have some when they have it mounted....

Ok, S4 auxiliary radiator is mounted. Next up, mount the oil cooler. That won't require making end tanks, so hopefully that happens quickly...

Progress is being made!

S4 auxiliary radiator is mounted, oil cooler brackets are done and the oil cooler should be mounted by the end of the day, two additional hood louvers are installed.

Next up is plumbing both the oil cooler and radiator, bleed both systems and fabricate ducting for them.

Then it should be ready to drive...