Fender oil cooling options for 78 930

[Rob 930]

I'm trying to make the best decision on oil cooling for my track prepared (but streetable) 78 930 with EFI. The engine will likely produce 600-ish HP at 1 bar, but on the track will probably run in the low 500s. So, there will be significant heat generation. I'm clinging to the hope that I can maintain relatively stock appearance, and to that end, would like to explore the use of the stock front valence (which, on my car is from a post 84 model). That means fender coolers, two of them, are preferable to a center-mounted cooler, from my aesthetic point of view. I already removed the fog lights from that valence, cut out the fog light supports, and put screens over them (but haven't done very much ducting yet). Other facts: A couple years ago I installed a Fluidyne cooler in the right front fenderwell, with a Spaal fan on the front of it (this required removal of the horns). This cooler was installed for a previous iteration on the engine, which retained the engine-mounted cooler. Now, not only am I upping the power output on the new engine, but I've reduced the cooling capacity by removing the engine cooler in favor of a 993 oil filter console. So, I'm going the wrong way with demand vs. supply, and I need to upgrade my cooling considerably, I think.

Here are pics of my current valence and the Fluidyne cooler arrangement at the right front.
Fluidyne cooler, double pass DB30517
[img]
Fluidyne cooler, as installed
http://forums.pelicanparts.com/uploads6/Fluidyne+cooler+installed1131489019.jpg[/img] [img]
Stainless steel screen over fog light hole; maybe could be better if I just left the hole open for better airflow. Also may paint the screen black.
http://forums.pelicanparts.com/uploads6/Valence+duct1131489039.jpg[/img]

I spent some time searching Pelican and found a ton of photos and ideas. My current leaning is toward adding a 964 cooler to the left front, mounting it at an angle as needed to make it fit (which may mean the cooler is actually fore and aft in the fender well) and then doing what I can to duct the air so it all goes through the coolers. The next level would be to replace the Fluidyne cooler as well, with a 964 cooler and fan, in the event that it's more efficient than the Fluidyne.

Here are some examples of cooler arrangements that have me interested. Bill Verburg posted these recently:



Another Pelicanite posted a thread about his installation of Carrera coolers in his 911 that he converted to a 3.6. He notched his bumper fairly extensively which looked like it may be a good idea for those, like me, who would like to retain as much of the original bodywork as possible. My 78 bumpers already have some notching from the factory, however.


So here are my questions.

1) Is there a way to keep a car like mine cool while keeping the bodywork fairly original, as I'm trying to do? Can enough air be properly directed through the openings?
2) If so, I assume two fender coolers are the way to go. Is the 964 cooler the best choice for this or are there any aftermarket coolers that are significantly better? (One of the things that makes the 964 cooler attractive is that they can be had for $240 each.) Will they fit under each fender in some fashion? Will they have go "sideways?"
3) Might I get away with leaving the Fluidyne cooler on right side and just adding a 964 cooler to the left side (note, the washer bottle has already been removed).
4) If the 964 coolers are the best way to go, what is the best way to connect them to my system? I assume I would run two coolers in series. Right now I have -12 AN going to the Fluidyne (with 30 mm adapters off the factory hard lines).

I appreciate any advice in this matter. If it's not feasible, I'll consider a front center cooler, but I want to explore this option first.

Rob

[Bill Verburg]

twin 993 coolers as used on the 993 GT2 are sufficient to cool the ~500hp that they put out


The set up they use is a stock 993 cooler in the passenger fender and another identical one in the driver fender as pictured above.

The thing they need that is lacking in any stockish looking 911/930 that I have ever seen is a large quantity of air flowing through them, the entire center section of the 993 valance is an intake.

The holes in stock 911 front ends are just too small to let a generous volume of air through. Now a 934 front end on the other hand is perfect.

One smallish valance mount out in the hurricane generated by a car at speed is easily the equal or better of 2 large fender mounts in the relatively stagnant lee air of the fender/bumper.

I know that some have done the twin fender mounts in their n/a motors but I doubt that it will work well enough at the power levels you are talking about.

But i've been wrong before...

[Rob 930]

Thanks, Bill, for the reply.

My dilemma is this: I like the relatively stock look, and certainly the 930 look, as opposed to the C2 look of the later cars or the more radical 934. (I like the other looks too, but not for this car.) To my eye, the 930S spoiler is closer to the mark, but still has a front center opening that I'd probably best fill with a cooler. I'd prefer not to have the vulnerablility of the center cooler, but I may have to bite it and do that. But then I run into issues with clearance between the cooler and the tub again. I'd really like not to notch the tub. That means space between the 930S spoiler and the tub is limited, and I don't know if I can get a big enough cooler in there to do me any good. It doesn't do any good to wedge a big cooler in there unless there's vent space behind it.

Do you know if there's a good candidate center cooler that fits between a 930 S spoiler and the tub, without notching the tub? I'd plan to run this in conjuction with a fender cooler in the right front.

Another option: Would it be reasonable to use a 930 S spoiler to bring in the air, but direct that air to two fender coolers? I'd have to fashion some sort of splitter behind it (not sure how) so that air would flow to the two fender coolers. Ever heard of this being done? I'm not sure how efficient that air flow would be.

Are there any other moderate valence designs that may allow me to use two fender coolers successfully without going to a C2 or 934 nose?

[Bill Verburg]

There used to be a 930S cooler that was designed to go in there, the Ruf cooler is similar but smaller. I have a 5 1/2 X 2 1/4 X 20 B&B that fits in a Ruf bumper w/o tub mods.

[Bill Verburg]

If you use a 930S bumper w/ it's large intake and seal the bottom you could probably do the sideways mounted dual cooler trick ala 993GT2.

[Bill Verburg]

FWIW here is the GT2 setup, I can give you the parts list too

[Rob 930]

Thanks, Bill. That's what I was wondering. If I fashion an air box our of thin alumimum sheet, to contain and direct all the air from the center air inlet, then maybe I can force that air to go to each of the coolers in the wings. Basically, I would make my own splitter. I'd rather try that than install a big front cooler or notch the tub.

To clarify one thing: the stock 993 cooler is the same as the 964 cooler, isn't it? And are they identical for right and left, or is there a different part number for each side? I'm thinking they only put one in each car, so there may not have been one for each side.

Any suggestions for hose and fitting? Does Aeroquip make metric fittings (are they 30mm?) for the 993 cooler? I'm currently using -12 AN hose. Is that sufficient, or would -16 really provide a noticeable benefit. The -16 stuff is heavy and expensive, and I'd like to stick with -12 unless there's a compelling reason to do otherwise. Are there any factory mounting brackets that would be of any benefit in getting these coolers retrofitted to a 930?

[Rob 930]

Bill,

Your latest note, with the GT2 oil cooler diagrams, came to me just after I posted my note above. Thank you very much.

The parts list would be great too. I wish I could go see a 993 GT2. I don't think I've ever actually been near one. It looks from the diagram that the two coolers are connected in parallel. True? I wasn't planning to do that. I bet there's a raging debate on that topic. What's your take on that?

Do you know if the coolers shown are the same as 993/964 coolers? I can imagine that a few of those parts might be nice to have for a 930 retrofit. Not sure which ones, though. It's hard to tell, but it may be that part number 34 in the upper diagram is some sort of mounting bracket that would be nice to work from, as well as the rubber isolators.

Great help!

[Bill Verburg]

The GT2 uses 2 standard and identical 964/993 coolers mounted in series

here is a pic of the factory kit for the drivers side


I'll scan the GT2 parts list for you

Cargraphic makes a similar kit

[Bill Verburg]

Here is the parts list for the 2 GT2 coolers and installation hardware, it will be much cheaper to fab you own lines and brackets

[KobaltBlau]

Originally posted by Bill Verburg
The GT2 uses 2 standard and identical 964/993 coolers mounted in series

not to nit-pick, but the diagram looks like the coolers are in parallel.

Rob, have you seen GeorgeM's setup? he moved the stock valance forward to fit a center cooler in, the stock valance is just about even with the bottom of his front bumper if I remember correctly. I don't think he cut the tub. picture below:



GeorgeK has a very stock looking setup as well, but he cut the tub (carrera 3.0 on right):

[Bill Verburg]

not to nit-pick, but the diagram looks like the coolers are in parallel.

I know but if you read the accompanying test in the 993GT2 Evo shop manual they are mounted in series.

[Rob 930]

Bill and Andy,

Great ideas and information. I appreciate your help. At this moment (subject to change of course!) I'm leaning toward twin 964 coolers and doing something about ducting. After all, the 993 TT had just one such cooler and generally does quite well with it. I bet that two of them will be enough for me. I'll probably fab the brackets as you suggested; I bet those things cost a fortune. Not sure what to do about oil line fittings, though. Are metric fittings available? Maybe I should have AN fittings welded onto the coolers. Sure hate to go slicing into a new cooler though.

Regarding ducting, I like some of the creative ideas that involve using the stock valence. But I may also consider a 930S valence as well. Either way, looks like I'm going to be doing some serious work with aluminum sheeting to box it all in.

Whichever way I go, I'll post pics when there's something to see.

Rob

[KobaltBlau]

Thanks Bill, fair enough.

Rob, I believe your main issue with the 964 coolers is going to be sufficent air flow. let's assume the 964 cooler(s) will be mounted "sideways" as in the 964 and 993 cars. In this case, you will need a good air supply coming from the center of the front end to the side of the cooler facing the center. I propose this "theorem": The room you will need for a good air duct equals or exceeds the room you would need to mount a front cooler, no matter what valance arrangement you use.

Escapes I see from this "theorem":

1. if you can somehow mount the 964 cooler perpendicular to the direction of the car (as a carrera cooler is mounted), or at least angled pretty well forward, and duct air in from the foglight area and above (turn signals, headlight bucket) This isn't possible in a regular body but maybe in a wide body...

2. if, in the 964 and 993 cars, the fan actually does most of the work, even on the track. I suspect this is not true but do not really know. Bill?

if neither of these escapes is viable it seems like it would be easier to mount a front cooler, considering that it won't take any more space than the air ducting for the side 964 cooler(s).

I more than welcome corrections/disagreement! just trying to think through this...

[Rob 930]

Andy,

I completely agree that airflow is the key. It seems the question, regardless of center or fender coolers, is how best to get it. There's no doubt that the most effective cooling is a center cooler, a notched tub, and some serious ducting, say through the hood. But for those of us that don't want to be so radical, it gets trickier.

I'd be interested in seeing how 964 cooler(s) have been mounted in earlier cars like mine. I know it's been done. Can anyone who's done this post their thoughts or photos? I'm going to get the dimensions of such a cooler and see if it looks like it makes sense for my car. I'm guessing that a slight angle may be possible, but probably not even 45 degrees.

I'd agree that the more perpendicular the mounting, the better in general. But it's interesting how well the parallel mounting seems to work in the 964/993 cars. I realize that they were designed for that though, and all the air that enters the valence opening must flow through the coolers. So maybe the orientation of the coolers isn't that critical. The opening on a C2 is 43 in long and 3 in high. That's 129 sq in. On my stock 84 valence with two holes where the foglight were located, the total area is only about 64 sq. in. (plus a bit more for the bumper notch). Still, it's quite restrictive. The center opening on a 930 S spoiler (measured by a friend last night), is about 90 sq. in, plus there are still the fog light openings, which I assume are simlar to the stock valence. So, that means there's approximately 154 sq in. available, which is starting to look reasonable. There also may be ways to modify a stock valence neatly for additional flow (as in the photo you posted).
Here's a pic of a 930S front valence that I found on the web.

To your theorem: I'm not sure I agree that the air duct necessary to adequately service a fender cooler occupies the same space as that taken by a front center cooler. Of course, I'm just guessing about this. But the problem with the center cooler is that unless you notch the tub, you also need to have several inches of ventilation space behind the center cooler, otherwise it becomes ineffective. So in essence, you need both mounting space and ducting space. And from what I can gather by looking at others' projects, there's not much space behind the cooler with an unnotched tub, if you use a 930-like valence. If there's no cooler in the opening, though, there should be a lot of air ducting space, I would think. But of course, the whole thing needs to be boxed in to contain that air and force it through the coolers.

I'd like to know how effective the oil cooler fan is for cooling of the 964 and 993 when at speed. I'd expect it would only be called upon for cooling at low speeds, and it would not be as effective as ram air on the track. Anyone know? In fact, I would think that at speed, the fan would actually be a detriment to cooling, whether it's running or not.

Bill, I see from the GT2 parts list that the cooler(s) shown have different part numbers. Do you know why this is? Also, neither of those part numbers match the number I was given for the 964 cooler, which is 964 207 220 02. I thought 993 coolers and 964 coolers were identical and had the same number. Do you have any futher insight?

Rob

[Rob 930]

Pic of 930 S valence, I neglected to include with the last note.

[Grady Clay]

Rob,

You are getting a lot of good advice above. Clearly you are going to want two fender coolers. One of the “arts” is to do this where it appears to be an original Factory installation. That takes clever selection of Porsche parts and custom “Porsche appearing” parts. You can even use the smaller windshield washer container from an early 911 that fits in the trunk.

For the track you probably will need to use the “Rubbermaid Solution”. I don’t think you can get enough fender cooler to match what a 935 (~650 hp) has in the center (and it has a larger engine cooling fan.)

I would prefer to have the coolers in parallel. In series there may be enough restriction to open the pressure relief bypass in the thermostat assembly.

Best,
Grady

[Bill Verburg]

I'd like to know how effective the oil cooler fan is for cooling of the 964 and 993 when at speed

A lot of the tracked 993/964 cars using the dual cooler setup remove the fan altogether. At speed it is actually an impediment to full flow. On my 3.8RS I use a single midsize B&B w/o fan w/o any issues whatsoever and my 993 fan has never been on since I have owned the car. Your situation is very much different but the massive heat issue will only occur at speed, hopefully a nice cool down lap or two will prevent any subsequent heat soak issues.

I see from the GT2 parts list that the cooler(s) shown have different part numbers. Do you know why this is? Also, neither of those part numbers match the number I was given for the 964 cooler, which is 964 207 220 02

No I don't know why, I have the race shop manual for the car but obviously no car to go w/ it.

I do know that the 993 dual cooler kit uses an identical cooler on the left as was stock on the right. The # you gave is the correct part # for the 964 and 993 stock oil cooler.

[Rob 930]

Gentlemen.

Thank you.

Grady, I like your Rubbermaid solution, which I was aware of from my poking around here for a while, but in reading your post just now, this made me chuckle:

"This system works best in hot, dry weather. It is basically ineffectual on a cold, damp (100% humidity) days."

Hmm. I live in Seattle. Swamp coolers don't work too well around here! But then again, we have hot, dry days too, and that's when the risk of high engine temps is greatest. So it may be a good backup in the event that whatever I come up with isn't adequate.

Bill, interesting that you don't run a fan at all. I think if my car were destined to be a trailered, dedicated track car, I'd omit the fan too -- and maybe even the thermostat. But being that it has to drive to the track, and there's the possibility (er, likelihood) that I'm going to get stuck in traffic, I probably need a fan.

Still, I'm wondering what the best solution is for plumbing. Where can I get metric fittings so I can make up some oil lines? Do you have a suggested source? Or is it better just to convert to AN? To do so, though, means six fittings must be converted -- two at the termination of the hard lines, and two on each cooler. If I go parallel, then things get even more complicated -- I'd also need two Ys. Or Tees maybe, but I would think Ys would be better. Any suggestions on how to do that?

[KobaltBlau]

Rob, while I realize you are leaning toward the two side coolers, I spent some time finding some good threads on center coolers, for my own purposes as well. For plumbing, Warren (Early_S_Man) has a trick for using the short carrera hoses for their ends and attaching to -16 hose, I believe it is covered in one of these threads:

RSR bumper and Center cooler done! Many pictures inside
Front mounted cooler install
Frt.valence oil cooler
Looking for some kind of front valance

worthwhile reading, I think.