Oil cooling system design and suggestions

[Sandeep]

Hi all,

I've got the engine installed, and am now looking to purchase the parts for my oil cooling system. The app is stock 914 2.0 into a bug, with BAS exhaust, FAT Porsche cooling and 44 IDF's. Weekend circuit track racer and daily driver ... future 2270cc.

I've got an oil cooler adapter that fits over the stock T4 oil cooler location, and provides an entry and exit from the block. The stock oil filter is going to be left in the stock location, unless I need to change it.

Here's what my proposed design includes:

1. 180 deg oil thermostat (mechanical) that stays partially open to keep the system full of oil. This will open up at 180 degrees to let oil flow to the cooler. Below 180 degrees, it will be shut and reroute oil back to the block. The reasoning is this will let the oil get up to operating temps, I hope.

2. 180 degree inline fan switch. This will turn on the fan on the cooler at 180 degrees. This will help limit the oil temps after reaching operating temps, I hope.

3. Mesa Cool oil cooler. I'm unsure of the size here. 48 plate, 72 plate or 96 plate ?

4. Appropriate size fan. If I get the 96 plate cooler, I can get it as a kit with the fan.

5. 1/2" ID oil hose with appropriate fittings.

6. NACA ducts to channel ambient air to the fans. I'm thinking of mounting the ducts on the underside of the car so I don't have to mess with the rear quarter windows. I saw this mod on the net. I'll try and find the pics.

So, what do you think ? I'm unsure of the cooler size at this point. If I mount the cooler/fan under the rear parcel tray, I've heard that hot air won't have a chance to escape. Can I combat this by ducting air from the NACA ducts to the fans ? I think I can but maybe someone else has some ideas ?

Comments ?

Thanks

Sandeep

[kdanie]

The NACA ducts under the car sound interesting. With an air dam, I don't think they would help much, without the air dam it would probably work ok. I think the rest of your system sounds ok for your stocker. When you go to the stroker engine and more HP/rpm you should do the full flow mod that Jake recomends. It's an easy mod when the engine is apart so why not improve the oil system. I am using a 96 plate mesa cooler, smaller coolers may work ok but I got a good deal on this one so why not be sure you have the cooling capacity you need. VWs have been mounting oil coolers under the package tray for a zillion years, with the 96 plate and a fan, I think you would be ok even without the NACA ducts. I have the thermostat also, it doesn't make much sense to run a cooler without one to me.
ken

[zen]

sandeep, glad we are on the same step or even better, you one step ahead of me. i have been debating this for the past week. figured i would save on some shipping and try to get a bunch of stuff at once.

i have heard everything from 96 with fan to Mocal (although i can't seem to find these anywhere under that name) with no fan. AN fittings (damn expensive) and 1/2" SS braided lines seem to be the common theme.

jake told me 72 or 96 for the stocker and his 2270, but did not specify fan or no fan. he also mentioned "a great place to mount it", but said to just get with him when i am ready and he would help out. so i know i am not a whole lot of help there.

i have been thinking of picking up the CB thin line and electric warrior (plus therm and fan switch), but have been holding off until i can find something on the Mocal.

based on what i have seen and heard (since i have no experience on this), the NACA ducts aren't really neccesary, but if done right wouldn't hurt.

[danielzink]

On my bug - 78x103 - I have a Mocal 180 degree oil filter tstat. Basically when the oil reaches 180 it heads for the 2 oil coolers I have mounted on either side of the transmission. I have fans mounted to the coolers that are thermosatically controlled. When that oil reaches 210 the fans kick on until the oil is back to 180. I got the mocal oil tstat and fans from http://www.batinc.net/.
The coolers came from JC whitney. The wiring kit and thermostatic sender came from Jegs ( or summit ). The inline T fitting to hold the sender came from the hardware store (my fabrication).
the oilstat goes on the oil filter location and your oil filter just spins on to it.
I'm also running the stock oil cooler on a DTM. On the highway at 20/30 minutes +/- 100mph the oil temps were crawling over 210 (with both coolers) until I added the fans.

Pics ?
I can provide 'em !


Dan

[Sandeep]

Ken,

I agree on the 96 plate and cooling capacity.. atleast its there incase you need it.

Here's the pic I was looking for...



Its from a Lotus Europa race car... they mounted the duct underneith the car in the airstream.

Dan,

Thanks for the real world information. Can you please post some pics ?

Zen,

I find it alot easier when 2 people are working on the same problem... divide and conquer ! What do you have in store for your system ?

I want to drive this car HARD on the track so now is the time to design the system. I beleive I will go with the 96 plate Mesa, as Ken suggested. I just want to build a template out of cardboard with the proper dimensions to see where to put it, and to see where I would put the NACA duct, just incase it was needed.

Sandeep

[Farmer]

If you wanna drive it hard, - and or on the track, there is NO substitute for a front mounted cooler. And it is also the cheapest way of doing it. OK it takes some routing of oil hoses or pipes, but it works.
A Mercedes 530 mm cooler is more than sufficient in most cases and is easy to come by financially.

I went down that road with underneath mounted coolers because it was easy to put there and not much routing of hoses. But I had problems during long fast rides on the autobahn. Switched to a frontmounted, and never heard from it since. Not even on left lane catch runs. Temps always stays between 80 - 97 degress C.

[zen]

i am only looking at street use, so the need will be a little different. i want to keep mine in the back since i am not running bumpers and my car is VERY low. since i was placing a CB order, i did order the therm, but nothing else yet. i just don't want to run a fan if i don't have to, but will if needed. i too still need to do a mock up. problem is, i don't have my car. will have it back on about 3 or 4 weeks i hope.

[i heart vw]

what is the best way to "route" the hose for a front mounted oil cooler?

[Farmer]

the very best way would be to get some hydraulic pipes and route them though the center channel and then have real hydraulic or AN fittings in the end with good quality hose from the pan out to the cooler and from about the torsion tubes to the engine. That is however a very difficult thing to do with the body on.
My next choice would be lining them vertical on the right side of the channel, then make a 45 degree bend just after the Napoleonhat and route hoses up over the steering parts and out to the cooler.

Then there is how most people do, and get away with it most of the times too, but DEFINITELY NOT recommended on severely lowered vehichles !!!
They simply route one pipe or heavy wall hose into each "U" where you bolt the pan and the chassis together. then you have good oportunity to find securing places, but ypou have weak spot or exposed spots especially in the front where you go from the "U" to the front of the car, because you will have to go underneath the cornerbolts in the "HAT" before you can secure the hoses again.
I have done this though, with heavy wall hoses, but every time you hit something your heart skips a beat :broken: , because what if ....
- Luckily I have never had a failiure because of a broken hose, but I have replaced twice on that car, (not mine) because the rubber was worn off right into the steel reinforcement on the hose (!)

[Sandeep]

Ok ... the stuff finally arrived.



Now time to get my hands dirty. Only 11 weeks till fire up and first drive !!

Sandeep

[Sandeep]

Question:

Should I be using teflon tape on the threads of the brass fittings ?


Thanks

Sandeep

[Richie]

It depends. It isn't necessary if your brass fittings are NPT. Then a little bit of Loctite Hydraulic seal is enough. In the other cases, except AN can you use teflon tape, but just as little as really necessary and look out for loose threads. They WILL come loose and get into the engine.

Cheers,

Richard

[kdanie]

Do NOT use teflon tape on the fittings. It can shred off in little strands and cause problems.
Ask Jake what he uses, I'm sure he has some trick that works better and is safer.
ken

[Pillow]

As for Teflon tape. I use it, but you need to very very careful. I start taping mine about 3 threads back on any fitting I use. You want none of that stuff to get in the oil stream. There is liquid sealer available these days for air hoses so check that out. One of my next purchases when I find it. For AN fittings I do not think sealer is necessary, for NPT you may or may not need it.

As for the Mesa cooler what is the internal diameter of the cooler input output lines? I have heard they are 3/8 ID and not the 1/2" like are needed.

For fans... Go to the junkyard. Cheap and you can find all sorts of models.

When running an external cooler be sure that you have a good oil pump to push the extra volume through the cooler and lines. Usually a T1 gets a 30mm pump. With a T4 it gets more complicated. I guess a waffer adapter on the oil filter will work, but make sure the flow is still good. Granted the waffer with built in t-stat sounds like a great idea.

For my bus I plan on mounting an RX-7 oil cooler under the middle body floor section. But with no fans (could be added later).

On a Beetle I would try anything possible to move the cooler to the front for the air flow (like a RUF 911). Also use hard metal or AL lines to run the length of the car body as they aid in cooling as well. I am thinking either a low mount RX-7 cooler (RUF style) or two Volvo coolers one mounted in each front fender and run in series. Those Volvo coolers are very nice and cheap with built in mounting nuts and all.

Just some of my thoughts on the matter.

[kdanie]

Adrian, You are correct on the fans, there are many suitable fans out there cheap. I just built some mounts for a BMW 320i a/c condenser fan that I took off way back in '92 and have been draging around the world with me since then. It's a nice Bosch fan and fits a Mesa 96 plate well. Total expense for my Cooler/fan/thermostat=$46.00!! I have more time than $$ so I can wait for a good deal.
ken