Will this oil cooler vent work?

I think you're on to something with 3 vents, the front being the shortest, with the back 2 being progressively longer.  You may have to experiment to find out how long to make the first louver (so it's actually diverting air into the cooler), and I would cover the bottom with a metal fine mesh screen so nothing enters and damages the cooler.

CSP makes a torsion tube mounted cooler that uses a similar louvered cover…. that may serve as inspiration. Their pdf attached files are handy. ;-)  picture below also provides perspective on louder sizing.

https://www.csp-shop.com/en/en...tml?cache=1572992642

Kudos for trying!  There are lots of complicated formulas regarding air flow, and what shapes work best in different applications.  A general principle to remember is that air flows at maximum efficiency from high pressure to low pressure, much like wind in the environment.

Thus, with a fan involved, you want to increase pressure on the fan inlet side, and ensure that the outlet side of the fan is not obstructed, thus allowing pressure to decrease.

NACA ducts are their own engineering subset, with shapes formulated by engineers.  In later years, computer modeling and wind tunnels helped increase efficiency.  The vents you are building are a type of NACA duct.

When you engineer vents like you propose, you may want to prepare a few versions, then try them out.  Try inexpensive and easy-to-make versions first, even plywood should work.  Then, when your test results show you which version is most effective, you can fine-tune the shape, using aluminum or galvanized sheet metal.

My suggestion is that you test and record your results with the various iterations.  To do that accurately, you would need to replicate conditions as closely as possible for test 1, 2, 3, etc.  Ambient air temp may be the most critical factor that should be kept as standard and constant as possible.  I suggest that you develop a means of measuring oil temp even if you don't have an oil temp gauge.  Put marks on your dial gauge or something similar to tell you what the oil temp is when the gauge is at point X.  A candy thermometer or something similar in the dipstick can tell you actual oil temp.

Then drive the same course at the same rpm with your different vents in place, and try to keep air temps the same for each driving test.  I know that we don't have test tracks like the big dogs, but do your best to keep conditions the same.  Cars immediately ahead of you will influence your test results, so a road with little traffic is preferable.

Test results may surprise you.  Please keep the group informed, as this is how we all learn.

@JB356SR Does that fan push or pull air through the cooler?

If your fan is on a thermostatic switch, and pushes air down through the cooler, I'd make the louvers point backwards and I'd make as many as you can fit. If the fan pulls, then I'd point the louvers forward with the same amount of louvers. Try not to restrict the flow.

My thinking here is, the fan is there to do the work and if it has a thermo switch, it knows when you'll need cooling. Directing air over the cooler all the time might over cool the oil. I'd use the aluminum louvered shield as just that, a shield against debris and for air direction.

On a similar note, I have sled tins on my list of thing to fabricate. Mostly for cooling of the heads, but also for deflection of cooling air. My driveway is gravel and I travel on short sections of gravel. With the air blowing down, it stirs up the gravel dust and makes a mess of my engine compartment. I have a Spyder, so no engine tins.

My 2 cents.

I have my fan pack and cooler mounted in a similar location and I did not cover the bottom with any type of plating with louvers. In the five years it's been on the car I have damaged the fan pack and cooler in any way.

@Carlos G posted:

@JB356SR Does that fan push or pull air through the cooler?

If your fan is on a thermostatic switch, and pushes air down through the cooler, I'd make the louvers point backwards and I'd make as many as you can fit. If the fan pulls, then I'd point the louvers forward with the same amount of louvers. Try not to restrict the flow.

My thinking here is, the fan is there to do the work and if it has a thermo switch, it knows when you'll need cooling. Directing air over the cooler all the time might over cool the oil. I'd use the aluminum louvered shield as just that, a shield against debris and for air direction.

On a similar note, I have sled tins on my list of thing to fabricate. Mostly for cooling of the heads, but also for deflection of cooling air. My driveway is gravel and I travel on short sections of gravel. With the air blowing down, it stirs up the gravel dust and makes a mess of my engine compartment. I have a Spyder, so no engine tins.

My 2 cents.

I will check tomorrow to see if it is a pull fan or push fan. I do have a thermal switch and I will be running a Mocal sandwich plate with thermostat.

@JB356SR posted:

I will check tomorrow to see if it is a pull fan or push fan. I do have a thermal switch and I will be running a Mocal sandwich plate with thermostat.

IIRC you can switch the direction of the fan to make it a pusher or a puller by changing which terminal the wires go to. There should be something in the small print instructions regarding that.

Yes, you can control the direction of spin, but the shape of the fan is usually optimized for one direction.

@Lane Anderson posted:

Yes, you can control the direction of spin, but the shape of the fan is usually optimized for one direction.

THIS ^

Some fans are not optimized for one direction and can go either way. Best to check the directions on yours to make sure.

I just checked my fan. It is a pull fan. I'm going to make a 3 louvered vent.

1. The underside of the car is a high pressure zone while you're underway. You don't need scoops or louvers to pull air up from just behind the torsion housing. The setups in your picture will block more air than they let in.

2. The fact that the underside of the car is a high pressure zone means that, also, the space in front of the firewall, above the torsion bar housing, behind the rear "seats" is also a high pressure zone. Not as high as just under, but pretty high, because it's right there. It's where the under-car high pressure air naturally wants to go.

3. To make the oil cooler work well you'll want to create air flow. To do that you need to find ways to get the high-pressure air out from that void above the torsion housing and in front of the firewall, etc. One way a lot of people do this is by cutting a hole in front of their engine fan, which promotes air into the engine's cooling system. And it's cool air, mostly—but will be a bit less cool if you put your oil cooler where you're planning.

Will it work anyway? Yes, almost certainly, unless your engine has some other problem. Just run your puller fan on top of your oil cooler, mounted parallel or slightly canted (front a little higher than rear) on a bracket from the torsion tube. The fan will promote enough flow through the cooler, and the heated air will find its way out of the space—whether you have the fan hole or not. Put some hardware cloth in a bracket front and under the oil cooler to keep rocks and junk from damaging it.

@edsnova posted:

1. The underside of the car is a high pressure zone while you're underway. You don't need scoops or louvers to pull air up from just behind the torsion housing. The setups in your picture will block more air than they let in.

2. The fact that the underside of the car is a high pressure zone means that, also, the space in front of the firewall, above the torsion bar housing, behind the rear "seats" is also a high pressure zone. Not as high as just under, but pretty high, because it's right there. It's where the under-car high pressure air naturally wants to go.

@aircooled (Bruce) did some interesting air pressure testing on his Speedster-             https://www.speedsterowners.co...5#418024413176885525 he found that the space in front of the firewall is not a high pressure area, which answered some questions, but (for me, anyway) created a couple more- the main 1 being "why is there no benefit to the hole in the firewall"?  Actually, it answered the question all too well, and my next question was " how can we take advantage of this space to feed more fresh air to the engine, which it clearly needs"?   After thinking about it off and on for a while (if I can remember it I really do never let it go- hard to believe it's been almost 8 years!) and of course, seeing a couple things along the way I think I have the answer.  Because the area between the back of the passenger compartment and the firewall is a 'dead' space with a relatively small opening which runs across the airflow path instead of lengthwise, there's not enough area for that under car airflow (which is a continuous straight flow) to pressurize the above area when the car is at speed (anything over 40? 50? mph?).  Maybe a diverter is needed to direct air up to that dead space, and once the pressure forward of the firewall is higher than in the area behind it, air will flow to the carbs/fan, and if high enough, through the engine compartment, taking some heat radiated off the engine with it. The engine being fed a steady supply of unheated air and getting rid of this radiated heat from the engine instead of being re-ingested by the fan (and carbs) would go a long way toward controlling engine operating temps.

Now, while this was built to deflect air onto the sump/bottom of the engine for more cooling (the guy claimed 40° oil temp reduction on the Samba but someone pointed out it was probably that much only at the sender, which I think is fair, but I also think the premise is valid), I also think something like it could be used to pressurize the empty space in front of the firewall. If Bruce had tested something like this, how different would the results had been?

I love data. Thanks, Al.

I may have some help here. Our departed friend Angela(and husband Steve Lane) had cooling problems in their 3.0 or 3.2 six powered Spyder.

The solution was a small spoiler that extended the width of the engine compartment to scoop the air and direct it up the firewall and into the 911 fan that resides about 4 or 5 inches behind the firewall(Spyders are mid-engine). This solved their cooling problem, giving the engine enough fresh air at speed to keep cool.

Pretty similar to Al's posted picture above.

@DannyP posted:

I may have some help here. Our departed friend Angela(and husband Steve Lane) had cooling problems in their 3.0 or 3.2 six powered Spyder.

The solution was a small spoiler that extended the width of the engine compartment to scoop the air and direct it up the firewall and into the 911 fan that resides about 4 or 5 inches behind the firewall(Spyders are mid-engine). This solved their cooling problem, giving the engine enough fresh air at speed to keep cool.

Pretty similar to Al's posted picture above.

Hell yeah!  Good stuff Danny!

I sit corrected! That the dead space is dead, and not high(ish) pressure just makes the proposed oil cooler and puller fan placement easier and better.

Al, it's funny, Angela's Spyder 6 cylinder had a cooling problem at speed.

My 4 cylinder had a problem at low speed, in traffic with high temperatures.

Both cars have 911 shrouds. Her solution, a fresh air spoiler/diverter.

My solution is homemade sled tins to get the hot/used air going backwards out of the car rather than get sucked back into the fan.

Jim Kelly is right, airflow behaves in unexpected ways.

@DannyP posted:

I may have some help here. Our departed friend Angela(and husband Steve Lane) had cooling problems in their 3.0 or 3.2 six powered Spyder.

The solution was a small spoiler that extended the width of the engine compartment to scoop the air and direct it up the firewall and into the 911 fan that resides about 4 or 5 inches behind the firewall(Spyders are mid-engine). This solved their cooling problem, giving the engine enough fresh air at speed to keep cool.

Pretty similar to Al's posted picture above.

Danny  I assume they had 911 flat sixes?  I know mine runs a lot hotter than when I had a flat four in my previous speedsters.  I sometimes have to have the twin oil coolers' fans going even at speed.  I think it's the nature of a flat six engine to run hotter.

It took a while for me to get used to the temperature gauge rising up in my current car.

I installed a sensor on one of the heads and on the tranny called Engine Guard.  It helped me understand what was going on with the engine and tranny and how the temps change with environment, driving and how long it takes for the tranny to warm up etc.  

Information is empowering and you might find it something you want to do.  

I got tired of not knowing and the VDO idiot needle not providing enough info for me anyway. Just saying.

@IaM-Ray- could you explain a little more? Got a link?  This Engine Guard thing sounds very interesting.  How hot does a transaxle get?

https://engineguard.com.au

These are contact or head temp sensors you bolt on a headbolt or a low bolt on the tranny.  You can order a display that can handle one or more sensors.  What you find is that the engine oil or casing takes a while to heat up.  and even more so the tranny.  Then you notice that before you do get to 180F on the engine your running for many miles.  btw They do sell water sensors too FYI.

There is buzzer for temp limits too.

In hot weather I have seen the temp go to 220 if I remember right.  Hard driving @140kph for an hour makes it get hot and the outside temp is a big factor because if your outside temp is 100F then you can expect to get high as well.   On cool days everything stays at 180F.  

Tranny temp will eventually match the engine pretty much but your surprised at how long it takes.

This to me shows the variability of car building and rad placement and cooler placement and when fans should turn on and whether the fan capacity is acceptable.  Remembering that without these sensors having a custom built car leave you IMO in the DARK.

I just finished installing my oil cooler install.

@JB356SR posted:

I just finished installing my oil cooler install.

Very clean. Any concerns with the oil filter being so close to the exhaust canister? Any insulating material going in there to offer some protection?

@Robert M posted:

Very clean. Any concerns with the oil filter being so close to the exhaust canister? Any insulating material going in there to offer some protection?

It's about a 1" away from the exhaust. Haven't had any issues so far.

@JB356SR posted:

It's about a 1" away from the exhaust. Haven't had any issues so far.

Nicely done. The camera angle made it look a lot closer than it is.

Very nice installation. Regarding the filter and the exhaust, I've had my filter assembly on the 2x2 rear frame piece above and behind the exhaust for a few years and have never had heat problems. I've running a 1776 so it isn't stressing the cooling environment, though.

Really pro-looking install. Kudos.