Rear Fender Mounted Coolers

Rusty, your theory sounds good at first glance but...

I think either way the result will be the same.

While idling, the air will be drawn from all directions including underneath the car. Depending on how long your stop lights are, it's possible that fan direction could have a small difference in oil temperatures (though I doubt it).

While driving, the air will (mostly) be drawn from beneath the moving car and from the fender well hence the air should be cool and the fan pull-direction will have little or no difference in temperature, certainly not enough to affect the oil temperature.

But...if you feel better about it with the pushing fan, go for it and enjoy the ride!

So, my theory may just be a lot of hot air...! It will get put to the test this weekend at SLO.

Rusty,

Your plan may well produce positive results.  To do it correctly, you would run the same course twice in identical conditions: weather, time of day, etc.  If you don't have an analog oil temp gauge, now would be a good time to install one.

The fan industry publishes data that are very useful for sales, but not performance.  Example: most fan makers will state cubic foot/minute data (cfm), but that data is at zero pressure.  That means data is accurate if the fan was blowing air in a large, empty room with no pressure differential between inlet and outlet.  So, you could call it the potential energy of the fan.  

However, when we use fans in our cars, we create pressure differentials.   We push or pull air, usually through a heat exchanger of some type: radiator, oil cooler, trans cooler, etc.  Air will naturally flow from high to low pressure, so we want to increase pressure on the fan inlet side, and decrease pressure on outlet side.  Ducting and shrouding can help increase air pressure on the inlet side, and decrease it on the outlet side.  The air we are moving needs a low pressure outlet, an escape to atmosphere.

In a conventional radiator situation, a pusher fan sits right in the incoming air stream as it tries to shove air through the rad, so there is a blocking effect of the fan itself, housing, motor, etc.  This is the reason why, in most applications, a puller fan is rated at higher cfm than a pusher.  This means that Spal fan A1, for example, has a 10" diameter, 5 curved blades, with a 2.5" motor.  Data will show an increased output when those components are used in a puller orientation, as opposed to a pusher orientation.  These two applications (pusher vs. puller) are the same component pieces, just with the blades flipped, and the fan motor direction reversed.  However, when actual pressure differentials are included, which means when we use them in a real world application, almost all of the data has been proven wrong.

Same is true of water pumps for liquid-cooled engines.  Available data is bogus.  Bottom line from my perspective: data logging is where it's at.  Take before/after readings that are as accurate as possible, under weather conditions as identical as possible, on the same road course.  Do test runs before and after swapping out the parts in question.  Only then will you know how effective each change is for your application.  Best of luck and please let others know what changes you find.   

Great info Jim thank you. I just did a 3 hour run in 90-95 degree weather. My oil temp was running 212-215. Not bad but I am hoping for a little better with this setup. I'll post my results.

Rusty S posted:

...I just happened to have a brand new fan just sitting around that is configured as a "pusher" fan. Last night I took the entire cooler assembly out and replaced the fan. I ran it with the new configuration and it is now blowing the air toward the engine rather than drawing air from the engine...

Rusty, I think you have to ask what's really going on here.

You're a car guy. You have this really cool car that's running perfectly fine. You have lots of tools and some extra parts sitting on the bench not doing anything.

And this is a car without any PIA computers that are going to throw error codes or otherwise have a hissy fit if you start monkeying with things.

The right thing to do is to have at it and get your hands greasy. That's really one of the reasons we all get cars like this in the first place.

You're probably not going to make things much worse than they already were. And if you can convince yourself that they're better afterwards, that's a victory, right? I wouldn't bother getting an accurate temp gauge and gathering any scientific data about whether or not the new fan setup is actually any better. There's too much potential for disappointment there.

It's like fiddling with the carbs. Half the time they're not really any better when we're through than they were when we started. But we convince ourselves that the engine's running much smoother now thanks to us knowing how to do guy stuff.

We buy these cars to make us happy. And screwing around with the fan without making a real mess out of it is going to make you happy.

Party on, Garth!

You're right we all like to tinker but more than that I like making good things better. If I thought this would make no difference then believe me when I say I would rather sit on my a$$, have a beer, and watch a good movie!

Change, whether good or bad, will not come about while doing nothing. That's what is really going on here! Honest!

Sorry Rusty, just me busting chops a bit.

For what it's worth, my cooler is angled across the wheel well (at about a 45-degree angle) so, in theory, it gets air flow coming off the wheel. The fan is behind the cooler and pulls air through it.

But none of us is an engineer or has the tools to analyze what's actually happening. With this kind of stuff, shade tree assumptions are often wrong. I'm thinking about how most of the aftermarket designs for alternative engine cooling fans and shrouds that look great have turned out to be less efficient than the boring-looking setup VW engineers did in the '30s.

Moving the cooler out of the space in front of the engine bay and into the wheel well did make a huge difference, though, in oil temps and in temperatures inside the engine compartment.

I usually don't have to turn on the oil cooler fan until outside temps reach about 70 degrees.

Mine is located in that area ahead of the engine bay as yours was Mitch. However, my fan is wired straight to the ignition, and comes on immediately. That seems to be a good thing down here in Florida about 10 months of the year.

I looked briefly at access to remove it for relocation. Doesn't appear to be an enjoyable adventure getting it out of there.

I'm really liking where Teby and I put our Setrab Coolers. They're along the driver side frame rail ahead of the rear axles. They're mounted horizontally with the fan pack on top and they push air through the fins.

With a 180 degree thermal switch installed it comes on when needed and shuts off when the oil gets to 170 degrees (iirc).

The only thing was that it required a custom fabricated mount but that really wasn't that difficult. That and the Mesa oil cooler won't fit in that spot.

Here's a previous thread with pictures:

https://www.speedsterowners.com...8#489946812098078608

BobG posted:

Mine is located in that area ahead of the engine bay as yours was Mitch....

...I looked briefly at access to remove it for relocation. Doesn't appear to be an enjoyable adventure getting it out of there.

No, it's not easy if the transaxle is in. I think some builders put it there because it's very convenient when the car is being built, before the tranny goes in. The bulkhead is one of the few available places that's big enough without having to fabricate a custom mount.

When we upgraded to a Setrab, we just left the old Mesa on the bulkhead. It will be removed when the tranny is swapped out for a five-speed in a few months.

So hey - there's another reason to put in a five-speed!

Sacto Mitch posted:

It will be removed when the tranny is swapped out for a five-speed in a few months.

 

Dog.

Do tell!

Stan Galat, '05 IM, 2276, Nowhere, USA posted:

Sacto Mitch posted:

It will be removed when the tranny is swapped out for a five-speed in a few months.

 

Dog.

Do tell!

Well, not to hijack a thread about oil coolers, but yeah, I mentioned this a while back.

Last summer, someone made me an offer I couldn't refuse involving a Gene Berg five speed advertised on the Samba. It's now been redone with ratios appropriate to my leisurely driving style and modestly powered but cool-running stroker.

Here are the five speeds charted against the four I now have.

The box is done and I'm awaiting a slot on Anthony's busy dance card for the install.

Rusty, this is the orientation of my DeRale.  It's about the same as a Setrab and mounted in the driver's wheel well just inside and behind of the rear wheel.  Been cooling great for over ten years.  Turnpike speed oil temp in ANY outside ambient temp up to 102F is about 200F.

Rusty,

I mounted mine in the space in front of the fire wall and mounted to the wheel well on the drivers side with the fan pushing the air through the cooler and out into the wheel through openings cutout in the wheel well. 

The fan is on a temp switch (180 degrees) and it works well here in North Carolina with normal oil temp running 210 on the hottest days.

Setup is 1915, dual dells and full flowed.

Robert, Mitch and I have the Setrab 625 which is one size larger than you and Teby's coolers, trust me, they won't fit where yours are installed, hence the drivers-side wheelwell location.

Robert M posted:

I'm really liking where Teby and I put our Setrab Coolers. They're along the driver side frame rail ahead of the rear axles. They're mounted horizontally with the fan pack on top and they push air through the fins.

With a 180 degree thermal switch installed it comes on when needed and shuts off when the oil gets to 170 degrees (iirc).

The only thing was that it required a custom fabricated mount but that really wasn't that difficult. That and the Mesa oil cooler won't fit in that spot.

Here's a previous thread with pictures:

https://www.speedsterowners.com...8#489946812098078608

That looks very clean. I have a similar engine as Teby. I didn't think the Setrab would be big enough but it works well?

I took my car out yesterday after work and ran it pretty hard. My oil temp never got past 195 but the outside temp was mid 70's. Looking forward to the SLO trip where the weather should be in the 90's.

Gordon Nichols posted:

Rusty, this is the orientation of my DeRale.  It's about the same as a Setrab and mounted in the driver's wheel well just inside and behind of the rear wheel.  Been cooling great for over ten years.  Turnpike speed oil temp in ANY outside ambient temp up to 102F is about 200F.

This is what I'm trying to achieve on my car! I'm pretty sure if I was driving in 102 degree heat the oil temp would be in the 220's. We will see.

Stan Galat, '05 IM, 2276, Nowhere, USA posted:

Sacto Mitch posted:

It will be removed when the tranny is swapped out for a five-speed in a few months.

 

Dog.

Do tell!

Stan - with my new gear ratios I don't think I would want a 5 speed. This new setup is perfect. Up hills, curvy roads, very even acceleration through all gears. This setup gets the car going fast...fast!

How the hell do you get to your beer if the cooler is in the fender well?

Robert, if you guys plan on wine tasting in the Templeton-Paso area, it's going to be 100+ Saturday and Sunday

Jethro, we keep Teby tied to the rear rack, he passes beers faster than he drinks them. Besides, it's against the law to drink beer while riding on a luggage rack.

I'm not sure where Scott aka Slofuzz is taking us wine tasting on Saturday for the SLO Cruise. Did you say you were going?

I spoke to him yesterday. He's taking us inland where the temps will be about 110-115 so we can test my fan /cooler setup...

Rusty S posted:

I spoke to him yesterday. He's taking us inland where the temps will be about 110-115 so we can test my fan /cooler setup...

Guess I'll try out my new sunblock as well.

you know, we have over 400 wineries in SLO county, there are a bunch near the coast...jus sayin'