Cheap Junk 1971 Build

[oprn]

There are several reasons for the transaxle swap.

1) The old swing axle one is popping out of 4th gear.
2) To accommodate a change to IRS suspension.
3) To utilize 944 rear suspension and disc brakes that I already have.
4) Change to 15" Fuchs wheels all around and eliminate the Chevy wheel spacers and offset.

I also went to 28" tall tires. I am hoping that this is not overkill and I will still have enough power and cooling on the highway. According to my calculations that will be 2900 RPM at 60 mph and 3100 RPM at 70 mph. Time will tell. This car is strictly a highway cruiser.

[Piledriver]

If all else fails you can put a 356 pulley on it for more fan speed.

[oprn]

Not on the direct drive fan on a type 4 engine. There seems to be quite a bit of discussion about the optimum fan speed for the type 1 cooling fan but I have never seen any data about the type 3 or type 4 fans.

I am giving consideration to moving the fan up top and mounting it like Chevy did with the Corvair. That would open up a whole world of fan speed possibilities.

[Ol'fogasaurus]

Not on the direct drive fan on a type 4 engine. There seems to be quite a bit of discussion about the optimum fan speed for the type 1 cooling fan but I have never seen any data about the type 3 or type 4 fans.

I am giving consideration to moving the fan up top and mounting it like Chevy did with the Corvair. That would open up a whole world of fan speed possibilities.

For what it is worth, I'd be careful doing that. The "Babbitt Beaters" had a lot of problems with that setup.

The airflow across the upper and side surfaces of the bdy was one of the problems mainly because the air flow was horizontal (more or less) and the fan, also horizontal, so it had to pull (suck) it down for use. Having to pull the air in from the side like some of the "rails" tried also lead to cooling problems.

Lee

[oprn]

Not too worried about airflow on an in the open engine glass Buggy. I thought I might have airflow issues using the stock type 4 fan and having it face rearward but it prover to be fine. With the fan on top the air flow would be mostly from under the car, over the transaxle with some coming from the wheel wells too.

One of the ideas of doing this is to divorce the fan from the alternator (upright conversion) and crankshaft (type 3 & 4) so it could be controlled according to need. Some sort of hydraulic coupling perhaps? Activated by engine temperature? The fan only needs to run at full output on a hot day at full load otherwise it is just sucking up power for no reason.

If someone has already tried a temperature controlled fan I would love to hear about it.

[Ol'fogasaurus]

Not too worried about airflow on an in the open engine glass Buggy. I thought I might have airflow issues using the stock type 4 fan and having it face rearward but it prover to be fine. With the fan on top the air flow would be mostly from under the car, over the transaxle with some coming from the wheel wells too.

One of the ideas of doing this is to divorce the fan from the alternator (upright conversion) and crankshaft (type 3 & 4) so it could be controlled according to need. Some sort of hydraulic coupling perhaps? Activated by engine temperature? The fan only needs to run at full output on a hot day at full load otherwise it is just sucking up power for no reason.

If someone has already tried a temperature controlled fan I would love to hear about it.

https://www.bing.com/search?q=air+flow+ ... 7c&pc=LCTS

I can't find the air flow pix I want. But the shape of the different dune buggy bodies have the potential to cause air flow problems. My buggy is a sand use buggy, so I don't drive that fast, but I have talked to others and seen others over the years where cooling has been a problem for them.

There is one buggy guy here who does do fairly long trips with his buggy, I haven't heard from him for a while but he might be the one to talk to.

My post is for what is it worth.

Lee

[oprn]

We have done many long trips with this one. A few with the original 1600 DP and many more since with the type 4 engine 11 hours duration several times and many 5 & 6 hour runs. In flat hottish country in the summer and through the mountain passes too. I have sat in the back and ran temperature tests, air flow tests with both my hands to feel the pressure gradients and tufts on a stick. I have observed the shape of the air in the rain too so I am pretty familiar with how the air flows around and especially behind this Buggy. It was a real learning experience for sure!

The air profile behind this car is very different with the type 4 cooling system than it was the type 1 I can assure you! I also changed my present exhaust system design based on these findings to keep the exhaust heat from concentrating behind the crank pulley like it did with the type 1 engine.

Yes I would be happy to see other's results who have studied this too! If we get further into this topic it might be better to start a new thread rather than to clutter up Clatter's build thread with off topic stuff.