Trans coolers, fans and consistency.

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motorpirate

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As I am looking over the "to do" list and replacing the ring and pinion (3.55's) on the Cuda for Dany's next Bracket Racing attempt I am wondering:

Car now has the factory steel 8 blade AC cooling fan (need to attach the original shroud to the aluminum radiator somehow, that's what got me thinking about the fan)
A clutch fan would free up a little HP, but if it gets hot enough waiting in line to engage on one pass and not another where she starts closer to the front of the line I would think that would add to inconsistency?

What about the trans cooler? If I were to add an external cooler, would it make sense to eliminate the cooler in the radiator?
It is my understanding the cooler in the radiator is there as much to heat the fluid in cold weather as it is to cool it, so eliminating it and just using an external cooler would keep the trans cooler and a more stable temp as it isn't being heated by the radiator if it gets warm in line?

This car has no cooling issues or trans issues at this time.
And I am trying to add the original shroud back on it as much to quiet the fan (it is noticeably louder than it was with the original radiator/shroud) as to keep the temps more stable.

Would consider a flex fan of some sort if you guys think that would help in the HP department, but am I wrong that a clutch fan cutting in and out leads to inconsistency?
 
There are two kinds of clutch fans, straight viscous coupling and Thermostatic.
The viscous slips all the time never quite locking up, but the hotter the air coming thru the rad, the closer it gets.
The T-type is more sensitive to the air-temp coming thru the rad. It cuts in and out around a non-adjustable preset temperature point. This is nice for a streeter, that spends a lotta time at slower speeds.

Once the car gets over 30 mph, you can probably depend on ram-air thru the rad to cool your engine, so I would chose the straight viscous type.
I've never seen an 8-blader, that's a lotta blades. You could experiment with fewer blades, but I had no success with a flex-fan.
 
Last edited:
AJ/FormS said:
There are two kinds of clutch fans, straight viscous coupling and Thermostatic.
The viscous slips all the time never quite locking up, but the hotter the air coming thru the rad, the closer it gets.
The T-type is more sensitive to the air-temp coming thru the rad. It cuts in and out around a non-adjustable preset temperature point. This is nice for a streeter, that spends a lotta time at slower speeds.

Once the car gets over 30 mph, you can probably depend on ram-air thru the rad to cool your engine, so I would chose the straight viscous type.
I've never seen an 8-blader, that's a lotta blades. You could experiment with fewer blades, but I had no success with a flex-fan.
Click to expand...

I have been experimenting w/ fans the last couple of weeks. Testing in 95-96 degree hi humidity.
I could almost write a book on fan set ups now. The currant set up is a belt driven 2 1/4" Pitch 6 blade , 10,000 rpm flexfan, its as good as anything I have tested , and maybe the best! I have a dual 14' fan setup in a shroud/wired w/ a relay that will run both , a short " new" jaguar thermal
(2 5/8" tall) clutch/w/ 7 blade alum fan , 17 1/4" 6 blade flexfan , 6 blade 17" steel belt driven ,
not a lot of diff. between them on a 700 plus h.p. engine.
 
famous bob said:
I have been experimenting w/ fans the last couple of weeks. Testing in 95-96 degree hi humidity.
I could almost write a book on fan set ups now. The currant set up is a belt driven 2 1/4" Pitch 6 blade , 10,000 rpm flexfan, its as good as anything I have tested , and maybe the best! I have a dual 14' fan setup in a shroud/wired w/ a relay that will run both , a short " new" jaguar thermal
(2 5/8" tall) clutch/w/ 7 blade alum fan , 17 1/4" 6 blade flexfan , 6 blade 17" steel belt driven ,
not a lot of diff. between them on a 700 plus h.p. engine.
Click to expand...
Yea we are still a 180 HP 273 for the moment...every pony counts!!
 
Engine masters did a video of fans and hp loss. Clutch fan is the way to go absent electric fan. I think he means 8 impeller blades on the water pump. I run an external cooler in series with the internal cooler. I know some say not to, but I can hot lap the car 5-6 runs. Not even shutting the car off before the trans starts to get warm and I mean just warm. Also because I have a govenor that shifts the car at 6300 rpm I let the trans shift itself. I think it is important to have a stable fluid temp. No too hot, not too cold because it can change the rpm it shifts at.
 
Also something I learned last year. I ran a ac 8 impeller water pump with the stock 68 ac waterpump pulley. Which I believe is smaller in diameter. I had noticed the year before that there was some cavitation pits in the timing cover. Not many but some. Pulled it apart a year later and there were pits everywhere! Its see’s 6400 rpm max. I was in there to cut off four of the impeller arms anyway so I installed a anticavitation plate. Higher rpm and the 8 blade impeller really needs an anticavitation plate.
 
In the old days we used to take off the belt for the water pump and alternator in the ready lanes. In a low HP situation you can get by with no water flow for 1 pass as long as you didn't heat it up before getting into the lanes.
The little electric motors that run the water pumps and electric fans are relatively cheap nowadays. I would go that way. Advantage: you can run the water pump and fan in the pits and cool things off in between rounds. Best solution is an electric water pump that replaces your mechanical one, but they are more expensive that the little $80 electric motor kit.
 
RockinRobin said:
In the old days we used to take off the belt for the water pump and alternator in the ready lanes. In a low HP situation you can get by with no water flow for 1 pass as long as you didn't heat it up before getting into the lanes.
The little electric motors that run the water pumps and electric fans are relatively cheap nowadays. I would go that way. Advantage: you can run the water pump and fan in the pits and cool things off in between rounds. Best solution is an electric water pump that replaces your mechanical one, but they are more expensive that the little $80 electric motor kit.
Click to expand...

None of this applies to my car, big block 723h.p. street car I have tried all the things mentioned, so far a 10,000 rpm belt driven flexfan , w/ flowkooler water pump , and water wetter , in my 28x19 crossflow rad.has been the best. My set up is on the edge, a clutch fan blocked enough air that it wouldn`t work for me . I do have a new one that is only 2 5/8" tall and set up for a big block , if anyone is interested.
 
famous bob said:
None of this applies to my car, big block 723h.p. street car I have tried all the things mentioned, so far a 10,000 rpm belt driven flexfan , w/ flowkooler water pump , and water wetter , in my 28x19 crossflow rad.has been the best. My set up is on the edge, a clutch fan blocked enough air that it wouldn`t work for me . I do have a new one that is only 2 5/8" tall and set up for a big block , if anyone is interested.
Click to expand...
It wasn't supposed to. The message was intended for the originator, motorpirate.
 
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