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I don’t mean to obsess over your engine fan choice! It’s that I am working on a project where I had to mount the radiator lower for hood clearance. I plan to use electric fans, but have been pining over how much fan to install. There are no formulas or rules of thumb that I can find to figure out required fan sizes.

It’s a slippery slope - more fans/larger fans means bigger alternator, etc.
 

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Discussion Starter #162
I don’t mean to obsess over your engine fan choice! It’s that I am working on a project where I had to mount the radiator lower for hood clearance. I plan to use electric fans, but have been pining over how much fan to install. There are no formulas or rules of thumb that I can find to figure out required fan sizes.

It’s a slippery slope - more fans/larger fans means bigger alternator, etc.
Indeed. More variables than one cares to ponder. Once I get the opportunity to sit and stare at the engine bay for a while, I'll hopefully come up with some mods to increase the static airflow. Where there's a will, there's a way.

I think the stock alternator is only 270 amps. Makes me wonder how it ran the passenger heater core/evaporate blower motor, the condenser fan motor, the overhead blowers, the driver's blower and the 400ish light bulbs on these things. I'm sure relays were set to only allow so many motors to run at once, but damn. I've eliminated all but the driver's blower. Surely this can handle an electric radiator fan or two or four.
 

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Most of the time this will be a highway cruiser wont it? How about a giant NACA duct or giant sized scoop ala aircooled VW?



You would still need fans for traffic/stop and go, but I cant imagine 40+ MPH ram air would hurt, and could possibly cut down on fans needed at least at highway speeds.

Fell free to tell me to fuck off too, just thinking out loud.
 

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I did some digging and their 11” fans are 20ish amps and their 15” is 40 or 50amps. There are 8 fans on that housing. So it would seem you need 200 amps when cooling demands are high.

And that’s on a transit bus, so an 8v92 on a hot dry day up a big steep hill is going to be higher.

Between all the AC and engine cooling requirements on these busses, you wonder when it would make more sense to run everything off of a diesel genset.
is that running amps or startup amps?

You can get away with less if you stage the startups, but then you need a rather complex fan controller.
Batteries can accommodate the huge startup load if they all kick on at once, but wiring is gonna be pretty fucking big.

Personally I'd just stay engine driven if at all possible. Mechanical fans just flat out work and can pull way more CFM than electrics. Especially when you're getting it in 2nd gear WOT going up a hill and the RPMs are up.
 

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Ordered in a 4-1/2" diamond grinder wheel and a new trigger switch for my Rigid grinder. Hope that strips all the mill scale off in a decent amount of time.
ALL the millscale?? You don't plan to mechanically remove millscale from all those sheets do you??? All of it?




PS I agree with the fans. Flexalite fans cant keep most v8 swapped hot rods cool. :flipoff2: You're in heavy duty territory with poor air flow. You'll have to aim misters at your rads and keep 50 gallon drums of alcohol on board for evaporative cooling if you don't run enough fan.
 

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I would really really rethink flexalite fans to try and cool the engine.

7k cfm isn't even in the right ballpark. I seem to recall reading an 8v92/6v92 cooling fans on buses pull near 40hp at full lock. That's like 32k cfm using a crude calc. Sure it only needs 5hp or less most of the time (less than 10k) and you will be at less than GVWR all the time, but you're still undersized there.
I was working my way down to pass along the same thought.

No clue on this specific application, but we just did some work on an electromagnetic fan clutch for a similar application that is ~50hp for the fan. They were roasting the clutch due to overload in the bus applications. :smokin:
 

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Discussion Starter #167
Most of the time this will be a highway cruiser wont it? How about a giant NACA duct or giant sized scoop ala aircooled VW?



You would still need fans for traffic/stop and go, but I cant imagine 40+ MPH ram air would hurt, and could possibly cut down on fans needed at least at highway speeds.

Fell free to tell me to fuck off too, just thinking out loud.
Air ducting is already on my mind. Something similar to the pic. There's ample room for ductwork to be added and room for big air channels throughout to make a hell of a wind tunnel. No need to fuck off lol. Something will come together with help from all the posts.
 

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Discussion Starter #168
ALL the millscale?? You don't plan to mechanically remove millscale from all those sheets do you??? All of it?




PS I agree with the fans. Flexalite fans cant keep most v8 swapped hot rods cool. :flipoff2: You're in heavy duty territory with poor air flow. You'll have to aim misters at your rads and keep 50 gallon drums of alcohol on board for evaporative cooling if you don't run enough fan.
Yep. All of it. The project requires about 70% of the mill scale to removed for welding, so stripping it all at once will be much quicker than marking location to grind and double-checking that I hit the right spots. I was going to do the muriatic acid thing, but high winds make it near impossible to play with water without getting soaked. Acid waves aren't friendly. Coming up with some kind of containment to submerge each sheet wasn't working out, either.
 

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Discussion Starter #169
ALL the millscale?? You don't plan to mechanically remove millscale from all those sheets do you??? All of it?




PS I agree with the fans. Flexalite fans cant keep most v8 swapped hot rods cool. :flipoff2: You're in heavy duty territory with poor air flow. You'll have to aim misters at your rads and keep 50 gallon drums of alcohol on board for evaporative cooling if you don't run enough fan.
I was thinking a bank of CO2 fire extinguishers triggered to unload on the radiators at a certain temp.
 

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The airflow required is not so much the issue, its the pressure that will be generated as you try to create that.

The electric cooling systems posted above are in about the 10-15k cfm range and can be from 200-300 amps total on a 24 volt system. Used for transit and some coaches 280-450HP engines.

The restriction of the radiators in those systems are designed to work with the fans at the heat rejection required. Your MCI coach using a centrifugal blow type air moving device means that it is likely working against a very high static restriction, probably at least 4" H20 range. That is where all the horsepower goes.

Power usage is directly couple to the airflow restriction 2" vs 4" = half the power assuming you had 2 different fans systems with the same efficiency at the respective operating points.

To correctly engineer your cooling system you need to know required heat rejection and flow rates and the detailed specifications of the heat exchanges and fan(s). Unfortunately most of that information is not available in the aftermarket world so the best you can do is educated guess.

My recommendation do not even bother with the Flexalite fans, those cfm numbers are not even all that real in the first place plus they are not designed to work against any amount of static pressure that you would find in a heavy duty rad. Delivered airflow will be VERY low.




I would really really rethink flexalite fans to try and cool the engine.

7k cfm isn't even in the right ballpark. I seem to recall reading an 8v92/6v92 cooling fans on buses pull near 40hp at full lock. That's like 32k cfm using a crude calc. Sure it only needs 5hp or less most of the time (less than 10k) and you will be at less than GVWR all the time, but you're still undersized there.
 

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Discussion Starter #172
You're nuts. I hate my life mechanically removing millscale even over 1sq ft. You couldn't get pre pickled or cold rolled sheets?
Could, but for a much higher price. We're in such a rural area that products are marked up 2-4 times higher than anywhere else if the items have to be brought in from afar. I didn't have any that could haul that much steel, otherwise we would have gone to Colorado Springs or Denver like usual. We literally save money by driving over a 10k foot high mountain pass to a city two hours away for lumber at a big box store. Costs more to buy it here just a few minutes away.
 

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Yep. All of it. The project requires about 70% of the mill scale to removed for welding, so stripping it all at once will be much quicker than marking location to grind and double-checking that I hit the right spots. I was going to do the muriatic acid thing, but high winds make it near impossible to play with water without getting soaked. Acid waves aren't friendly. Coming up with some kind of containment to submerge each sheet wasn't working out, either.
https://www.youtube.com/user/submarineboat/videos
DIY sandblaster. Not sure if you follow the SVSeeker build in Oklahoma but he also needed to clean up a bunch of steel to build his boat and built a large sand blaster

https://www.youtube.com/watch?v=7ZnUim-gNMI

https://www.youtube.com/watch?v=A7tGlXXQ6Gs

Then he added water

https://www.youtube.com/watch?v=WdkoDzUOUsw
 

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Discussion Starter #175
Have you made a video of that Old Screamin Jimmy running ?

I am the only one who wants to hear that bastard run ??
I actually haven't. Got a teaser pic, though. I'm in the middle of rerouting fuel lines, wiring, and the air and power steering lines. It'll be a few before I fire it up again.
 

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https://www.youtube.com/user/submarineboat/videos
DIY sandblaster. Not sure if you follow the SVSeeker build in Oklahoma but he also needed to clean up a bunch of steel to build his boat and built a large sand blaster

https://www.youtube.com/watch?v=7ZnUim-gNMI

https://www.youtube.com/watch?v=A7tGlXXQ6Gs

Then he added water

https://www.youtube.com/watch?v=WdkoDzUOUsw
he's actually been using a Dewalt pressure washer with a blaster add on in his newer videos. That would be more practical for most people it seems.

 

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he's actually been using a Dewalt pressure washer with a blaster add on in his newer videos. That would be more practical for most people it seems.

https://www.youtube.com/watch?v=mYtbPG1RKgY
He was $55 in sand to blast that tank but the results look pretty sweet. I think the guys who do that water sand blasting use an additive in the water to prevent flash rusting.
 

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Discussion Starter #178
I'm envious of his tool selection and workspace. For the $20ish to get the diamond wheel, I'm gonna have to stick with it as long as it works. We have one sandblaster guy here that uses a pull-behind. His fee is high and his work sucks. Had him do some Corvette parts and was thoroughly disappointed. I was joking a few weeks ago about chaining up each sheet to the Pathfinder and dragging them through the valley. It's all desert here. The sand is coarse and sharp.
 

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Discussion Starter #180
I bet that diamond wheel loads right up and becomes ineffective. Hope I'm wrong.

Have you seen these walter flexcut? I haven't tried them.
https://www.walter.com/en_CA/products/abrasives/blending/flexcut-mill-scale
https://www.youtube.com/watch?v=rBH4hs0wWdQ
I hadn't. Those are gnarly. Little worried about them eating too much of the good steel away, but definitely worth a try. Those Germans build some solid stuff. Especially dig that since both sides of my family are German. I'll work with the diamond and Flexcut and report back. Thanks for the suggestion!
 
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