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Discussion Starter · #1 ·
This last weekend I was riding my 2001 502 and was thinking through the desired results of changing my older-style, smaller radiator for the newer, larger one. I have one problem with this whole concept though.

My goal is not necessarily to get the engine coolant temp lower, but for ME THE RIDER to be cooler. Here is my concern. The 502 is going to produce the same amount of heat regardless of which radiator is cooling it. The larger radiator is reported to bring engine coolant temps down by 20 degrees, but where does that heat go? It seems to me that the heat produced will flow past my legs and crotch to a larger extent due to the added size of the radiator. Maybe I'm wrong about this.

I just don't want to spend some big bucks to make this change and not realize added comfort as the rider.

Does anyone have seat time with the 502/small radiator combo and then switched it out for the larger one? Was there a noticable increase in rider comfort?

I am also holding out to hear more info about the whole reverse-flow concept that seems to be emerging.

Thanks for any help/comments.

Bill Taylor
 

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Re: Upgrade to larger radiator...cooler engine, hotter rider

Bill Taylor said:
This last weekend I was riding my 2001 502 and was thinking through the desired results of changing my older-style, smaller radiator for the newer, larger one. I have one problem with this whole concept though.

My goal is not necessarily to get the engine coolant temp lower, but for ME THE RIDER to be cooler. Here is my concern. The 502 is going to produce the same amount of heat regardless of which radiator is cooling it. The larger radiator is reported to bring engine coolant temps down by 20 degrees, but where does that heat go? It seems to me that the heat produced will flow past my legs and crotch to a larger extent due to the added size of the radiator. Maybe I'm wrong about this.

I just don't want to spend some big bucks to make this change and not realize added comfort as the rider.

Does anyone have seat time with the 502/small radiator combo and then switched it out for the larger one? Was there a noticable increase in rider comfort?

I am also holding out to hear more info about the whole reverse-flow concept that seems to be emerging.

Thanks for any help/comments.

Bill Taylor
Sorry Bill there is no fix except to lower the friction in the motor--this can be done to some extent with oil but my 540 runs 10 to 15 degrees cooler than the 502. The engine has roller cam and rockers and is built to a higher degree of precision than the 502 means less friction. That being said, there is no free lunch with the big blocks—now you may find this tough to believe but the big headers I use on my bike have the shields in the garage as the bike and the rider actually run cooler with them off!

Also run Royal Purple’s “Purple Ice” in the radiator and use the highest % of water you can to transfer the heat—then in the fall if you are up north add more coolant. I just got back in from lunch, the temperature here is about 94, and my engine only got up to 160! In traffic this afternoon at about 98 it should get up to around 190 to 200 on my 28-mile ride home.
 

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Bill
You, Ed Sbanz and I seem to be the only ones that get the concept that a larger radiator and/or larger fan just get rid of engine heat better and send it onto your body! The engine running cooler just means the heat of combustion which has to remain the same regardless of your cooling system is being sent out into the airstream to cook you sooner! I'm staying with my stock (small) radiator and fan so the engine runs a little hotter and I stay a little cooler.
Joe
 

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502 Cooling

Well guys I have been sitting here biting my tongue. I think I am the only contributor to this thread who actually has owned and experimented with 502 cooling. I have owned three 502's starting with a two wheel 502 in 2000. I now ride a 2003, 502 Trike.

Yes, I did a bunch of experimenting starting with the 2000. I changed the small, stock radiator on the 2000 to a super large Chopper City radiator with a 16" fan (stock is 14"). And, yes this helped.

My 2003 came with a larger radiator from the factory but I have replaced the puny 5/8" ID lower pipe with a 1" ID pipe (gentle sweep curve). I changed to the higher capacity water pump and modified its input pipe and output fitting to larger ID's. I also remanufactured the water distribution maniflold on the front of the engine to a larger ID.

Let me say this. All of my testing and modifications (and about 30,000 miles of riding in all conditions, I live in Florida) have brought me to the conclusion that I'd rather have 160 degree air blowing over my body than 200 degree air. The way I am setup now I never see temps above 180.

My wife wears sandals and shorts which she was never able to do before.

Anyone who also believes that cooler air blowing across their body is an advantage, contact me directly.
 

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I forgot to mention the new water pump but it flows 20% more water than the old pump--and looks a whole lot better than the old ugly one!!
 

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Does anyone know for sure wether or not the factory is going to use the jabsco pump on the 05 bikes? I take it this is the upgraded pump Dave mentioned.
 

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TJzz4 said:
Does anyone know for sure wether or not the factory is going to use the jabsco pump on the 05 bikes? I take it this is the upgraded pump Dave mentioned.
Yes it is--saw 2 of them in a box from BH to Texas Boss Hoss.
 

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Tom,
I saw the new pumps on a couple of Factory Demo bikes at Marcus Dairy this past Sunday.
 

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Good deal... Thanks Don. Still waiting arrival on my new boss. Another 3 weeks yet. Just want to stay on top of things. Still..... Going to be a LONG three weeks.... :?
 

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Sorry to bust all the bubbles!!!! Just so happens there is a nice article in August 2004 of Hot Rod mag, "Ideal Coolant Temp". In a nut shell,,, want the best gas mileage and lowest emissions, then 200 to 210 is where you want to be.. Want the best all around temp then 180 to 200 is were you should be.. Remember it the oil that cools the engine. Put an engine oil cooler on the Boss and you'll drop water temps..

Just remember also as stated in the artical quote unquote, "research has shown that running an engine with standard viscosity oils below 180 degrees is harder on the oil pump, engine bearings, and piston rings.."
Race engines produce more power the cooler they run, denser fuel at lower temps but then again they only get one race out of an engine or in drags only seconds.. Your choice..

My Boss runs right in the 180 to 200 range with the small radiator and higher temp switch. Fan doesn't come on at all when cruising, no noise and I'm comfortable even at 90 degrees outside. I don't care what you do, if you are stuck in a traffic jam you are going to be hot and get your nuts dry roasted... Bigger radiator, more GPH pump, high temp switch.. etc it don't matter.

I have have been thinking of experimenting with baffles behind the radiator ducting the hot air away to the sides..I do believe Tom Breedlove has done something along those lines already..
 

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Tune you air filter

A super good article in August 2004 Hot Rod mag, "TUNE YOUR AIR FILTER" Very interesting stuff on really making power with the right air filter setup.. sorry way too much info to post!!
 

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fasteddie said:
Sorry to bust all the bubbles!!!! Just so happens there is a nice article in August 2004 of Hot Rod mag, "Ideal Coolant Temp". In a nut shell,,, want the best gas mileage and lowest emissions, then 200 to 210 is where you want to be.. Want the best all around temp then 180 to 200 is were you should be.. Remember it the oil that cools the engine. Put an engine oil cooler on the Boss and you'll drop water temps..

Just remember also as stated in the artical quote unquote, "research has shown that running an engine with standard viscosity oils below 180 degrees is harder on the oil pump, engine bearings, and piston rings.."
Race engines produce more power the cooler they run, denser fuel at lower temps but then again they only get one race out of an engine or in drags only seconds.. Your choice..

My Boss runs right in the 180 to 200 range with the small radiator and higher temp switch. Fan doesn't come on at all when cruising, no noise and I'm comfortable even at 90 degrees outside. I don't care what you do, if you are stuck in a traffic jam you are going to be hot and get your nuts dry roasted... Bigger radiator, more GPH pump, high temp switch.. etc it don't matter.

I have have been thinking of experimenting with baffles behind the radiator ducting the hot air away to the sides..I do believe Tom Breedlove has done something along those lines already..
Sorry--my discussions with one of the best engine builders out there do not agree. My engine started as the ultra street and was modified with different grind Brodix heads, roller cam, roller rockers etc. Scott Shafiroff advised no more than 180 and Mobil 1 or Amzoil and we spoke at length on this subject. Your analysis of race engines to ours is fundamentally flawed as tolerances in a true race motor are not as tight in some critical areas (that’s why it takes about 5k for the stock BH motor to loosen up). The 350 or the 502 is not a race motor but it is not an emission restricted engine either so who care's about emissions---a hot engine runs cleaner than a cooler one but will make less HP and that is a fact. The Dyno run on my motor had water temps between 137 and 143 with measurements taken every 100 RPM. Would it not make sense if what you said was true the Dyno runs would be run at higher temps?

My 540 in stop and go traffic yesterday never got above 190 and it was 95 here. The tranny did get up to 195 in the worst of it. The less friction there is the less temperature will be generated.
 

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sorry but you didn't read what I wrote! I said yes a cooler engine will make more HP because of denser fuel mixture making more power, but, the cooler temps are harder on the engine parts. It has nothing to due with tolerances it's the oil as I stated..Ideal engine temps for "street" are between 180 and 200 has nothing to do with emissions but for all around street performance and engine longevity. Get the mag and read the article.. don't shoot the messenger...



I think we're saying the same thing just a little differently..
 

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finally figured it out about this temperature thing.. I just looked all you guys that say their bike is running cooler are from Florida and Texas (thin blooded) ..Hell 175 degrees blowing back is cold to you guys. Anybody north of the Carolina's think anything higher then 100 blowing back is just too damn hot!!!

Problem solved!!!
 

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Discussion Starter · #16 ·
Fast Eddie,

I love the idea of somehow manipulating the flow of hot air to either the sides of the bike, or maybe even under the bike (completely away from the riders legs, etc.).

I have also thought about the possibility of this while riding my bike. I sell attic ventilation products for residential roofing ventilation manufacturer. A competitor of mine makes a ridge-vent product designed to ventilate attics that is a plastic product that looks like corrugated cardboard. The product is called Cor-A-Vent. It seemed to me that this type of product possibly could be formed in a way to direct air where you wanted it to go, if you could flow enough volume of air through it. It is designed to withstand shingle roof applications so it should be able to withstand the air temps behind the radiator.

I'm not a good enough designer/engineer to fab-up something like this, but maybe someone else reading this would want to take this ball and run with it.

Imagine, riding a 502 with only the ambient heat of the engine on the rider. Having no fan-driven air heating you up would be an amazing thing to have on our already incredible machines!

Bill
 

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fasteddie said:
finally figured it out about this temperature thing.. I just looked all you guys that say their bike is running cooler are from Florida and Texas (thin blooded) ..Hell 175 degrees blowing back is cold to you guys. Anybody north of the Carolina's think anything higher then 100 blowing back is just too damn hot!!!

Problem solved!!!
:D I hate the heat! The tranny is what burns my butt--literally! HAHA

TBH just installed a tranny cooler behind the radiator and that has helped big time lost about 30 degrees!
 

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Bill - I once saw a Boss on e-bay a while ago with two smaller radiators in front and both were angled out slightly to the sides, each having it's own fan. I e-mailed the guy for some more detailed pictures but he never responded. The Bike was a little on the ugly side thoughbut none the less it looked like he tried to solve the heat on the legs thing.
 

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Dave - If I can borrow my daughters digital camera I'll wing you a shot on my tranny cooler. I mounted a tranny cooler below and behind the tranny and then mounted two small 12v High flow PC fans to it. It really works well. The fans are constantly pulling air through it even at a stand still.

I never liked the behind the radiator tranny cooler idea too much. You are blowing 180 air through it. Seems to me that would be like a convection oven. Better then nothing but not the most efficient and cooliest location.
 

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Radiators and Cooling

Bill,
If you decide to buy the bigger radiator, let me know as I would be interested in buying your smaller one. (for another project)

I have a 1996 Boss that I built from a kit. It has the smaller radiator and the stock fan switch that turns on at 160 and off at 140. The engine is NOT a ZZ3 or ZZ4. It is an older engine that I rebuilt. It does not have aluminum heads that dissipate heat better than iron heads. I have checked running temps with an infrared digital thermometer and most of the time it runs around 170. This depends greatly on the ambient temp because there is no thermostat. On a hot day running at 80 to 85 mph for an extended period I might see 190 or 195. I never see 200 degrees. On a cool night it might run below the 160 because the fan won't come on.
Yes, my fan runs mostly all of the time in the warm weather. But I am moving mostly all of the time too so I really don't have an issue with this.
I have riden the big blocks and they do run hotter. In comparison, even the aluminum head small blocks seem to radiate more heat to my legs than my iron head motor. I guess this is just the nature of the beast!
Let's face it, these engines were not designed for motorcycles!!
Just my 2 cents,
Rick
 
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