Mac
Member
Here is a new radiator installation. My Viper 780 has run hot the last several years. I feel its the reason I cant keep pistons more than 2000 miles. Now with the air cooled setup I'm hoping to run in the 135-140 degree range. Testing tomorrow. I found this Radiator on ebay $60.
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ExpertXViper
New member
Cool idea, wish I had room to do that. But the 3 into 1 SLP Silencer would make that mod impossible.
Mac
Member
I think we have success - one cool Viper!
Tested yesterday in Hazelton PA. Ran the sled about a half an hour. Then after a couple of 100mph passes checked the coolant. Having no thermometer I'm useing the old stick your finger in the coolant experiment. I can open the radiator and leave my finger in the coolant where it comes directly from the head and its flowing fairly fast. Anyone want to guess how hot water needs to be when you cannot stand the temp and must pull away? I could easily withstand a few more degrees before having to pull away.
Tested yesterday in Hazelton PA. Ran the sled about a half an hour. Then after a couple of 100mph passes checked the coolant. Having no thermometer I'm useing the old stick your finger in the coolant experiment. I can open the radiator and leave my finger in the coolant where it comes directly from the head and its flowing fairly fast. Anyone want to guess how hot water needs to be when you cannot stand the temp and must pull away? I could easily withstand a few more degrees before having to pull away.
jwiedmayer
New member
Is that a single pipe? With that much more mass (water) in the system its going to take a lot more time to level out before you are going to see if runs any cooler. Unless of course its got way to much mass and then its never going to get to operating temperature. If you believe friction decreases power and friction goes up with decreasing temperature then infact you probably reduced the power output.
ExpertXViper
New member
jwiedmayer said:
If you read or looked at the pics you can easily tell its not a single piped or a STOCK sled. And the mod he did is a good idea to keep his screaming hot Viper cool. If I had to choice between replacing pistons every 2000mi or losing a few hp, I'd take the few HP lose. But I doubt hell lose any hp cause of the mod itll just take much longer to get to operating temps.
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anything over about 140+ degrees gets you the "ouch" reaction.
jweidmayer: a 2 stroke engine makes MORE power the cooler it is, the cooler it is run, the denser the mixture is in the crankcase and the more hp it will make. The hotter it is the richer they run and the less hp they make. Once the engine is at temp the cranshaft becomes stabil at a certain temp, the warmer the temp the more it warms up the mixture of air and fuel while its being compressed in the crankcase. Heat is the number 1 enemy of a 2 stroke engine. So if he can lower the operating temp about 20 degrees and be still in the safe temp, because you need a certain degree of temp to operate without problems such as cold seizure on pistons and various other issues related to thermostat opening temps, etc.
jweidmayer: a 2 stroke engine makes MORE power the cooler it is, the cooler it is run, the denser the mixture is in the crankcase and the more hp it will make. The hotter it is the richer they run and the less hp they make. Once the engine is at temp the cranshaft becomes stabil at a certain temp, the warmer the temp the more it warms up the mixture of air and fuel while its being compressed in the crankcase. Heat is the number 1 enemy of a 2 stroke engine. So if he can lower the operating temp about 20 degrees and be still in the safe temp, because you need a certain degree of temp to operate without problems such as cold seizure on pistons and various other issues related to thermostat opening temps, etc.
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mmmmmm, I only see one pipe. 
I think J's point was that if its not at the correct operating temp(to low), it will lose HP.
With this mod, maybe you could run the thermostat to help bring it up to temp. I would definitly consider adding a temp gauge so you could be sure were the temp is at all times.
The old, sticking-the-finger in the antifreeze trick is probaby not the most accurate!
I think J's point was that if its not at the correct operating temp(to low), it will lose HP.
With this mod, maybe you could run the thermostat to help bring it up to temp. I would definitly consider adding a temp gauge so you could be sure were the temp is at all times.
The old, sticking-the-finger in the antifreeze trick is probaby not the most accurate!
And like I said, the colder it is the more power it makes!
Take any dyno run and look at the sheets, if you run the engine cold it will show you a 1 time flash of higher hp, because of the density of the mixture is more pure, makes more hp! Once that engine comes up to higher temps the hp will drop, its very simple with a 2 stroke!
Looking at those dyno sheets also tells you if your getting real world numbers or just a 1 time flash number to sell parts, the higher the water temp the less power it makes, so a water temp of say 80-90 degrees will not cold seize the pistons but will show you big numbers on a dyno run once, then when the water temp and cranckcase temp are up above 130 degrees this is what you would have out trail riding the sled, more real world numbers, take a look at some magazine sheets and youll see.
The other easiest way to explain this to you is did you ever notice how your sled really runs good and crisp at 5-10 degrees versus running the same sled/set up at 30 degrees? its simply the air and fuel mixture is much denser at those temps, it makes more hp. Heat is the number 1 enemy of a 2 stroke!
Take any dyno run and look at the sheets, if you run the engine cold it will show you a 1 time flash of higher hp, because of the density of the mixture is more pure, makes more hp! Once that engine comes up to higher temps the hp will drop, its very simple with a 2 stroke!
Looking at those dyno sheets also tells you if your getting real world numbers or just a 1 time flash number to sell parts, the higher the water temp the less power it makes, so a water temp of say 80-90 degrees will not cold seize the pistons but will show you big numbers on a dyno run once, then when the water temp and cranckcase temp are up above 130 degrees this is what you would have out trail riding the sled, more real world numbers, take a look at some magazine sheets and youll see.
The other easiest way to explain this to you is did you ever notice how your sled really runs good and crisp at 5-10 degrees versus running the same sled/set up at 30 degrees? its simply the air and fuel mixture is much denser at those temps, it makes more hp. Heat is the number 1 enemy of a 2 stroke!
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yahadriver23
New member
How do those metal brackets look, just in my opinion from looking at the side it would look sweet if they were all black, but can't really tell.....
ExpertXViper
New member
SnoXr you may only see one pipe in the pics but if you ever seen CPR pipes before youll know its not a single piped sled. Plus this mod would not be necessary on a single piped Viper, it was all done for the excessive heat thats built up by the pipes and big bore kit. And from what Ive read you cant run a 780 kit with a single pipe, but maybe Don could clear that possible rumor up.
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The "ouch" reaction
I gotta disagree with you Don on the Ouch reaction at 104 degrees. Hell I run my hot tub at 104 degrees. Sure you jump a little when your boys hit the water on the way in but to touch the water with the tip of you finger 104 doesn't really feel that hot. I bet you'd nee at least 115 on your finger to get an "ouch"!!!! Mac, get a water temp guage buddy. Excell Motorsports sells a nice one.
Madmatt
I gotta disagree with you Don on the Ouch reaction at 104 degrees. Hell I run my hot tub at 104 degrees. Sure you jump a little when your boys hit the water on the way in but to touch the water with the tip of you finger 104 doesn't really feel that hot. I bet you'd nee at least 115 on your finger to get an "ouch"!!!! Mac, get a water temp guage buddy. Excell Motorsports sells a nice one.
Madmatt
Mac
Member
More Info
Here are a couple of more pics which may help with some of your questions. Sorry guys no single pipe here. I do have a temp gauge but don't have it connected correct. Since the probe needs ground and its shielded on either side of the tee with rubbber hoses. I thought I should use a wire (white wire in pic) clamped to the probe then bolted to the frame. Well that didnt work because it reads about 195 degrees when running. Any help as how to fix this would be great. Its a brand new cyberdyne gauge and probe. The louvers are black anodized .040 sheetmetal. All the bent sheetmetal parts are made on my granite countertop in the kitchen. When my wife saw me using a rubber mallet forming the corners my sled season almost ended. . . The sheet stock is only black on the outside. Also I am running a brand new thermostat and it was installed for this test. Mr.Viper You are the only one who responded with respect to the temp. guesstimate. Don't you think you wash your hands in 110-115 degree water?
Here are a couple of more pics which may help with some of your questions. Sorry guys no single pipe here. I do have a temp gauge but don't have it connected correct. Since the probe needs ground and its shielded on either side of the tee with rubbber hoses. I thought I should use a wire (white wire in pic) clamped to the probe then bolted to the frame. Well that didnt work because it reads about 195 degrees when running. Any help as how to fix this would be great. Its a brand new cyberdyne gauge and probe. The louvers are black anodized .040 sheetmetal. All the bent sheetmetal parts are made on my granite countertop in the kitchen. When my wife saw me using a rubber mallet forming the corners my sled season almost ended. . . The sheet stock is only black on the outside. Also I am running a brand new thermostat and it was installed for this test. Mr.Viper You are the only one who responded with respect to the temp. guesstimate. Don't you think you wash your hands in 110-115 degree water?
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Mac
Member
jwiedmayer
New member
Sorry you guys missed the sarcasim.. "If you believe"
I only said this becuase I had a master level IC engine class where the professor swore by increasing the temperature on the cylinder walls you could get more power. He went on to say this is why the heads are cooled first blahblah blah. I always snickered, sounded like the typical theoritcal babbler with no practical experience.
Doesn't the one pull on the dyno kind of go along with my comments about having to wait for the system to stabilize before you can get an accurate measure on the cooling performance?
And BTW I've never seen a piped viper and could not tell by the picture how many pipes there where. Not a nock on MAC but I seen people do strange things. Like I was at the local dealer and this young kid salesman says come check out my new exhaust. I go look at it its a MXZ500 that he took to the muffler shop to butcher a pipe between the stock muffler to an afermarket can.
As for the sensor. On the VMAX like I'm familiar with the power supply is ac. Make sure you are feeding that sensor dc and you should be able to run a wire from the chassis to the sensor body to complete the ground loop if its a one wire sensor.
Another theoritical point is that the air flow will be extermly hampered by the nearly 90 degree bend to get to the radiator. It should build up a nice high pressure area in front of the radiator but the back side of the radiator is vented to the underhood which is also a higher pressure area because of the vents in the hood and backed up agains the chassis so it has to do another 90 to get out. A fan would do a better job if you still have problems.
I only said this becuase I had a master level IC engine class where the professor swore by increasing the temperature on the cylinder walls you could get more power. He went on to say this is why the heads are cooled first blahblah blah. I always snickered, sounded like the typical theoritcal babbler with no practical experience.
Doesn't the one pull on the dyno kind of go along with my comments about having to wait for the system to stabilize before you can get an accurate measure on the cooling performance?
And BTW I've never seen a piped viper and could not tell by the picture how many pipes there where. Not a nock on MAC but I seen people do strange things. Like I was at the local dealer and this young kid salesman says come check out my new exhaust. I go look at it its a MXZ500 that he took to the muffler shop to butcher a pipe between the stock muffler to an afermarket can.
As for the sensor. On the VMAX like I'm familiar with the power supply is ac. Make sure you are feeding that sensor dc and you should be able to run a wire from the chassis to the sensor body to complete the ground loop if its a one wire sensor.
Another theoritical point is that the air flow will be extermly hampered by the nearly 90 degree bend to get to the radiator. It should build up a nice high pressure area in front of the radiator but the back side of the radiator is vented to the underhood which is also a higher pressure area because of the vents in the hood and backed up agains the chassis so it has to do another 90 to get out. A fan would do a better job if you still have problems.
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jwiedmayer
New member
BTW I believe water heaters are set up to deliever around 120 degrees at the tap and a little higher in the tank..
People can have a 104 degree fever right? Then again I'm not a doctor.
People can have a 104 degree fever right? Then again I'm not a doctor.
And I'm not a gambler, but I'm willing to bet it's a typo. 104=140???
your right yamer down its 140, my typo mistake, you cant put your hand on something that hot for more then about 1-2 second, this all goes back to clutch tuning and tuning it by the touch of the clutch sheaves.
JeepTherapy
New member
I am a little curious about the direction you have the louvers pointed? I would have thought that it would work better to draw the air out the side and in the front? Looks like a very slick setup tho.
