Stock vs Underdrive Pulleys

[Dusterb318]

I am running a set of March Underdrive Pulleys on my car right now. I have been experiencing warmer than I'd like to see water temps when sitting in traffic it was about 75 out the other day and I got up to 200* nothing really higher that that but it's a little warmer than I'd like to see. I have an aluminum cross flow rad (16lb cap), Perma Cool 2950cfm electric fan and a FlowKooler water pump. Once I start cruising the temp drops back down to ride the 180* thermostat. I know some of it has to do with the air moving through the radiator but I can't help but to feel my low speed cooling has something to do with the under drive pulleys spinning the water pump slower than normal. I wanna try out a set of stock pulleys to confirm this. I mean how much HP will i really lose by going back to the stock pulleys....maybe 5hp. I could switch to a 160* thermostat to open up the flow to the radiator sooner but that won't help my higher temps while sitting in traffic. Should I switch to a stock 8-blade A/C car water pump and ditch the FlowKooler pump? I honestly think it was a waste of money but it doesn't leak or anything so why change it out. I need to get a shroud on the fan but I know guys that run the same fan and rad with no shroud in warmer climates that don't have issues but he does have an electric water pump so he has a constant flow of water.....and a lot more radical motor to boot. I know my tune-up is good. It's not running rich or lean, the timing is dead nuts on as the burn on the plug ground strip is right on the bend. 16* initial and 34* total. I run about 70% water and 30% antifreeze and 2 bottles of Redline Water Wetter. I know the pump gas will run hotter than race fuel as well. So am I on the right track or an I worring about nothing?

 

[djwhog]

Boy it really sounds like it just needs more RPM on the pump. Maybe the 8 blade will give a little better flow. Regarless of thermostat 160 or 180 once it is at temp that is not going to make it run hotter say 200 etc. This is a matter of moving enough water in the radiator and enough air throught the radiator to cool the water.

Also what kind of fan are you runing and how far is it fromthe radiator?

Last question. With the car in park if you were to bring the RPMS up does it also cool off too? Reason I ask is when still you get less air movement over the radiator, but if it really seems to cool off just about as well as when driving, then it is the speed of the pump not being suffiecnt enough for your application with those pulleys at low RPM speeds.

Probably going back to stock pulleys would give enough speed for pump, but if you want to keep the March pulleys you may need more water pump or a better fan and or a shroud to get the air/water movement you need to cool at low speeds.

And yes 200 is not that warm, but on a day only 75 that is at least something to look into as you mention.

 

[Dusterb318]

Also what kind of fan are you runing and how far is it fromthe radiator?

Permacool electric.....it's 1/2" from the radiator

Last question. With the car in park if you were to bring the RPMS up does it also cool off too? I ask is when still you get less air movement over the radiator, but if it really seems to cool off just about as well as when driving, then it is the speed of the pump not being suffiecnt enough for your application with those pulleys at low RPM speeds.

It definetly levels off....doesn't climb up anymore. Never sat at a light long enough for it to make a difference. I don't HAVE to keep the march pulleys.....I have been looking at the Flex-a-lite balck magic fans that have the built in shroud as an option as well...but the pulley swap would be a lot cheaper and then I could sell the underdrive pulleys and use that money to buy the fle-a-lite fan/shroud combo.

 

[340mopar]

It sounds like a flow thing to me also. Next time you drive it and it does it again put the car in neutral and raise the rpm about 1000 or so and see if it starts to drop, if it does, not enough flow, if it doesn't drop then I would say it is not enough fan/air flow. Changing to a higher flow pump may cure the problem at idle but at the higher rpm's it will rob more power so it would be no different than using stock pulleys.


Chuck

 

[Dusterb318]

I'll try that Chuck. I'm really beginning to think it's a combonation of both air flow and pump speed. The FlowKooler is supposed to be a high output pump....but I'm not sold on it.

 

[Dusterb318]

On a side note......I have always had this problem even with the clutch fan and copper/brass radiator.....the only thing constant has been the water pump and pulley combo. The temps have been the in the same range....hmmm I think it is a flow problem. This electric fan will hold a T-shirt to the front the radiator so i know it is working.

 

[Dusterb318]

Well I changed the WP out to a HD 8-blade unit and I built a fan shroud. Once I get some money to fill the tank back up with fuel I'll take it for a test drive:

 

[AdamR]

Once I get some money to fill the tank back up with fuel I'll take it for a test drive:

Sad isnt it ? Race gas is $7 a gallon here. Once I get the car together it will take another year of saving to fill the tank.

 

[Dusterb318]

Luckily I run on pump premium 93 so it isn't that bad....still it's bad. I laughed the other day that Diesel has finally stayed steady and is finally cheaper than gas...the way it should be.....then I realized that I still had to put gas in the wife's Durango....I gotta get her a diesel Liberty and then we can brew our own fuel at home for the daily drivers.