Latest upgrades to turbo SC cooling system

David Neibert

SCCoA Admin
I've been unhappy with the cooling system performance on my 93 SC with a v8 turbocharged motor since it was first built in 2005. Since that time I have done numerous things to improve the engine cooling, but I still couldn't get it to run cool enough that I was comfortable driving the car for extended distances in the summer. It's already got the biggest Griffin aluminum radiator I can fit into the engine bay, Mrk8 puller fan, Spal 14" pusher fan and a heat extractor vent in the hood. But it was still getting up to around 210-215 in the summer. In the winter it would stay right around 180-185. I couldn't really do much more to improve the air flow to the radiator, so for this round of work I decided to concentrate on coolant flow.

I replaced the stock style 180 t-stat with a Robert shaw high flow 160 degree unit (that I stove tested) and replace the stock mechanical water pump with a Meziere billet 55 GPM electric water pump. To make engine cooling between rounds at the track a little easier a water pump over-ride switch was installed inside the car to allow running the pump with the engine and ignition turned off. The DCC mrk8 fan I'm using, already operates independent of the ignition, so no changes to the fan controls were needed. When testing the cooling system for proper operation and getting the air out, it was discovered that the vent on the radiator overflow catch can was clogged causing it to build up excessive cooling system pressure. Dan removed the vent plug and replaced it with a 90 degree fitting and nylon hose and now it's no longer got a rock hard upper radiator hose.

On the 35 mile drive home from the shop that installed the parts (Hyperformance), I never saw temps higher than about 170 and that is about what I expected with the cooler thermostat when outside temps are in the 30s. I won't really know if this has improved the cooling system performance until it starts getting warmer in the spring, and the real test won't be until summer. Here are a couple pictures I took.

BTW, this pump was an even tighter fit than the old belt driven one was, and required a little clearance milling on the pump to clear the aftermarket balancer and MSD crank trigger wheel. And a little notching on the fan shroud to clear the pulley on the new pump. It was also necessary to switch to a belt that was about 7/8" shorter to maintain same tension with the smaller diameter WP pulley

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David
 
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Looking very nice.... It will be very nice if you can get the control you are looking for in the cooling system.
 
After looking at the picture I posted, I think the next thing I need to do is spend a few hours under the hood just giving it the clean and shine treatment.

BTW, it doesn't run any worse when temps get to 215, it just bugs me.

David
 
It got up to about 64 degrees today, so I decided to take the car for an extended test drive with a mix of city and highway driving. About 10 miles into the drive I noticed my coolant temp had creeped up to about 195 and I was feeling a little dissapointed with the results.

Then within a couple miles of being on the highway the temp had fallen to just a little over 180. After getting off the highway and driving another 5 miles in traffic going about 40 mph with frequent stoplights, I noticed temp was back up to 195. Clearly this was an air flow issue.

When I got to my daughter's house I popped the hood and the fan was barely running, like all I was getting was the 10% voltage it runs at whenever ignition is on. I wiggled the temp probe wire that was jambed into the radiator fins and the fan suddenly started running much faster. BY the way this is a DCC mrk8 temp controlled varible speed fan. So I got a pair of needle nose pliers and when I pulled on the wire to remove and relocate the probe, the friggin probe broke off the wire and stayed lodged in the radiator cooling fins :eek:

So now I had no way to make the fan run more than 10% and I was freakin out. While burning my hand on the radiator I accidentally touched the end of the temp probe wires to ground and the fan came on at full blast...yeah baby ! So I stripped the wires and twisted two together and the fan ran at full speed. Unfortunately it will keep running until the battery dies, so I had to unhook the wires until I was ready to start the car.

With the fan wired to run at full speed, coolant temps stayed slightly below 180 for the entire trip home (city & highway) and even after getting on it hard several times the highest temp I ever saw was just a tick over 180, which is much cooler than the car has ever ran before :)

Now I just need to get a new temp probe and wire in a full speed override switch, and I'll be ready for the next round of testing.

David
 
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I was half way thru reading it and was going to tell you to try and touch to ground, but you figured it out already. A buddy bought Damons old mustang and had a simmilar problem with the temp sensor so we just grounded it..
 
Right on! Have you thought about going to a threaded temp sensor instead of the radiator fin probe? It would be a more reliable method of measuring coolant temp.

I finally took mine out today to enjoy this weather, too. Both methanol systems are fully functional. Real world testing of the systems may have finished off my rear tires though. :)
 
Right on! Have you thought about going to a threaded temp sensor instead of the radiator fin probe? It would be a more reliable method of measuring coolant temp.

I finally took mine out today to enjoy this weather, too. Both methanol systems are fully functional. Real world testing of the systems may have finished off my rear tires though. :)

Rod,

I'm not sure what types of sensors are going to be compatible with the DCC controller. I checked their website and they no longer sell the fans or the type of controller I've got. Sent them an email to see if I can buy another sensor and get some wiring instructions to make sure the way I did the override for the trip home isn't going to cause any problems.

It's a 3 wire connection to the temp probe and I just accidentally put two of them together to make the fan run. I don't know if doing that is grounding one wire or just completing a circuit, or what the 3rd wire does. Hopefully I can get a little wiring info from DCC, then I can figure out how to use the water pump override switch to make the fan run at max speed too.

David
 
Get a new sensor from DCC. it has a very specific response curve that the controller will be looking for. Other in the core sensors from other vendors are not nearly as responsive. That is why the DCC can get away with a sensor in the fins, that works pretty dang well.

The ability to use the stock in head temp sensor of the SC, was why I went with the SPAL PW1 controller, but the DCC controler can handle more current and has more options.
 
Get a new sensor from DCC. it has a very specific response curve that the controller will be looking for. Other in the core sensors from other vendors are not nearly as responsive. That is why the DCC can get away with a sensor in the fins, that works pretty dang well.

The ability to use the stock in head temp sensor of the SC, was why I went with the SPAL PW1 controller, but the DCC controler can handle more current and has more options.

Mike,

I got in touch with Brian at DCC today and he's sending me a new sensor attached to a couple feet of wire. He also confirmed that the way I stumbled onto putting two of sensor probe wires together to make the fan run, will be fine for forcing the fan to operate at 100% with motor running or shut off.

So it's all good.

David
 
I've been unhappy with the cooling system performance on my 93 SC with a v8 turbocharged motor since it was first built in 2005....

It's already got the biggest Griffin aluminum radiator I can fit into the engine bay, Mrk8 puller fan, Spal 14" pusher fan and a heat extractor vent in the hood.

David
David. I'm slow to arrive, but I recently picked up a Griffin rad myself. One thing that was obvious was that due to its thickness, it will sit back further and closer to the engine which reduces the amount of space behind it for air to pass thru which hinders cooling. Have you tried anything that moves it forward?

I've had good results with my plain jane rads by sealing up the gaps around the condenser with flaps of whatever will bend. In particular, I closed up that gap beneath the bumper cover and the radiator support.

That flap that was originally under the rad and tied to the frame cross bar, is supposed to make a big difference as well. It prevents the hotter air from rolling back underneath and back into the radiator. You know, its the one that EVERYONE tosses aside ;).. including me. :rolleyes:

Just some thoughts.
 
I was half way thru reading it and was going to tell you to try and touch to ground, but you figured it out already. A buddy bought Damons old mustang and had a simmilar problem with the temp sensor so we just grounded it..

groundig that wire turns on the relay the way I have it setup
 
David. I'm slow to arrive, but I recently picked up a Griffin rad myself. One thing that was obvious was that due to its thickness, it will sit back further and closer to the engine which reduces the amount of space behind it for air to pass thru which hinders cooling. Have you tried anything that moves it forward?

I've had good results with my plain jane rads by sealing up the gaps around the condenser with flaps of whatever will bend. In particular, I closed up that gap beneath the bumper cover and the radiator support.

That flap that was originally under the rad and tied to the frame cross bar, is supposed to make a big difference as well. It prevents the hotter air from rolling back underneath and back into the radiator. You know, its the one that EVERYONE tosses aside ;).. including me. :rolleyes:

Just some thoughts.

I've done exactly what you are describing with the sealing and still have that flap on my 91 SC. With the MP chin spoiler and no AC condenser it does a great job of keeping the engine temps low in pretty much any weather. On this car the radiator is actually mounted onto the MP FMIC core and sits about 3" closer to the motor than the standard radiator location.

Unfortunately, my 93 SC is a lot more crowded in that area and even with the radiator located in the stock location, the longer V8 motor really results in a tight fit up front. The 4" thick full width front mounted inter-cooler is probably the biggest obstacle to engine cooling. As installed it's blocking a large portion of the air flow going to the radiator and the stock air dam location isn't really helping either. This post has some pictures.

http://www.sccoa.com/forums/showpost.php?p=974596&postcount=13

I don't have any space to move the radiator further away from the motor, and the small gap between the radiator and the FMIC has been filled with a Spal 14" pusher fan, that runs on a separate control and set to come on at 160 degrees. I looked at raising the FMIC about 4" to allow a portion of the incoming air to bypass the FMIC and go directly to the radiator, but it can't be raises unless I remove the front bumper supports. That's not happening because this car is mainly street driven.

I think a custom chin spoiler would be better than the stock air dam that is on the car now, but I haven't gotten to that yet. But I did cut a hole in the hood last year and added a heat extractor vent that seems to have helped some. See this post for heat extractor pics.

http://www.sccoa.com/forums/showpost.php?p=976554&postcount=88

David
 
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