AutoX Cooling Problems
Thread Starter
Instructor
Joined: Dec 2007
Posts: 184
Likes: 4
From: Hilliard OH
AutoX Cooling Problems
I have an 85 that is used exclusively for AutoX. Engine mods are pretty mild (Intake, Headers, mild head work, etc.). I like to start a run with the water temp. in the 185° range, so I have a low temp. thermostat & the cooling fan turns on at 180°.
The car has the original single core radiator with the single puller fan. I removed the AC heat exchanger a while back.
In the 10-20 minute gap between runs, I end up spending the whole time cycling the motor on/off to circulate water to the radiator so it can be cooled. On most days I can get the temp back to where I need it in time.
Now, I am planning to add a second driver. My time between runs will be half as long, so I must find a better way to get the car cool.
A fancy racing radiator is out of my budget. Should I:
1/ Add the auxilliary pusher fan that came on the Z51?
2/ Find an aftermarket 2-3 core OEM style radiator?
3/ Do something else I haven't thought of?
Thanks for any help.
BeerMan
86 Rag Top
85 Coupe (#71 XP)
The car has the original single core radiator with the single puller fan. I removed the AC heat exchanger a while back.
In the 10-20 minute gap between runs, I end up spending the whole time cycling the motor on/off to circulate water to the radiator so it can be cooled. On most days I can get the temp back to where I need it in time.
Now, I am planning to add a second driver. My time between runs will be half as long, so I must find a better way to get the car cool.
A fancy racing radiator is out of my budget. Should I:
1/ Add the auxilliary pusher fan that came on the Z51?
2/ Find an aftermarket 2-3 core OEM style radiator?
3/ Do something else I haven't thought of?
Thanks for any help.
BeerMan
86 Rag Top
85 Coupe (#71 XP)
Race Director
Joined: Jun 2004
Posts: 13,952
Likes: 706
From: WI
I would use a large blower fan pointed at the front of the car. Perhaps even two would be best, one pointed under to cool the trans. If the event does not have power, you can take a power pack a long.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Do you open the hood between runs? If you do have to wait 20 minutes between runs, then an open hood will allow a lot of cooling simply letting air into the engne compartment and the heat to escape.
The aux fan in front of the radiator may do some cooling between runs, but it may only affect what coolant is in the radiator. A factory HD radiator may help but you do need to get as much air thru it as possible.
Cutting the time between runs will obviously be a factor in cooling the motor but what differences do you see in run times if you don't cool the engine down between runs? I would thibnk that more frequent runs will keep the tires from cooling down and that may be more important than coolant temps.
The aux fan in front of the radiator may do some cooling between runs, but it may only affect what coolant is in the radiator. A factory HD radiator may help but you do need to get as much air thru it as possible.
Cutting the time between runs will obviously be a factor in cooling the motor but what differences do you see in run times if you don't cool the engine down between runs? I would thibnk that more frequent runs will keep the tires from cooling down and that may be more important than coolant temps.
Thread Starter
Instructor
Joined: Dec 2007
Posts: 184
Likes: 4
From: Hilliard OH
Do you open the hood between runs? If you do have to wait 20 minutes between runs, then an open hood will allow a lot of cooling simply letting air into the engne compartment and the heat to escape.
The aux fan in front of the radiator may do some cooling between runs, but it may only affect what coolant is in the radiator. A factory HD radiator may help but you do need to get as much air thru it as possible.
Cutting the time between runs will obviously be a factor in cooling the motor but what differences do you see in run times if you don't cool the engine down between runs? I would thibnk that more frequent runs will keep the tires from cooling down and that may be more important than coolant temps.
The aux fan in front of the radiator may do some cooling between runs, but it may only affect what coolant is in the radiator. A factory HD radiator may help but you do need to get as much air thru it as possible.
Cutting the time between runs will obviously be a factor in cooling the motor but what differences do you see in run times if you don't cool the engine down between runs? I would thibnk that more frequent runs will keep the tires from cooling down and that may be more important than coolant temps.
Is there a standard factory HD radiator available for the early C4? I've checked with a couple OEM replacement companies & say say that there is only one radiator part number for my 85.
Thread Starter
Instructor
Joined: Dec 2007
Posts: 184
Likes: 4
From: Hilliard OH
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
RPO V01 was the Heavy Duty Cooling package in 85 and I think that included a 2-row radiator and the auxilary cooling fan. It could be that you may only be able to get the standard radiator anymore given the age of the car.
An electric waterpump might be hard to do given that the serp belt drives the water pump. You would have to make major changes to the drive belt setup to run everything else.
A Be-Cool aluminum radiator from Summit Racing is $500 for a C4 without the tranny cooler for an auto trans or 4+3. It's $650 for the one with the internal tranny cooler. How does that compare with prices of OEM-style replacement radiators?
I would think that a large pusher type fan that you control with a switch may be your best bet. A radiator with larger capacity is probably only going to delay the coolant temps getting high. Once they get to 180+, it's just more coolant to cool down.
You also should consider battery drain with a fan running for up to 20 minutes between runs. A single run would not allow the alternator to keep up with the fan runing between a bunch of runs.
An electric waterpump might be hard to do given that the serp belt drives the water pump. You would have to make major changes to the drive belt setup to run everything else.
A Be-Cool aluminum radiator from Summit Racing is $500 for a C4 without the tranny cooler for an auto trans or 4+3. It's $650 for the one with the internal tranny cooler. How does that compare with prices of OEM-style replacement radiators?
I would think that a large pusher type fan that you control with a switch may be your best bet. A radiator with larger capacity is probably only going to delay the coolant temps getting high. Once they get to 180+, it's just more coolant to cool down.
You also should consider battery drain with a fan running for up to 20 minutes between runs. A single run would not allow the alternator to keep up with the fan runing between a bunch of runs.
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Thread Starter
Instructor
Joined: Dec 2007
Posts: 184
Likes: 4
From: Hilliard OH
Maybe I should look on the "parts 4 sale" board to see if anyone is selling a radiator from a car with RPO V01.
BeerMan
86 Rag Top
85 Coupe (#71 XP)
Last edited by bspvette; Jan 6, 2008 at 07:40 PM. Reason: typo
Le Mans Master
Joined: Feb 1999
Posts: 9,922
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Put a paper clip between the ALDL A/B terminal, turn ignition ON and let the fan run to cool the radiator fluid, then when you start it, that water will cool your engine very well. I do this at the drags, and autocross here in Hawaii.