I have a 91 RS with a custom built 350 in it. The engine is very similaar to the ZZ4 crate engine. I use the L98 heads which yield about 10:1 compression in my engine. I run the stock TBI system, but I have had it modified to handle the higher horsepower.

My problem is cooling in the summer here in the Phoenix. Once the outside temperature gets above the 95 degree mark, the car wants to heat up mainly when sitting in traffic. It will reach temperatures of 220-230 if I spend much time sitting at a light or moving slowly in traffic.

Here is what I have done so far to fight the problem: 4-row custom radiator, twin electric fans to replace the stock unit, low temperature fan switch (comes on at 200 degrees), additional transmission cooler.

If someone has some additional ideas, please let me know since I do not know what else to try.

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Robert Scott
1991 Camaro RS 350
Best E.T. 13.86 @ 99.4 mph

[This message has been edited by 91RS350 (edited July 11, 2001).]

 

higher flow thermostat, remix your coolant for optimum cooling in your temperature range (above 100 degrees), make sure you have a fan spoiler

other than that, you would need to ground the fans so they run all the time, or something of that nature

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Webmaster: www.IROC-Z.org

 

Sounds pretty normal to me. It's certainly not an indication of a defect or a problem.

The stock fan switch doesn't even turn the fan on until 234° or thereabouts. I'd have a real hard time getting excited about seeing 220° on the gauge sitting still on a hot day.

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"So many Mustangs, so little time..."
ICON Motorsports

 

i thoguht it was around 243.2 or something that the fans were turned on..

regardless, i don't like seeing high temps either, i'm going to put in a lower temp thermostat in my car even though it may hurt gas mileage

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Webmaster: www.IROC-Z.org

 

RB83L69,

Look at my post again and you will see that I have a lower temperature switch for the fan which activates the fan at 200 degrees instead of the stock 235. Unfortunately, at 10:1 compression and 92 octane fuel, the engine starts to detonate at temperatures of about 230 degrees.

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Robert Scott
1991 Camaro RS 350
Best E.T. 13.86 @ 99.4 mph

 

Do you have a stock water pump or an aftermarket pump. I've heard good things about the Stewart high flow pumps that at least double the flow of the stock pump at idle. Run as much water and as little coolant as posible maybe even all water and some water pump lube/rust inhibitor.
I have a 91RS with a manual fan switch and when the temp reaches 220 with the car idling it takes forever for the temp to come back down. I also have an 86IROC that I have manual fan switch on and when the temp reaches 220 idling the fan will bring the temp right back down to 170 fairly quick. Go figure! Both cars are stock.

Steve