SPZ510

Please be patient. Ok, I just got my 4port 13b running in my 2nd gen. I have a K2RD rad. in it with a factory t-stat. The engine warms up normally, maybe a little faster than my other stock 2nd gen but not that bad. I have a snap-on temp prob thru the fins near or at the rad. inlet and the water flows at about 175 deg. Ok fine. I have a single flex-a-lite fan turning on at the lowest temp which is 160 according to the Hayden cooling fan controls I wired in. So the fan is coming on very early at 160, the water flows at 175ish and even though the fan is on and the water is flowing the temp continues to rise to 185 before I turn the motor off. Take into consideration the temp is not exactly water temp, it's fin temp so it may be a little off. This is all just idling. I feel that the temp should reach 175 about the water should flow, the fan should come on, temp rise some more and them cool down, cycling the fan. Right.? The temp should fluctuate with the cyling of the t-stat and fan. Well mines not it just keeps slowly rising. Even with a huge rad. Is this right, should I get another fan? Ohh, I also have the RB main pulley to slow things down. Please give me your opinions. Thanks.

SPZ510

Yeah, right. Thanks alot guys. I knew just where to go for help. That's the last time I ever post a tech question on this board. This has happened too many times before with the same results. How lame!

80-CU.IN.T

Just because you have a large water reservoir does not mean the engine will stay cooler. It will just take longer to heat up and (TO COOL DOWN). Radiator efficiency = (surface area + fin design) preferably frontal surface area which is exposed to huge amounts of cool air. The majority of cooling takes place in the front ½" to 1" of your radiator. Look at any new car design. The radiators are thin but have huge frontal surface areas. Yes as air passes through the radiator it cools it but it heats up as it passes through there by becoming less efficient. Really deep core radiators are not practical ( In my opinion ) ( I know I will get bashed for that) in street applications because you are not traveling fast enough to push enough air through the radiator for it to become efficient. Typically fans don't Pull enough CFM and are not ducked properly. Pull through fans are not as efficient as blow through fans. Blow through are a hindrance when you are up to speed. Increase the surface area, check your ducking, run more CFM., multiple fans with possibly 2 different temp settings or increase the frontal opening of your car to let in more air. Remember the air has to be able to get out also. Having a huge front opening only works if the air has some where to go. If it doesn't, it becomes a wall.

Also what it the temperature rating of the factory thermostat? Check it in is a pot of water on your stove. Replace it with an appropriate one.

Lastly, I am not a rotary guru but 185 degrees F. seems a bit cool to me. I would think an operating temperature of around 200 or even higher would be optimal for efficiency. Of course keeping it at around that temp is the trick. Just keep your intake charge ice cold by limiting it's exposure to heat. JUST MY $.O2

peejay

If you run a rotary past 210 it's generally bad news. The aluminum rotor housings get crushed because the aluminum tries to expand faster than the steel tension bolts. It'll run OK until it cools back down again, at which point they shrink to their new dimensions and bolt tension is lost, and you start leaking coolant into the engine.

80-CU.IN.T

Very COOL ( NO PUN INTENDED ). The expansion rates of aluminum and steel are completely different so that makes sense to a point. Even different grades of aluminum expand at different rates. Thanks for the info. Does anybody else have any input on this.

SPZ510

Damn, thanks guys. I really appreciate the input. Scratch what I said earlier. I believe i just need a bigger fan to move more air. I talked with GNXRX7, he also has a second gen but with much more power so I knew his setup was dealing with as much or more heat than mine. He said he has a twin 10in. setup from Flex-a-lite and has never had an overheating problem at standstill. I forgot to mention right know I have a single 12in Flex-a-lite. One of the engine builders from K2RD was down here tonight and he laughed when he saw my fan. I'm looking at getting the Flex-a-lite Black Magic, 15in. Something like 2800cfm. I think Flex-a-lite 12in. fans push around 800-1100cfm. When I get that on I'll post again. Thanks again guys.

m j

the temp guage should be at the cold outlet of the rad as should the fan trigger
measureing hot water as it enters the rad isnt relevant to rad performance at all
did I misinterperet

RX-Midget

I thought is was more like 240*F when you loose the coolant seal.

Nathan Kwok

He was talking about losing the bolt tension, not actually warping the housings or destroying the coolant seals outright. Basically the different expansion ratios cause the main bolts to slowly loosen over time. Its a good idea to retorque the main bolts everytime you have the tranny off (unless you take it off a lot, hehe) due to this expansion problem. Supposedly the rotor housings and coolant seals can actually take coolant temps as high as 280F without warping permanantly as long as the coolant isn't boiling (ie using Evans). Its boiling the coolant that kills things because then the cooling properties break down and the actual metal temperature soars well above the coolant temps. Remember rotary exhaust gases are almost 2000 degrees, how come no one ever complains about that?

JONSKI

Does anybody suppose that the notoriously short-lived coolant seals of turbo rotaries could be longer-lived by regularly retorquing the tension bolts? If so, how often? Perhaps every 15kmi - 20kmi assuming no over-heating?