# Overheating at the Track **URL:** https://forums.speedlife.net/t/overheating-at-the-track/127438 **Category:** SON240sx Automotive **Created:** [August 24, 2009, 5:54pm UTC](https://forums.speedlife.net/t/overheating-at-the-track/127438 "2009-08-24T17:54:32Z") **Posts on this page:** 1 **Showing post:** 18
### Author: ![Aaj2k5](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/aaj2k5/32/5731_2.png) [@Aaj2k5](https://forums.speedlife.net/u/Aaj2k5) #### Post date: [September 14, 2009, 11:11am UTC](https://forums.speedlife.net/t/overheating-at-the-track/127438/18 "2009-09-14T11:11:01Z")
> [@The irony is strong...](https://forums.speedlife.net/t/the-irony-is-strong/23910/17): > > Aren’t they the same fan motor? I thought just the blade design and shroud was different. > > I think the taurus fan pushes something like 2500cfm on low and 4000cfm on high, and my circuit makes the low speed turn on at 189 and off at 182 F, and the high speed turns on at 212 and off at 200 F. I did this with two sensors and two 70 amp relays, and it’s been good for 2 weeks now. Mark VIII (P# RF123) fans do not have the same motor as the Taurus 3.8 fans, and they have 18" blades compared to 17". Output is said to be 3000+ CFM on low and up to 4900 on high 🆒 Similar RF125 fans use a Lincoln motor on a taurus 17" fan, which still gives good CFM, but not RF123 output. RF24 and taurus fan’s are the ford motor on the 17" blades which put out something like you said 2500 low and 3900 high. Maximum draw on startup for either is still under 45 amps I believe, with average high draw of 30-35 for the bigger RF125 motor, 25-30 for the RF123. Sounds like you have a solid setup though, I’m overbuilding the hell out of mine, but yours is more than enough - is the Z31 switch ballin’ or why did you choose it? --- _[View the full topic](https://forums.speedlife.net/t/overheating-at-the-track/127438)._