Mishimoto Race thermostat

[Daryl]

Perusing the Mishimoto website during half-time and found that they have a “Race” thermostat that opens at a cooler temperature than the stock thermostat of theirs. I don’t believe this was available when I bought the stock version t-stat…. Or, I just flat out missed it!
I’m thinking this would help keep temps down when my stroker starts getting hot on hot days, in traffic, or while getting out through the paces?

If I do order, will flush and probably get some of their pre-mix. But what color? They don’t have green. So… yellow? Orange? Purple???

 

[95opal]

You can have your fan come on earlier with a tune or manual fan switch. Personally I like having manual control of the fan.

 

[cobrajeff96]

Opening of the Tstat earlier just starts the cooling process sooner is all. You have to experiment and fine tune because ideally you want the motor held in an optimal range and that could be of your choosing or by recommendation of your engine builder and certainly an engine tuner. If you're in frequent competition or just messing around in autocross or open track, you want to find what gets the motor into that optimal range and hold it there, planning for overhead do to max effort durations however long they may be.

That said, bear in mind that a Tstat that opens sooner prolongs the warm-up period and the motor is less efficient until it reaches that desired optimal range (when desired peak temp is reached and the fan kicks on and cycles back down to the lower end of that range, usually about a 20*F sweep but even that's up for grabs). And then it also depends on the pressure of the whole system. If you're running a 16 - 19 psi cap then you're kind of limited to about 230*F max before you ought to think about cooling down and/or shutting off. If you push a higher pressure, you can go higher and higher. I think F1 race engines are going 250*F and beyond. A hotter motor simply makes more power but of course to a limit.

 

[ttocs]

they make thermostats in various temp ranges that you can get from the store. Save yourself the premium that mishimoto puts on both their antifreeze and thermostat and get your parts from the store as the premium you pay for their name is not going to get you anything extra this time.

 

[Daryl]

Opening of the Tstat earlier just starts the cooling process sooner is all. You have to experiment and fine tune because ideally you want the motor held in an optimal range and that could be of your choosing or by recommendation of your engine builder and certainly an engine tuner. If you're in frequent competition or just messing around in autocross or open track, you want to find what gets the motor into that optimal range and hold it there, planning for overhead do to max effort durations however long they may be.

That said, bear in mind that a Tstat that opens sooner prolongs the warm-up period and the motor is less efficient until it reaches that desired optimal range (when desired peak temp is reached and the fan kicks on and cycles back down to the lower end of that range, usually about a 20*F sweep but even that's up for grabs). And then it also depends on the pressure of the whole system. If you're running a 16 - 19 psi cap then you're kind of limited to about 230*F max before you ought to think about cooling down and/or shutting off. If you push a higher pressure, you can go higher and higher. I think F1 race engines are going 250*F and beyond. A hotter motor simply makes more power but of course to a limit.

I’m running a 19lb radiator cap and the time recently that caused me concern was when the temp gauge went up to 220*

 

[cobrajeff96]

220 is ok as long as the total cooling system is able to bring it back down when fan comes on. My general rule is if the car is sitting idle as if standing still at a light or in heavy traffic, the system should be able to bring the coolant temp down to the lower end of operating temp within two minutes of the fan spinning up (and you ought to see the temp creeping downward during fan activation). No matter the weather. Of course on colder days this'll be accomplished quicker but we're not really worried about system performance on colder days, it's the hot days we're concerned about because it does have an effect and should be factored in. But 220 is fine. With a 19lb cap you need to be concerned when it crosses 230 and still rising. If it doesn't come down within seconds then the car either needs to get wind through its gills quick or it needs to be pulled over and shut down.

Remember, boiling point of water in ambient is 212 and one atmosphere is 15psi, so the actual boiling point in the system is higher due to a 19lb cap.

 

[Daryl]

220 is ok as long as the total cooling system is able to bring it back down when fan comes on. My general rule is if the car is sitting idle as if standing still at a light or in heavy traffic, the system should be able to bring the coolant temp down to the lower end of operating temp within two minutes of the fan spinning up (and you ought to see the temp creeping downward during fan activation). No matter the weather. Of course on colder days this'll be accomplished quicker but we're not really worried about system performance on colder days, it's the hot days we're concerned about because it does have an effect and should be factored in. But 220 is fine. With a 19lb cap you need to be concerned when it crosses 230 and still rising. If it doesn't come down within seconds then the car either needs to get wind through its gills quick or it needs to be pulled over and shut down.

Remember, boiling point of water in ambient is 212 and one atmosphere is 15psi, so the actual boiling point in the system is higher due to a 19lb cap.

I know the 212* boiling point of water of course (!), but that last part helps a lot, thx++

In the hot afternoon when I got up to 220*, it did come back down, but pretty slowly. Definitely not in a few minutes. Maybe the stock fan isn’t up to snuff anymore??

 

[95opal]

I know the 212* boiling point of water of course (!), but that last part helps a lot, thx++

In the hot afternoon when I got up to 220*, it did come back down, but pretty slowly. Definitely not in a few minutes. Maybe the stock fan isn’t up to snuff anymore??

You can check the resistance on the fan to make sure it's not failing or up to snuff. The fans on these cars are actually really good.

 

[Daryl]

You can check the resistance on the fan to make sure it's not failing or up to snuff. The fans on these cars are actually really good.

Yes, so I’ve learned here on this Forum. Would consider a stock replacement as 1st choice or the compatible Mishimoto shroud/fan combo to go with the Mish radiator, brackets, hoses etc already in there.

How do I check fan “resistance “? Gotta remember: I’m technologically and electronically challenged! Ok, completely inept. But I digress… LOL

 

[ttocs]

the mishimoto fans are shit. I got one and was having temp issues both at idle, and while rolling. After some research I think mishi fans were rated to move 650 cfm where the stock fan was 1300 or so? I found one on amazon that said it moved 2500 cfm and put it on the mishi shroud(it does look nice powder coated) and then my temp issues went away.

 

[Daryl]

Here’s what I have now…
The stock fan and shroud are in place

 

[cobrajeff96]

If you're gonna replace a fan, I might suggest the SVT Contour dual fan setup. They are beastly, but I say good luck because that secret was out ages ago and I think you'd be lucky to find them these days. Aftermarket fans usually aren't up to the task. Not sure about the 5.0 pushrod fan setups, but I know these 4.6 modular fans draw 70A and move a ton of air. You could easily get one in there but the shroud setup would have to be customized and maybe the relay swapped out. I just don't know much about the old 5.0s.

I do know that it's an iron block though, so that might be why the temp reduction was sluggish. Iron insulated more than aluminum. As long as it comes down you might be fine just the way it is. It's something you have to monitor over time. Cars ain't easy.

 

[Daryl]

Think I’ll just leave well enough alone and keep an eye on it as suggested. Thank you, everyone… AGAIN!!

 

[07GtS197]

One thing to keep in mind is that the boiling point of water is dependent on the atmospheric pressure. It goes up when the pressure goes up so don’t worry about it boiling with a pressurized cooling system. Are you sure both fan speeds are working? Also I know you take good care of that car but make sure there isn’t anything between the fine of the radiator. And timing can drive up temps too.

 

[95opal]

Here’s what I have now…
The stock fan and shroud are in place

Looks like your missing a clamp on your upper rad hose.