Mountune Radiator questions

[Zala]

1. Will upgrading to the Mountune unit help keep my air conditioning cool as well? It seems every time I go to Vegas and it’s 110+ outside my car begins overheating at idle, and even when the temps are under “control” 235* on highway the Air Conditioning never feels cold.

2. I notice a pretty big power hit when it’s hot outside. Will having cooler coolant temps control result in noticeably more stable power?

Last summer in 95° weather, I had my car tap the overheat alert when picking up my wife in a parking lot running the A/C. Our summers easily peak to around 100-105° with high humidity. The rest of the summer, I learned that I was going to have to run my ST without A/C use if I was to take anything other than a 15 minute drive. I found this unacceptable considering my 300WHP Miatas can go a longer before needing to stop the A/C due to heatsoaked ECTs and the whole point of the hot hatch is to have something practical with at least more basic comforts.

I wanted to add my recent 2-3 weeks with my Mountune radiator that I installed last month.

1. Night and day difference in cooling.
   • In 70°+ weather, that car only needs an extra few minutes or miles to fully warm-up.
   • The most I've been able to push ECTs so far is to 196° with A/C running and back to back pulls on boost. With similar driving, I'd have easily pegged 220° in short order and would be turning off the A/C for a while to keep moving.
   • The car sits between 188-190° with regular driving A/C on or off.
2. Aside from filing down the stock radiator fan shroud tabs bit, the radiator was a direct fit.

Ultimately, I definitely feel like the radiator upgrade may cool too much so I'll be watching warm-up temps in the winter, but my objective for non-winter weather is accomplished. To balance out the warm-up a bit, I've swapped my OEM box to a Woosh short-ram (plus the noise is fun and.. a bee filled my ITG panel filter with some honey I found, so needed that out for a bit). I now watch IATs so I can get a better sense of when the car has warmed up. Usually the temps will be a good +40-50° over ambient as I radiator is dumping all the heat into the engine bay and of course is compounded by the heat radiated by the engine and turbo.

I have no plans to upgrade the car further as I enjoy it just fine in it's full-bolt-on state (how I acquired it). With the radiator upgrade, I simply love that I can drive the car hard and not even think about temps overall.

 

[JorJorBinks]

Last summer in 95° weather, I had my car tap the overheat alert when picking up my wife in a parking lot running the A/C. Our summers easily peak to around 100-105° with high humidity. The rest of the summer, I learned that I was going to have to run my ST without A/C use if I was to take anything other than a 15 minute drive. I found this unacceptable considering my 300WHP Miatas can go a longer before needing to stop the A/C due to heatsoaked ECTs and the whole point of the hot hatch is to have something practical with at least more basic comforts.

I wanted to add my recent 2-3 weeks with my Mountune radiator that I installed last month.

1. Night and day difference in cooling.
   • In 70°+ weather, that car only needs an extra few minutes or miles to fully warm-up.
   • The most I've been able to push ECTs so far is to 196° with A/C running and back to back pulls on boost. With similar driving, I'd have easily pegged 220° in short order and would be turning off the A/C for a while to keep moving.
   • The car sits between 188-190° with regular driving A/C on or off.
2. Aside from filing down the stock radiator fan shroud tabs bit, the radiator was a direct fit.

Ultimately, I definitely feel like the radiator upgrade may cool too much so I'll be watching warm-up temps in the winter, but my objective for non-winter weather is accomplished. To balance out the warm-up a bit, I've swapped my OEM box to a Woosh short-ram (plus the noise is fun and.. a bee filled my ITG panel filter with some honey I found, so needed that out for a bit). I now watch IATs so I can get a better sense of when the car has warmed up. Usually the temps will be a good +40-50° over ambient as I radiator is dumping all the heat into the engine bay and of course is compounded by the heat radiated by the engine and turbo.

I have no plans to upgrade the car further as I enjoy it just fine in it's full-bolt-on state (how I acquired it). With the radiator upgrade, I simply love that I can drive the car hard and not even think about temps overall.

Wow this is a great first hand experience! I appreciate your time for making such an informative post. I do have the same questions for you!

1. Do you notice less powerloss from heat soak?
2. Do you notice the air conditioning being more consistently cold?

 

[Zala]

Wow this is a great first hand experience! I appreciate your time for making such an informative post. I do have the same questions for you!

1. Do you notice less powerloss from heat soak?
2. Do you notice the air conditioning being more consistently cold?A/C.

1. Yes, but that's because I no longer have to back off the boost to let ECTs recover. The car doesn't really make a lot of noticeable power loss for me, but I have an upgraded intercooler for the entirety of my ownership.
2. My A/C never struggles to run cold. This was interesting since my Miatas will cut power to the A/C when I hit 230° temps, but that wasn't my experience with the fiesta. I got the overheat warning before anything affected the

 

[figlin]

https://www.ebay.com/itm/3546372304...nbK2deaSeq&var=&widget_ver=artemis&media=COPY

if you want to shop around more I put into the eBay search " Ford Fiesta ST 3 row gpi racing radiator"

Is this the link for the updated model with no mods needed to mount the fan?

 

[TyphoonFiST]

Is this the link for the updated model with no mods needed to mount the fan?

The shroud never had to be modified with a Mountune radiator. The Mishimoto i know comes with its own shroud though.

 

[JorJorBinks]

Is this the link for the updated model with no mods needed to mount the fan?

This is similar to the GPI one I got, but the exact one I bought is no longer available. https://www.ebay.com/itm/2667227377...kdQbkvyQ4W&var=&widget_ver=artemis&media=COPY

(edit: grammar)

 

[figlin]

This is similar to the GPI one I got, but the exact one I bought is no longer available. https://www.ebay.com/itm/2667227377...kdQbkvyQ4W&var=&widget_ver=artemis&media=COPY

(edit: grammar)

Did you have to make your own brackets to mount the fan or did they end up changing it so the stock fan can mount up without mods?

 

[JorJorBinks]

Did you have to make your own brackets to mount the fan or did they end up changing it so the stock fan can mount up without mods?

So the stock fan and shroud are one piece. All I did was bend the tabs a bit and zip tie the original fan shroud to the radiator. It sits a little off but it is very sturdy and you don’t need to rewire anything.

I’m okay with the jank tbh. I went up to the local mountain town (Big Bear, CA) with it being 95*f and a pretty heavy load in the car A/C the whole time. I saw peak temps of 215 coolant and 235 oil.

Those clone kits with the aluminum shroud and fan require wiring in the new fan which I wasn’t about to do. I can’t speak to the Mishimoto or Mountune stuff though.

 

[figlin]

So the stock fan and shroud are one piece. All I did was bend the tabs a bit and zip tie the original fan shroud to the radiator. It sits a little off but it is very sturdy and you don’t need to rewire anything.

I’m okay with the jank tbh. I went up to the local mountain town (Big Bear, CA) with it being 95*f and a pretty heavy load in the car A/C the whole time. I saw peak temps of 215 coolant and 235 oil.

Those clone kits with the aluminum shroud and fan require wiring in the new fan which I wasn’t about to do. I can’t speak to the Mishimoto or Mountune stuff though.

Okay than you for that info! I'm willing to try out one of these cheaper radiators but I didn't want to end up spending as much as one of the name brands because I have to purchase an angle grinder and aluminum stock to make the mounts lol.
This sounds like it will work for me though! I just moved from California by the way and my wife and I really miss Big Bear. It's such an awesome little ski town!

 

[JorJorBinks]

Okay than you for that info! I'm willing to try out one of these cheaper radiators but I didn't want to end up spending as much as one of the name brands because I have to purchase an angle grinder and aluminum stock to make the mounts lol.
This sounds like it will work for me though! I just moved from California by the way and my wife and I really miss Big Bear. It's such an awesome little ski town!

Yeah when I say modify I’m not talking like Richrebuilds modify. Haha all I did was bend tabs, and apply zip ties. 😂 I do deliveries for work in my Fiesta so I’ve put about 3-4,000 hard delivery miles on this set up so far and it’s been great!

Yeah Big Bear is so great! I was just stoked the other day to be making money to drive those canyons. 🤙

Also if you need any help feel free to DM me.