Mishimoto radiator pics and some data.

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I just finished the last bits of the Mishimoto radiator install this morning. See pics below. I'm pretty happy with the first results. I may have finally ended my 7-year battle with excessive engine temperatures, on my '96 Cobra.

Some relevant details:

-All temperature measurements were taken with my full-sweep Autometer temp gauge, as well as via datalog on my SCT tuner.

-My Autometer gauge, with the sender mounted in the stock crossover location, always reads 4-6 degrees hotter than the PCM datalog readings. I actually just replaced the original ECT sensor this morning, and that delta remained the same. So for example, when the ECU commands the low speed fan on at 208, my Autometer gauge reads 212. (I suspect this may reflect the actual difference in running temperatures between the two heads).

-I recently removed my "performance" chip, which returned my fan on/off speeds to stock (low speed on at 208 degrees, and high speed on at 228, I believe). For years, I'd had them programmed to come on about 13 degrees cooler--mainly as a band-aid. Also, I was happy to find that the car seems to run better without the chip--pulls harder, and runs more consistently.

-Years ago, I'd swapped out the dense '96 AC condenser, for a less restrictive 97+ unit. This did very little to improve my operating temps.

-A week ago, I replaced the original fan with a stock replacement unit--just because I thought I should. This made no difference in engine temps.

The results so far:

After getting the last of the air out of the system, I drove the car for about 40 minutes, in 85 degree weather. Driving around town, with no AC, and some stoplights, per the gauge, I ran anywhere between 198 and 213 degrees (so 194 to 209, according to the computer). This was about how it ran before--which seems normal, I'd say, with the stock thermostat and fan settings. Around town, the biggest difference I noticed with the new radiator was in how quickly the engine would cool itself back down--either from the fan turning on, or from getting the car moving again. Also, if I could keep moving, the motor ran at around 203, and the fans would never run at all. This was never the case with the old radiator.

Then I turned the AC on, and took the car on the freeway in 80mph traffic. This is where it gets good. With the old radiator, under these conditions, within just a few miles, I'd see temperatures of 230 degrees on the gauge (or 225 according to the computer). That's about as hot as I'd ever let it get, before I'd always turn the AC off, and just suffer (and even then, the temperature would only slowly drop several degrees). Mind you, I'd see these temperatures even driving gently/carefully.

With the Mishimoto radiator however, under the same conditions, the temperature rose to about 211 as I blasted onto the highway, but then within a mile or two, rather than just getting hotter and hotter, actually began to decrease. This was unheard of, with the old radiator.

In short, when I would have normally been running at 230 degrees (per the gauge), I stabilized at right around 208 degrees (or 204 according to the computer). That's 22 degrees cooler than with the old radiator, under similar conditions. Even when I'd downshift into 3rd and hammer it a bit, the temperature still stayed under 210. I'm very pleased so far. I'll give more updates on the performance this week, during the heatwave.

By the way, the install wasn't bad at all. The one thing nobody told me though, was that you have to cut a notch in the lower beam of the radiator, so it will clear the overflow tank prop-rod mount. (Wish I took a picture of the notch I cut, but it didn't occur to me. I used a small cutting wheel, and cut an inch and a half rectangle out of the sheet metal on the bottom of the radiator). Anyhow, once I figured that out, the install went pretty quickly.

Edit: I recently learned that there may be two different styles of prop-rod mount, used on these cars. Mine is a big round cylinder, with a bushing in the center, and the rod through that. I saw one online the other day, that is supposedly OEM, where the rod just mounts on a flat plate. I guess if you have that kind, you might not need to notch the bottom of the radiator. Not sure though.

Thanks again.

Tom





With stabilizers




With fan


Old vs. new


Thickness comparison


Old radiator thickness. (The Mishimoto is spec'd at 1.57" thick).



Mishimoto mounts.

Oh, I should also mention that I'm not of the camp, who believe 'the cooler the better.' To me, ideal is anywhere between 195 and, say, 215. That's my target range.

I say that because I know some guys are running at 195 max, calling that hot, and trying to figure out how to run at 175 or something--which is all good. I just have a different mind on it. Anyhow, just wanted to add that.

Just an update, for anyone who may ever consider a radiator upgrade. I am beyond impressed with this unit. I just spent over an hour driving the car in 90° weather, in all kinds of conditions. The sole purpose of the trip was to put the radiator through its paces, and see how it actually performs.

I spent a fair amount of time deliberately trying to heat the motor up, and overwhelm the cooling system. I couldn't though--and anytime I thought I was making progress (so to speak), the motor would start cooling back down before I'd get the chance to get more heat into it.

Here are some temperatures, in different conditions. Again, this is with the stock 188* thermostat, and fan settings (low/high on at 208/228). This is also via my Autometer gauge, which reads 4-5 degrees hotter than the PCM.

--With AC off, idling in traffic, the temp would slowly rise to 212 (or 208, according to the computer), and the fan would come on. The temperature would continue to rise 1 or 2 degrees for about 10 seconds, and then the needle would start to come down, developing momentum as it went. In less than 30 seconds (I think), it would drop to 207 (203), and the fan would turn off. (As a side note, I'd actually taken a 20-minute trip earlier, before traffic, and the fan never ran once. With the stock radiator, it would have been running most of the trip).
--AC on, on the freeway, it behaved the same as yesterday. Blasting up the ramp, uphill, at full throttle, to merge with 80 mph traffic, the temperature hit 211. Within a minute, it would start dropping, and seem to settle at 208 (the computer's 204). From there, it might dip a couple degrees higher or lower, depending on the load. This is compared to 231°, and climbing, with the stock radiator.
--Around town, the car ran much cooler with the AC on, than off (with the fan running the whole time). This was never the case with the old radiator. Even when I'd hammer on it from stop lights, AC blasting, in varying terrain (picture a hilly desert), I don't think I ever saw more than 210 degrees. At one point, down a very long hill (a few miles), it got down to 192.

This same hill (uphill) has always been my testing ground, anytime I'd make changes to the Cobra's cooling system--and even for high-speed tuning of motorcycles, back in the day. It's' a solid test area, where you don't stand out as a maniac while screaming up the road. The speed limit is 60-65, but people routinely do 70+. With the old radiator, in this weather, AC running, driving very gently, I might have seen 225 degrees by the time I'd reach the top. Today, I drove up that hill 3 times, at times, very aggressively--downshifting for no reason, just to lay it wide open repeatedly. The highest temperature I could muster by the top of the hill, was 214 degrees--and that was only for several seconds, before it started cooling off again.

Basically, with the Mishimoto, even driving the car hard, I couldn't get to within 10° of where it used to run, driving gently. Even getting it hot, at all, was difficult. Before, I would often choose my other car in 85+ degree weather. Now, I have no concerns driving the Cobra in SoCal. I'm actually looking forward to seeing how it performs at the end of August, when it's 105°.

One interesting thing about this radiator is that, in normal driving, at a glance, the temperatures might not look all that different. Day-to-day driving around town, in fair weather, if you're not watching them actually vary, the temps look about the same. Where this thing shines is in its overall and reserve capacity, under load and stress, and also in its ability to cool things back down quickly. This makes me think that if your stock radiator already handles heat well--which most do--then you might not notice the glaring difference that I did. This thing definitely seems to have solved my "96 Cobra cooling problem."

By the way, I also suspect that my 97+ AC condenser is actually helping now, whereas with the stock radiator, it made very little difference. Anyhow, thanks again everyone, for helping me talk through my cooling drama.

Oh, I also don't work for Mishimoto or anything. Haha. Just sharing my experience with what seems to be an awesome radiator.

Tom

Thanks for the follow through.
So many just ask questions, fix their problem and never post back.

This is the stuff I like to see.
Great info.

I used them on my old convertible, great bang for the buck! With the stock radiator it would start to over heat in about 5 minutes of spirited driving. My budget was super tight at that time so I thought I would order a higher dollar setup later on. Surprisingly there was no need to upgrade that later on. I did several DE weekends at redline for 20-30 minutes at a time and it was flawless. I was very impressed


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shurur said:

Thanks for the follow through.
So many just ask questions, fix their problem and never post back.

This is the stuff I like to see.
Great info.

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+1 Always appreciate the full circle threads!

shurur said:

Thanks for the follow through.
So many just ask questions, fix their problem and never post back.

This is the stuff I like to see.
Great info.

Click to expand...

Thank you. Yeah, I read threads like that all the time, that drop off into nowhere, and waste and your time when you're looking for info. They don't even thank everyone for the help. I always think that's weird.

geoffmt said:

I used them on my old convertible, great bang for the buck! With the stock radiator it would start to over heat in about 5 minutes of spirited driving. My budget was super tight at that time so I thought I would order a higher dollar setup later on. Surprisingly there was no need to upgrade that later on. I did several DE weekends at redline for 20-30 minutes at a time and it was flawless. I was very impressed


Sent from my iPhone using svtperformance.com

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It's good to hear that the radiator holds up under those conditions. Did they last a while? No problems?

Twisted2 said:

Thank you. Yeah, I read threads like that all the time, that drop off into nowhere, and waste and your time when you're looking for info. They don't even thank everyone for the help. I always think that's weird.

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Picked one up on my last build and like it a lot. My only issue is I'm thinking of swapping my Reische 170° now after the summer. Temps drop low on the highway when cruising and its cold out...

Double post malfunction. Sorry.

Black02GT said:

Picked one up on my last build and like it a lot. My only issue is I'm thinking of swapping my Reische 170° now after the summer. Temps drop low on the highway when cruising and its cold out...

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I bet. I had a Motorcraft 180° thermostat in for about a week, when it was still cool out. My temperature would drop below 185 at times, and I didn't appreciate it, so I went back to stock. The cooler thermostat only made the motor run cooler when I didn't want it to.

Makes me curious as to what my car runs. I go by the fairly inaccurate dummy gauge on the dash. It generally stays on the "O" of NORMAL when driving around, regardless of outside temp. If sitting still and not using a/c, it'll go up to the middle of the "R". With a/c on, it never goes above the "O" no matter how I drive or how hot it gets outside.

Interesting results, thanks for the info. Something to look in to at a later date if I need to upgrade.

xblitzkriegx said:

Makes me curious as to what my car runs. I go by the fairly inaccurate dummy gauge on the dash. It generally stays on the "O" of NORMAL when driving around, regardless of outside temp. If sitting still and not using a/c, it'll go up to the middle of the "R". With a/c on, it never goes above the "O" no matter how I drive or how hot it gets outside.

Interesting results, thanks for the info. Something to look in to at a later date if I need to upgrade.

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Thanks for reading. I'd be curious what temperatures you run too. I'd always been curious when people would talk about their cars running cooler with the AC on, versus hotter. With the new radiator, now having seen both situations on the same car, it seems like it's related to reserve cooling capacity--like if you're not already running near the radiator's limits, then the fan can control the added heat from the condenser, and then some. That's just based on my recent experience.

I've also always wondered if maybe not all cars had dummy gauges. On my car, the middle of "O" was 185, the middle of "R" was 195..."L" was 225. The only thing that changed this was system voltage. Any load on the system would make the gauge read slightly higher, until that accessory turned off. For instance, turning the headlights on and off, the gauge would nudge up and down. Short of that, my factory gauge seemed very sensitive and accurate. Strange how different these cars all behave.

I've never seen my temp gauge move based on vehicle voltage drops that I'm aware of.

I'm pretty sure most cars run the fan on high when max a/c or recirculate is selected. I've never bothered to look but it wouldn't surprise me if the fan is on low with the the a/c is on normal or even if the defrost is on.

Temps have been consistent throughout the cars life and also in different states. It's been to FL, AR, LA, and MN. It's seen low temps and 110+ with humidity and not once has the car even been over half, doing blasts down the road or while idling in traffic on the hottest days.

xblitzkriegx said:

I've never seen my temp gauge move based on vehicle voltage drops that I'm aware of.

I'm pretty sure most cars run the fan on high when max a/c or recirculate is selected. I've never bothered to look but it wouldn't surprise me if the fan is on low with the the a/c is on normal or even if the defrost is on.

Temps have been consistent throughout the cars life and also in different states. It's been to FL, AR, LA, and MN. It's seen low temps and 110+ with humidity and not once has the car even been over half, doing blasts down the road or while idling in traffic on the hottest days.

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That's interesting info. I wonder if that's because yours truly is a dummy gauge, or if you just got a better-cooling car from the start. If you ever get an aftermarket gauge at some point, I'd love to know the actual temperatures it runs.

You brought up another difference between cars. I too have heard others say their fan runs on high with the AC on. My fan runs on low with the AC on, both per data log, and the sound of it. I'm guessing it would run on high if the temperature was over the normal threshold for high-speed. My car does this both with the stock tune, and a performance tune (just with lower thresholds with the latter). Interesting stuff.

Twisted2 said:

It's good to hear that the radiator holds up under those conditions. Did they last a while? No problems?

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Lasted years. Never any problems.


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You may have tried these 2 things while trying to get the original radiator to cool. If so, forgive my over sight.
Water Wetter improves the cooling ability of the coolant. I thought it would be snake oil, but I tried it on a marginal overheating issue and it brought the temp down to an acceptable range. I know you are where you want to be temp wise, but it breaks down the cohesive traits of water allowing it to make a better contact with the engine parts, or something like that.

Another cure for a less than new car, is to clean the a/c condenser and radiator on the outside.

I sprayed both with a cleaner, like Simply Green or etc, and was surprised by the amount of gunk that rinsed out of the fins of the radiators.

Do not use a pressure washer. It will fold the fins over, bad!

Sounds like you are a happy camper, with the new rad.

thanks for all the info!

I wish I could get a thicker core radiator that would tuck up into the core support and still clear my fan and 8rib prochager setup. I will not get rid of my AC.

railroad said:

You may have tried these 2 things while trying to get the original radiator to cool. If so, forgive my over sight.
Water Wetter improves the cooling ability of the coolant. I thought it would be snake oil, but I tried it on a marginal overheating issue and it brought the temp down to an acceptable range. I know you are where you want to be temp wise, but it breaks down the cohesive traits of water allowing it to make a better contact with the engine parts, or something like that.

Another cure for a less than new car, is to clean the a/c condenser and radiator on the outside.

I sprayed both with a cleaner, like Simply Green or etc, and was surprised by the amount of gunk that rinsed out of the fins of the radiators.

Do not use a pressure washer. It will fold the fins over, bad!

Sounds like you are a happy camper, with the new rad.

Click to expand...

Great suggestions. I thought about water wetter before, but never tried it. Part of it was just being stubborn, feeling like the car shouldn't require it. Haha. I'm more inclined to try it now, that the core problem seems to be resolved. Thanks for bringing that up.

geoffmt said:

Lasted years. Never any problems.


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That's great to hear. Thanks again.

DSG2003Mach1 said:

thanks for all the info!

I wish I could get a thicker core radiator that would tuck up into the core support and still clear my fan and 8rib prochager setup. I will not get rid of my AC.

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That's tough. Sounds like a good problem to have though--I bet that's a fun car!

I wonder if anyone has made a radiator with the bottom mounting pegs more offset toward the rear, to push it more forward into the core support. On mine, there's about a 3 or 4 inch gap between the condenser and radiator, which I wonder if it would be okay to lessen. Anyhow, thanks for reading.

Twisted2 said:

I wonder if anyone has made a radiator with the bottom mounting pegs more offset toward the rear, to push it more forward into the core support. On mine, there's about a 3 or 4 inch gap between the condenser and radiator, which I wonder if it would be okay to lessen. Anyhow, thanks for reading.

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i have read where guys have had custom radiators made for a decent price that move forward toward the condenser but it's not a critical issue at this point, Im good in all but super hot weather stuck in traffic with the AC on. I diluted my coolant mix down as thin as possible (it's good to about 10 degrees, I'll never see that in FL) along with water wetter and it helped marginally.

with the aluminum radiator - did it come with a sacrificial anode? I know Summit Racing was selling a drain plug that had the anode for $20 or less, something to consider to help preserve it.