What's your 2GR water temp? - MR2 Owners Club Message Board
 
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post #1 of 9 (permalink) Old July 6th, 2019, 13:11 Thread Starter
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What's your 2GR water temp?

I'm getting 205* on the scanner and it's pretty flat there. Warmer than I would like. I see they make a 192, 180 and 170 degree. Curious what others with a stock T stat run at before I change this.
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post #2 of 9 (permalink) Old July 6th, 2019, 14:02
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This is a good question. There is some voodoo that goes into determining running temp.

From the 2GR-FE manual, in a native 2GR chassis, the low-speed radiator fans come on at 207F and shut off at 203F. The high-speed fans come on at 216F and shut off at 212F. (See the first attachment). This means effectively the design operating range is 203F to 216F. Probably the ECU's binary file can be edited to change these values. Given that we know the conversion factor for temperature it should be possible to search for these values in the file and modify them.

In a SW20 chassis, the fans are controlled by the AC Amplifier, independently of the ECU. The range for low speed fans is 185F to 194F. High speed fans come on at 194F. (see the second attachment). So this means effectively the operating range will be 185F to 194F. Probably you could open the amplifier and change some resistor on the board to modify this.

Anyway the takeaway is that the 2GR-FE engine is designed to run hotter than what we're used to in a SW20 chassis. The first time that I worked on a Camry 2GR (in a Camry) I started to freak out when the temps went north of 200 and the fans did not come on. LOL.

PS. There's another important difference. In the 2GR-FE the controlling temp is monitored at the water neck. In the SW20 it is monitored at the radiator.
Attached Images
File Type: jpg FANS-2GRFE.jpg (52.6 KB, 4 views)
File Type: jpg FANS-SW20.jpg (100.1 KB, 4 views)

Last edited by merryfrankster; July 6th, 2019 at 14:05.
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post #3 of 9 (permalink) Old July 7th, 2019, 06:29 Thread Starter
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Mine is not fan related. It was 205 on the freeway. My fans also come on at 185, off at 175 (aftermarket thermo switch). I'll drive it today and see what the max I get. I won't sweat it so much now though.
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post #4 of 9 (permalink) Old July 7th, 2019, 14:27
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On the highway my SW20/2GR car with a 170F thermostat runs 180-185F with fans off. The other SW20/2GR car that I work on runs 190-195F with a 180F thermostat. On both cars the temps rise under load. If you are running 205F on the highway with fans on I would look into blockages, air pockets, malfunctioning thermostat, et cetera. Any coolant leaks?

PS. Temporarily I had an electrical issue that kept the fans on constantly. Under these conditions the temp barely broke 170F on the highway. CEL came on for insufficient temp for closed loop.

PPS. The thermostat is a right pain to deal with. Be aware that to access it you must remove the idler pulley first.

Last edited by merryfrankster; July 7th, 2019 at 14:32.
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post #5 of 9 (permalink) Old July 7th, 2019, 15:11 Thread Starter
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No leaks and I just bled the radiator for air again this morning. Just a little farts worth of air came out. It didn't change the out come though. It got to 204 but not above that. If you are seeing 190-195 with a 180 T stat, mine might have a 192f T stat in it. I don't think it's a rad issue as it is new but for a 2000-2005 Corolla, it's what fit good (non MR2). Thanks for the heads up on removing the idler first.
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post #6 of 9 (permalink) Old July 7th, 2019, 16:04
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Well if you're using a radiator designed for a 1.8 liter 120whp engine it's understandable it will run somewhat warm under the heat rejection requirements of 3.5-liter 280whp. I'd be concerned about running under load i.e. track or hill-climb it might exceed the safe limits of water and oil temperature. Now that I think of it, your car is a Europa, maybe you can look at the cooling solution for the stock Exige V6 for guidance.
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post #7 of 9 (permalink) Old July 7th, 2019, 17:40 Thread Starter
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Quote:
Originally Posted by merryfrankster View Post
Well if you're using a radiator designed for a 1.8 liter 120whp engine it's understandable it will run somewhat warm under the heat rejection requirements of 3.5-liter 280whp. I'd be concerned about running under load i.e. track or hill-climb it might exceed the safe limits of water and oil temperature. Now that I think of it, your car is a Europa, maybe you can look at the cooling solution for the stock Exige V6 for guidance.

I knew it was on the small side but then so are MR2 radiators. Elise/Exige's run a horizontal radiator and have much more room. I have mine pretty slanted and it is tight just due to the hood clearance when it pivots. It was 104F outside today and it got to 217F with very mild driving, never got over 50mph and drove like everyone else with a/c on so I don't think it's a 192F T stat problem but airflow or waterflow. I need to add one more bottom piece to the air box, if that doesn't do it (likely not) I'll get a thicker aftermarket aluminum radiator or run this and an aftermarket lotus one in the stock location with the Corolla one in front.
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post #8 of 9 (permalink) Old July 8th, 2019, 11:29
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Garage
SW20's have a fairly sizable radiator, and most people run an aftermarket aluminum one that's like 3" thick.


https://www.mishimoto.com/toyota-mr2...tor-90-97.html
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post #9 of 9 (permalink) Old July 8th, 2019, 14:55 Thread Starter
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I just looked through my notes. It is a 2000-2005 Celica, not Corolla radiator. Mishimoto's is 1.97" thick for a Celica, MR2 is 1.65" I don't know the width on the MR2 but the hoses won't work for me on it. https://www.mishimoto.com/toyota-cel...diator-00.html

Air can still pass by on the bottom by 2", I'll seal that and drive it this weekend.

This is how tight it is

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