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Discussion Starter · #1 ·
:huh:Noticed something peculiar while driving in mid-20 F weather (and sunny, no precipitation). I have had the rev lights flash and the rev-limiter cut off fuel when I reach speeds above ~120 mph, especially if its sustained for any length.

The Exige (presumably Elise as well) has an effective temperature-based variable rev-limiter.

The digital engine temp will read ~185'sh. When accelerating at these ambient air temps the engine temps will drop expectedly then completely disappear. This is when the lights start flashing.

Is this car so efficient at aero-cooling the engine? Is it dangerous to the mechanicals?

Short of sticking a piece of cardboard over the roof scoop are their any suggestions?
 

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Mulholland>SCC
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People (not Lotus specific) block the air flow to the radiator, NOT their engine.
 

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The temperature limiter is 60C and 70C, so i might be looking elsewhere for the issue if you're seeing 85C.

Was it a solid on off blink, flicker, did it limit to 6000 RPM until the temps went up again ?
 

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So it must be dropping below 60C coolant temps, i don't think blocking off the roof scoop is going to do much for that..

If it is a flickery light vs a solid light or flashing on/off it might be a power supply problem.

If it is just limiting the engine because of the temp, it shouldn't do it any harm. Since thats what its designed to protect against.
 

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Discussion Starter · #7 ·
I suppose an alternate question would be: If we didn't have temperature based rev limiters and didn't have a rev-limit activation, would I be doing harm after the engine is has been running hard, well-warmed, and having an influx of cold-air?

Is the variable rev limiter system just very simple.... {computer speak ~ temperature this..... rev limit that} ....?
 

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Its based on two temperature thresholds 60C and 70C and a time based parameter, for the low setting its 6000 regardless of the time, for the higher temp it can bring it down to 8000.

To the best of my knowledge its primarily related to oil temperatures, and given there is no oil temp sensor, i guess the rationality is that if the coolant temperature is 70C+ then the oil temperature will be high enough to properly operate the higher rpm/cam and the engines lubrication needs.

There is a second limiter that is based on a serious fault, and a third limiter of sorts which seems to be related to electrical issues in that its not a specific condition as such, it just seems to happen on power issues, more of a general electrical or mechanical limitation than an artificial limiter.

So given all that if it is a cold running issue, and the oil is below the temps that the factory preset, it'll be limited to the range that they want it to be, so it should be ok, but as a precaution i'd be laying off the high loads if its somehow that cold.

maybe thermostat related as seb says, tough to say what it actually is without more data.
 

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thermostat issue. My car had the identical problem a few years ago.

i would be racing racing...2nd gear roll....by the time im in my 4th gear, it would cut out and the temp went from 185 down to no display

change the thermostat ;) dealer warrantied it for me back when it happened to me and my car was still covered since it was like a year old.
 

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Discussion Starter · #10 ·
thermostat issue. My car had the identical problem a few years ago.

i would be racing racing...2nd gear roll....by the time im in my 4th gear, it would cut out and the temp went from 185 down to no display

change the thermostat ;) dealer warrantied it for me back when it happened to me and my car was still covered since it was like a year old.
Do you recall anymore info that the dealer passed on to you so when I get it back to my dealer. I can only imagine their expression when I go in and ask for a new thermostat.
 

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...i have the same issue and am planning to replace my thermostat later this month...
 

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:huh:Noticed something peculiar while driving in mid-20 F weather (and sunny, no precipitation). I have had the rev lights flash and the rev-limiter cut off fuel when I reach speeds above ~120 mph, especially if its sustained for any length.
You might notice something peculiar in that your tires lose significant amount of grip in below freezing temperatures. If you're driving at 120mph in freezing temps, I hope you're confining it to a track.
 

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I also had exactly the same issue.

The thermostat is sticking open.

As far as what to tell the dealership: Uh... my thermostat is sticking open. Please replace it.
 

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The same happened with my '08 S240. Thermostat replaced under warranty. No questions asked. I did not realize the problem was so wide spread.
 
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