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Discussion Starter · #1 ·
I just bought a Mr. Gasket 180 degree thermostat from summit for my 1991 5.0 and when checking out it said "check your items as you live in California and some of your parts may not pass emissions standards" or something like that... I purchased it anyways

Now on the box it said for "racing use only, not for Freeway driving cars". What is that about? It said nothing of the sort online, and it seem everyone throughout these forums are using 180 degree thermostats...

Is it strictly because the stock thermostat is 195 (i believe I read that somewhere) and that the lower temp you go, the richer fuel ratio the ECC put out; hence emission problems?

Sorry for the retarded question here, but I drive my car on the freeway like 50% of my time and I was hoping with my new aluminum radiator and a 180 degree thermostat, by car might run a little cooler. my current radiator is very corroded (stock) and my car runs hot (and lean) in warm weather

Any thoughts?

Thanks
 

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Very good questions,and I'd l;ike to "piggy back" your post.Will the 180 degree thermostat work well in an '87 H.O. car with Speed Density?
 

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You can ask someone at a smog cert. shop. I wouldn't sweat it. Everything's illegal in CA. Nobody is going to look at your therm. and it should help your car. The only worry is if it will pass smog.
 

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Discussion Starter · #4 ·
But seriously though, why would a little thermostat affect a smog test ? :)

And what is up with the "freeway" warning? that just doesn't make much logical sense to me... any explanations?
 

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Ok, here you guys go. When your car is cold, it runs rich in order to act like a choke on a cabureted car. Basically you are dumping more fuel in to allow your car to idle easier. Now, when you dump a 180 degree thermostat in your car, you obviously lower the temp from stock which is 197. There are many things working here. First lowering the temp will send the signal via the ECT that your car is not yet fully warm, and the ECU will very slightly richen the mixture. This is good in one aspect which is that running slightly rich will allow your car to get both better gas mileage and have more power. There are downsides as well though. First of all, all engines theoretically reach their peak efficiency at temps right before the overheat and fail... This means that by lowering the temp you are actually lowering the efficiency of your engine. Also, a drop too low in temp and your car may run in open loop (ie. without reading signals from the o2 sensors and such, like at early morning start). Dont go below a 180 degree thermostat, 160 is just too cold and car wont run as well. Its essentially a measure of efficiency vs. running slight rich, and which one nets more power. It is likely that each car with its own individual conditions will have a different answer for this equation. I run a 197 and get 28 mpg on the freeway, now thats with 2:73 gears still, but thats about the best you ever hear from a 5.0L, because they are (unfortunately) not very efficient to begin with.

They are illegal in California because it does increase unburned hydrocarbon production, and California has strict emmissions (obviously). Larry Sergent is right though everything pretty much is illegal in Cali nowadays. Running at 14.7:1 is what our EEC-IVs attempt to do. This is where the least amount of emissions are released. Running about 10% rich will increase your hydrocarbons (an power) , and running lean will actually drop power, release ungodly amounts of NOx and potentially melt pistons. Hope this helps guys
 

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Thanks a lot.I'll keep my regular thermostat.I'm getting good power,good MPG,so,no need to swap it.
 

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Discussion Starter · #7 ·
Thank you very much for that extensive post!

Well I think I will be doing just fine, as the motor has been running on the lean side of things for years and I have recently been having temp rises and power losses (too lean). So the 180 degree stat and new radiator should keep me in the richer area of running, and my car passed smog last time around with flying colors.

Also, I am keeping my fingers crossed that this richer scenario will help damper the issues that I brought up about my power loss in this thread: http://www.allfordmustangs.com/forums/showthread.php?t=48433

Thanks again guys!
 
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Well, the switch isn't based solely on engine temps, but it can happen as low as 160-170. Tmoss wrote an article about the eec, he had tweecer readouts and stuff.
 

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[QUOTE='95.0 stang]Well, the switch isn't based solely on engine temps, but it can happen as low as 160-170. Tmoss wrote an article about the eec, he had tweecer readouts and stuff.[/QUOTE]

Thanks for the responce.

Next Question:
I an running a griffin aluminum radiator,Mr Gasket 180 thermostat,Edelbrock water pump and a electric fan pre set to come on at about 180-185.My problem is that during freeway driving going down hill driving say a minute or more my temp will go down from its normal running freeway temp of about 165-175 to 150.And it takes a long time to get back up to that temp again after level driving and some times will only get to about 165.Any ideas as to whay it runs so cold.I checked the thermostat before installing it and it opens at the correct temp.And yes it is installed correctly.Evening driving temp will get to maybe 165.Never have a problem with cooling and the fan does not come on till after at least 180.I would think that it should run right at or a bit below 180 but 165 seams low to me.Is my Griffin radiator to efferent? This is in Mid west Calif. during summer and winter this it is more prononced at night. :tongue
Gerhard
 
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I'm not quite sure what to say about that, it seems if the thermostat doesn't allow coolant flow until 180* then it should never get colder than that. I know there is a small bypass hose but for such little flow to be cooling the engine that efficiently is impressive. Also, how are you measuring engine temp?
Here's the article "Below is a graph of data collected by Rick Wagner, which illustrates the conditions under which his EEC made the transition to closed loop. One thing that stands out here is that temperature is only one of the parameters that the EEC looks at for closed loop. This A3M computer (same base tables as A9L) went into closed loop with ECT temps down to 140 degrees. "
 

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[QUOTE='95.0 stang]I'm not quite sure what to say about that, it seems if the thermostat doesn't allow coolant flow until 180* then it should never get colder than that. I know there is a small bypass hose but for such little flow to be cooling the engine that efficiently is impressive. Also, how are you measuring engine temp?
Here's the article "Below is a graph of data collected by Rick Wagner, which illustrates the conditions under which his EEC made the transition to closed loop. One thing that stands out here is that temperature is only one of the parameters that the EEC looks at for closed loop. This A3M computer (same base tables as A9L) went into closed loop with ECT temps down to 140 degrees. "[/QUOTE]

Thanks for your reply. I have a auto meter electrical water gauge plus my stock gauge.
 

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Getting that cold is probably not good, I would buy another thermostat (197) and see what it does.... Maybe the radiator is just too good, thats probably a good problem to have...:)
 

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Discussion Starter · #15 ·
So I put in my new "direct-fit" Summit radiator (which wasn't direct fit at all. everything including brackets and holes had to be adjusted/redrilled) and my new 180 themostat. The Engine is cool as ice and runs much stonger (i think my computer was retarding my engine when it got too hot).

The needle sits pretty much rock solid on the first line in the gauge where as before it would float from the second bar to half way on the guage... huge difference.

So I think my power loss probably has to do with bad sensors... because it still feels just a little tiny bit weak when running for a while, but no where near what it was at before.

And the 180 degree thermostat... I can say I love mine (combined with a nice aluminum radiator that can keep the coolant cool :) )
 

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Stangboy5666 said:
Ok, here you guys go. When your car is cold, it runs rich in order to act like a choke on a cabureted car. Basically you are dumping more fuel in to allow your car to idle easier. Now, when you dump a 180 degree thermostat in your car, you obviously lower the temp from stock which is 197. There are many things working here. First lowering the temp will send the signal via the ECT that your car is not yet fully warm, and the ECU will very slightly richen the mixture. This is good in one aspect which is that running slightly rich will allow your car to get both better gas mileage and have more power. There are downsides as well though. First of all, all engines theoretically reach their peak efficiency at temps right before the overheat and fail... This means that by lowering the temp you are actually lowering the efficiency of your engine. Also, a drop too low in temp and your car may run in open loop (ie. without reading signals from the o2 sensors and such, like at early morning start). Dont go below a 180 degree thermostat, 160 is just too cold and car wont run as well. Its essentially a measure of efficiency vs. running slight rich, and which one nets more power. It is likely that each car with its own individual conditions will have a different answer for this equation. I run a 197 and get 28 mpg on the freeway, now thats with 2:73 gears still, but thats about the best you ever hear from a 5.0L, because they are (unfortunately) not very efficient to begin with.

They are illegal in California because it does increase unburned hydrocarbon production, and California has strict emmissions (obviously). Larry Sergent is right though everything pretty much is illegal in Cali nowadays. Running at 14.7:1 is what our EEC-IVs attempt to do. This is where the least amount of emissions are released. Running about 10% rich will increase your hydrocarbons (an power) , and running lean will actually drop power, release ungodly amounts of NOx and potentially melt pistons. Hope this helps guys
this isn't true if you don't know what you are saying don't post a comment the lower temp just helps with cooling fuel delivery is not affected by the cooling system summit only put that warning for liablity
 

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Back to the question...

California requires a manufacturer of auto parts that in any way effect the emissions to have that part tested by the state of California at the manufacturers cost. The procedure is VERY expensive and why spend the money on something that has little profit when labeling it for off road use bypasses the need for a test and allows the sale of the part. :handball:
 
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nykmad said:
this isn't true if you don't know what you are saying don't post a comment the lower temp just helps with cooling fuel delivery is not affected by the cooling system summit only put that warning for liablity
Yeah, running rich will definitely not give you better gas mileage.
 

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Discussion Starter · #19 ·
:)
Thanks for the feedback!
 
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