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Probably a dumb question but I'll ask anyway. I have a 180 thermo and had plans on putting it in for the usual benefits. I talked to a local mechanic and he said it could cause emission problems especially in conjunction with a resistor used to "trick" the computer in to thinking the intake air was cooler. Any thoughts or experience with this? I don't have to meet Cali standards for emissions. Thanks

04 Hemi, Sleeping Beauty
 

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I am running the 180 thermo and AIRRAM's PowerWire which is the IAT mod/resistor trick for the computer. I got no problems and recommend doing it. JUST DO IT!
 

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O5 Hemi thanks. I am expecting the powerwire, scoop and intake from Nick tomorrow according to fedex. I didn't want to mention any names until I heard something. I looked ito a lot of intakes etc before going with airram and thought it was a good choice. The same Mech also didn't like my Cali suspensions leveling kit with ranchos around the block so I was suspicious. He does drive a Chevy, so again I was suspicious. Thanks for the input, always appreciated.

04 Hemi, Sleeping Beauty
 

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Moral of the story: Find a new mechanic
 

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i ve been running a magnaflow, with a mac cai, and a resistor for 12,000 miles now.. everythings just fine except ,my tires smoke real easy, i always run 89 octane fuel also..
 

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HEMI05RAM said:
That may be correct in general. But many members on this site haven't had any issues with them on the HEMI's.....so adding those mods haven't cause any problems.

Not in general. The problems running cooler temps apply to the computer controlled Rams. I'm just talking about the 180 thermostat mod that was the subject of the thread. Just because you haven't read of anyone having symptoms YET doesn't mean there are no problems. Do you know anyone who has been running one for 70 - 80K? Why take the risk when there is no measurable performance gain?

Quote from the Specialty Equipment Market Association

Computer-controlled vehicles also are programmed with a specific thermostat opening temperature in mind. If the thermostat opens at a cooler temperature, the computer may think your engine hasn't warmed up yet. Needless to say, the computer would create a situation equivalent to running with the choke on all the time for a carbureted car, which would be detrimental to performance, fuel economy and emissions. In this case, if you really want to change to a cooler thermostat, you will need to swap computer chips--or reprogram your existing computer--to eliminate these problems and maximize your performance gains.
 

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I also use a 180°F t-stat in my modified 5.7L Hemi Ram and have not had any problems. The 180°F t-stat will lower the under hood temps as well as the air inlet charge temps. The engine will also be a lot less prone to spark knock with the cooler cylinder head temperatures which is very important when the modifications that have been done result in a leaner air-fuel-ratio because of the speed density engine control system which is what the 5.7L Hemi uses. I highly recommend the use of a 180°F t-stat in all modified 5.7L Hemi engines.

I also found this in another thread.

in the Sept 2002 MOPAR Magazine

quote
Q: "I have a 1997 Dodge Dakota with a 318 Magnum. I heard that the Magnum engines run better with a colder thermostat other than the stock 195 degree, such as a 180 or 185. Is there any truth to this ? Also, does Mopar Performance Parts make a 185 degree thermostat for this engine ?"

A: " A cooler rated thermostat can maintain a cooler intake manifold temperatures, which leads to a denser intake charge, and offers a little additional mid-range power. Keep in mid this does change the emissions cycle and should be used in off-road applications. The cooler operating temperatures also offers a bit less octane sensitivity and less detonation potential. The factory MPI systems are designed to come off of the "cold start" program at 177 degree F so you can effectively use a thermostat rated as low as 180 degrees F. Mopar has not found it necessary to offer colder rated thermostats, since they're readily available throughout the replacement parts industry."
end quote
 

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DonRam said:
Not in general. The problems running cooler temps apply to the computer controlled Rams. I'm just talking about the 180 thermostat mod that was the subject of the thread. Just because you haven't read of anyone having symptoms YET doesn't mean there are no problems. Do you know anyone who has been running one for 70 - 80K? Why take the risk when there is no measurable performance gain?

Quote from the Specialty Equipment Market Association

Computer-controlled vehicles also are programmed with a specific thermostat opening temperature in mind. If the thermostat opens at a cooler temperature, the computer may think your engine hasn't warmed up yet. Needless to say, the computer would create a situation equivalent to running with the choke on all the time for a carbureted car, which would be detrimental to performance, fuel economy and emissions. In this case, if you really want to change to a cooler thermostat, you will need to swap computer chips--or reprogram your existing computer--to eliminate these problems and maximize your performance gains.
I ran one in my 03 HEMI for 65000 miles before I traded it in. Had zero problems.....I took it out at the dealer and was going to put it in my 05, but since they are so cheap, I just bought a new one.

In my 05, I will be running a thermostat, IAT mod, and the programmer when it comes out.
 

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The 180 degree thermostat will cause more emissions from the 5.7 - but it will mostly be in the first 4 minutes after a 'cold start'. Since most State emissions testing stations do their checks while the engine is running you are likely to have no problems during the yearly check. If you are worried make sure that the engine is fully warmed up and has been run for 30 minutes. If you are even more worried, leave the engine idling while you wait your turn to be tested.

I think that 5.7 Hemi engine owners who install 180 degree thermostats without a Bypass post {like the 63 mm factory original 203 design} are making a mistake.

Without the bypass post to close off the coolant bypass hole, their 5.7 Hemi will be getting much less cooling at full throttle high rpm operation and the cylinder head will get much hotter, and the chance of pinging or more serious detonation will be greater.

As far as 180 degree thermostats helping 5.2/5.9 V8 Magnums, Kenne Bell company in 1998 tested 180 degree thermostats versus the stock 195 in a 5.9V8 Ram on their in house wheel dyno and report NO CHANGE IN HP OR TORQUE AT ANY RPM. Kenne Bell went on to say that they didn't see anything wrong with installing a 180 anyway.

When people read in some hot rod magazine that 180 coolant temperature causes less pinging than 195 on an engine they should realize that the writer is talking about JUST THAT CHANGE ALONE with no other difference in the engine. On the 5.2/5.9 V8 Magnums, the PCM computer will ADVANCE THE TIMING when it senses 180 degrees instead of 195. This negates the pinging advantage, but it might result in a bit more torque if high enough octane gasoline is used to prevent pinging. I say this knowing that the 5.2/5.9 does not have knock sensors - because even 'silent detonation' lowers torque output. The Kenne Bell dyno test shows that even this does not happen.

In a 1995 Magnum 5.9V8 I have tried 195, then 205, then no thermostat, then 180. I have also tried 50/50 coolant, straight water, and Evans NPG coolant. I have had a Robertshaw thermostat fail closed when using the NPG and have driven about 30 miles with the temperature gauge near 300 degrees when the outside temperatue was 95 degrees.

In all of the above the only time I have seen the engine ping less on 87 octane at FULL THROTTLE was with straight water with no thermostat with the coolant gauge staying around 140 degrees. I don't recommend this as bore wall wear will be much more at this low temperature.

If owners think that putting in a 180 degree thermostat will make their truck 'leap tall buildings in a single bound' they are going to be disappointed.
 

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HankL said:
I think that 5.7 Hemi engine owners who install 180 degree thermostats without a Bypass post {like the 63 mm factory original 203 design} are making a mistake.

Without the bypass post to close off the coolant bypass hole, their 5.7 Hemi will be getting much less cooling at full throttle high rpm operation and the cylinder head will get much hotter, and the chance of pinging or more serious detonation will be greater.
I agree 100% that changing the coolant flow in any way is not a good idea. If you use the Stant 14168 64mm 180°F t-stat with the bypass blocker it's a non issue. The OD of the 64mm t-stat just needs to be sanded down 1mm to 63mm and the Stant 14168 works great.
 

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HankL said:
I think that 5.7 Hemi engine owners who install 180 degree thermostats without a Bypass post {like the 63 mm factory original 203 design} are making a mistake.
Is that the little metal piece about a cm long? If so, I moved the stock one over to the new one. It had a little hole, so I assumed that was what it was for. Hope I was right.
 

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dodge3471 said:
If you use the Stant 14168 64mm 180°F t-stat with the bypass blocker it's a non issue. The OD of the 64mm t-stat just needs to be sanded down 1mm to 63mm and the Stant 14168 works great.
I went up to the store to grab a 14168 and when I checked it out it didn't have a hole or a bypass. It was a 64mm 180 thermostat however. Could the wrong thermostat had been in the box or is the part number not the one I need??

I was also thinking about removing the popper and just having a hole there. Maybe even drilling a 2nd hole on the other side. Would that work fine too?
 

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HEMI05RAM said:
I went up to the store to grab a 14168 and when I checked it out it didn't have a hole or a bypass. It was a 64mm 180 thermostat however. Could the wrong thermostat had been in the box or is the part number not the one I need??

I was also thinking about removing the popper and just having a hole there. Maybe even drilling a 2nd hole on the other side. Would that work fine too?
I think you may be confusing the vent which is for filling the system with the spring loaded bypass on the side of the t-stat that goes into the engine. The Stant #14168 is correct but it is 64mm. The vent on the 14168 is there but you have to look closely to see it. As long as the one in the box looks just like your stock t-stat you are fine. The are pics in this thread. The one on the left is the bad example and the one on the right is the stock one. http://www.dodgetalk.com/forums/showthread.php?t=28029
 

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I have the thermostat on the left.
 

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It does....I think I was just looking for the wrong thing. So the vent doesn't really matter?
 

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The stock one on the right is sitting on the bypass blocker. When the t-stat opens the round plate moves out and seals a passage in the front cover (the t-stat bypass passage.)
 

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So get the 14168....got that. What about drilling holes in it? Looks like many people do that too. Small 5/16" holes.
 
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