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Hey,
Just finished dynoing Bill Hall's 06 300C Hemi. Only mod is Dynomax cat-back. Honestly didn't think the t-stat would make that much difference. How wrong I was! With the car completely warmed up it made 284rwhp & 323rwtq. While still on the dyno I changed the stock 203 deg t-stat to a 180. Started and ran for a few minutes. Not up to full temp and made a pull. The car responded with 306rwhp & 351rwtq!! Did another pull and it almost laid directly over the first (about 2-3 hp less). Finally, with the car completely up to temp it made 300hp & 334tq. IMO, great mod for the $. I used a Napa 191 t-stat and drilled a small 1/16" hole for an air bleed facing up. Hopefully we'll have tuning software at the begining of January and can really fine tune these cars/trucks. I'll try and post the graph this evening.

Brent
 

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I've always been skeptical about running cooler, but I'm not surprised at your results since going to the track and being dissapointed at the results from my heat soaked motor (~210degree)

I'm curious what the difference would be between the GSM aux fan mod and the 180 t-stat results.
 

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vvv90 said:
I've always been skeptical about running cooler, but I'm not surprised at your results since going to the track and being dissapointed at the results from my heat soaked motor (~210degree)

I'm curious what the difference would be between the GSM aux fan mod and the 180 t-stat results.
Fairly obviously, it requires both to do any good in off-dyno conditions (no mongo fan blowing through the radiator core).

1. A lower temp tstat requires a healthy dose of air through the radiator core to have any effect. With no GSM fan mod you'll still be running in the two-teens, even 220s, in heavy traffic, because the PCM, as currently programmed, will not engage the radiator fan (the larger of the two) until coolant temps are very high.

On the highway you'll see EVIC-displayed coolant temps approaching the temp of your particular tstat.

2. The GSM fan mod (with engine running) can only cool to the temp of the tstat, 203 degrees f with stock, the low 170s with the heavy-duty euro unit I run.

The combination of the GSM fan mod and a 170 degree tstat is - as the current slogan says - priceless. At my most recent track event, with multiple runs - several of which were back to back with less than 10 minutes between runs - coolant temp as I prepared to stage was always in the 160s.

This provides very consistent runs, with times varying only with changes in ambient air temp. Heat soak is now essentially non-existent.
 

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Impressive results! Do you guys see any drivability issues at all or loss of gas mileage? Just some thoughts.... I am wondering what the computer thinks of the car at 180 deg temp? Would it still be in enrichment mode at all due to it not being fully warmed up (to factory specs)? Can't wait to the programmers start coming out...to compensate for these changes and allow control over the fans.
 

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HEMI~C~ said:
Impressive results! Do you guys see any drivability issues at all or loss of gas mileage? Just some thoughts.... I am wondering what the computer thinks of the car at 180 deg temp? Would it still be in enrichment mode at all due to it not being fully warmed up (to factory specs)? Can't wait to the programmers start coming out...to compensate for these changes and allow control over the fans.
No driveability issues, no codes HEMI~C~. Mileage appears to be up a bit, as the car makes more power running at these cooler temps.

That said, it's important to allow the fluids to frequently warm sufficiently to flash off moisture and other contaminants. That's easily done by simply not engaging the radiator fan when tooling around town.

Until you spot a 'Vette - then it's all switches to Combat Mode. ;)
 

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This is the same car that laid down the 8.90 @ 78 in the 1/8th at Hertford, NC. That was without the stat. Going back this weekend to test the results of the stat and the 17 fuse trick.
 

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Oddly enough, I just came back from Napa with a 180 degree thermostat...part number 191. My times on the track last week, for 1/8th miles was (1/8 9.144
mph 78.15) and 14.200 at 97.17mph. I have a free flow exhaust setup, am adding the thermo and a CAI next week. Just wanted to get the part on the workbench before I started.

Concern...I have to drill a hole in the thermostat? Any pics of where/why...much appreciated.

DJ
 

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Two questions about running at a lower (180 degree) temperature.
1. Will this effect the life of the engine since the parts may not be running at the design temperature? By this I mean that the parts may not have expanded to the design tolerances.
2. Will running at lower temperatures cause the car to fail an emissions test?
These are the only two things that would hold me back from doing this mod.
 

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PaCharger said:
Oddly enough, I just came back from Napa with a 180 degree thermostat...part number 191. My times on the track last week, for 1/8th miles was (1/8 9.144
mph 78.15) and 14.200 at 97.17mph. I have a free flow exhaust setup, am adding the thermo and a CAI next week. Just wanted to get the part on the workbench before I started.

Concern...I have to drill a hole in the thermostat? Any pics of where/why...much appreciated.

DJ
Not required, PaCharger. I ran my 180, a twin of yours, for several months with no problems before switching to a 170.

If you plan to avoid (recommended) the waste of time & coolant that draining the radiator merely to change the tstat entails you'll never miss having the bleed hole. However, if you do ever have a legitimate need to drain the radiator completely, the bleed hole helps accomplish that. Otherwise you'll probably need to unseat the tstat to effect a complete draining.

If you do decide to mod yours, drill a small hole about twice the diameter of a pencil lead about a 1/3" in from an edge of the main valve plate. Orient this new hole to the top of the tstat housing when you install it.


FOAMAVEN said:
Two questions about running at a lower (180 degree) temperature.
1. Will this effect the life of the engine since the parts may not be running at the design temperature? By this I mean that the parts may not have expanded to the design tolerances.
2. Will running at lower temperatures cause the car to fail an emissions test?
These are the only two things that would hold me back from doing this mod.
I fully expect my engine to last longer, FOAMAVEN, as it runs much hotter than optimum, stock, here in the desert unless I manually intervene via the fan switch.

Expect no problems when going to emissions. As I've already explained, your engine will still be running in the warmish 200s in town unless you manually engage the radiator fan via the GSM mod switch.

For all: One more time - in town, without the GSM fam mod running the fan (at your command) your engine will run as hot with a 170 as it does with a stock 203.
 

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Food for thought with the 170 T'stat, the service manual stats the PCM will stay in "Warm-Up Open Loop” for a certain time period depending on temperature. The last example it stated was if the PCM reads 168 it will stay in closed loop for 15 seconds then check the temp again.
The manual did not give a temp for when it will go to Closed Loop and stay there but it does state that 180 is normal operating temperature.
 

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maneval69 said:
Food for thought with the 170 T'stat, the service manual stats the PCM will stay in "Warm-Up Open Loop” for a certain time period depending on temperature. The last example it stated was if the PCM reads 168 it will stay in closed loop for 15 seconds then check the temp again.
The manual did not give a temp for when it will go to Closed Loop and stay there but it does state that 180 is normal operating temperature.
Re-read posts #5 and #9. ;)

From post #9: "For all: One more time - in town, without the GSM fam mod running the fan (at your command) your engine will run as hot with a 170 as it does with a stock 203."
 

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Who sells the thermostats?
 

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shanemcse said:
Who sells the thermostats?
180 degree thermostat for LX Hemis:
Cross reference the Stant 180-degree thermostat #13078 at your local auto parts store. Your new tstat should be less than $8.

170 degree thermostat for LX Hemis:
Prestone 383-170. Available at Checker / Kragen / Schuck's Auto Parts stores.
Made in Germany by Cooper Standard/Robert Shaw
63.5mm vice stoker's 63mm. Requires small flat blade driver, or similar, to help tuck rubber gasket into receiver due to slightly tighter fit.
Heavy Duty, has brass dog-bone wobbler in air bleed hole. Orient bleed hole to highest point of the thermostat during install.
Fail-Safe feature insures thermostat valve moves to full open position in event of a failure.
 

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What are LX Hemis? I have a 300C with 5.7 Hemi.
 

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shanemcse said:
What are LX Hemis? I have a 300C with 5.7 Hemi.
Then you've got one, by golly. :)

The LX designation refers to the new body style(s) that came out with the 2005 models. The LX chassis replaced the LH, cab forward, style.

The other LX Hemis are the V-8 Magnums, the V-8 Chargers, and the SRT8 versions of these 3 fine cars.
 

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Sweeeeet. I just called Kragen and they do have the Prestone 383-170 in stock. There price was $19.99
 

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shanemcse said:
Sweeeeet. I just called Kragen and they do have the Prestone 383-170 in stock. There price was $19.99
Good show, shane. I forgot to mention earlier that the deluxe unit runs $18 to $20. Well worth it IMO.
 

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Meister said:
Re-read posts #5 and #9. ;)

From post #9: "For all: One more time - in town, without the GSM fam mod running the fan (at your command) your engine will run as hot with a 170 as it does with a stock 203."

Did I disagree with you?
NO
You are absolutely right but some people have been known to drive on the highway.
 

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maneval69 said:
...You are absolutely right but some people have been known to drive on the highway.
Rarely without a slow-speed transition at one or both ends, however, maneval. :) That allows the fluid temps to get elevated for a while.

If one starts getting CELs, even with proper fan management, then an adjustment will be in order. If not - Steady As She Goes!
 

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Here are the installation directions for the thermostat. I got them off of the Prestone site.

1) Allow cooling system to cool before servicing. Remove radiator cap.
2) Drain cooling system and remove thermostat housing.
3) Before removing old thermostat, note orientation of jiggle pin/bleed hole so the new thermostat can be installed in the correct position. Remove old thermostat and gasket or O-ring.
4) Clean gasket mounting surface.
5) Install thermostat into groove with cone point toward radiator.
6) Install new gasket.
7) Replace housing; tighten evenly.
8) Refill cooling system with system air bleeds open (if engine is so equipped). Close air bleeds. Replace radiator cap. Fill coolant recovery system to a point midway between the “hot” and “cold” levels. Run engine until thermostat opens, check for leaks.
9) Run engine and allow it to reach normal operating temperature. Turn engine off and allow to cool. DO NOT REMOVE RADIATOR CAP UNTIL ENGINE HAS COOLED. Remove radiator cap and recheck coolant level. Add coolant if necessary. Reinstall radiator cap.
 
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