What thermostat came with my 2010 srt8? Some state i should get a 180. Also some talk about a hole in the thermostat, some said to put the hole up and other down. What is the correct way? Ya'll think its too late for an oil catch can? 97000 miles. Thx
The stock thermostat is rated at 195 degrees. Some have switched to a 180 but Dodge does not recommend it since the higher thermostat is designed to help reduce emissions and bring the engine up to operating temperature faster. The pin (breather) of the thermostat installs in the 12 o'clock position. At 97K miles, you probably have some carbon build-up. Despite that, installing a catch can now, may help, especially if you plan to keep your Challenger for many years.
My counsel regarding engine thermals is to limit the PEAK temperatures, while keeping the operating temperature in a desirable band. Ergo, for people who go for lots of power, why not just upsize the radiator, and any other fluid coolers? The ones that need it are thermostatically protected, anyway, so you won't be overcooling them. These aren't air-cooled plane engines like the P47 or Vought Corsair (one of the sexiest planes in history, both the prop and jet-powered versions.) The lower-temp thermostat does not increase the cooling capacity of the engine. It just lowers the temp at which the thermostat says, "okay coolant going to the radiator now." What it ALSO DOES NOT DO is throw more heat out when your engine is running at full chat. That is determined by your radiator capacity and airflow. Get a bigger set of coolers and install them. With the same-as-stock thermostats, you will experience better ability to advance the spark, more fuel mileage, and more power. The thermostat, once it's open, which happens soon after you tip into the throttle in any great way, only opens as much as the 195 degree version, anyway. With the larger radiator, coolant is kept cooler when you REALLY NEED IT TO BE, which is under higher throttle openings, when any thermostat is going to be open anyway.
Keep in mind the Temp still has to get at a certain temp for the Fans on your Radiator to kick in regardless. So its more of a PITA to swap for a 180. and nothing is gained nothing because PCM / BCM.
I think someone would have to program the PCM to interact properly with one's fans, etc. to maximize any benefits they wanted to see. Imagine how much timing the booosted cars could get away with if their IAT's were brought down to ambient. That would take one big, whopping set of charge coolers and radiator, and oil coolers, too, I think. Lowering it even further to well-below ambient would take even more engineering. Some have managed to chill the actual coolant of the aftercoolers below ambient, but the amount of hp to go 30 degrees or so below ambient would be, I estimate, around 12hp, which, to me isn't a great sacrifice if one can pick up a large amount of timing advance or compression to take advantage of it. The primary obstacle, to me, would be the sheer surface area of the aftercoolers and refrigerant coolers. There is only so much air at so much velocity that can be brought through a stock set of grille openings. But, considering the amount of area on an AC unit's cooling coils, I think it would be doable, but the airflow would have to be quite carefully managed to take advantage of the ram air. Sitting in traffic may see more of a battle to get adequate airflow, unless one had added enough fan capacity to the various coolers. Also, 12hp is not too far off of what it takes to move an entire car along at 60mph, for example, so it would definitely dip into fuel mileage if it was a necessary-all-the-time part of the system. Example: The Hellcat, (all numbers are theoretical, not necessarily exact) with 700hp to do 200mph would only use 18.9hp to go 60mph. Piling another 12hp on top of that to run a compressor would mean around 31hp, which at the ICE engine's efficiency of .40 lbs/hp-hr would mean 12.4 lbs/hr of gasoline burned, versus 7.56 pounds per hour for the car without the cooling, a little over a pound per hour. Doesn't sound right. It SOUNDS like the engine is FAR from its peak BSFC at low throttle openings at normal highway speeds, but that is no surprise as most engines make their best BSFC at wide open throttle, or WOT. So, a gallon to go 60 miles? Sounds inaccurate. it's more like 3 gallons per hour, or 20mpg. Now, if that is the case, that is 22 or so pounds per hour. That is pretty dismal for a BSFC, far worse than 7.56. Is there that much wasted power from the combustion chamber to the tires? 22 lbs/hr to produce 18.9hp is a steep 1.16 lbs/hp-hr. At 200mph, it supposedly gobbles 18 gallons in 11 minutes, or 36.666 miles. That's 2mpg at a BSFC of 0.4 lbs/hp-hr thus 280lbs/hr. That's 35 lbs/hr per injector. Holy Duty Cycle, Batman! However, if the engine at 700hp is using 18 gallons in 11 minutes, that is 98 gallons per hour for 700hp, which is also 687.27 pounds per houror about 0.98 lbs/hp-hr. of effective power, far worse than the "best gasoline engine efficiency" of 0.4 lbs/hp-hr. But, anyway, adding a 12hp compressor load to a 19hp load would not be terribly efficient, unless that 12hp had a way of GREATLY increasing the efficiency of that engine at low throttle settings. As is often decided, such as by ships, airplanes, planes, and big rigs, a big, slow-turning engine will give give the best BSFC. If Dodge dropped the RPM of the Hellcat to around 700 at highway speeds, they would experience a marked increase in mpg. An engine is usually getting better BSFC when its throttle is open more widely. An engine at WOT and 1000 RPM will get better BSFC than the same engine at part throttle and 5000 RPM. For better overall mileage, they just had to add a loafing highway gear to the Hellcats, which have 485 ft-lbs of torque all the way down at 900 RPM.
