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At what temperature range do hellcats perform the best?
For optimum performance that would have to be determined by testing. Lab (dyno) and field testing and eliminating as best as one can the affects of temperature, humidity, barometric pressure differences. I dare say only a few owners who compete in motorsports would find it worthwhile to go to this effort.

For the vast majority of owners as long as the engine coolant/oil is up to an acceptable operating temperature that is where the Hellcat delivers its best performance.

As an aside on the drive home last night as I made my way on surface streets to the BART station to drop off a co-worker I watched the oil temperature go from cold to 210F then after dropping off the co-worker and once on the freeway after a few miles drop to 178F. I also had the oil pressure displayed and I noticed -- not that I was surprised by this -- oil pressure at a given RPM change with the temperature. With the oil hot at 210F and at around 1500 RPMs the oil pressure was 60 psi. When the oil temperature was 178F with the engine at the same RPMs the oil pressure was up 3 to 4 psi.

Clearly at a low temperature the oil pump is working harder which is a parasitic load that diminishes the HP delivered to the rear wheels. So at some point, colder ain't always better.
 

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I know air intake temperatures over 140 degrees Fahrenheit the computer will pull timing...less power delivered to protect engine. Drove to work this morning it was 49 out...air intake temp was 90 degrees on highway...boost weather they say.
 

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Discussion Starter #4
Does anyone know what was the temp and direction of the wind when dodge had their record run?
 

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At what temperature range do hellcats perform the best?

While temperature has a direct effect on this, what you're really asking (I think...), is what DA (Density Altitude) do Hellcats/Demons/Redeyes/cars in general perform best at...

The answer for the sake of argument is lower is better, more air into the engine is more power...


A lower DA means the air is denser and more gets pushed into the engine by the blower...
 

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right now in Mt. Holly NJ we have a DA of -1204 my Cat felt very strong-most stock cat A8 pull about 660 on the dyno at sea-level. Today felt like 700 for sure temp 43 intercooler temp 50 on highway...
 

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I have driven one in real negative DA here in MN. The difference is very amazing. Usually then the tires won’t stick, because of cold pavement AND compound that with more torque. Yea, right... hang on!

Sometimes up at BIR early or late in the year we start the mornings with temps in the 50’s and low dew points. It is a lot of fun.
 

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Discussion Starter #9
While temperature has a direct effect on this, what you're really asking (I think...), is what DA (Density Altitude) do Hellcats/Demons/Redeyes/cars in general perform best at...

The answer for the sake of argument is lower is better, more air into the engine is more power...


A lower DA means the air is denser and more gets pushed into the engine by the blower...

thanks for the info Bull!
 

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Discussion Starter #10
I have driven one in real negative DA here in MN. The difference is very amazing. Usually then the tires won’t stick, because of cold pavement AND compound that with more torque. Yea, right... hang on!

Sometimes up at BIR early or late in the year we start the mornings with temps in the 50’s and low dew points. It is a lot of fun.

you need traction glue from Amazon and you will be breaking PR(s)
 

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The only downside I have found to running in colder weather (yeah, I know, does it really get cold here in Florida?) is a lot and I mean a lot more wheel hop under hard acceleration....and I do have the diff brace.
 

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During normal summer driving, the HP gauge in the car never gets past 650, nor does it make 11psi. When I goose it on the highway in the winter, when it's 30*F or so... she makes 11psi easy and has gotten as high as 720 or so. Even with great snow tires and 300lbs in the trunk she is a handful at highway speeds.

Such an animal in the cold.
 

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During normal summer driving, the HP gauge in the car never gets past 650, nor does it make 11psi. When I goose it on the highway in the winter, when it's 30*F or so... she makes 11psi easy and has gotten as high as 720 or so. Even with great snow tires and 300lbs in the trunk she is a handful at highway speeds.

Such an animal in the cold.
You have to be careful. That the HP or boost doesn't get as high in warmer weather vs. colder weather could mean just the opposite of what you think.

With my 996 Turbo nominal max. boost was 0.7 bar. Also, it took the right conditions to see this. Most often I was successful when accelerating up a grade in 5th gear and just flooring the gas pedal and holding it down. The boost rose to 0.7 bar and stayed there for a while but dropped off some as RPMs climbed. And oh the speed of the car...

But sometimes the boost only got to 0.6 bar. The reason is the engine controller tries to satisfy the torque demanded by the driver which is based on how much throttle he is applying. If the torque demanded can be satisfied with 0.6 bar of boost that's all the engine controller will allow. OTOH, in some cases -- most often at higher elevations -- I'd see prolonged readings of 0.8 bar boost even 0.9 bar boost (at elevations approaching 9000 feet above sea level). This was because at higher elevations the engine controller had to supply more boost to get the engine to deliver the torque demanded by the driver.

I have not had any real chance to test/observe what boost/HP levels my Hellcat can obtain. The thing gains speed so quickly I'm too busy driving the car to watch Performance Gauges display.

In your case what could be happening is when you see HP of 650 and boost less than 11psi it is because the conditions are such the engine makes the desired torque with less boost.

When you see the higher HP number and more boost it is because the conditions are such the engine can't make the desired torque with the lower boost so the engine controller has to allow more boost.

While I have found over the years engines generally run better in cooler weather there is a threshold of temperature below which the benefit goes away. Too cold of intake air temperature tends result in less power because the incoming charge is too cold. My memory of how my other cars fared in cold temperatures was under 50F things were getting better -- but it had to be low humidity too -- and in the 40s things were definitely better. The engine would have a bit of sparkle to it that was absent in warmer weather. But much colder temperatures didn't seem to have as much benefit and I recall driving in the very low 20s/teens and even a few times with the temperature down to 0F/1F and while the engine ran ok it didn't have the sparkle, so to speak, it had at higher (but still lower than usual, well lower than summer at any rate, temperatures. The incoming air was just too cold. Also, the intercoolers -- air to air intercoolers -- were of course subjected to the ambient air temperature and the intercoolers removed even more heat from incoming intake charge temperature which lowered its temperature way down.
 

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Rockster
I’m pretty sure the car is making a ton more power in the winter. I don’t know that any cold air a Hellcat would be exposed to would be detrimental to making power. It is thicker, oxygen rich air, with cooling properties.

I also don’t know that the HC has any regard for torque demand, when you’re WOT the blower will spin the same as it does in the summer but the boost goes up because the air it is compressing is thicker.

Same happened on my turbo cars. Aftermarket turbo and oem, all loved the cold Buffalo air. Not sure I ever saw temps cold enough to start losing power. Makes me think of the chillers guys are using, they are trying to get subzero air - because it makes the most power.
 

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Mine always runs best behind the Safeway leaving the bar. Great unobserved burnouts
 
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