Traffic motor performance issue 440

[jibbers66]

Hi Guys, 72 440 727 Cuda. Car runs great. Temp is stable even in traffic. I do notice a change in performance if I am stuck in stop and go traffic and temperatures rise.

It never gets even half way up the temp gauge, but idle and acceleration begin to stumble a bit until it gets good cool airflow.

Then it runs perfectly again.

Could a different thermostat help eliminate this issue?

 

[Chryco Psycho]

You do not want to go lower than 180* , but tuning the carb precisly could help , it may be to rich when hot or a Coolcarb spacer to keep the carb temp down .

 

[jibbers66]

Thanks for the response Psycho, I’ll try that…

 

[Challenger RTA]

You do not want to go lower than 180* , but tuning the carb precisly could help , it may be to rich when hot or a Coolcarb spacer to keep the carb temp down .

I would do the above first. If there is still an issue I would consider doing a vapor separator. Be aware it is not a fuel filter. That is a misnomer of the name. 72 didn't come with a 440. There is a lot of heat generated and nowhere to go. Might be the symptom of vapor lock. Also check the fuel cap to be correct for the application. I know this from personal experience. In the 70's and 80's driving a company truck it would do the same and then die. Had to open the gas cap to unlock system. Then it was good until the next time. It was a Ford go figure!

 

[Xcudame]

It gets hot in LA (and I'm not talking about the fires earlier this year). Are you running a fan shroud and clutch fan? 22" or 26" radiator? Lots of little things were one can be out and it causes you symptoms. But regardless, it's going run better when moving well then stopped in traffic.

On really hot days here, I try to avoid traffic with the 70 Challenger. Spent a lot of years in roll/stop traffic with no AC and it sucked! Don't want to do that anymore unless I'm in one of my newer Mopars were the AC works well!

 

[cuda joe]

sounds like vapor lock .check all of the above first . if that doesn;t work what i did was put a 440 fuel lines it comes with a return line you will need to also buy the vapor separator 440 fuel pump and 440 fuel pickup that goes in the tank that cured that problem

 

[540HemiCuda]

Sounds like heat soak. Today's fuels are much more sensitive to high temps that yesteryear's fuel. Is the heat cross-over in the intake blocked? If not, do that first. In certain circumstances, there could be small down sides to doing that, but running our dinosaurs on today's pump swill requires some compromises.

Insulating the carb from the intake is also a very good idea. Wood is the best insulator, but most guys use other materials. A little more plenum volume might be a performance improvement to boot. Deciding which is best for your application; open or 4 hole can only be determined with experimentation. I would start with a 4 hole for a mild street engine.

The carb is NOT starving for fuel or it wouldn't respond when the throttle is opened. More demand with limited fuel would only exaggerate the problem. It is the fuel vaporizing in the intake. Cool down the intake, carb, and maybe even the fuel any way you can. But cooler fuel cannot overcome a carb and intake that is too hot. Cooler fuel can only compliment a cool intake and carb.