Exhaust Flames

[peterd]

I have just finished my 408 stoker which includes a FAST EFI unit. You plug in a laptop and set fuel maps and other parameters. The setup is good enough to drive however I still need some fine tuning. I am struggling with the problem of exhaust poping and flames appearing when I take my foot of the gas. What is this a symptom of.

[SCOBRAC]

Problem?? sound like it's just rich enough. Seriously, you are pushing raw fuel out the exhaust. Yoo may need a little less injector or a calibration of the FAST unit. (is it able to be calibrated?)

This isn't as big a problem as it seems as long as it isn't frightening small children or spooking the livestock. Some people know when the mixture is just right by the color of the flame. You want a bright orange or redish flame.

[Jim Werth]

If you have an exhaust leak between your headers and side sidepipes, this can cause the flames. Thats what caused mine. I had 3-4 foot flames. Looked really neat at night. Jim

[Mestizo]

Cool, where do you get a leak kit?

[aumoore]

Flames in a Cobra? Cool

For what it is worth it is better to run rich than too lean. Rich will burn fuel but lean will burn parts.

[Mark IV]

...you have the "exhaust igniters" that were on Blackcobras "original 427 with tons of horsepower Cobra?"

Ah yes, the old days.....

Rick

[DavidWard]

Are you using some type of fuel-air ratio meter for tuning? My bet is it's too lean. I'm running Wayne Presley's EFI stack system, and too rich will cause back-firing through the stacks. Too lean will cause popping and flames from the exhaust. I can cause exhaust flames at will by just turning the mixture knob towards the lean side.

David