Coyote Gen 3 sound question

[cfriedman67]

I have a Coyote Gen 3 FF headers and Gas N side pipes. The car runs great with no issues. My question is when I am in 2nd or 3rd gear for instance and going down hill if I take my foot completely of the gas pedal to slow down the exhaust grumbles and gets louder until I step on the gas again. Is this normal?

Thanks Craig

[facultyofmusic]

I've seen something similar when I rode in a fellow cobra builder's car going downhill. If he doesn't keep giving it at least a little gas it starts backfiring and may even stall. He said it was a tuning issue with the motor that happens when cruising at low RPM with no throttle. I'll text him to ask more about it and post updates here.

[john42]

Heh... I'm in a 302 with Trickflow "everything" and FFR pipes. Whenever I let off the gas, hill or no hill it's, "grumble grumble, pow pow pow, grumble pow, pop pop pow grumble" and sometimes with flames! :-)

[facultyofmusic]

Guy said it was just a tuning issue. Didn't get it properly tuned yet.

[cfriedman67]

Thanks. I had it tuned via Lund Racing. I asked them and they said they don't think its a tuning issue. I might spend the $150 for them to look at another data log and see if it will make a difference. Was your friends engine a coyote?

[Bob Cowan]

Yes, this is normal. Don't worry about it.

Backfiring is NOT normal, and can damage your mufflers. That is a tuning issue. Take a look at your zero throttle fuel cut.

[cfriedman67]

What is "zero throttle fuel cut"?

[Hoooper]

What is "zero throttle fuel cut"?

When coasting at zero throttle, above a certain RPM threshold, the computer cuts fuel

[GTBradley]

With my gen 2 and long tube headers I get the rumble and occasional pop, but it sounds pretty cool and it’s way less aggressive than what some of these kids are making their Hondas and Subarus sound like. When my tuner asked me if I wanted an aggressive tune or a mild one, where mild meant more efficient on gas, I asked if we could go middle of the road and he said sure.

[cfriedman67]

Thanks Bradley. I dont mind it but I was just concerned that maybe something was wrong. In a perfect world if a tuner could make it less pronounces I would.

[Hoooper]

Thanks Bradley. I dont mind it but I was just concerned that maybe something was wrong. In a perfect world if a tuner could make it less pronounces I would.

I dont know what the Coyote crate computer has on it, but I would expect it still has all the settings for zero demand fuel cut that the mustang would have, which would allow the tuner to enable zero demand fuel cut and then set the parameters for zero demand fuel cut which will turn off injectors when youre coasting off the throttle long enough and above a certain RPM. With no fuel you should have no way to have popping. That would take care of 90% of the decel popping. There might still be some during transition and low RPM coasting below the switching RPM, but that will account for way less of it.

[cfriedman67]

Thank you. I sent the question to Lund who tuned the car and I am waitng for a respmnse.