What exactly determined if the exhaust crackles when slowing down and shifting to 1st?

[SHxTGUN]

Yeah I had a Roush axle-back/H-Pipe on my '19 A10 GT and noticed it from time to time on those harder downshifts. It really did sound nice. I also can get it to do it a lot more when paddle shifting and just letting off the accelerator in the lower gears like 2 & 3.

When I went back to stock resonator but kept the Roush, it did do it a bit less, but it was still there from time to time. Just harder to hear in the car I think.

Oh and I also think I noticed it did it a little more for me while I'm on E85 as compared to 93.

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[beetle6986]

Well, "naturally" is a misnomer. Ford has the system setup to produce the pops and crackles because that's what people want - a car that sounds like an older carbureted engine. They're dialed in from the factory. If Ford desired, there wouldn't be any.

It didn’t do it at all with the factory exhaust. It was only once it had an aftermarket mid pipe with high flow cats and a catback.

So my car is running normal thats why it doesnt pop on deccel?

It’s perfectly normal for some cars to do it. BMW put it on there M cars from the factory now. I had a X3 m340 and it crackles like crazy in msport mode.

 

[derklink]

It didn’t do it at all with the factory exhaust. It was only once it had an aftermarket mid pipe with high flow cats and a catback.


It’s perfectly normal for some cars to do it. BMW put it on there M cars from the factory now. I had a X3 m340 and it crackles like crazy in msport mode.

I had the same (X3 M40i). At first I really liked it but it got old and somewhat embarrassing after a while. Got rid of it after a year and went back to the sweet sound of a Coyote.

 

[Jmtoast]

The manuals on stock exhausts are the same. Add an aftermarket exhaust and it changes big time. Mine crackles and pops a lot.

Some of that is the Roush Phase 2 tune. Mine has doubled since getting phase 2. Seems to run very rich to try and protect the overheated cats? But yes having no resonator and getting a after market exhaust is part of the equation.

 

[Jmtoast]

No fuel = no pop. DFCO.

you should start a permanently sticked thread called "Ask the Engineer"... Would be a hit.

 

[Bandi]

I've noticed on my car that if I go into Sport mode and make the car aggressively downshift but hold the RPMs a bit by lightly putting my foot on the gas for a few seconds and then letting off I can make the exhaust burble almost on demand.

 

[308 Cal. Bullitt]

The Bullitt seems to hav some sounds on deceleration. Some say its only cuz of the GT350 intake/& larger TB.

Some hav said Ford Engineers claim to hav designed this unique pop/crackle/burble into the pkg...??

What ever the phluck people wanna call it.
Its there. Its unique. No idea how a regular GT stang w/active compares w/DI - Gen3.

I know when we cleaned the deck on the Puter it seems to need to relearn the cracks/pops.

Well. After we did a crank/cam phase--
aka, crank re-learn.. just to cover bases.

Some hav said the exhaust components & the tune are not why.
If thats correct & they are normal GT components..

Only variable is the intake manifold/TB
& any Ford tune that accommodates those parts..

those that cause a ruckus of notes on decel.

Some 1st time passengers w/o much car knowledge wonder if the sound was due to something or somebody after manufacturing.

I havnt been around other Bullitts to compare our own to another.

Very few in our area it seems. Our Detailer has done 1 thats in a car collection & never gets driven.

1 other older guy has 1 & never drives it.. Even had it for sale. Said to buy a condo in deep south was why. A Yr old car & barely broken in. we never heard either running.

Way more GT350s on the road here.

I drive in Track Mode mostly..So maybe that contributes to these decel notes more. As I assume the Bullitt activite Exh hardware pcs front to rear are same as a GTs active exh....?? Why wouldn't it be..

Can these supposed Ford Engineers take credit for the supposed unique Bullitt sound?

Or did it just wrk out that way on this car w/these parts?

I thk some prefer to say its in programming to accommodate intake manifold. I hav no evidence to support anything. Only know it sounds decent for a stk production exh. & the tune might be unique w/the above cyl head components.

Just know it ( burble/crackle/pops) went away till we relearned it, after cleaning deck, & had to drive it a while.
& it came bk again, as it was previous.

Not sure if the Bullitt really has a truely diff sound or just bullchit... vs say a GT.

i didn't buy 1 cuz of this topic,
& its of no relevance to us. But we do like the way it sounds.. As stk even..

Get compliments of how it sounds, both idle & @rpm, from my GM friends, most w/LS cars, who usually spent $$$ on new exh system,
while this design is from Ford. Just stk active exh.

I leave it to the utube test crowd to decide if its any diff than a GT 5.0 or not.
I lnow it dounds better than a lot of my ole Cleveland and Windsor chit.

For us personally.. Only some max wedge mopar stuff & the Boss 9 stuff,
truely runs away from everything else, both on the water brake dyno & in chassis.
Sound wise. But not a lot if cracks & pops even on carbs. The Boss on decel would bend the top plate of the sheetmetal intake dwnward momentarily on decel when throttle blades qwikly closed. The vacuum was so high. Yeah. We wdnt to a thk'r material.

Having two 4150 dominators bolted next to ea other, u woulda thought would make that alum 6061 top plate rigid enuff to not bow. I say bow, not bend, cuz it returned to its original shape. Cam grind was very uniquefor its time, & designed more for torque than HP.
So a more typical valve event cam profile may hav not shown us this situation.
Yes. All irrelevant info. I cone bk & edit it off later .. :+)

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