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Discussion Starter #1
Okay this may be super specific and not to everyone's taste, but I figured I'd start asking here at least.

I'm looking to add a bit of "burble" (I guess that's the best description for it?) particularly on deceleration. My old car, while too loud, would kind of burble and pop on deceleration in gear and I kind of miss it. The exhaust had rusted and snapped at the flex pipe so neither the resonator nor the muffler were attached. Otherwise it was stock.

Right now I have a muffler delete and am tuning with HP Tuners (I'm in the US so tuning options are limited). The volume level is good, at least for me, but the tone itself is too smooth for my taste.

I don't want the super loud "pops and bangs" that are available on some of the European tunes, or that are common on VWs and BMWs (at least in my area), just a little extra noise on deceleration.

So far I have tried essentially disabling DFCO via HP Tuners so the injectors are still on during deceleration, but all that has gotten me is significantly less engine braking.

Does anyone know if there's anything I should be looking into in the tune to achieve this, specifically or conceptually? I was under the impression that in order to get this a little fuel needs to make its way into the exhaust on deceleration, but not a huge amount to avoid ruining the fuel economy, catalytic converter and making ridiculously loud banging.

My other thought was that no matter what I do in the tune, the cat and resonator are going to smooth everything out anyway.

Any help, input, or other ideas would be greatly appreciated.
 

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I'm a Euro shop manager and most of the time when we achieved a good crackle at my last shop it was done with a catless downpipe. Do you have an option to tune out the cat? That may help get you the result you want.
 

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Discussion Starter #3
No, I'd have to physically remove it first. I'd rather not if possible, as I'm not looking for huge bangs or anything, and I'd rather avoid the catless smells since this is still my daily.
 

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Well right, you'd have to remove it of course lol, I meant tune it out so that the engine doesn't care that it's missing. Running rich and exhaust flow are more or less the recipe for a crackle. If you're still not getting it after tuning the injectors to stay on, I don't know how much luck you'll have. Probably the reason your old car with the broken exhaust did it was because you had air being added into the exhaust stream which was allowing unburnt fuel to combust. Maybe cut a hole in your exhaust! :LOL: Just kidding, don't do that.
 

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Discussion Starter #5
The old car still had the cat connected though, it was right next to the header. It was disconnected where the red line is, and 9 is the cat.

I'm thinking it was probably because of the lack of resonator at this point, which means I'd either have to shell out cash for a legitimate aftermarket one or go get one fabbed up. I don't know if I could run even a catted straight pipe on a daily again, so I'd have to get some sort of muffler put in the back.
 

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Hmm interesting, you have me stumped then. Maybe you're right and it is crackling but you can't hear it because the exhaust is being muffled by the uh, muffler. Maybe your exhaust leak really just allowed you to hear it on that last car
 

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Discussion Starter #7
Right, but probably more the resonator than the muffler. Out of this diagram, I removed 15 and put a straight pipe there. The volume is perfectly fine, just the tone is a little too... civilized...? for my tastes. Removing the resonator from 13 would probably add some character, but I'm afraid of it being too loud at that point.

That's kind of why I was hoping for a tuning solution, since I'm already able to change the tune whenever I want, but if it's not possible then I'll have to either deal with it or mess with the exhaust again.
 

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Seems like messing with the exhaust may be your only option. Cool car by the way, I like those little 3 bangers.
 

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SRT4's have a great burble on decel, but stock they don't have mufflers, just a cat and resonator. I'm going to guess the muffler is probably doing too good of a job at muffling for you to hear it, or the cat is doing too good of a job at burning unspent fuel.

There's also a chance that the fuel is still getting ignited in cylinder regardless of DFCO setting. What are the AFR's during that phase? You may have to experiment with richness, cam phasing, and timing to achieve your result. Just be cautious not to excessively heat up your cat by sending gobs of unspent fuel into it, or heat up valves with crazy timing changes.
 

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Discussion Starter #10
I technically have the same exhaust setup then right now, just the cat and resonator. You're probably right about the cat being too efficient in this case.

I didn't measure the AFR's with that tune, turning off DFCO basically meant that there was no engine braking so I reverted the changes. I have already adjusted the fuel pressure, allowed for the maximum duty cycle and increased the max injection angle to prevent running lean, but those are only limits, not actual settings.

It sounds like at this point I'll have to probably remove the resonator, then if it's too loud put some sort of straight through muffler in just to lower the volume again.
 
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