Possible Detonation?

[AquamanCHS]

I recently did a whole slew of mods (PI headswap, VT stage I cams, BBK LT headers, BBK X, magnaflow catback) and got a mailorder tune via SCT microtuner from Tim at Modular Ford Powerhouse. Now, when I'm driving and I punch it in second gear at low RPMs (2k or so), I sometimes hear a low garbled gurgly noise momentarily that seems to come from right under my feet (I can feel it in the floor pan). Is this something that's normal for my setup or could it be detonation? I don't hear any loud rattles, either.. I don't experience the "marbles in a can" sound. Anyone have any ideas?

EDIT: I'm also running 93 octane gas

 

[AquamanCHS]

Anyone?

 

[jbrown]

to me it sounds like your new exhaust

 

[bierbelly]

You know, with all the stuff you did, you may be running lean and causing backfiring. You'd hear this in your exhaust system, but it would be muffled by the mufflers. Have you checked your A/F ratio?

 

[stang976]

You know, with all the stuff you did, you may be running lean and causing backfiring. You'd hear this in your exhaust system, but it would be muffled by the mufflers. Have you checked your A/F ratio?

 

[nickthegenius]

My guess is the X-pipe. They make odd sounds under your seat that sometimes could be mistaken for detonation. My UPR pipe with the stock manifolds and my Trubendz (big POS by the way) pipe with my Mac LTs both make similar sounds to what you describe.

 

[AquamanCHS]

I got a tune from Tim at Modular Ford Powerhouse, I assumed he knew what he was doing . I plan on getting a few dyno runs but I haven't had the time.

 

[bierbelly]

Any mail order tune is at best an educated guess. But if you were running lean, I'd expect that you'd be hearing pinging under hard acceleration too.

 

[Red35th]

Like bierbelly said, even the best tuner can't get a mail order tune perfect.

Put it on a dyn or borrow a wideband from a friend and check your a/f. If your a/f is good it's either an exhaust deal or the timing is too high.

Try putting in some 103 or 110 and see if it still makes the noise. No way you'd ping with that high an octane unless your a/f was WAY off.