Sounds like exhaust leak.... is it ping?

I did a little intake tinkering (starting on my cai/fwi but it's incomplete) and went for a ride today. Under light load in OD, I hear something that sounds a lot like a leaky exhaust manifold, but with hood up, revving throttle, there's no leak.
Is this dreaded detonation? I know, I know.. get a scanner. I'm working on that... but can detonation sound like an exhaust leak?

I saw no significant increase or decrease in power, just an increase in SC whine with the modified intake (I've not done a good job isolating engine bay air away from the filter, so I'm probably running a warmer AI right now... just tinkering with the mock-up design right now)...

I'm just curious if ping/knock can sound like an exhaust leak.
Thanks ya'll!

It absolutely can sound that way, depending on who's listening. An exhaust leak is more predictable, though, and it comes on gradually. If this is happening only some times, or if it seems to come on all of a sudden, it could be knock. To me, Audible knock sounds like a sharp banging on metal, easier detected at low RPMs, because it isn't particularly loud. You can hear it best next to a wall or guard rail.

What octane fuel are you using? What year is your car? Stock?

'98, stock aside from intake tinkering, 92 or 93 (depending on station) octane and I never buy 80/20 gas.

I don't hear the sound under hard acceleration, only under light acceleration at/around 1800rpm while in overdrive. I also put it in first and rode the brake to put a light load at 2k rpm and also heard the sound. It really sounds like a single cylinder noise, not like rattle knock I've heard in older cars on a hot day going up a steep hill.

I don't think you're hearing knock. It shouldn't happen in a torque brake situation like you're describing. Could be a vibration, or a lifter?

Could be that your filter is rattling around , and idk i think engines tend to make a lot of vibration under torque converter lockup. Mine makes some noise under light throttle in OD, And FWI FTW! I basically stuck a pvc elbow to the stock intake tube and ran a filter from that into the fenderwell and i noticed an increase in power that i wasn't really expecting and that was going from a gutted airbox w/KN drop in to my setup now with a cheapo cone filter. Best part about mine is it only cost a little over 30 bucks when all was said and done. And the whine is amazing.

Now that I remember, I had a vibration similar to yours a couple years ago. It was the heat shield around the exhaust. Got under the car with a pair of pliers, put a bend in the shield. No more noise.

One of the things I find helpful to track down these little things is a stethescope. You can listen during idle to all the various things and rule out a leak pretty easily.

Another thing to keep in mind is if you have a leak, you'll usually see the black carboning effect around the joint that is leaking.

Aaron, when I say "brake torqued", I don't mean heavy throttle, just enough to simulate the load in the same RPM range as when in OD. (to keep the car at the same speed and not accelerate)

It's possible that it's a vibration, but it sounds soooo "ping-ey/chuffy" like a manifold leak on one cylinder... but again.. I've listened under the hood at idle, light throttle and then revving situations and I don't hear it...

I'm definitely going to finish the FWI install soon and I'm going to be sure to use at least 2 rubber couplers to allow for engine mount flex

Bill, I'll second that suggestion to use a mechanic's stethoscope to find most rattles, knocks and vibrations, but it's not easy to do at 45mph.

Got another question I'm going to put in another thread... see ya'll there

The load experienced by the car in 1st gear vs. in OD are vastly different, even though the RPM is the same. You are in fluid couple when brake torquing, but at a 1:1 lock-up in OD. Brake torquing at 2kRPM is not enough load to create knock. OD at 2kRPM is more than enough, especially if going uphill.

If it's the same sound heard in both situations, it's most likely not knock; that's a good thing!