Will PL show ign problem?

[87NAT]

This is going to sound crazy. My car has a popping sound out the exhaust at WOT. I thought it was the old Pitbull mufflers I had on there getting worn out so I changed them to Magnaflows. The car does the same thing. This does not sound or feel like an ignition or fuel miss. The PL numbers are great across the board. The car pulls like a bat out of hell. It just has this sound out of the exhaust that is it never did before with my old combo. Maybe thats how its supposed to sound. Its almost like the flow of air is straining to get out of the tail pipes but it cant do it fast enough. I dont believe it is a real miss because I have had problems with miss/sputter/popping over the years and it is not the same. It could just be how this ATR SS dual system sounds. Anyway back to the question. If I did have a FP-lean issue or an ignition problem would PL pick it up? I have the the FP logged and it is rock steady at 67 psi the whole time under WOT.

 

[87NAT]

Just read some old threads. Could this be exhaust pulses making this noise?

 

[Topjimmy]

If I did have a FP-lean issue or an ignition problem would PL pick it up?

Yes it will by affecting the many parameters it can log: IDC, AFR, Knock etc. The power pass you describe will be a great benchmark for tuning and troubleshooting in the future.

Assuming no major vacuum leaks causing a miss at idle (recorded if you are logging Boost/Vacuum on PL) and considering how low the back pressure is with the ATR/Magnaflow system is it seems you've hit it exactly; exhaust pulses. Those `Flows look like a steel pack hi-po muffler from the 60's inside but they've taken off the ragged-edge sound of the old-school cans. You could change the tone with an electric cutout opened to whatever your aural taste is but I think it will still pulse.

Can you post or send your doc. file? Sounds like a clean pass, I'd like to review it.

- Jimmy

 

[87NAT]

Here is my Pl file from a 40 mph to 90+ mph run on the street.

 

[87NAT]

Here we go. Still figuring out files and such for posting on the computer:redface:

 

[notacarlo]

I think it's fair to say that it is the exhaust "pulse". Kinda like an old Ford pickup with glaspacks, just not as loud.

I have no muflers and a 3.5" pipes aft of the downpipe. I hear it too, and I like it.:biggrin:

 

[87NAT]

I think it's fair to say that it is the exhaust "pulse". Kinda like an old Ford pickup with glaspacks, just not as loud.

I have no muflers and a 3.5" pipes aft of the downpipe. I hear it too, and I like it.:biggrin:

I was kinda sure thats what it was but I just wanted to ask.

 

[Topjimmy]

87NAT, Looking sweet! Nice 23/24 psi power pull. I saw a bit of knock at @ 56 MPH (max 2.1 deg.) just as the RPM dropped from the shift. False knock? Shift flare? Other than that; Zero knock anywhere. Narrow band O2s in the 700's would freak out most racers even a few years ago but your wide band AFR is solidly in the 10.50 - 10.60's. Looks like a great tune with good quality parts & accurate sensors.
Next let's see some track passes with ET and more .DATs!

Thanks for sharing,

-Jimmy

 

[87NAT]

Thanks Jimmy. My track does not start test n tune till October.:frown: Looks like I will have to wait till then.