I had my Joez exhaust installed a few months ago. Since then, I've noticed that the engine revs about 100 rpms or so whenever I gently put my foot back on the accelerator pedal after engine braking.

After the surge, if I take my foot off the pedal again and gently get back on it, the engine doesn't rev. I would have to give the car a little bit of gas and start over again. Surprisingly, the throttle blip doesn't happen when I gently get back on the gas immediately after coasting for that second or so before the car starts to actually slow down via engine braking. I would have to wait for the engine braking for the throttle blip to occur.

The car doesn't noticeably surge forward, but because the exhaust is now much louder, I can clearly hear the slight throttle blip (and see the tachometer needle jump).

Is this normal? Or is this some sort of back/after-fire or exhaust leak?

Thank you in advance for any feedback.

 

.... Everything is normal.....Enjoy the F and the Joe Z exhaust, lol.....!

V.

 

Completely normal, my borla/bazooka does it too. It surprised me too when I first put it on.

 

Thank you to you both for the quick replies; glad to know it's normal.

What are the mechanics behind it? Is because of the deleted secondary cats? I'm not too familiar with automotive design. Sorry for the newbie questions...

 

The torque converter unlocks when you let off the gas so when you reapply throttle the rpms will jump up until it locks again. It did the same thing before exhaust you just couldn't hear it. All is good. Now you jneed some headers so you can hear the 6 to 5 rev match downshift in all its glory.

 

^^ that 6 to 5 rev match is no joke

 

Headers are probably not in my future. If I was considering it, I would've just bought the Borla to save $500.

Anyways, I also noticed that the throttle doesn't blip in F mode. Is it because in F mode, there's 100% lock-up in gears 2 thru 8?

 

it should beep if you are in manual mode for sure once you hit the rev limit, just out of curiosity is the sound from the exhaust like a little hiccup?

 

Beep? I'm not referring to the audible shift notification by the car.

It's not a hiccup. It sounds exactly like revving the engine. Perhaps 50 rpms, not 100.

 

I checked out the car again, and it actually does blip in F mode, but not as pronounced and as often. Actually, quite infrequent.