930 Exhaust sounds like a fart - Help

[T77911S]

WG opening?

I could not hear any farting on vid.

[JFairman]

The exhaust and motor sound in the video sounds normal to me.
I don't know what you mean by the exhaust sounding like farts.
Human farts can sound like anything from a little squeak to a huge FRABALADAPPP...

If you're talking about the popping in the exhaust during deceleration that's totally normal from a 930 or 911 turbo with the original CIS fuel injection.

I believe 930 deceleration exhaust popping is caused by unburned fuel exploding in the primary tubes of the exhaust headers during deceleration.
There is some unburnt fuel in the exhaust during deceleration because Bosch K-Jetronic or CIS (Continuous Injection System) is an old mechanical fuel injection system that was a compromise and far from perfect. It's air fuel mixture never stops spraying some fuel if the motor is running and it leans out a lot during closed throttle deceleration.

[HamiltonSeth]

Thank you all for the continuous feedback.

The noise is definitely not rubbing.

I am not trouble shooting the deceleration popping as it sounds great - A sound I know and love. I am talking about the Honda with a cheap muffler sound that comes about when on boost. This sound was there before and after the fabspeed exhaust, just now louder with the exhaust. The video I took did a poor job of catching the sound, perhaps I will have someone film from outside the car.

I will start to really dig into it and figure it out.

[clutch-monkey]

swap out a muffler and see if it's still there?

[HamiltonSeth]

Originally Posted by clutch-monkey

swap out a muffler and see if it's still there?

It was there with the OEM muffler and still there with fabspeed

[kevinbodman930]

I hear it.It almost sounds like a excaust leak.By chance are you running the stock headers?if so they could be cracked.I dont think it broken head studs.Do you have a way to put her up in the air?to check for cracks or even loose excaust manifold?

Sent from my SM-N950U using Tapatalk

[JFairman]

If you check that the exhaust header nuts are tight and any of the nuts turn and don't become tight the exhaust port stud threads in the heads are stripped.
If the female threads in the head are pulled or stripped an 8 x 1.25mm time-sert can fix it and make the threads stronger than they were because they are hardened steel instead of aluminum.
https://www.amazon.com/Time-Sert-M8x1-25-thread-repair-1812/dp/B01MSPN7NH
ebay has them too.

[JMS935]

I’ve been following this thread wondering what the answer is to the farting noise, which btw, I don’t hear. Those that do must have some well trained ears. Hopefully it’s nothing major like head studs.

I never realized how much I need a trunk monkey, that little guy is great!

[porschyard]

+1 trunk monkey, everyone should have one, world would be a safer place
+1 head studs

[krasuskyp]

OEM headers?

sounds just like Jacob's old car w/ SSI's and RL8 muffler IMO - mine w/ OE and then Powerhaus headers and RL8 muffler sounded entiiiirely different than his... his had that distinct vroooom sound like yours

if OEM, then yeah I'm guessing maybe manifold leak @ flange?

[Dominik 930]

the sound of the exhaust is really nice !!
The sound is certainly a metal that vibrates.
Have you already checked the heat shield...

[Mocker]

Originally Posted by JMS935

I never realized how much I need a trunk monkey, that little guy is great!

Anybody know where I can get a frunk monkey?

[1979-930]

I do hear some sort of noise that is timed with the exhaust. It sounds like a metal vibration. I would look for something that is close to touching, cracked or loose. I may take the torque of the engine to make the two pieces touch and make the noise.

I did have the intercooler charge pipe slightly out of position where it would rub on the body, near the engine mount, and make a similar noise. But mine made the nose at idle not boost.

[HamiltonSeth]

I figured out the issue. It was a small crack on the headers, small enough to only make the sound while under boost. New fabspeed setup going on soon. Problem solved, thank you all for the help!

[djb25]

Thank you for giving the update. I just read through this thread and was worried there would be no conclusion. Glad you figured it out.

[ljpviper]

I put the Fabspeed supercup on my 89 930, love the sound. Very happy with it.I had a stock muffler with a Fabspeed cat delete prior. I am going to list the cat delete on the parts classified this week.

Thanks,

Larry

[RarlyL8]

Want headers guaranteed not to crack? Produced by a 20+ year Pelican member. 321 stainless, TIG welding, and a proper tuned design that also helps reduce boost creep.



And if you want to shave 20 pounds off the rear with a choice of 3 sound levels and 4 tailpipe configurations, also in 321 stainless and guaranteed never to crack this is the ticket.

[Alan L]

Brian, your work is superb. I have your headers (and zork) on my track beast (7+ yrs now at least).
No issues, and only run at WOT basically. And nice to perv at under the car.
Alan

[93097004xx]

Originally Posted by RarlyL8

Want headers guaranteed not to crack? Produced by a 20+ year Pelican member. 321 stainless, TIG welding, and a proper tuned design that also helps reduce boost creep.







And if you want to shave 20 pounds off the rear with a choice of 3 sound levels and 4 tailpipe configurations, also in 321 stainless and guaranteed never to crack this is the ticket.

I know absolutely nothing about exhaust but that is art work, beautiful.

I wish porsche would have conceived beautiful artistic exhaust like this.




Sent from my iPhone using Tapatalk Pro