Exhaust back pressure?

[Jlai14]

Just got my baby resonators replaced with MF 11385 and deleted big res. Yes it sounds good for the cost but I feel my throttle response has suffered. It’s not as quick to get torque kicked in and overall the slow feels more sluggish. Anyone else have this problem, does it have to do it back pressure?

[JKoehle]

https://youtu.be/jjPeP_Nn2B4

[kelseysautobody]

Nothing happened to your throttle response. There is just more noise associated with smaller throttle input and your brain is thinking you should be going faster than you are.

[JACKAL]

The only time I noticed reduced throttle response when I was messing with my exhaust was when I briefly eliminated the large center resonator with straight pipes and didn't have any sort of x-pipe in the system. The scavenging and pulse-balancing impact of an x-pipe is significant. The 11385 is an X though so there shouldn't have been any loss of performance.

[Jlai14]

I also did large res delete with the X pipe, a lot of people are saying it’s in my head but I know my car and the thing is a lot more sluggish!

[onlyaudis]

I also did large res delete with the X pipe, a lot of people are saying it’s in my head but I know my car and the thing is a lot more sluggish!

I have had this happen before on some older cars where a small change in the exhaust altered the throttle feel significantly . i added a straight through small rear muffler in place of a straight pipe on an old Alfa to try and quiet it down a little, & it killed the power. The muffler shop had no clue why it would do that. It felt like I had an obstruction in the exhaust. took it off and the power came right back. On the same car, putting a better resonator right after the manifold quieted it down and did not affect the power feel at all.

exhaust tuning is a black art IMO, and sometime its just trial and error to get it right on a given car and tune. lots of variables!

[Jlai14]

I have had this happen before on some older cars where a small change in the exhaust altered the throttle feel significantly . i added a straight through small rear muffler in place of a straight pipe on an old Alfa to try and quiet it down a little, & it killed the power. The muffler shop had no clue why it would do that. It felt like I had an obstruction in the exhaust. took it off and the power came right back. On the same car, putting a better resonator right after the manifold quieted it down and did not affect the power feel at all.

exhaust tuning is a black art IMO, and sometime its just trial and error to get it right on a given car and tune. lots of variables!

Yeah this is the second time it’s happened to me I had an axel back on my old car and it made it feel so unresponsive. Reason why I got the s4, I feel like if I added the resonator back it would help but I would lose a lot of the sound. Such a headache

[mys4.org]

I have the exact same exhaust setup as the OP and I can't not report the same results in throttle. It felt exactly the same before and after.

Either your exhaust shop blocked the pipe some how or it is in your head. I have heard of the filler in magnaflows coming out of the exhaust as they get old. Is the 11385 new? Maybe ask them to take that out and check the flow if you are super concerned. Or I guess you can drop the entire exhaust, shine a super bright flashlight and see if any light shows on the other end. If there is light passing, then you got flow.

You could also discount your battery and allow your car to re-adapt as another option. Just shooting out ideas here....

[doughboy17]

exhaust tuning is a black art IMO,

LOL So true!

[Jlai14]

I have the exact same exhaust setup as the OP and I can't not report the same results in throttle. It felt exactly the same before and after.

Either your exhaust shop blocked the pipe some how or it is in your head. I have heard of the filler in magnaflows coming out of the exhaust as they get old. Is the 11385 new? Maybe ask them to take that out and check the flow if you are super concerned. Or I guess you can drop the entire exhaust, shine a super bright flashlight and see if any light shows on the other end. If there is light passing, then you got flow.

You could also discount your battery and allow your car to re-adapt as another option. Just shooting out ideas here....

I was watching him out on the whole setup no blocks or anything in the piping/xpipe. The 11385 is brand new and the welds looked super solid so I don’t think there are any leaks. Maybe it is in my head but the difference feels enough for me to just go back to stock lol

[mys4.org]

What about your cats? Still stock? It could just be by chance they went bad around the same time and restrict flow. Check the tips for metallic dust.

[TFSI]

as far as I know, our OEM exhaust system is almost full straight through system. Just a lot of resonated areas. Shouldn't affect performance. Like others stated, could be your brain or catalytic converter is going bad.

[Jlai14]

as far as I know, our OEM exhaust system is almost full straight through system. Just a lot of resonated areas. Shouldn't affect performance. Like others stated, could be your brain or catalytic converter is going bad.

It’s weird i am getting a weird smell out of exhaust which I thought that was xpipe. I’m only stAge 1 at 37k miles so I doubt it could be the cats

[GID]

I am a firm believer that there is more to it and it's not in your head. I experienced a very similar Lack of throttle response when replacing my exhaust. I also had some drone to go with it so I used a pair of the auger style resonators and placed them Inside of my vibrant ultra quiets, which were put in place of the baby res. It killed the drone and also gave me some of the trottle response I felt was lost.

I have a full custom mandrel bent pipes from the cats back. In line are a pair of vibrants to a magnaflow resonated x, then to awe mufflers.

Sent from my 6060S using Tapatalk

[brs2c]

Did you change anything else at the time of the exhaust?

As others have said there is no way these changes hurt your performance. However, that’s not to say that you are delusional, as there could be some other issue working here...our jump in temps here in TN has me wondering where my power went, lol.


Sent from my iPhone using Audizine (http://r.tapatalk.com/byo?rid=87676)

[Legion]

Just run open head and you'll be fine.

[GID]

Did you change anything else at the time of the exhaust?

As others have said there is no way these changes hurt your performance. However, that’s not to say that you are delusional, as there could be some other issue working here...our jump in temps here in TN has me wondering where my power went, lol.


Sent from my iPhone using Audizine (http://r.tapatalk.com/byo?rid=87676)No other changes at that time. No issues at the time.

Sent from my 6060S using Tapatalk

[Jlai14]

I have a feeling the center res delete is what is causing this throttle response problem I’m wondering if adding another 11385 or an ecs xpipe will help the airflow

[kelseysautobody]

I have a feeling the center res delete is what is causing this throttle response problem I’m wondering if adding another 11385 or an ecs xpipe will help the airflow

This is all in your head but go for it man. Adding a second 11385 will just quiet the exhaust down to basically stock levels with a different tone. That might bring the perception of noise to throttle response back to where it was before you altered the exhaust.

Or just go stage 2...

[hellovaras]

https://youtu.be/jjPeP_Nn2B4

I really appreciate those videos. That dude is really smart. I should have paid more attention in school.

[Envy187]

I really appreciate those videos. That dude is really smart. I should have paid more attention in school.

+1.

I love the Caucasian Blueface's videos. He's got a great review of our S4 as well. [up]