B9.5 Delayed Boost (after exhaust/intake install)

[IgnoRS5]

Hey all,

I'm probably a little out of place as I'm not much of a "car guy" other than the enjoyment I get out of driving lol, so excuse any ignorance/incorrect terms.

I drive a 2021 RS5 Sportback, B9.5 - built in late '21

I recently upgraded my exhaust to Armytrix's catback exhaust, as well as APR's CAI

https://www.armytrixusa.com/armytrix...152573826.html
https://www.goapr.com/products/engin...parts/CI100042

After these were installed, I notice that often times when I go really heavy on the gas around 2nd gear, boost fails to initiate (gauge doesn't increase, just regular throttle) but if I let off the gas completely for even 0.1 seconds then re-pedal the boost initiates no problem.

I saw some threads on delayed throttle for various reasons, such as downshifting time delay in non-manual mode, but IME this doesn't have to do with waiting to downshift as I'm already in 2nd, and I also noticed this never happened until I installed the exhaust and CAI.

To my knowledge I've only experienced this with valves fully open (it's usually how I drive).

I thought maybe it has to do with too much air inflow or something? (Again, car ignorance here, I know nothing)

Thought maybe an ECU tune might fix things up, only to find out APR doesn't support late model b9.5 tuning on RS5 yet (?)

Anyway, does anyone have any theories on why this might be happening, or maybe how I can better narrow this issue down?

Thanks.

[bloodstar57]

ensure the clamps for the intake are tightly installed.

[IgnoRS5]

Just checked and the clamps do seem pretty secure, but I did notice that the "PCV connection" was a little loose when I softly jiggled it, not sure if that's normal?

From this step here: https://i.imgur.com/wWTuP5o.png

Not sure if this would be related at all? I can't seem to get the connection to be any tighter though, doesn't screw just kind of pushes on but pushing it on further does nothing and almost afraid it would break it if I push harder.

[bloodstar57]

Just checked and the clamps do seem pretty secure, but I did notice that the "PCV connection" was a little loose when I softly jiggled it, not sure if that's normal?

From this step here: https://i.imgur.com/wWTuP5o.png

Not sure if this would be related at all? I can't seem to get the connection to be any tighter though, doesn't screw just kind of pushes on but pushing it on further does nothing and almost afraid it would break it if I push harder.

So I would troubleshoot:
Run the engine and check for intake leaks.

put the intake back to stock and see what happens.

[Burrcold]

Are you actually feeling boost not coming on, or are you just going by the gauges? If you are going by the gauges, the exhaust can play games a bit since (I believe) it's no longer using the valves. I noticed something similar when I had the CETE controller and had the valves staying open all the time.

[IgnoRS5]

So I would troubleshoot:
Run the engine and check for intake leaks.

put the intake back to stock and see what happens.

Thanks, will try to do this when I can

Are you actually feeling boost not coming on, or are you just going by the gauges? If you are going by the gauges, the exhaust can play games a bit since (I believe) it's no longer using the valves. I noticed something similar when I had the CETE controller and had the valves staying open all the time.

Both, first it was just feeling the boost not coming on, and has actually been a bit risky since I drive anticipating reliable boost so when I merge or whatever and I accelerate like an '08 corolla it freaked me out haha, but now that I'm more aware of the issue I was checking the gauge as well which stayed at about 10% even with full pedal pushed.

---

Appreciate the responses so far and will continue to look into it and see what's up.

[Mav281]

Are you actually feeling boost not coming on, or are you just going by the gauges? If you are going by the gauges, the exhaust can play games a bit since (I believe) it's no longer using the valves. I noticed something similar when I had the CETE controller and had the valves staying open all the time.

Recently had my car mapped by a very reliable/trusted tuner in the UK (DMS Automotive) and was told I was not doing my car any favours in terms of performance by having plugs in the exhaust which left the valves open all the time. One of the first things they did was to remove the plugs, reconnect the exhaust valves and then remap the car with the valves in place.

This topic has been debated many times across many different forums with some suggesting that the valves on the exhaust are there for far more than just noise control and should not be unplugged, whilst others maintain that there is no difference in performance and you are safe to unplug the valves/delete them/pull fuses etc.

Obviously puts owners of non-valved exhausts in a bit of a pickle if it turned out that the valves are needed. Having said that, I can't say I've seen any definitive evidence to support either case, either way, but for the time being I'll be leaving my valves plugged in given that I'm happy with the results of my remap and the way the car now drives albeit it slightly quieter when not "fully on it".

[IgnoRS5]

Recently had my car mapped by a very reliable/trusted tuner in the UK (DMS Automotive) and was told I was not doing my car any favours in terms of performance by having plugs in the exhaust which left the valves open all the time. One of the first things they did was to remove the plugs, reconnect the exhaust valves and then remap the car with the valves in place.

This topic has been debated many times across many different forums with some suggesting that the valves on the exhaust are there for far more than just noise control and should not be unplugged, whilst others maintain that there is no difference in performance and you are safe to unplug the valves/delete them/pull fuses etc.

Obviously puts owners of non-valved exhausts in a bit of a pickle if it turned out that the valves are needed. Having said that, I can't say I've seen any definitive evidence to support either case, either way, but for the time being I'll be leaving my valves plugged in given that I'm happy with the results of my remap and the way the car now drives albeit it slightly quieter when not "fully on it".

With the Armytrix exhaust they have 3 settings, valves always open, always closed, and the hybrid (opens at X RPMs, as is standard AFAIK).

I guess I'll be trying out more hybrid driving to see if that has an effect. Thanks for the input.

[034Motorsport]

Hey all,

I'm probably a little out of place as I'm not much of a "car guy" other than the enjoyment I get out of driving lol, so excuse any ignorance/incorrect terms.

I drive a 2021 RS5 Sportback, B9.5 - built in late '21

I recently upgraded my exhaust to Armytrix's catback exhaust, as well as APR's CAI

https://www.armytrixusa.com/armytrix...152573826.html
https://www.goapr.com/products/engin...parts/CI100042

After these were installed, I notice that often times when I go really heavy on the gas around 2nd gear, boost fails to initiate (gauge doesn't increase, just regular throttle) but if I let off the gas completely for even 0.1 seconds then re-pedal the boost initiates no problem.

I saw some threads on delayed throttle for various reasons, such as downshifting time delay in non-manual mode, but IME this doesn't have to do with waiting to downshift as I'm already in 2nd, and I also noticed this never happened until I installed the exhaust and CAI.

To my knowledge I've only experienced this with valves fully open (it's usually how I drive).

I thought maybe it has to do with too much air inflow or something? (Again, car ignorance here, I know nothing)

Thought maybe an ECU tune might fix things up, only to find out APR doesn't support late model b9.5 tuning on RS5 yet (?)

Anyway, does anyone have any theories on why this might be happening, or maybe how I can better narrow this issue down?

Thanks.

Shoot us an email at [email protected] - we may be able to help you out with a tune ;)

-Sean@034

[O&G]

I had the same exact issue after I installed my CAI and Kline Exhaust. Took it to Audi, let them run through it and it still had delayed boost sometimes. It felt like the wastegates were not opening and I would have to double pump the gas in order to get the car into boost. It's actually pretty dangerous. The car has now seemingly fixed itself. I have not had the issue again in some time. Regardless, I'm looking to get the car tuned, but unfortuyanlty my ECU model can not be flashed by a dealeer, I have to send it in to APR.