FL5 stock exhaust valve: Fuse pulled/always open - exterior sound clips

[SoulsKind]

Thanks for the guidance! Worked like a charm. Already love the slight deeper tone.

Will keep an eye out for the possible stuttering/lower rpm but don't think I'll notice much being in CA heat wave currently.

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[TypeRGirl]

That is so frustrating, hope you get to the bottom of it shortly. It is definitely a rotational issue, springs wouldn't cause that sound. Just like the dealership to blame it on that though. Recently got charged $200 for diagnostic fee due to a blown Options fuse in the interior fuse box. They blamed it on the exhaust valve fuse I removed in the engine bay fuse box...

(Copied this fr another thread) Can you elaborate more on this? How was the car presenting that made you take it in for a diagnostic? Was it drivable? I recently pulled my fuse and so far so good but this concerns me bc my FL5 is my daily.

 

[Bazgab]

(Copied this fr another thread) Can you elaborate more on this? How was the car presenting that made you take it in for a diagnostic? Was it drivable? I recently pulled my fuse and so far so good but this concerns me bc my FL5 is my daily.

You are all good, I wouldn't worry. The car was drivable, there were just some warnings, mostly for the Hondasense systems. It just put me in default options as far as drive mode customization. Had I known it was a fuse it would have been a 5 minute fix.

There is zero interaction between the exhaust valve fuse and the interior fuse box as far as I am aware in my cursory inspection of the fusing/wiring in this car. I only posted to illustrate how full of shit dealerships can be.

The tech also said something to the effect that "looks like your car has been in some sort of front end collision...". No basis in fact and there is no physical damage to my car. They only said it due to the "missing" fuse and some "messy" wiring under the dash. I have never opened up the interior dash under the steering wheel where the interior fuse box is so it is however it arrived from the factory. I am escalating my issue to Honda corporate but not holding my breath.

 

[TypeRGirl]

You are all good, I wouldn't worry. The car was drivable, there were just some warnings, mostly for the Hondasense systems. It just put me in default options as far as drive mode customization. Had I known it was a fuse it would have been a 5 minute fix.

There is zero interaction between the exhaust valve fuse and the interior fuse box as far as I am aware in my cursory inspection of the fusing/wiring in this car. I only posted to illustrate how full of shit dealerships can be.

The tech also said something to the effect that "looks like your car has been in some sort of front end collision...". No basis in fact and there is no physical damage to my car. They only said it due to the "missing" fuse and some "messy" wiring under the dash. I have never opened up the interior dash under the steering wheel where the interior fuse box is so it is however it arrived from the factory. I am escalating my issue to Honda corporate but not holding my breath.

Okay thanks for sharing. I was so confused how pulling the exhaust fuse could cause an interior fuse to blow

Lol, that tech was really reaching for an answer with that diagnostic!

 

[sashimi]

I put my fuse back in last night. I've noticed a few quirks during cold start driving that could be attributed to the valve being open. There has to be a reason Honda kept the valve closed at low RPM in +R mode since even with it open it's not that loud. On cold starts all of the exhaust is coming out of the center pipe which could change the flow and the car is trying to compensate.

This is all a theory and I'll report back after some more driving.

Went back and forth many times with the valve fuse pull. I can safely say hesitation and stuttering is intermittently present setting off in 1st when the valve is always open. Maybe something different is done on the ITS to mitigate this when the valve is always open in sport+ mode. This isn't rocket science. The valve is there to help the weak exhaust flow at low rpm against atmospheric pressure. At the end of the day, if anyone deems the sound gain is worth it over the slight low rpm struggle, it shouldn't cause any significant issues in my mind

 

[TypeRD]

@sashimi Yes, this all makes perfect sense. Question : Could running the valve always open, on the stock exhaust, cause excess buildup in the catalytic converter? I’m thinking it could, potentially, since the exhaust isn’t getting pushed out as intended (at startup and low RPMs).

 

[CTRifecta]

I've been running flap open permanently for 4,000 miles now, no issues at all. Only thing you get used to is a little more exhaust soot on the center pipe.

Honestly it's still way too quiet with me with the flap open, but it's better then nothing and free.

 

[Tickle]

I decided to put the fuse back in. I have followed this topic but I didn't think I had any issues to be honest.

I had moments every now and again where I felt hesitation. Twice I felt like... did I just drop my clutch?

Now that the fuse is back in... call me crazy but I feel like the car is happier for it. There is a smoothness that I didn't notice I lost but now that the fuse is back in, it feels like a welcome addition.

Could be all in my mind but I'm certainly convinced.

 

[sashimi]

I decided to put the fuse back in. I have followed this topic but I didn't think I had any issues to be honest.

I had moments every now and again where I felt hesitation. Twice I felt like... did I just drop my clutch?

Now that the fuse is back in... call me crazy but I feel like the car is happier for it. There is a smoothness that I didn't notice I lost but now that the fuse is back in, it feels like a welcome addition.

Could be all in my mind but I'm certainly convinced.

This isn't just you. I've said this before, the car is just easier to operate with the valve functioning as intended. This car does not stall if you let out the clutch slowly without any gas. However, the engine judders and begs for life with the fuse pulled. The exhaust is simply having trouble overcoming the atmospheric pressure when trying to exit through the center pipe with the valve open at low RPM. This might not be as noticeable for those to punch throttle past 3K RPM when setting off in 1st or reverse. In the end, the engineers knew what they were doing, and claiming otherwise is just placebo effect. What extra sound you get is nice though. No right or wrong here really.

 

[Jester04]

This isn't just you. I've said this before, the car is just easier to operate with the valve functioning as intended. This car does not stall if you let out the clutch slowly without any gas. However, the engine judders and begs for life with the fuse pulled. The exhaust is simply having trouble overcoming the atmospheric pressure when trying to exit through the center pipe with the valve open at low RPM. This might not be as noticeable for those to punch throttle past 3K RPM when setting off in 1st or reverse. In the end, the engineers knew what they were doing, and claiming otherwise is just placebo effect. What extra sound you get is nice though. No right or wrong here really.

The valve is there only for sound. There is no mechanical advantage for the engine with the valve closed. FK8 did not have a valve and it was fine. Also no issues overcoming atmospheric pressure. Those experiencing shuddering I would look more towards the tune in the ECU. I won’t have more data until I get the hondata software but will post results when I have them.

 

[sashimi]

The valve is there only for sound. There is no mechanical advantage for the engine with the valve closed. FK8 did not have a valve and it was fine. Also no issues overcoming atmospheric pressure. Those experiencing shuddering I would look more towards the tune in the ECU. I won’t have more data until I get the hondata software but will post results when I have them.

if the valve is strictly there for sound, I need you to explain why the car wants to almost stall with the valve open.

 

[Jester04]

if the valve is strictly there for sound, I need you to explain why the car wants to almost stall with the valve open.

Mine does not stall at all. No hesitation or shudder, the FK8 is the same powertrain similar exhaust and no valve. Its there for sound since all the back pressure you need is at the turbo. Now saying that, I think some people might be getting stuttering or shudder but I’m suspicious of other things like fuel quality, or maybe tune related. No way to check unless you can monitor fuel trims, tps and other things.

 

[CTR]

The valve is there only for sound. There is no mechanical advantage for the engine with the valve closed. FK8 did not have a valve and it was fine. Also no issues overcoming atmospheric pressure. Those experiencing shuddering I would look more towards the tune in the ECU. I won’t have more data until I get the hondata software but will post results when I have them.

You're making some pretty broad statements about the valve that mean nothing unless you have inside information from an engineer at Honda.

Many of us have reported MINOR issues when the valve is kept open. It is most likely there for emissions reasons which would explain the stalling or hesitating in cold start conditions only. The sound is barely different with the valve open and makes no sense that it opens in ALL modes if it's strictly there for sound.

You are also located in a warm climate just like the guy who argued with us last time. Maybe your cold starts aren't as bad as some of us that live in seasonal climates. Do whatever you want with your car but don't make statements that are completely untrue. It gives bad info to others in the community who might not have read the earlier posts in this thread.

 

[Jester04]

You're making some pretty broad statements about the valve that mean nothing unless you have inside information from an engineer at Honda.

Many of us have reported MINOR issues when the valve is kept open. It is most likely there for emissions reasons which would explain the stalling or hesitating in cold start conditions only. The sound is barely different with the valve open and makes no sense that it opens in ALL modes if it's strictly there for sound.

You are also located in a warm climate just like the guy who argued with us last time. Maybe your cold starts aren't as bad as some of us that live in seasonal climates. Do whatever you want with your car but don't make statements that are completely untrue. It gives bad info to others in the community who might not have read the earlier posts in this thread.

Ok, let me break it down for you since you are accusing me of making untrue statements.

First of all when I joined here was to share knowledge and bring the platform further if I can even in the smallest way. I would never make a false statement or something to steer people in the wrong direction. With that being said I do have a background in ECU programming on street cars and race cars. I have seem some crazy stuff even on oem cars tune wise. Without being able to monitor these parameters I dare not go further with a explanation for the hesitation. I do have a suspicion that it will be tune related since cold start follows a very specific sequence that makes cars run at higher idles and rougher due to cam timing retardation, cranking fuel etc.

Now when I say the valve is there for sound, its just one of its functions. Its there for a cold start to act as a harmonics cancelation of certain frequencies. Not for actual sound since the type R is terribly quiet even with the valve open. If you look at valve placement there is enough space in the tube for the exhaust gases to smash into the valve and bounce back to cancel these pulses that cause unwanted frequencies. Look up hemholtz resonators if in doubt. The other function is to maximize flow for performance by reducing restriction so power can be more efficiently extracted.

Another point that points toward my suspicions which for the shuddering to be tune related. The FK8 had the same problem. Where is the valve in that car?

Tagged this so you can have some proof that its a prevalent issue even on previous gen. I never dismissed anybody’s claim that its not a problem. No I do not live in a colder climate, I’m not spewing misinformation.
https://reddit.com/r/Civic_Type_R/s/3ScMoh2S82

You do what you want with your car, I’m just saying that the chances of the valve being the cause of it is so minuscule its almost negligible. Now for more “untruthful” statements, that reinforce my belief that its software related. Ok showing on colder climates, not showing on warmer climates. How does the valve affect startup on the engine? It doesn’t. What does get affected by temperature is how the software calculates the startup. The tables there will reference certain values depending on temperature to make the calculations for how much fuel it will need to start the car. Fuels now a day even include ethanol which even makes the variations bigger since there is just an estimation of how much ethanol can be in a fuel. The FL5 does not have a ethanol sensor to make changes on the fly for fuel calculations.

If this is not a coherent statement, or if any of this seems untrue then feel free to ignore it. Instead of assuming its the valve, why don’t we come together as a team? Report where its happening if its more prevalent in colder conditions. Gather data, when people start getting Hondata we can monitor some parameters and maybe come up with an answer. I just gave a very general explanation and sorry if you felt it was being untruthful.

And I will leave it at that. Don’t be a smartass and have a normal conversation. Don’t make statements as bold as saying a comment is untrue if you have not asked for a explanation from a person, we can discuss it as peers of the platform in a respectful manner.

 

[CTR]

We're trying to tell you that multiple people (myself included) noticed some weird cold start behavior after keeping the valve open. When the valve is open a vast majority of the flow goes through the center pipe. You can see it for yourself if it's cold enough that all of the exhaust is coming out of the center pipe instead of the 2 side pipes.

• Maybe they were forced to add the valve to comply with emissions as the cold start is monitored heavily by the government? How quickly the catalytic converters warm up is critical for complying with emissions so a change in exhaust flow could definitely have an impact.
• If the flow of the exhaust has changed and the software cannot compensate for it this may lead to the feeling of stalling or shuddering.
• Your theory of it canceling out drones at cold start is a good one - that could be part of it too.

I don't know what the root cause of the difference in driving characteristics. I'm just saying it is happening. You are arguing telling us it makes no difference or we are imagining it or something. I made the decision to my fuse back in and keep the car running as well as it can.

There was a noticeable difference before and after. Maybe the ECU can learn around it but I wasn't willing to wait and see for no actual benefit.

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