NPP fuse pull trick/result
Thread Starter
Drifting
Joined: Jun 2007
Posts: 1,425
Likes: 238
From: Macomb MI
Originally Posted by runutzzzzz
How about just selecting "OFF" in the Engine Sound Management setting?
It's off all the time except when in V4 mode which I'm sure sounds like crap anyways.
It's off all the time except when in V4 mode which I'm sure sounds like crap anyways.
The only issue is #3 in my original post. There are certain conditions even in "OFF" when the NPP valves close independent of driving mode. That's been my experience in 2 different M7 NPP cars.
It was also an experiment to see what happened.
Last edited by xp800; Mar 21, 2014 at 10:59 PM.
Tech Contributor
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From: Saint Louis MO
St. Jude Donor '14-'15
Building on your statement there, though, we're also aiming to remove the tip-in required to open the valves (1700-2000rpm mark) in the different modes.
It sounds like, if I'm reading your post correctly, the valves stay open, but not until 1700+ rpm when the setting is set to "OFF". This would allow them to remain open constantly.
Le Mans Master
Joined: Oct 2004
Posts: 8,615
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From: Haymarket Virginia
That's how I have mine set, and it does what it's supposed -most- of the time meaning NPP open independent of driving mode.
The only issue is #3 in my original post. There are certain conditions even in "OFF" when the NPP valves close independent of driving mode. That's been my experience in 2 different M7 NPP cars.
It was also an experiment to see what happened.
The only issue is #3 in my original post. There are certain conditions even in "OFF" when the NPP valves close independent of driving mode. That's been my experience in 2 different M7 NPP cars.
It was also an experiment to see what happened.
Experiment away! I was just curious to see if I was missing something.
Tech Contributor
Joined: Jan 2006
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From: Saint Louis MO
St. Jude Donor '14-'15
xp800, if you feel like you want to pull the fuse(s) without the CELs, I can point you in the right direction to make that happen. Just not sure if you're liking having them open all the time, hence the idea you gave me.
Thread Starter
Drifting
Joined: Jun 2007
Posts: 1,425
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From: Macomb MI
Originally Posted by runutzzzzz
Mine does the same thing, especially in 4th gear at low RPMs.
Experiment away! I was just curious to see if I was missing something.
Experiment away! I was just curious to see if I was missing something.
I notice it just as you describe. Typically 3-4 upshift at low RPM or lugging the engine until past 1700 RPM almost exactly. Then the valves pop open and let the music out.
I will say that I noticed a bit more boominess in the low RPM tip-in/lugging when the fuse was out. So I think I get why the GM development/NVH engineers may have wanted to reduce this by closing the valves in this condition. That said, I almost preferred it since it gave me better feedback.
It would be great to get more thoughts on the NPP (really) off sound from others. So go pull #41 folks. Then when Theta comes up with his magic NPP^2 box, we will all want it and we'll get it on a group buy.
Thread Starter
Drifting
Joined: Jun 2007
Posts: 1,425
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From: Macomb MI
I am going to drive around more without #41 to see if there are any downsides I didn't notice. Provided there aren't, your anti-CEL solution would be great in the near term.
Eventually your "open source" solution would be the way to go if I add the headers I've been thinking about. Then a quiet switch really matters.
Tech Contributor
Joined: Jan 2006
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From: Saint Louis MO
St. Jude Donor '14-'15
I need to call Littelfuse on Monday to check on the Micro2 LEDs. I'm not sure if they're in production yet, as I don't see them in the Digikey catalog. Here I was hoping we had Micro, but nope - pulled 41 and it's a Micro2.
Doesn't affect the circuit design, at least.
If you're handy with electronics or EE, you're simply going to a) blow the fuse, and then b) solder a 12v 200ma surface mount LED to the two top exposed fuse posts.
If you're not into that, I can either make you one once I test it, or find out if they're being made yet.
Doesn't affect the circuit design, at least.
If you're handy with electronics or EE, you're simply going to a) blow the fuse, and then b) solder a 12v 200ma surface mount LED to the two top exposed fuse posts.
If you're not into that, I can either make you one once I test it, or find out if they're being made yet.
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Thread Starter
Drifting
Joined: Jun 2007
Posts: 1,425
Likes: 238
From: Macomb MI
I need to call Littelfuse on Monday to check on the Micro2 LEDs. I'm not sure if they're in production yet, as I don't see them in the Digikey catalog. Here I was hoping we had Micro, but nope - pulled 41 and it's a Micro2.
Doesn't affect the circuit design, at least.
If you're handy with electronics or EE, you're simply going to a) blow the fuse, and then b) solder a 12v 200ma surface mount LED to the two top exposed fuse posts.
If you're not into that, I can either make you one once I test it, or find out if they're being made yet.
Doesn't affect the circuit design, at least.
If you're handy with electronics or EE, you're simply going to a) blow the fuse, and then b) solder a 12v 200ma surface mount LED to the two top exposed fuse posts.
If you're not into that, I can either make you one once I test it, or find out if they're being made yet.
Ironically in all of this, if the NPP off really meant off, all this would be moot. Then we would have quiet and loud, plain and simple.
So I look forward to the T-Box!
Tech Contributor
Joined: Jan 2006
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From: Saint Louis MO
St. Jude Donor '14-'15
It might just end up being a gigantic failure, but there's always a chance. 
I'm just glad there's at least one other person who gets upset by the 'completely open' meaning only after 1700rpm.
Perhaps I'm just a bit 'rude', but I like to hear the car scream wide open when it starts up.
I'm just glad there's at least one other person who gets upset by the 'completely open' meaning only after 1700rpm.
Perhaps I'm just a bit 'rude', but I like to hear the car scream wide open when it starts up.
Melting Slicks
Joined: May 2006
Posts: 2,936
Likes: 260
From: Westchester County New York
That's how I have mine set, and it does what it's supposed -most- of the time meaning NPP open independent of driving mode.
The only issue is #3 in my original post. There are certain conditions even in "OFF" when the NPP valves close independent of driving mode. That's been my experience in 2 different M7 NPP cars.
It was also an experiment to see what happened.
The only issue is #3 in my original post. There are certain conditions even in "OFF" when the NPP valves close independent of driving mode. That's been my experience in 2 different M7 NPP cars.
It was also an experiment to see what happened.
Tech Contributor
Joined: Jan 2006
Posts: 4,761
Likes: 240
From: Saint Louis MO
St. Jude Donor '14-'15
Thread Starter
Drifting
Joined: Jun 2007
Posts: 1,425
Likes: 238
From: Macomb MI
Le Mans Master
Joined: Oct 2004
Posts: 8,615
Likes: 60
From: Haymarket Virginia
It might just end up being a gigantic failure, but there's always a chance.
I'm just glad there's at least one other person who gets upset by the 'completely open' meaning only after 1700rpm.
Perhaps I'm just a bit 'rude', but I like to hear the car scream wide open when it starts up.
I'm just glad there's at least one other person who gets upset by the 'completely open' meaning only after 1700rpm.
Perhaps I'm just a bit 'rude', but I like to hear the car scream wide open when it starts up.
If so there's a easy solution. Buy a M7 and keep it out of ECO
Pro
Joined: Jul 2004
Posts: 681
Likes: 39
From: Columbus Indiana
Very interesting thread. I wondered what was happening on my ( M7) car at 1700 RPMs tip in. Almost sounded like the secondaries opening on my '65. Hope the blown LED fuse solution works. FWIW: that was also a solution for CAGS bypass on C6 cars.
Tech Contributor
Joined: Jan 2006
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From: Saint Louis MO
St. Jude Donor '14-'15
Negatory - it's still closed up until the 1700rpm mark on the M7 even in race mode. Also, you can't start the car up in Track/Comp mode that I know of (and I've played with that for quite a while trying to do so).
Last edited by Theta; Jul 13, 2014 at 11:12 PM.
Tech Contributor
Joined: Jan 2006
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From: Saint Louis MO
St. Jude Donor '14-'15
If the LED or resistor trick works, we'll all have a 5-minute and 30-cent solution. The wireless aspect is more for grins.
Le Mans Master
Joined: Oct 2004
Posts: 8,615
Likes: 60
From: Haymarket Virginia
The only time the valves close for me is when I'm lugging the engine. Are you sure you had it on "off?"