HKS Supercharger noise
03-20-2024, 02:56 AM
#21
Reply from an HKS rep on the flutter noise:
"The tuner got back and said hes fitted and mapped probably about 300 of these chargers. Some cars do it some cars don’t. It mostly comes down to how the pipework is setup and the BOV position along with the intake manifold of the car. But in all cases it usually comes down to how fast the BOV reacts rather than it not opening enough. Hes got 500hp cars running the stock valve and it’s fine for flow. He’s done a few S2k and never paid to much attention to it but he’s at the point where the flutter noise is never a huge issue as its usually only when off throttle as the BOV opens initially. He did say to double check the Recirc valve is definitely working and staying open, he vacuum tests all his as a tiny split can make the BOV react slowly or initially open then close as it loses pressure. But basically said it’s pretty normal and he’s never attributed a failure due to it."
Will be vacuum testing the BOV to make 100% sure but I'm now satisfied that the stock HKS BOV is fit for purpose and the flutter noise is not causing any damage to the charger based on this reply.
"The tuner got back and said hes fitted and mapped probably about 300 of these chargers. Some cars do it some cars don’t. It mostly comes down to how the pipework is setup and the BOV position along with the intake manifold of the car. But in all cases it usually comes down to how fast the BOV reacts rather than it not opening enough. Hes got 500hp cars running the stock valve and it’s fine for flow. He’s done a few S2k and never paid to much attention to it but he’s at the point where the flutter noise is never a huge issue as its usually only when off throttle as the BOV opens initially. He did say to double check the Recirc valve is definitely working and staying open, he vacuum tests all his as a tiny split can make the BOV react slowly or initially open then close as it loses pressure. But basically said it’s pretty normal and he’s never attributed a failure due to it."
Will be vacuum testing the BOV to make 100% sure but I'm now satisfied that the stock HKS BOV is fit for purpose and the flutter noise is not causing any damage to the charger based on this reply.
Last edited by PanteraChris; 03-20-2024 at 05:45 AM.
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Kyle (03-20-2024)
03-20-2024, 05:28 AM
#22
Reply from an HKS rep on the flutter noise:
"The tuner got back and said hes fitted and mapped probably about 300 of these chargers. Some cars do it some cars don’t. It mostly comes down to how the pipework is setup and the BOV position along with the intake manifold of the car. But in all cases it usually comes down to how fast the BOV reacts rather than it not opening enough. Hes got 500hp cars running the stock valve and it’s fine for flow. He’s done a few S2k and never paid to much attention to it but he’s at the point where the flutter noise is never a huge issue as its usually only when off throttle as the BOV opens initially. He did say to double check the Recirc valve is definitely working and staying open, he vacuum tests all his as a tiny split can make the BOV react slowly or initially open then close as it loses pressure. But basically said it’s pretty normal and he’s never attributed a failure due to it."
Will be vacuum testing the BOV to make 100% sure but I'm now satisfied that the stock HKS BOV is fit for purpose and the flutter noise is not causing any damage to the charger based on this reply.
"The tuner got back and said hes fitted and mapped probably about 300 of these chargers. Some cars do it some cars don’t. It mostly comes down to how the pipework is setup and the BOV position along with the intake manifold of the car. But in all cases it usually comes down to how fast the BOV reacts rather than it not opening enough. Hes got 500hp cars running the stock valve and it’s fine for flow. He’s done a few S2k and never paid to much attention to it but he’s at the point where the flutter noise is never a huge issue as its usually only when off throttle as the BOV opens initially. He did say to double check the Recirc valve is definitely working and staying open, he vacuum tests all his as a tiny split can make the BOV react slowly or initially open then close as it loses pressure. But basically said it’s pretty normal and he’s never attributed a failure due to it."
Will be vacuum testing the BOV to make 100% sure but I'm now satisfied that the stock HKS BOV is fit for purpose and the flutter noise is not causing any damage to the charger based on this reply.
Personally, I kind of like the whistle the charger makes if it's also a normal trait. My Rotrex blower on my TTS kit did it ever so faintly at idle, but it was a larger charger (C38-92), but I have noticed that the smaller C30 Rotrex headunits have a more pronounced whistle at idle and partial throttle which I was kinda sad I didn't get. As far as I know, I believe HKS contracted Rotrex to make their chargers; I couldn't see anyone else doing it independently as the Rotrex planetary setup is a patented design. Either way, good to hear that all is well. Enjoy my friend! You should get that crazy twisty header HKS makes to compliment the supercharger kit now! It's a cool piece.
03-20-2024, 06:56 AM
#23
Yeah I'm not sure where all this needing an upgraded BOV talk is coming from?
The tuner they are referring to here is based in Japan and has fitted over 300 kits and never seen a failure due to the BOV, so what is the issue exactly?
HKS surely would have changed their kit design if there was an obvious issue after all these years of kits being fitted.
I will now be able to enjoy my car in the knowledge it has been signed off by an HKS expert and if anything does go wrong I have some comeback as they have said it is set up correctly.
The tuner they are referring to here is based in Japan and has fitted over 300 kits and never seen a failure due to the BOV, so what is the issue exactly?
HKS surely would have changed their kit design if there was an obvious issue after all these years of kits being fitted.
I will now be able to enjoy my car in the knowledge it has been signed off by an HKS expert and if anything does go wrong I have some comeback as they have said it is set up correctly.
03-20-2024, 03:22 PM
#25
But was it 100% proven that it was the bov or just forum conjecture?
If this Japanese HKS tuner with a massive amount of experience and my own tuner are saying there is no issue to worry about, I'm happy with that answer.
If this Japanese HKS tuner with a massive amount of experience and my own tuner are saying there is no issue to worry about, I'm happy with that answer.
03-20-2024, 09:22 PM
#26
Just wanted to give some background on why people might be biased to blame the BOV. Seemed to have been a pretty common issue.
If you trust your tuner and he says it's fine that's great
If you trust your tuner and he says it's fine that's great
03-27-2024, 01:13 AM
#27
I got a kit back in 2017 and had flutter, the BOV wasn't big enough and causing back pressure (flutter), this puts added strain on the charger shaft and "could" cause premature wear.
I replaced with a bigger TIAL BOV and it not longer flutters.
BOV's aren't expensive and if it reduces potential risk of supercharger failure then its a no brainer to be on safe side.
I replaced with a bigger TIAL BOV and it not longer flutters.
BOV's aren't expensive and if it reduces potential risk of supercharger failure then its a no brainer to be on safe side.
03-27-2024, 05:33 AM
#28
I got a kit back in 2017 and had flutter, the BOV wasn't big enough and causing back pressure (flutter), this puts added strain on the charger shaft and "could" cause premature wear.
I replaced with a bigger TIAL BOV and it not longer flutters.
BOV's aren't expensive and if it reduces potential risk of supercharger failure then its a no brainer to be on safe side.
I replaced with a bigger TIAL BOV and it not longer flutters.
BOV's aren't expensive and if it reduces potential risk of supercharger failure then its a no brainer to be on safe side.
As mentioned, there isn't much of a downside going a little overkill on bov size, other than cost and hassle.
But a question. This thread the flutter is present even at low rpm, where biv size shouldn't be an issue. Was that your experience as well that larger bov resolved?
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