Announcing TopgunZ ACE Supercharger Kit!

TopgunZ · 06-08-2020, 07:57 AM

It is absolutely the BOV being under the right conditions to allow it to fluctuate between open and closed. When that condition is just right it is not under enough vacuum to be pegged open and the air the SC is making (which it is always making) has to escape. The valve gets pushed up by the air, the spring pushes it back down, due to not enough vacuum. This happens repeatedly and quickly giving that chopping/fluttering sound. I experimented forever with this on my initial kit back in 2014. Vacuum changes from car to car and from environments, namely altitude.

If you get flutter then try a slighlty stronger spring, or you can throw in a shim, like a really thick washer. This makes the spring stronger. Also, adding resistance to the output will help. Place a filter on it (Return style only). I bet if you bought the cover that makes the Q50 return style, it would be gone.

As long as the BOV is staying open in idle and decell, and shut during boost anything goes. Maybe the 3psi spring would work better.

redondoaveb · 06-08-2020, 09:22 AM

Quote:

Originally Posted by TopgunZ

It is absolutely the BOV being under the right conditions to allow it to fluctuate between open and closed. When that condition is just right it is not under enough vacuum to be pegged open and the air the SC is making (which it is always making) has to escape. The valve gets pushed up by the air, the spring pushes it back down, due to not enough vacuum. This happens repeatedly and quickly giving that chopping/fluttering sound. I experimented forever with this on my initial kit back in 2014. Vacuum changes from car to car and from environments, namely altitude.

If you get flutter then try a slighlty stronger spring, or you can throw in a shim, like a really thick washer. This makes the spring stronger. Also, adding resistance to the output will help. Place a filter on it (Return style only). I bet if you bought the cover that makes the Q50 return style, it would be gone.

As long as the BOV is staying open in idle and decell, and shut during boost anything goes. Maybe the 3psi spring would work better.

The Q50 comes with a 2 psi spring and unfortunately, it appears the next stronger spring is a 6 psi. The QR and QRJ don'r share the same spring. The bottom QR section can be bought for $60.00. I ran a Q50 and now a QR50 (the QR because I'm running a silencer) in the location as the V1 series kit and have/had no issues with flutter.

What is strange is the Q50/QR50 has a 50mm valve and the QRJ has a 38.5 valve yet the QR50 has a smaller outlet port (22mm) compared to the QRJ (35mm).

DUSHER · 06-08-2020, 01:07 PM

Quote:

Originally Posted by TopgunZ

It is absolutely the BOV being under the right conditions to allow it to fluctuate between open and closed. When that condition is just right it is not under enough vacuum to be pegged open and the air the SC is making (which it is always making) has to escape. The valve gets pushed up by the air, the spring pushes it back down, due to not enough vacuum. This happens repeatedly and quickly giving that chopping/fluttering sound. I experimented forever with this on my initial kit back in 2014. Vacuum changes from car to car and from environments, namely altitude.

If you get flutter then try a slighlty stronger spring, or you can throw in a shim, like a really thick washer. This makes the spring stronger. Also, adding resistance to the output will help. Place a filter on it (Return style only). I bet if you bought the cover that makes the Q50 return style, it would be gone.

As long as the BOV is staying open in idle and decell, and shut during boost anything goes. Maybe the 3psi spring would work better.

so do you think I should try adding a washer? I have plenty of them at the shop.

TopgunZ · 06-08-2020, 01:42 PM

Quote:

Originally Posted by DUSHER

so do you think I should try adding a washer? I have plenty of them at the shop.

Try one that is at least 1/4" thick and see if that helps. Might need to go to 1/2". More of a spacer at that point. You can always make one too with some rod stock and a drill press or mill.

G37XSedan · 06-08-2020, 02:01 PM

This looks like the perfect solution for the power level I'm looking for in the G37X sedan. What are the filtration options for this? It will be on a daily driver.

TopgunZ · 06-09-2020, 08:56 AM

Quote:

Originally Posted by G37XSedan

This looks like the perfect solution for the power level I'm looking for in the G37X sedan. What are the filtration options for this? It will be on a daily driver.

It is the Velocity intake with the Prefilter. The filter does a great job of keeping anything that could be harmful out of your engine while bringing in as much air as possible.

If you want added protection, you could place a second filter on essentially doubling the micron filter element.

The filter is easily removable for cleaning unlike the old filter that would require removal of the supercharger for cleaning. You can always still use the old KN style I sold with my first kits if you want, but I find it unnecessary with this new design I offer.

Check out the new website! www.topgunspeedworks.com

As of the current date I only have the 370Z page fully populated with all items but everything that is there works on the G37.

06-08-2020, 07:57 AM	#1 (permalink)
TopgunZ A True Z Fanatic Join Date: Jun 2012 Location: Minneapolis Posts: 2,651 Drives: 06 350Z , 09 370Z MT Rep Power: 6834	It is absolutely the BOV being under the right conditions to allow it to fluctuate between open and closed. When that condition is just right it is not under enough vacuum to be pegged open and the air the SC is making (which it is always making) has to escape. The valve gets pushed up by the air, the spring pushes it back down, due to not enough vacuum. This happens repeatedly and quickly giving that chopping/fluttering sound. I experimented forever with this on my initial kit back in 2014. Vacuum changes from car to car and from environments, namely altitude. If you get flutter then try a slighlty stronger spring, or you can throw in a shim, like a really thick washer. This makes the spring stronger. Also, adding resistance to the output will help. Place a filter on it (Return style only). I bet if you bought the cover that makes the Q50 return style, it would be gone. As long as the BOV is staying open in idle and decell, and shut during boost anything goes. Maybe the 3psi spring would work better. __________________ ROTREX SUPERCHARGER TUNER KITS - $6799/ CUSTOM STILLEN AIR TO AIR KITS -$2100/ 700+ WHP!! WWW.TOPGUNSPEEDWORKS.COM

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06-08-2020, 02:01 PM	#5 (permalink)
G37XSedan Base Member Join Date: May 2020 Location: Utah Posts: 1 Drives: 2009 G37X Sedan 7AT Rep Power: 6	This looks like the perfect solution for the power level I'm looking for in the G37X sedan. What are the filtration options for this? It will be on a daily driver.