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).

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.

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.

I messaged Tial tech support to get the inner diameter of the BOV and he did not give me the measurements. Instead he mentioned that they do not recommend adding a spacer to the BOV. They said adding a spacer will cause premature wear. It has the potential of causing the bov to bind or stick.

Truth be told, I fell like after spending around $3.7k on both kits I feel like there should be a better solution to this flutter.

They said to go to the next spring up. I'll send you one.

It's kind of ironic that Tial doesn't recommend using a washer because they say it will cause premature wear yet they use the same springs for their bv and q series but the bv has a higher spring rate because it gets compressed more. :rofl2:

Lol. So true. But do you really think Tial wants people to use a spacer when they can sell them a spring for a 200% markup?

However, I get it as a customer you dont want to do something the mfg doesnt recommend.

Some great information I got from Tial today regarding the Q/QR and the QRJ:

I believe you would be just fine in retaining the QR, but I also think that, if you use the QRJ, and when installed correctly, it will provide a more linear response.

It's perfectly okay to use the -3.0psi spring, as that would also allow the QRJ to be open at idle, to act as a bypass, and if that provides you with the best performance, that's great news. In many other cases, the -6psi spring would provide that same bypass, but the BOV would not respond as quickly. That is exactly why the 'default' part numbers for the QRJ only contain either the -1.5 or -3.0psi springs, then, from there, the springs become an optional item.

Sometimes this just comes down to the specific engine dynamics, and sometimes it's about personal preference, but, again, that's why we offer options.

I am sure that, if there was a suitable demand, we could work with our spring supplier to offer a spring that sits 'between' the current offerings, but that demand has really not been strong. The Q/QR and QRJ actually have some overlap as to spring use, as the required dimensions at the spring cup are identical, but some springs can't be used in some bodies, as they could limit piston travel, etc.

Now, as to why a Q would be more apt to 'flutter' than a QRJ, this really comes down to the design, and as I mentioned, for most applications, I would tend to recommend the QRJ, as it's designed to provide that more linear response, and it's less likely to exhibit 'flutter' than the Q or QR, especially when installed correctly.

The Q and QR tend to be more "on-off-on" in terms of response, where the QRJ has the advantage of that piston/chamber design.

Many times, kit builders choose the Q because it is well-known, robust, and reliable, and has tremendous flow, but in a lot of cases, they would probably benefit from using the QRJ. We try to educate customers as best we can, but in the end, this is precisely why we offer both designs.

That said, I can assure you that for one person that wants to rid the system of any 'flutter', there is an equal and opposite person that actually wants to enhance that very same 'flutter'.

So it does become somewhat subjective.

Some added info from Tial:

The QRJ also has a unique v-band set of it's own (different than Q/QR), and threaded v-flange that allows for it to mount directly where a Q or QR was originally. There's also a 'diffuser' outlet for atmospheric discharge, and, of course, you can also simply run the unit without any discharge adapter of any kind, and this is very common. It's also very loud in that configuration.

As for which is best for you, that's more about flow than boost pressure (which is irrelevant), but consider this:

Q has flow to support 1800HP worth of bypass flow
QR has flow to support 1200HP worth of bypass flow
QRJ has flow to support 900HP worth of bypass flow

All three are capable of a significant amount of bypass flow, so unless you are exceeding the peak flow rate of whichever BOV you currently have, there's no reason to change unless you simply prefer the feature or fitment of one over the other.

All of that aside, we typically will suggest that a customer consider the QRJ for many applications, as the design favors a more linear power transfer for on-off throttle, which is advantageous for road and road/track cars, particularly those with FWD or AWD configurations.

One thing worth noting: The QRJ is designed to be installed with the inlet as the 'side' port, and the discharge as the 'end' port. The unique tapered piston and large chamber that surrounds it lend to the best performance when installed this way. It will still work if installed 'backward' but all of those benefits are lost when this is done. There are sometimes reasons why this doesn't matter, and the design allows this, due to the spacing of the ports.

For a supercharged application, the -1.5psi spring will allow the BOV to act as a bypass for the supercharger at idle and under light-load, which reduces the load on the drive system (usually a belt) and reduces the forces acting against the throttle body, and, of course, prevents odd tuning issues that occur when positive pressure is present in the intake manifold at idle.

I'm personally a big fan of the QRJ, but I also don't own anything that requires the flow rate of the larger devices.

I also wanted to point out that this "flutter" is different from any other flutter I've heard. Normally when people mention that word it's happening only when shifting it letting off the throttle. Mine does it when accelerating from 10-50% throttle.

I also wanted to point out that this "flutter" is different from any other flutter I've heard. Normally when people mention flutter it's happening only when shifting it or letting off the throttle. Mine does it when accelerating from 10-50% throttle.

I sent the information over to Seb and he thanked me for the great information as he has a remote tune customer that was asking him about a fluttering issue :tiphat:

appreciate it buddy. He literally copy and pasted the info on his email. I saw your post about 15 minutes later lol