Your plastic Bosch DV is too small, period. Ideally you'd want to recirc from the cold side so you're not feeding the hot pre IC air back into the blower, but given your piping setup, it doesn't seem feasible to do it any other way unless you want to run an atmospheric dump DV which is annoying as absolute shit. Besides, I think the disclaimer not to plumb hot air back into the inlet of the blower is strictly a Rotrex protocol as they spin twice as fast and generate quite a bit more heat.

Regarding the DV, I'd stick to something tried and true. The problem you're looking at right now is port size and how much air these can flow. Moving from the Bosch DV you have now to what you're showing seems like a mild upgrade but it's all about port sizing. Looks like your piping has bungs sized for your current DV; you realistically need ports in the realm of 45+ mm...Not sure what the Bosch one has but I'm sure it's tiny in comparison. Get a Forge Supersize or a TiaL QRJ and call it a day.

 

Thanks. I am actively looking at options for DV. Need to see if the hoses etc. I have now will support one of the new DVs for an easy DIY swap or if I am going to have to get a pro involved.

 

I'd get that "top shop" involved as it's obvious this ain't right. (You're in Florida, was this LHT?)

-- Chuck

 

Yes, it was LHT. I've been texting with John and I don't think he thinks there is any issue. He says some valves are just quieter than others. He told me he's done 150 supercharger installs with this exact same set up. Maybe its just a personal preference thing, but the flutter is so loud it really detracts from enjoying the car. LHT is a two hour drive from me, and I haven't had any luck getting an appointment, so I'm trying to solve the problem on my own. John said he has used a Turbosmart DV with 2.5psi spring in some instances and finds them to be a little quieter. So I guess that is another option.

 

I'd expect better service. Especially for the several thousand dollars you paid ...

-- Chuck

 

In fairness to them, I was not the one who paid for the work. The owner before me had them do the work and then I purchased it from him. So I don't have an existing relationship with them.

 

If this noise is actually compressor reversion, like we think it is, the noise is NOT coming from the valve. Its coming from compressor, and its bad. Real bad.

The root cause would be the valve nit flowing enough, but noise actually compressor howling in pain.

 

I'm sorry...no disrespect to LHT but...they have no idea what they're doing. Yes, they're excellent mechanics, and they know the nuances of the platform in and out by now. I'd absolutely trust them to build something, but you can't trust them to know what parts are actually good and what aren't, period. John seems like a very prideful and opinionated guy, and it seems like he generally scoffs at the "normies" within the community as complete heretics. But funny enough at the same time, it's interesting to see him quietly start offering what everyone says works and no longer offering things he did previously....

Just please listen to what people are saying and your issues will be solved....get a DV with LARGE ports.....supersize, qrj, and the lightest spring you can find. Boom, done. Literally....I can tell you without a shadow of a doubt that I was running quite a bit more boost than you, and I never heard a thing with my supersize valve or my blower. This is not something that requires overthinking. Switch to a much larger diverter valve, get new bungs welded onto your piping, and call it a day. You may even need to switch to a 90 degree aluminum elbow for the blower and ditch the silicone elbow so you have something to actually weld a properly sized port to, which is fine, it looks better anyway.

 

Keyle - thanks for that advice. I am 100% getting a new DV.

 

Mine did exact that when I bought that plastic re-circ VW/Mini/BMW valve from amazon, to replace also a failed OEM one. The Amazon one failed within the 1st two weeks.

All I had to do, to test it, is take it out and try to push the valve in, it was jammed and other one wasn't moving freely.

Take it off, and push on the valve, should be smooth movement.