Ive seen that Greddy makes a relief valve to prevent boost spike . Does any one think this could be used on a SC set up .Ive got a smaller pulley [2.87 serp pulley ] and would like to see if this valve could be use to vent off boost above [say 9psi ] I know it would have to go on before the Mass air flow sensor . If I can get into full boost sooner and vent off the rest....from ...like 6,000rpm to 7,000rpm . Any thoughts ?

 

I think that it would best be put between the blower and the intercooler , so the intercooler wouldnt have to cool the extra boost and then be vented .Even a Wast gate may be able to be used before the intercooler

 

isn't that essentially what you are doing. making a wastegate for a blower? If so then yes definitely before the IC. Ideally as in a turbo as close to the blower outlet as possible. Hmm...now that I think about it wouldn't a regular wastegate be better anyways? If so I'd go with a Tial wastegate instead. Interesting idea. Is it correct to assume you are doing this so that you can run the 9lb pulley to get into boost quicker but you only want the motor to see 7 lbs?

 

Yes...I have the 3.12 pulley on now . Making 9.5psi at 7,000rpm .One other member and I are talking about this . We both have the 2.87 serp pulleys sitting on the shelf .I suggested the relief valve and he the wast gate . He has a sedan and has the room to put the wastgate on . I dont know if I could get it to fit right after the blower [ coupe ]. Do the wastgates only release the pressure above a set psi ? And how is this adjusted ?

 

Yes the waste gates are set to open at a certain boost level...Most are not rpm adjustable...but if you only want to boost 7 lbs then just set it there.

 

Is there a set scew adjustment ? Like a SC BOV ? Or is there a controller that is needed ? Sorry for all the ?....Im am turbo dumb

 

Someone posted this question a couple months ago. It was a good idea, but everyone said it was not workable. If it was, every SC kit in the world would use this technique to build boost quicker, and vent off excess. A wastegate with an SC is not practical or feasible.

I'm sure someone else can chime in with the technical details.

 

Thinking about it . I f you were to try to put one on before the intercooler .....the boost is 2 to 4 psi higher on the blower side of the intercooler than the engine side . So you would have to find a psi on the blower side to match the psi you would want at the engine side of the intercooler . I would like to know why this wouldnt work . The Vortech blower can make the boost [ 10 to11psi ] and all we would want is 9 to 10psi . Just have it come on sooner and hold at that psi

 

This was discussed a while back but I don't remember where. I believe the problem was you'd have to have a pulley to go to about 22lbs of boost in order to do what you want to accomplish, and I think it was just too much stress on the compressor due to it being crank driven rather than just exhaust gases being passed out. A wastegate passes out the gas before it gets to the turbo, rather than the other way around like you are asking. You want already boosted air to be wasted which is going to cause compressor failure.. something like that.

 

The problem can be seen if you look at the compressor map. While it would be possible to spin the supercharger up enough so that at 3000 engine RPM it could make 7 PSI, at 6600 RPM it would be completely off the efficiency map. In other words, the supercharger would likely be damaged at redline if you belt it up to turn fast enough at 3000 engine RPM to provide 7 PSI.

 

Wasnt thinking the blower could even come close to 7psi at 3000 or 4,000rpm . What I was thinking is that you could get boost a little sooner and vent off any thing over 9psi . Now I dont hit 9.5 psi untill 7,000rpm .If I could hit 9psi at 5,500rpm and then vent off every thing after that . It still wouldnt be stressing the blower that much

 

Booger - Here is the original post I created on this subject, please see the comments I received.. Tommy

https://my350z.com/forum/forced-induction/86048-10-lb-boost-at-3500-rpm-vortech.html

 

Did you get the new injectors working ?

 

Damn after reading that I guess it would cause more harm then good. Guess its time to switch to a turbo (cough...burp...cough Turbonetics)