Nice. Did you get a before dyno to see the difference it will have made?

 

Please say yes!! Their posted dyno chart isn't very clear, and is from a 350Z. I'd love to see how this improves the 1200 on an S2000.

 

heres my 2 cents, if it was me. i woould get the most efficient impellar installed for like 18 something psi. then i would install a pulley to run 18psi up top. then i would use that valve so that only 12-13 was seen up top at the intake mani. at least that way when the blower is spinning for 18 psi its not blowing just hot air and hating its life.

how is your blower at 15 psi? is it way out of its efficieny range? i love the bleed off valve idea and am surprised noone has done it before.

 

no sorry I dont...Im going from N/A to 21-22psi right out of the gate.

 

Yeah I think I need to have the blower rebuilt to be able to handle that much boost. I think 15 psi is basically maxing the blower out. 14 psi or so is max efficiency I believe. After that will not be as much power per psi but will not be overspun until over 15 psi I believe which takes it to 52000 rpms.
So if I had the bearings rebuilt etc to be able to spin to say 18 psi would it just be able to spin that high but the max efficiency would still be at around 14 psi?

Yeah I am surprised as well. If I can get this to work and run a 17-18 psi pulley it would have an incredibly nice powerband then seeing 12 psi around 6k rpms or so and holding that till redline.

 

Dammit!!!! Wish I had known about thise before I put the new 1200 on ><

 

I'd do it if you don't mind putting more wear on your blower. Also, you need to remember that spinning the blower doesn't come free. You need to use HP from the crank to spin the blower, and depending on efficiency levels of the blower, and the non-linear demand of HP to spin it, you may be pushing hotter air through the motor, thus lowering volumetric efficiency, as well as taking more HP to spin the blower, lowering your HP per Psi and subsequently hurting your HP at peak. Who knows though, you should try it and find out!

 

Yeah that's what I was asking about upgrading the blower to spin faster. If I rebuild it to spin to say 62k rpm's even though it can spin that fast now without overspinning it, would the max efficiency range still be the same as the stock vortech blower and not increase since I can safely spin the blower faster now?

 

If you're not changing the impeller or housing, then the blower's efficiency should not change. The bearings and seals are a rpm limitation due to mechanical failure risk, but changing them doesn't affect how much air the compressor moves.

If you change the impeller, the opposite should be true. That would totally change the blower's efficiency as well as how much cfm it moves. Meaning the compressor map would be totally different, and we could only guess at what rpm it's most efficient.

Unless 928 motorsports has done testing to prove the results, it's only a guess that changing the impeller AND spinning it faster would combine to make the most power. From their website, though, they do seem to hint at it being effective.

 

Now, here's another question. Where were you thinking of putting the boost limiter valve? I've been kicking ideas around for a few days and came up with the following:

• Tee into the return hose between the aftercooler and the compressor intake. (The one that feeds the existing blowoff on SOS kits, not sure if VT kits have one.)
• Tee into the hose going to the factory air pump on SOS kits.
• Drill a hole in the aftercooler, right on the front where the blower feeds in, and weld on the limiter valve fitting.
• Drill a hole in the aftercooler, near where it exits toward the throttle body, and weld it there.
• Drill a hole in the throttle body and weld it there.
• Drill a hole in the intake manifold and weld it there.

The examples on 928 motorsports' website show it welded onto aluminum charge piping, which our kits don't really have much of... I'm leaning toward putting it on the aftercooler exit, as close to the throttle body as possible. I'll have to stare at it for a while to see if there's space.