03 350z de
vortech with 3.33 pulley
uprev osiris dynotuned by r/t tuning
megan headers
bc stage 2 cams
kinetix hfc
hks true dual
plenum spacer

i made 392 whp and 333 wtq... now im going to custom fab a cold air intake for it and drop the 3.12 and i was also wondering how safe it would be to run a 3.12 and get the 928 impeller and swap it . retune with 3.12 and make pretty good power hopefully with new cold air intake and with the impeller... but my question is since the 928 ups the boost 2psi wouldnt it be the same thing as me dropping the 2.87 or would i be running more efficient dropping the 3.12 AND doing the impeller upgrade. im just looking to make more power and try to possibly be more efficient... which is why i upgraded cams,and i saw this 928 impeller.. any input is cool thanks

 

3.12 and 928 = win for stock block
2.87 may have a chance of overspinning the blower.. 3.12 makes good power though.

btw great numbers for that pulley!.. dyno sheet?

 

idk how to post on this site.. but vince of rt tuning is on here and has my file saved.. im sure he can chime in here and show my sheets.. so if im at 392 with the 3.33 if i upgrade to a nice cold air intake and 928 impeller and the 3.12 do u think ill have good power curves... and power coming in pretty early? much more reliable than the 2.87?

 

The blower will be spinning slower with the impeller to make the same power as the smaller pulley.

 

hurry up vince!!!!


yes the power band will be much different.. going from 3.33 to 3.12 is night and day IMO

 

im looking to order the impeller within the next week or 2 and my buddy will make my cutom cold air and i can get the car out to rt and have vince tune it up... somone pm vince and have him post my dyno sheet. Im hoping to have a nice feel in power increase and have the boost come in a bit harder and quicker... hopfully impeller and 3.12 and retune will yeild solid power curves with the cams..

 

vas why was ur power so low with ur vortech numbers when u were running the 2.87 was that done on vinces dynojet. what were your supporting mods back than?

 

it wasnt on vinces dyno... but it was still a dyno jet... I had the V2 with 2.87 and gtm mod.. plenum spacer, test pipes and nismo exhaust.. thats it. Its not really that low.. usually people with the 3.12 and 2.87s get about 400-430.. maybe some 450? idk.. i guess ur motor is running good to be putting out almost 400 with just the 3.33

 

Keep your rev-limiter at 6600 and go with the 2.87 and the 928 impeller. You will find that the 2.87 still won't be enough. Not sure how the cams will affect boost but you should be around 12-13 psi. I think most agree that hp doesn't hurt our engines but the torque (should still be low and linear with a supercharger) and with a good tune I think this is a great way to max the potential of a stock block. Did you upgrade your injectors and pump?

 

yup deatschwerk 600s and walbro 255..im definitely not doing a 2.87 and a 928 impeller.. im not trying to over spin blower .. this guy i know just blew his motor byusing a 2.87 pulley only.. which is why i wanna do the impeller and 928 and hopfully get some great numbers....

 

I don't think you would have issues with overspinning the blower. Many guys on here including myself have been using a 2.87 for a long time without bearing problems. As for the motor blowing with a 2.87, it is really all in the tune. I'm sure you will get some great numbers with the 3.12 and the 928 impeller though. I'm just saying because I am really bored with my 2.87 and wish I could get some more midrange power.

 

why dont you add the 928 impeller with ur2.87 wouldnt that increase some more midrange.. and why are your numbers so low with the 2.87? 418rwhp? wat dyno?

 

I guess every car and every dyno is different. You really need to run a car at the strip to see what kind of power it is making. Mine was done on a dynopack dyno, some say they read high some say they read low so who knows. I would do the 928 impeller but I would have to do a re-tune and so that brings the cost up. For that kind of money I am considering a 4.08 gear but I'm not sure if this is a benefit either. I'm mostly just weighing my options. As for my power at the strip, I only got two runs and neither was good at all with lots of wheelspin on street tires but still trapped at 113mph, I will be going back soon with my set of MT's to redeem myself just as soon as it warms up here in Ohio.

 

here's my idea/plan for ref.

Following is my next step, which is another rout to step up the power.. The calculation formula is from the first page of vortech FAQ (FI Section), so I’m basing my research on it..

I'm running an SC trim v2 blower on Non-rev:

Max Speed: 53,000 RPM
Max Boost: 17 PSI
Max Flow:1050 CFM
Max Power:725 HP
Peak Efficiency:75%

I'm also running the smallest pulley (2.87")..

to calculate the impeller speed:
[5.75/SC pulley] x [upper cog pulley teeth/lower cog pulley teeth] x [3.6 x redline rpm] = impeller speed

5.75" = crank pulley diameter
SC pulley = 3.33, 3.12, 2.87, 2.62 pulley etc
non-REVUP kit: upper cog pulley = 32T, lower = 28T
3.6 = step up gear ratio

so it's: (5.75/2.87) x (32/28) x (3.6x6600) = 54,403 RPM @ redline (6600 rpm).That’s above the blower’s max RPM by a hair margin, but I never reached that other than over the dyno and few pulls on the street... I’m planning to upgrade the cog pulley for more PSI/boost (going with 34T).

if we redo the calculation including the upgraded pulley: (5.75/2.87) x (34/28) x (3.6x6600) = 57,803 RPM @ redline (6600 rpm). Now that's almost 5000rpm above the limit of the impeller.. so to compensate the added power/psi, I'll upgrade the impeller (928 Motorsports) which raises the impeller’s RPM to 60,000 @ redline, which also raises the boost and give me more space to play.

Now, by doing the above, i’ll have another 3,000 RPM on the impeller that isn’t being used (to reach 60,000 RPM). So I’m going to raise speed limiter RPM, which should (i assume) allow another PSI.

Redoing the calculation with higher redline RPM, I got the following:

6700 = 58,679 impeller speed
6800 = 59,555 impeller speed
6900 = 60,431 impeller speed
7000 = 61,307 impeller speed

By that, I know the best and safest I can go with is 6800rpm redline. But I was also concerned about another factor, which is the max flow (rated at 1050 CFM). I’m not sure what contributes to it and how can I go on about calculating it..

 

While the 928 impeller is rated at 60k it has been tested to close to 70k in overspin destructive testing. I believe it was spun to 15% over rating for something like ten minutes and the impeller never actually exploded. I actually ran that very impeller on my car after the testing didn't destroy it.

With that in mind, going to your redline shouldn't be an issue for the impeller by any means. The bearings on the other hand could be a different story. Not really sure.

 

I'm sure the much better balancing of the 928 impeller would put less stress on bearings also. Isn't the max rpm of the bearings on the Vortech rated for some sort of sustained use? Meaning if you go over the max it won't really hurt them because it would only be for a very short time and not happen very frequently? Tires have speed ratings too but you could take a set of "S" speed rated tires and drive 120mph and they won't blow off the car.

 

Quamen, did you ever get a compressor map for the 928 from Carl? I'm just curious if the the new impeller can be spun to 60k rpm and not just be blowing hot air into the engine...

 

I don't have the compressor map but I believe he does.

 

+1, i believe v3 bearings could probably handle the rpm...

 

The formula in MaxMood's post is assuming that we have zero belt slip correct? If that is the case, most of our applications well have some form of belt slip. Just something to keep in mind.

I am really liking the idea of getting the 928 Impeller upgrade with a 2.62" pulley rev'ing to 6800rpm with a V3 blower. I wonder how the stock block will like that.