Quamen

iTrader: (14)

So as many of you know I am making a custom one off Vortech V2 supercharger kit for my 350z.

However, during my build I noticed that the outer 1/2" of my V2 SC-trim impeller (which is what comes stock for the 350z) was machined off. This confused me at first as to why Vortech would make the impeller tips a smaller diameter and therefore have a slower tip speed and air velocity. I did some research and here are the specs incase you don't know between the S-trim and SC-trim that we have:

After looking at this I came to the conclusion that they must machine this off to reduce the tip speed to accomodate the higher revs of the import engines which could essentially "over clock" the impeller and destroy the tips.

I decided to call Vortech and guess what... I was right!

They did this because at the calculated max bearing speed the tip velocity of the impeller would be to great so the made the diameter smaller.

With this in mind, it would seem that ordering a replacement s-trim impeller (which will be a direct and easy swap with the exception of tuning) could be a good alternative for some people. This could allow people to run higher boost (sentry??) with the same pulley or further prevent belt slippage by being able to run a larger pulley and run the same boost.

This could be a cost effecient alternative to the T-trim for people and as long as you are not revving to 7500rpms I wouldn't think that there would be issues with tip speed.

I am trying to get a price for the replacement impeller from Vortech right now and I will post it when and if I recieve it.

sentry65

iTrader: (11)

yeah there's been a few people that have switched to an S-trim. No one has really posted a very detailed review though. I remember one guy went to an S-trim and also a 2.87 pulley then reported back that he was making more power (duh) so it wasn't really a SC vs S trim comparison.

the adiabatic efficiency drops to 72% though with the S-trim so I kinda wonder just how beneficial it'd be if the air is turning out to be a little hotter.



so for me with my car, I'm not sure I'm going to go for more power on the stock block anytime soon. The 34 tooth rear cog pulley is an option for me to add and the S-trim is too. But as it is right now, my car still has plenty of power and I'm happy with it so I haven't really been pondering how I can push the vortech further, when there's obvious things out there to do for more power.

To step up to the next 30whp I'd end up having to spend a bunch of money to get there and would involve:
-GTM larger intercooler, with stock diameter piping
-GTM pulley to wrap more belt around the jackshaft
- deal with any fuel issues that might happen at the top of the rpm band (right now my fuel pressure is ok, but still drops a little as boost increases. So adding more power would make it drop more and I'd have to deal with it)
-retune
-go back to the 3.5 final drive to try to keep my 2nd gear usable
- and then there's the whole "will I blow my engine" issue or possibly wearing out the blower more quickly

so I think I'm at a sweet spot with where I'm at right now

Recently I've started losing traction at the very top of 2nd gear. I think my rear tires are starting to lose some of their grip now that the miles have been piling up on them. They feel like normal street tires now instead of R compounds which I've heard a lot of people say happens with these tires. Anyway, I'd rather my car be reasonably balanced than have more power than can be used in half of my gears

I'd love to see people go beyond what I'm doing though. I'm also interested in seeing a T-trim setup on a built block with TIMROD's belt fix, the GTM pulley, and the other extra lower pulley like what's on my car. It could have potential to work out. And if it would still slip with the stock displacement, maybe a stroker kit would make things easier by reducing the boost pressure some

Quamen

iTrader: (14)

Obviously the adeabatic is going down from increased air velocity and tip speed but I would think that the 3% is marginal and horsepower loses from air temps could be offset by reduced bearing speeds/friction.

While the horsepower gain could minimal it could be a nice alternative for some to avoid belt slip.

sentry65

iTrader: (11)

yeah it probably would help belt slip a little, and it seems to me that it'd give you more low end power, at the expense of losing some high end power and possibly putting you a little closer to detonating at the top of the rpms from higher temps. I could be wrong though. From what I understand, it's only like $150 to switch to an S-trim

Quamen

iTrader: (14)

How would you lose high end power? I don't think the intake temps will be as bad as you think.

sentry65

iTrader: (11)

the lower efficiency seems to me it'd make the biggest difference at the highest peak boost. Maybe you wouldn't lose much top end power, I'm just guessing. But usually lower efficiency numbers mean less power at redline. That number also is the peak efficiency %. You'd obviously go beyond that peak % island as you go to higher rpms

I wish vortech would post a SC-trim chart on their site. They have the S-trim posted. We'd know how they compare better if we could directly see what's going on

booger

iTrader: (6)

I really dont know why most people think that there is a belt slip issue with the stock blower . Both the ATI and Vortech SCer's have shown that when a psi level of 13 to 15 psi is reached . The blower is getting to hard to turn and a serp belt will no longer hold . As long as my serp belt was tight , I never showed signs of belt slipping other the normal slight serp belt slip you would get with any system . Using the new mods to help with getting more grip with the serp belt should allow you not to have the belt so tight , but isnt going to get you more boost.
But going from the SC to the S trim will [ or should ] help dow low . I can say that going from the SC to the T-trim made a huge diff. down low . Sentry and I had a little arguement over why he was able to go WOT in second gear with 3.9 rear gears . And I couldnt even go 1/3 throttle in second gear with 3.5 rear gears with my AT5 tranny . I think Sentry was or is at 450whp and I am at 420whp . My BOV closes at around 1/3 throttle and with in 2 or 3 hundred rpm Im at 4 or 5 psi . The difference is night and day between the SC to the T-trim in the response down low .
If putting the S trim impeller in , is only a couple hundred bucks to do . I think it would be well worth it down low with very little [ if any ] lose of efficiency up top .

sentry65

iTrader: (11)

I 'm still a little skeptical though. Some people on other forums for other types of cars that have switched from SC to S-trim claim they felt no difference with pretty much the same looking dyno charts

The other thing is, if the S-trim can only handl 50k rpms, then it's less "overclockable" - meaning you could for instance use a 3.12 pulley with the S-trim, or a 2.87 with the SC-trim.

Isn't the stock SC-trim also a little quieter than the S-trim? Or do you have to specify you want a SQ S-trim?

Quamen

iTrader: (14)

I highly doubt that it can only handle that much. Generally speaking the recommended max rpm is not as high as it can really be spun. 928M spins there impeller at 70,000 rpms for testing but we state 60,000 I believe for impeller speed. Just to be on the safe side.

I believe this only has to do with the helical cut gears rather then straight cut gears and nothing to do with the impeller.

booger

iTrader: (6)

My T-trim blower has heavy duty gears in it . I believe they use this gear box in race blowers . But it is just slightly louder than my other T-trim and the SQ stock blower I had

Quamen

iTrader: (14)

They are straight cut gears and that is why they are louder and stronger the same as in the race gear sets for the transmission or our car and most cars for the matter.

QuadCam

iTrader: (8)

IIRC, the SC-trim first appeared on the vortech kits for the Ford 4.6 Cobra kits back in 1996. It was then, that people realized that the SC impeller was a cut cown S-trim wheel. I think it was about a $250 charge to send the blower back to vortech and have them swap an S-trim wheel in there. I picked up about 2 psi with the same pulley. those cobra kits were similar to the 350Z kit. they both use a CCW blower and only a 6-rib drive belt; traction was always an issue on thse kits too. So, this is nothing new....actually it's about an 11 year old trick.

sentry65

iTrader: (11)

the only point I was making was that vortech seems to be saying the S-trim will handle 3000 less rpms than the SC-trim. Whether people will drive both beyond what vortech says is the max is their own decision. But yeah I think the blowers can handle a lot more rpms than the kits come setup for with the stock configurations, but it would look like the S-trim has a little less headroom than the SC-trim. I don't think that means you can spin the blower to whatever rpm you desire though. I wouldn't go beyond 7100-7200 rpms with the 2.87 pulley with the SC trim or beyond 6700 rpms with the 2.87 pulley and 34 tooth cog pulley

klimaxx805

Interesting thread...but sorry we do not sell impellers or any internal part of the blower.

The impeller max speeds are the speeds that we test up to. I wouldn't overspin the SC or S-Trim by much over the max impeller speed. The T-Trim and YSI can be overspun and will hold up longer.

As far as gears and noise all V1s have spur/straight cut gears and V2s have the helical gears. The spur/straight cut gears have more backlash and that's why they're noisier under idle. We do offer a V2 T-Trim for those that don't like the noise.

I'd have to agree with sentry and say that converting to an S from an SC isn't going to make a big difference. The only benifit would be to help with belt slip as mentioned since you could use a bigger pulley and get around the same amount of boost as the SC. It may also help a little on the bottom end.

I have to say that I think what guys like sentry, booger, and quamen are doing is bad ***. Way to step it up guys and see what our kits/blowers are capable of.

--Frank

QuadCam

iTrader: (8)

but, will you still perform an impeller swap from and SC to an S for a fee?

klimaxx805

Sure, we can turn a V2 SC to a V2 S here.

--Frank

OldManZ350

iTrader: (23)

so how much to change a V2 SC Trim to a V2 T-Trim?

QuadCam

iTrader: (8)

t-trim requires a new blower.....you can't just do a simple swap. I think vortech still offers an upgrade though. they used to offer it on certain kits....but that might have been a mustang thing. it was only a few hundred dollars on the the trade in of your s-trim, but it is better than nothing.

booger

iTrader: (6)

I believe they charged me $1000..or something near that for a trade in from stock blower to a T-trim

Quamen

iTrader: (14)

Geez... for less then $1000 I might as well just convert my supercharger over to this:





More CFM and better adebatic effeciency due to improved blade design!


I guess the only problem with getting to the point of doing that would be having my crank pulley to even put the blower on my car