Preparation for the STILLEN supercharger

RCZ

Road Tuning is not the same as track testing. Its not because they haven't posted videos, its because they said nothing about it in their big press release. You would think thats where pertinent information about reliability and testing would go, but instead we got a lot about pretty parts, a lot about the supercharger they are using, a bunch of pictures, one dyno and a price. Sorry and some vids of a dyno pull. Not that there's anything wrong with that either, but thats what was released.

I'm not making any of this up, it is what it is. You guys are making a big deal out of this too. I just said Stillen has done testing, not that GTM hasn't. I just don't know about it if they have.

DannyGT

F that! They already have all the fun LOL

I'm not looking for a rinky dink shoot out between me and RCZ. I'm looking to meet a fellow member whom I respect so we can provide the community some great comparo's and real world footage (in HD!). Believe me, when this happens, I want to make this a real nice meet with tons of cars. I've got a huge crew that would just love to come out for a fun day at the track.

Cars, food, good people...Whats not to like!

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Performance GTM Stage 1 SC, GTM Res.Test Pipes, Invidia Gemini Exhaust, GTM HD Oil Cooler
Wheels & Suspension AME Tracer TM02's 19x9.5F 19x10.5R w/ 265x35F & 305x30R, Hotchkis Sways, BC (BR) Racing Coilovers (Car Sold)

1slow370

i'd love to see the 370z kit make more power than the g37 kit

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shumby

yet another day with no press release

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Originally Posted by SAM@GTM
Engine detonation is not normal and it should never never happen, and whoever told that need to do something else for living .
Sam

Phimosis

The dyno numbers look great. The torque curve is what I expected from a centrifugal supercharger. I'm still surprised/confused about GTM's torque curve. It looks like a roots or whipple supercharger, not a centrifugal. I've got a bunch of Stillen parts on my car as it is. I just want to know, when can I get the Stillen supercharger kit? I've had my Z for a year with N/A. I bought it because the Camaro wasn't availabile. Then the Camaro guys got their supercharger in just a few months. I know you guys had a prototype back G37 back in 5/09. Please, just give me a date when I can get your shop to install one!

phantom21

Raul,

You make it to SC, I'm there.

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2009 PG 6spd Sport || 30% side tint, 15% rear || All Redline fluids || Berk HFC's intalled~PITA Bolt || Stillen G3's || Berk CBE || BC Racing Coilovers with 10K/12K Swift springs & RA valving|| SPL rear camber arms || 20mm/15mm spacers

RCZ

Wes and Danny, I mean I'll do a supercharger tour if Stillen pays for it hahaha

Just kinda realized now that I've met quite a few of you guys since 08. Hard to believe I've been on here for well over a year now. Anyway, I know we have our differences sometimes but its all good as long as nobody forgets we are all in here for the same reason. Lots of tension lately, I think we all need to take a step back for a minute, chill out and remember a lot of this is friendly fire.

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Back on topic:

Whats everyone doing for a clutch?

stormcrow

Kyle - no offense meant, but I am not certain why dyno numbers can be posted but not the PSI which netted such numbers? The only option I have is to believe that it is a pretty high poundage which would be detrimental to the longevity of the stock motor? Knowing what I do about the Vortech blowers, I honestly can't imagine that it was under 10psi.


The GTM vs. Stillen torque curves is easily explained. Both are centrifugal blowers which are, in essence, like turbo chargers. The smaller the charger, the more torque it will create down low due to the reaching of full spool in the lower RPM range. GTM's rotrex is pushing more air at lower RPM due to its size. Conversely, the Stillen (Vortech) blower is taking longer to reach full spool due to it being fairly large. This easily explains its lower torque below the curve.

Kyle@STILLEN

Technically we did say that we are right on track for a release in early March. If we really wanted to we could stretch that out until March 14th if we really really wanted to LOL. That would technically still be the first half of March meaning "early" March.

It was absolutely under 10 psi. Keep in mind that the dyno we showed was using the same kit that we plan on sending to CARB for approval. It would be pretty challenging to get a 10 pound kit through CARB.

You are 100% correct and believe me when I say we want this kit out more than anyone. We have had this kit in development for a long time. Unfortunately Steve's GT R race car had to be completed by a certain deadline. Because there were no deadline's for any other R&D project, the GT R took precedence for a few months. We spent about 4 or 5 months tearing apart and rebuilding and developing and testing our GT R and our engineers were buried in that project. Once that car finally left for the rally they were finally able to re-focus their efforts back to the supercharger.

RCZ

You can do it with less than 10psi.

You are getting mixed up with spooling time vs. size of a turbo charger when looking at that graph. A sc's size has nothing to do with when it spools, it is mechanically driven, so what you want to talk about is power delivery and the ramp effect of the gearing within the scharger.

Easily explains it? The similarities with a turbo is in the way power is delivered. Since it is a compressor wheel, it will compress more air the faster it spins, like a turbo would as it spools up. That's about where the similarities end though because there is no hotside wheel that needs to be spun and spooled by exhaust gas...There is no lag, there is only RPM/Size/Gearing/wheel design.

Zsteve

Kyle how does psi matter in making a kit CARB legal? Does it have to do with emmissions? Im asking cuz I would need a CARB legal kit but would want it as high a psi as possible, to a point of course.

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2010 LS3 C6 Silver coupe corvette

stormcrow

So, then why not tout the PSI? What is the big secret? BTW, I don't see getting a 10psi kit past CARB. Vortech has already done it with some of their T-trim blowers, IIRC.

Really, what are we looking at here? More or less than 8psi? This question can be answered without giving away the 'trade secret'.

Are you kidding? Of course an SC's size has to do when it spools. Bigger compressor wheel, less CFM at lower RPM. Hence the reason why you can change either the pulley size that drives it OR the compressor size, itself, to change key aspects of air delivery. It really doesn't matter if drive is coming from a belt or from exhaust. Key physics do not change.

Analogy - A bike wheel spun by a chain and crank. The larger the wheel, the slower its rotation at a given speed of crank spin. Change to a smaller wheel and what do you get? Faster spinning wheel. Now imagine these wheels are compressor fans...which is going to produce more CFM at a constant lower speed or as the RPMs ramp up? The truth is, it takes the larger Vortech more RPMs to push the same CFM as the smaller compressor of the Rotrex at lower RPMs. It's not a huge amount, but definitely significant enough to show the differences in torque. The plus side of this? More power to be had when running higher boost as the larger blower will not run out of steam as quickly.

And, I don't think anyone at Stillen would disagree.

G Fo12ce

More boost = more fuel to run safe. More fuel means more emmissions.

Also some s/c require more load to spin, the traction drive on the other s/c is advertised to require less load to spin resulting in cleaner exhaust and different responce. That's why they load up your car on a small dyno in CA to test the emmisions. Either way if it passes it passes.

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Zsteve

gotcha

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2010 LS3 C6 Silver coupe corvette

RCZ

Hmm, You change the pulley to change the multiplier effect of the gear size differences and therefore the speed at which the compressor wheel is moving. Higher speed will yield more boost as long as the turbine wheel is within its efficiency range.

Changing the housing would be like getting a different trim and thats the same as getting a whole different supercharger.

You made your post sound like you were talking about spooling when you said "full spool". I don't know if you know this, but spooling refers to the amount of time it takes air exiting your engine to spin up (spool up) the exhaust turbine on a turbo. You are talking about a supercharger spooling? It doesnt spool, it spins up and down with engine speed. That engine speed + gear ratios between the crank pulley and the sc's pulley is what creates a certain speed in the compressor wheel. You are right about one thing though, the housing does affect the way power is delivered because different sized compressor wheels have different effects, speed being the same, with relation to their size. I didnt say it didnt, I said it doesnt have a difference on the "spool" of it because it is belt driven.

The size of the compressor wheel has no bearing on its speed. OK yea the tips of the blades are spinning faster because they are traveling more distance in the same rotation, but thats not what we are talking about here. Whether the compressor wheel is 2 inches in diameter or 4, its still spinning at a certain RPM that is produced by the gearing size differences in the pulleys. A bigger wheel should in theory move more air at the same RPM as a smaller wheel, granted I think each size probably has a different peak efficiency speed, I don't know, I didnt study turbines or fluid dynamics in college. Remember we arent changing the compressor wheel size when you upgrade, you usually change the pulley size to increase the multiplier effect and speed up the compressor per a given RPM and therefore making more boost. That is why bigger housings make more power, because they can move more air per rpm than the smaller housing. In other words they make more boost per rpm. You would only move up in housing when you have maxed out the efficiency zone/speed of the smaller housing.

You even brought up turbos and you are confusing the size thing with the SC. The turbo's are the ones that will produce boost quicker when they are smaller, but thats not because of the smaller compressor housing, its because of the smaller size of the hotside that needs to be filled up and spun up with exhaust air. The smaller that is the quicker the shaft spins up the quicker the compressor builds boost.