GTM STG 2 SC, when will it be available?

1slow370 · 01-12-2011, 06:20 AM

the problem with the calculation of the vortech unit you posted based on horsepower is that the vortech horsepower ratings are compensated for drive loss so the amount of horsepower it actually bumps is higher than the figure they post. also their cfm values can more accurately be turned back into airflow assuming non apocalyptic weather conditions rather than a horsepower number that is affected by many more variables than just temperature and pressure. the cfm value assumed to be a draw value at average temperature conditions 100kpa, 70degrees Fahrenheit, with a standered weight of air at STP of .0807 lb's per cuft, through the ideal gas law leads you to about 86lbs a minute of airflow. The point of hp ratings on superchargers is that it accounts for the airflow of the unit and the parasitic losses all in one number.

the issue no one is really talking about is that all that crap doesn't matter when you consider that it will cost you a freakin truckload of cash to build a motor capable of handling more than 500hp supercharged so both units will work fine(unless you feel the need to spend almost 10k to sleeve your block then you can care). the gtm stage1 is a good setup that focuses on response which with a centrifugal is key because they are designed to suck balls in this department, and once sam gets the cvtc at least figured out more power out of the stage one unit won't be a problem until you spend the money to build the block then you need an upgrade.

Edit: but if the vvel controller never surfaces (which i'll be damned if it doesn't) then the stage 2 or up pullied vortech are worth the money in order to make up for the airflow lost to the valve overlap.

Also god damn HKS for locking the VPro powerwriter softeware down to needing a dongle (and for being a piggyback in the first place). some of us don't like the idea of having to pay big cash if we wanted to even get our car to the tuner hell two trips and you double the price of the ecu Grr

Mike@GTM · 01-12-2011, 12:45 PM

Quote:

Originally Posted by 1slow370

the problem with the calculation of the vortech unit you posted based on horsepower is that the vortech horsepower ratings are compensated for drive loss so the amount of horsepower it actually bumps is higher than the figure they post. also their cfm values can more accurately be turned back into airflow assuming non apocalyptic weather conditions rather than a horsepower number that is affected by many more variables than just temperature and pressure. the cfm value assumed to be a draw value at average temperature conditions 100kpa, 70degrees Fahrenheit, with a standered weight of air at STP of .0807 lb's per cuft, through the ideal gas law leads you to about 86lbs a minute of airflow. The point of hp ratings on superchargers is that it accounts for the airflow of the unit and the parasitic losses all in one number.

the issue no one is really talking about is that all that crap doesn't matter when you consider that it will cost you a freakin truckload of cash to build a motor capable of handling more than 500hp supercharged so both units will work fine(unless you feel the need to spend almost 10k to sleeve your block then you can care). the gtm stage1 is a good setup that focuses on response which with a centrifugal is key because they are designed to suck balls in this department, and once sam gets the cvtc at least figured out more power out of the stage one unit won't be a problem until you spend the money to build the block then you need an upgrade.

Edit: but if the vvel controller never surfaces (which i'll be damned if it doesn't) then the stage 2 or up pullied vortech are worth the money in order to make up for the airflow lost to the valve overlap.

Also god damn HKS for locking the VPro powerwriter softeware down to needing a dongle (and for being a piggyback in the first place). some of us don't like the idea of having to pay big cash if we wanted to even get our car to the tuner hell two trips and you double the price of the ecu Grr

From a purely academic perspective, I would be inclined to agree with you. However, it has been our experience that Vortech is very generous with their power ratings as it is. Not to mention that their blowers aren't designed to spin at very high rpms. So while the compressor by itself may be able to flow high cfm, the rest of the rotating assembly simply can't handle the necessary rpms and would blow itself apart long before you reach the limits of what the compressor can do. It's a lot like some of the frankenstein turbos you see out there with huge compressors and small, restrictive, exhaust housings. Sure, the compressor may be able to flow 500hp worth of air, but the exhaust housing restricts things too much to ever achieve what the compressor could theoretically deliver.

In terms of needing a motor build, someone else here already mentioned the clinching factor, and that is torque. Given that horsepower is a function of torque and rpm and superchargers make their peak torque near redline, the overall torque they produce to achieve a given horsepower level is not necessarily high enough to require a built motor. Another thing to point out is the G37 TT we built making ~500whp daily with a stock motor and still running strong.

1slow370 · 01-13-2011, 03:42 AM

Quote:

Originally Posted by Mike@GTM

From a purely academic perspective, I would be inclined to agree with you. However, it has been our experience that Vortech is very generous with their power ratings as it is. Not to mention that their blowers aren't designed to spin at very high rpms. So while the compressor by itself may be able to flow high cfm, the rest of the rotating assembly simply can't handle the necessary rpms and would blow itself apart long before you reach the limits of what the compressor can do. It's a lot like some of the frankenstein turbos you see out there with huge compressors and small, restrictive, exhaust housings. Sure, the compressor may be able to flow 500hp worth of air, but the exhaust housing restricts things too much to ever achieve what the compressor could theoretically deliver.

In terms of needing a motor build, someone else here already mentioned the clinching factor, and that is torque. Given that horsepower is a function of torque and rpm and superchargers make their peak torque near redline, the overall torque they produce to achieve a given horsepower level is not necessarily high enough to require a built motor. Another thing to point out is the G37 TT we built making ~500whp daily with a stock motor and still running strong.

Well i have a few questions about that one as well if 500whp daily is the current safe build mark then i don't see superchargers going much further because you take the 430 available from a stage one kit and tack on the 50-70hp lost in driving said supercharger and the motor itself is actually seeing the load of a 480-500hp turbo motor less about 10-20% for the increased pumping losses and the heat wear on the exhaust side of the head. from what i've witnessed generally you can't push the internals to get the same whp from a supercharger that could from a turbo charger. And it isn't all about torque i would say it is all about cylinder pressures when you're talking about an 11:1 CP ratio. combustion heat and pressure, causing detonation are going to kill it long before the regular torque output of the setup will (not true with the de motors as they had bitch-rods). usually when judging between the two i like to go off system psi and air charge temp, so if the "safe" power level of TT setup is at 8 psi, and the air charge temps remain the same(intercooler and compressor efficiencies obviously), then i wouldn't try to push a supercharger setup much more than 10-20% over that so like 9-10 without more than one guy doing it first. now on the hr motors being able to run more psi safely with tuned valve timing to reduce the overlap, the same levels of power there should carry over between the engines do to the similarity of the build, less the increase in pressures for the half point of compression. Really there are quite a few unknowns on pushing a vhr supercharged as of yet. on another angle though the stage 2 could be worth the price if there is enough of a ceiling above the stage 1 blower and the kit price is close between the two. if an hr can run 14psi safely then it is a good bet that we should be able to get close to 12 with our compression maybe more because our heads have a smaller hotspot around the spark plug. then it is just a matter of making that 50-80 hp cost effective to the consumer in the upgrade price. on the same token the vvel controller would have to cost at least as much as the stage 2 upgrade or people will just buy the vvel controller and see the same gains for less jeopardizing stage 2 sales

It might be better to sell the -91 compressor as a stage 3 upgrade once the vvel controller is completed in that case, and sell the stage one plus vvel as the stage2.

Staples · 01-14-2011, 01:32 AM

Quote:

Originally Posted by 1slow370

Well i have a few questions about that one as well if 500whp daily is the current safe build mark then i don't see superchargers going much further because you take the 430 available from a stage one kit and tack on the 50-70hp lost in driving said supercharger and the motor itself is actually seeing the load of a 480-500hp turbo motor less about 10-20% for the increased pumping losses and the heat wear on the exhaust side of the head. from what i've witnessed generally you can't push the internals to get the same whp from a supercharger that could from a turbo charger. And it isn't all about torque i would say it is all about cylinder pressures when you're talking about an 11:1 CP ratio. combustion heat and pressure, causing detonation are going to kill it long before the regular torque output of the setup will (not true with the de motors as they had bitch-rods). usually when judging between the two i like to go off system psi and air charge temp, so if the "safe" power level of TT setup is at 8 psi, and the air charge temps remain the same(intercooler and compressor efficiencies obviously), then i wouldn't try to push a supercharger setup much more than 10-20% over that so like 9-10 without more than one guy doing it first. now on the hr motors being able to run more psi safely with tuned valve timing to reduce the overlap, the same levels of power there should carry over between the engines do to the similarity of the build, less the increase in pressures for the half point of compression. Really there are quite a few unknowns on pushing a vhr supercharged as of yet. on another angle though the stage 2 could be worth the price if there is enough of a ceiling above the stage 1 blower and the kit price is close between the two. if an hr can run 14psi safely then it is a good bet that we should be able to get close to 12 with our compression maybe more because our heads have a smaller hotspot around the spark plug. then it is just a matter of making that 50-80 hp cost effective to the consumer in the upgrade price. on the same token the vvel controller would have to cost at least as much as the stage 2 upgrade or people will just buy the vvel controller and see the same gains for less jeopardizing stage 2 sales

It might be better to sell the -91 compressor as a stage 3 upgrade once the vvel controller is completed in that case, and sell the stage one plus vvel as the stage2.

Although a lot of what you're saying is true, nothing can be justified until the VVEL is cracked and the cost of the controller is listed. I have a feeling the controller is going to be a lot more expensive then what people think. I still say the extra $500 can still justify the cost of the stage 2 for a pure plug and play kit.

Of course my 2 cents

xsnapshot · 01-14-2011, 11:35 AM

Long time lurker here. I'm a few months away from my engineering degree and have been looking heavily into getting a lightly used 370z as a replacement for my modified WRX. (they are fun, but just not as sexy as a 370z IMO....)

I've been keeping tabs on this VVEL development for quite some time, and have done some research on the matter. Very interested in how this plays out, as I would love to have about 350 to the wheels NA in a Z. Not looking to go FI, at least for now.

I have an idea that has been floating around in my head for a while. Why not compare the VVEL settings for the NISMO and the normal Z? Since the NISMO has the better intake and exhaust, the engineers "SHOULD" have optimized the VVEL for the increased volumetric efficiency of the system. Perhaps this comparison would then tell us what needs to be changed in NA applications when even further increases in VE are realized.

Who knows if they actually did modify the VVEL system for the NISMO, but its worth a look IMO, now that GTM has access to it.

I'm also wondering if the VVEL system could modified to two different sections.
<3000 RPMish optimize the VVEL on NA applications for greatest fuel efficiency
>3000 RPM adjust for optimum power?

The opensource nature, and ease with which the Subaru community is able to modify the WRX/STI is incredible, and hopefully someday,some genius programmers/coders will accomplish for Nissan's what romraider has accomplished for subarus.

In for results, and discussion! (P.S. love the technical nature of this discussion!)

Staples · 01-12-2011, 02:20 PM

Quote:

Originally Posted by 1slow370

Edit: but if the vvel controller never surfaces (which i'll be damned if it doesn't) then the stage 2 or up pullied vortech are worth the money in order to make up for the airflow lost to the valve overlap.

Good insight, but the only thing I question is the fact would it be financially worth it not to go with the Stage 2 kit? That all depends on the actual cost of the VVEL controller (answering my own question). Anytime you're dealing with tuning equipment it always costs damn near an arm and a leg. Plus you have to factor in someone who is competent enough to properly tune the vehicle or make minor adjustments.

If the controller is released I hope GTM has base maps for us in the event we don't have a trustworthy tuner.

Kastley85891 · 01-12-2011, 12:47 PM

I grow more impatient by the day for F.I.

Liquid_G · 01-12-2011, 01:44 PM

Quote:

Originally Posted by Kastley85891

I grow more impatient by the day for F.I.

do it.. the $$$ only hurts for a little while.

weiboy718 · 01-12-2011, 01:56 PM

Quote:

Originally Posted by Liquid_G

do it.. the $$$ only hurts for a little while.

that's not true, I'm still hurting pretty bad hahaha

NewYorkJon34 · 01-12-2011, 02:01 PM

Quote:

Originally Posted by weiboy718

that's not true, I'm still hurting pretty bad hahaha

Well ya that's what happens when you get raped by stillen, jk lol

weiboy718 · 01-12-2011, 02:07 PM

Quote:

Originally Posted by NewYorkJon34

Well ya that's what happens when you get raped by stillen, jk lol

Ya, luckily GTM is my savior!

Kastley85891 · 01-12-2011, 02:35 PM

Quote:

Originally Posted by Liquid_G

do it.. the $$$ only hurts for a little while.

Im gonna do it, just waiting on all the variables making the desired result (on my part !GTM's

)

Flyboy · 01-12-2011, 03:26 PM

So to comment on my other thread,

GTM SC Stg 2 + VVEL tuner = C6 Z06 Killer,,.,,,,.,,,., MAYBE!!

If so,

Where do I sign UP?

kevin1985912 · 01-12-2011, 05:35 PM

Quote:

Originally Posted by Flyboy

So to comment on my other thread,

GTM SC Stg 2 + VVEL tuner = C6 Z06 Killer,,.,,,,.,,,., MAYBE!!

If so,

Where do I sign UP?

until you met a SC Z06 aka ZR1~~~jk

G37sHKS · 01-12-2011, 10:10 PM

Quote:

Originally Posted by Flyboy

So to comment on my other thread,

GTM SC Stg 2 + VVEL tuner = C6 Z06 Killer,,.,,,,.,,,., MAYBE!!

If so,

Where do I sign UP?

A stock C6 Z06 then yes.. but bolts on C6 Z06 im sorry but we dont have a chance

01-12-2011, 06:20 AM	#1 (permalink)
1slow370 A True Z Fanatic Join Date: Aug 2009 Location: In the D Posts: 3,732 Drives: v8 74 260z ;) Rep Power: 7252	the problem with the calculation of the vortech unit you posted based on horsepower is that the vortech horsepower ratings are compensated for drive loss so the amount of horsepower it actually bumps is higher than the figure they post. also their cfm values can more accurately be turned back into airflow assuming non apocalyptic weather conditions rather than a horsepower number that is affected by many more variables than just temperature and pressure. the cfm value assumed to be a draw value at average temperature conditions 100kpa, 70degrees Fahrenheit, with a standered weight of air at STP of .0807 lb's per cuft, through the ideal gas law leads you to about 86lbs a minute of airflow. The point of hp ratings on superchargers is that it accounts for the airflow of the unit and the parasitic losses all in one number. the issue no one is really talking about is that all that crap doesn't matter when you consider that it will cost you a freakin truckload of cash to build a motor capable of handling more than 500hp supercharged so both units will work fine(unless you feel the need to spend almost 10k to sleeve your block then you can care). the gtm stage1 is a good setup that focuses on response which with a centrifugal is key because they are designed to suck balls in this department, and once sam gets the cvtc at least figured out more power out of the stage one unit won't be a problem until you spend the money to build the block then you need an upgrade. Edit: but if the vvel controller never surfaces (which i'll be damned if it doesn't) then the stage 2 or up pullied vortech are worth the money in order to make up for the airflow lost to the valve overlap. Also god damn HKS for locking the VPro powerwriter softeware down to needing a dongle (and for being a piggyback in the first place). some of us don't like the idea of having to pay big cash if we wanted to even get our car to the tuner hell two trips and you double the price of the ecu Grr __________________ ANSWER PRICE LIST Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50 Last edited by 1slow370; 01-12-2011 at 06:38 AM.

01-12-2011, 12:47 PM	#7 (permalink)
Kastley85891 A True Z Fanatic Join Date: Nov 2009 Location: ATX 370 - Sold Posts: 1,149 Drives: 2003 Wagon Rep Power: 19	I grow more impatient by the day for F.I. __________________ Boosted V8 hunter 2850 lbs and 375WHP

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01-14-2011, 11:35 AM	#5 (permalink)
xsnapshot Base Member Join Date: Jan 2011 Location: Nebraska Posts: 21 Drives: 2004 WRX Rep Power: 16	Long time lurker here. I'm a few months away from my engineering degree and have been looking heavily into getting a lightly used 370z as a replacement for my modified WRX. (they are fun, but just not as sexy as a 370z IMO....) I've been keeping tabs on this VVEL development for quite some time, and have done some research on the matter. Very interested in how this plays out, as I would love to have about 350 to the wheels NA in a Z. Not looking to go FI, at least for now. I have an idea that has been floating around in my head for a while. Why not compare the VVEL settings for the NISMO and the normal Z? Since the NISMO has the better intake and exhaust, the engineers "SHOULD" have optimized the VVEL for the increased volumetric efficiency of the system. Perhaps this comparison would then tell us what needs to be changed in NA applications when even further increases in VE are realized. Who knows if they actually did modify the VVEL system for the NISMO, but its worth a look IMO, now that GTM has access to it. I'm also wondering if the VVEL system could modified to two different sections. <3000 RPMish optimize the VVEL on NA applications for greatest fuel efficiency >3000 RPM adjust for optimum power? The opensource nature, and ease with which the Subaru community is able to modify the WRX/STI is incredible, and hopefully someday,some genius programmers/coders will accomplish for Nissan's what romraider has accomplished for subarus. In for results, and discussion! (P.S. love the technical nature of this discussion!)

01-12-2011, 03:26 PM	#13 (permalink)
Flyboy Base Member Join Date: Jul 2010 Location: Destin, Fl Posts: 152 Drives: Nismo Rep Power: 16	So to comment on my other thread, GTM SC Stg 2 + VVEL tuner = C6 Z06 Killer,,.,,,,.,,,., MAYBE!! If so, Where do I sign UP?