How NOT to turbocharge your LS1

[cygnusx1]

Cheap Boost :

 

how not to

 

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7930676464&fromMakeTrack=true

[Guest BigE]

PV=nRT is the Ideal Gas Law. It relates the environmental properties of a gas to one another. It has NOTHING to do with fluid flow. The V in this equation is volume, not velocity. The v in KE=½mv² is velocity, not volume. The KE equation deals with mechanical energy (ie, a body in motion). Also, n is not a constant. It is the number of moles of gas that you are observing. Not trying to be a jerk, just making sure correct info is out there.

 

The STS system is for folks who aren't power hungry and just want a little boost (no pun intended). Every person I've ever seen who modified their car for more power always wanted more. Whether they could get it or not was another matter. The STS system is very easy to install, requires no end-user input and is a "boxed" solution. Up to 5 psi, they claim no tuning or intercooler is needed. Well, the same is true for a conventionally mounted turbo. Intake temps will rise with either system regardless, but both will be able to handle the increase in temp without knock. However, to boost over 5 psi, the STS kit requires a methanol kit. This is a depleting solution and I'd hate to run out in the middle of a WOT run. This is where the STS system falls short. Up to 5 psi, it's great because it's easy and can provide the same benefits as a conventional system at that level. However, going further than 5 psi, the STS system has no benefits and is actually a detriment to performance. Conventional setups don't require methanol injection until somewhere north of 20psi (usually well north).

 

The crux here is that the STS system provides a solution in a very limited range. Most folks who turbo a car want to grow. They want room to improve performance. The STS ceases to be a viable solution past ~5psi due to pressure losses within both the intake and exhaust pipes and inadequate intake charge cooling through the intake pipe wall. So how many folks are going to invest over $3.5k only to hit a ceiling as soon as the product is installed? The STS system performs like a conventional setup up to 5 psi and then loses ground quickly. If you plan to never go past the 5 psi performance mark, it may be a kit to consider. However, like I said, performance enthusiasts won't invest in something that limits them as soon as it's installed.

 

On another note, I find it difficult to critique the members of a ZCAR site for not having a product that is not produced for a ZCAR. Tannji, if you are convinced and have faith in the STS system, please buy it and let us know how it turns out.

 

 

My thoughts on the STS system in a nutshell:

 

If you don't mind paying 20 dollars for a 10 dollar steak and getting chopped sirloin, go right ahead and buy it.

[Gollum]

wow this is one long thred i should have never started reading.

 

I personally think putting a turbo in the rear is a nice idea, good for some people, just not hardcore people running sub 12 street cars. Now, for the price i'd much rather go with something else. For a little more money you could get a procharger, wich as far as i know the most expensive boosting option available.

 

For the same amount you could easily build your own set up and i see no problem with that. Clutter in the engine bay :gasp: oh no! Try taking out a turbo b16 our of a delsol every weekend, tearing it apart and putting it back in. After a while it doesn't matter what's in the way, you get used to it and you get good at it. That arguement is for wimps that don't enjoy working on thier car. And the whole noise arguement... at 5psi no turbo is going to be THAT loud comeon' this is pathetic. Turbos need to be running significant amounts of boost to bother you noise wise. A little 5psi boost is maybe a little louder than the motor and it sounds so kewl. And with a V8 odds are your engine would be louder than the turbo anyways. Personally I see no problems with the common turbo setup. But i'll still say that i'm sure this product is perfect, for certain people. That's cool too, everyone has thier own things they like.

 

Now, i really think intake temp has less performance increase than some of you people think. If your intake manifold is cast iron and you upgrade to and aluminum you'll probly see about a 5% increase in hp. Granted that's alot but it won't make up for the difference of lesser quality of boost from lower temp exhast. But like i said, the people who buy these aren't looking for 600hp motors, so let them have thier fun. It's all good man. Just don't put it on my car

[Guest Jasonv8z]

I'm sorry, I took a few shortcuts, and may have been confusing.

 

PV=nRT is the Ideal Gas Law. It relates the environmental properties of a gas to one another. It has NOTHING to do with fluid flow. The V in this equation is volume' date=' not velocity. The v in KE=½mv² is velocity, not volume... Also, n is not a constant. It is the number of moles of gas that you are observing.

.[/quote']

 

Gas is a compressable fluid. The ideal gas law still applies if the gas is moving (flowing).

 

I wanted to show that that Pressure and Volume(or velocity) is related to Temperature. If you compare an STS vs. a conventional turbo at a given horsepower level, the n, and R, will be some value, but they will basically be the same in both turbo systems at a given power level. For the purposes of comparison, you don't care what values n and R hold, because they will effect both results equally. You're right, I confused my n and R though. To be technical, exhaust gas isn't an ideal gas, but that isn't going to change things considerably.

 

Volume and Velocity are directly related.

Velocity x (Cross sectional Area) = Volume/time. The cross section area of the exhaust tubing can be assumed constant. The look at the "V" in PV =nRT as Volume over some amount of time or Volume/time. Use the same interval of time for both cases, and it will not matter. You use Velocity when gasses are moving, and Volume when they are still.

 

 

The KE equation deals with mechanical energy (ie' date=' a body in motion).

.[/quote']

 

The turbo is powered by kinetic energy of the gas. Imagine every exhaust molecule hitting the turbine as a body in motion. Each molecule imparts a certain amount of energy based on its mass and velocity. The formula KE=½mv² works for exhaust molecules as well as billard balls.

 

If anyone wants a better explanation on this stuff, please private message me.

 

Jason

[tannji]

Actually, a point about that last post:

 

PV=nRT is a formula meant to be applied to gas in a chamber, static. It can not be directly, accurately applied to a dynamic, flowing gas, such as in turbo systems, as it is an open system, with velocity AND volume, and whose pressure MUST drop over the length of the tubing, or there would be no flow. That being said, I am sure that it is close enough to demonstrate certain concepts.... but most people who quote it in relation to turbos, and especially to the STS system are forgetting about gas Density, as opposed to velocity and volume. You can achieve the same turbo spool with a lower velocity gas, as long as it is dense, and the aperture of the turbo is sized appropriately. Does the STS system completely compensate for lower pressure and velocity? No, i doubt it does, even under the best of circumstances. It does however provide sufficient boost for certain people, and is not limited to around 5#'s, as suggested a few posts ago. The Z71 truck that is running 12's is doing so at 12#'s of boost, and there is apparently a car being assembled whose owner apparently intends to attain somewhere around 800 to 900 HP from his STS system. I would obviously want no where near that kind of power, but I wonder if the Z71 owner spent more, or less than others who have the same performance.

 

As for the STS requiring methanol over 5#'s of boost, not true, it requires charge cooling, whether by methanol or IC, just as a normal turbo. Nor would it be a concern to run out of methanol, unless you didnt read the installation instruction, it has provisions to automatically switch back to your predetermined low boost setting if you exhaust your methanol. STS does not Require methanol, it is an option, along with intercooling, to lower your charge temp, or raise the effective octane rating of the fuel.

 

On another note, I find it difficult to critique the members of a ZCAR site for not having a product that is not produced for a ZCAR. Tannji, if you are convinced and have faith in the STS system, please buy it and let us know how it turns out.

 

I wasnt even certain how to interpret that quote, but I assume it to mean that I made a criticizm of someone for not having an STS, and that it not being produced for Zcars meant that I was off-base.... but I never criticized anyone for having it or not.... and this IS HybridZ, where the majority of us have components "not produced for a Zcar".

 

The only reason I even got involved in this thread was that I have been following the evolution of the STS system, and thot the thread title was a little harsh for a pruduct that none of us own, or have experience with, and didnt deserve comparison the the electric turbo systems that caused so much amusement. I think the Zcar caused a certain amount of amusement in certain circles when it was announced.... but it was cheap and effective.... and managed to attract a devoted following, in spite of its detractors..... I keep getting hung up on some of the track times STS vehicles have already posted.... if a Z71 truck can run a 12.6 second 1/4, what would the same setup do in a car 3000 pounds lighter? Hmmm, let me dig out PV=nRT and do some figuring.....

[tannji]

 

I have an STS with the gt67 turbo upgrade and my horsepower numbers are still climbing strong at 6000 rpms. I think the t60 is to small for our cars to have a good top end pull. The gt67 still spools good on the street and actually shows a little lower IATs. My IATs stayed in the 125 area.

__________________

2000 trans am stage 2 heads, comp cam 224/228 .569/.572 112 lsa, slp ls6 intake, jet hot long tubes and 3 inch y pipe with cats, delphi 42lb injectors, 255 holley fuel pump, bbk tb, spec stage 3, findaza 12lb flywheel, ls1 edit, lowered, BMR suspention parts, pro 5.0 shifter,

405 rwhp 385 rwtq NA

STS on and lovin it but out of fuel pump

No Meth No Intercooler IAT's 125

5.5 PSI 498 rwhp 467 rwtq

Stange 12 bolt on the way

 

I would imagine that car developes boost a little late, and I dont need that kind of potential.... but interesting none the less.

[tannji]

Here is the guy that ran 630HP with the D1 SC.... Removed the D1, swapped cams for a turbo cam, and I think swapped FMIC's as well. Installed the STS kit with a GT70 turbo.

 

Last monday it went on the dyno but blew a head gasket. Give you an idea my 630hp runs (with D1SC)have been on all summer long and plenty of wot runs and never blew. One run with a gt70 at 10 psi and it shit the felpro right out With only 14 degrees timing to start as well. At 9 psi and the old SC cam it absolutely screwed once it made boost but it came on too late for me. So the new cam is in, gm mls gaskets are in. All buttoned up with a big fmic as well. It will be tuned this week and I will post all the numbers. Im starting at 10 psi and going from there. Hoping to make 550-600 rwhp and 650+ tq. We will see. Im willing to push the gt70 to 15psi. Wish me luck Also used to run the d1 with 24 degrees of timing and always had 0 knock but the iat's were 140+ after one run. After about 5 wot street runs with gt70 and fmic they were 78 degrees. Im gonna push the timing into the 20's as well.

 

On the dyno when it it blew it only had about 4psi but still put down over 500 rwhp and 490ish tq. So tripling the boost and upping the timing from 14 to 20+ outta be good.

[Guest NXRPERFORMANCE]

So did anyone find out if they will be making a version for the z32 with LS-1 swaps?